NTID73S
fy PRO^°
NOISE SOURCE ABATEMENT TECHNOLOGY
AND COST ANALYSIS INCLUDING
RETROFITTING
ENVIRONMENTAL PROTECTION AGENCY
AIRCRAFT/AIRPORT NOISE STUDY REPORT
27 JULY 1973
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NOISE SOURCE ABATEMENT TECHNOLOGY AND
COST ANALYSIS INCLUDING RETROFITTING
ENVIRONMENTAL PROTECTION AGENCY
AIRCRAFT/AIRPORT NOISE STUDY REPORT
27 JULY 1973
WILLIAM C. SPERRY, TASK GROUP CHAIRMAN
This document is the result of an extensive task force effort to gather all
available data pertinent to the subject discussed herein. It represents the
interpretation of such data by the task group chairman responsible for
this specific report. It does not necessarily reflect the official views of EPA
and does not constitute a standard, specification, or regulation.
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PREFACE
The Noise Control Act of 1972 (Public Law 92-574) directs the Environmental
Protection Agency (EPA) to study the adequacy of current and planned regulatory action
taken by the Federal Aviation Administration (FAA) in the exercise of FAA authority to
abate and control aircraft/airport noise. The study is to be conducted in consultation
with appropriate Federal, state and local agencies and interested persons. Further,
this study is to include consideration of additional Federal and state authorities and
measures available to airports and local governments in controlling aircraft noise.
The resulting report is to be submitted to Congress on or before July 27, 1973,
The governing provision of the 1972 Act states:
"Sec. 7(a). The Administrator, after consultation with appropriate Federal, state,
and local agencies and interested persons, shall conduct a study of the (1) adequacy
of Federal Aviation Administration flight and operational noise controls; (2) ade-
quacy of noise emission standards on new and existing aircraft, together with
recommendations on the retrofitting and phaseout of existing aircraft; (3) implica-
tions of identifying and achieving levels of cumulative noise exposure around
airports; and (4) additional measures available to airport operators and local
governments to control aircraft noise. He shall report on such study to the Com-
mittee on Interstate and Foreign Commerce of the House of Representatives and
the Committees on Commerce and Public Works of the Senate within nine months
after the date of the enactment of this act. "
Under Section 7(b) of the Act, not earlier than the date of submission of the report
to Congress, the Environmental Protection Agency is to:
"Submit to the Federal Aviation Administration proposed regulations to provide
such control and abatement of aircraft noise and sonic boom (including control and
abatement through the exercise of any of the FAA's regulatory authority over air
commerce or transportation or over aircraft or airport operations) as EPA deter-
mines is necessary to protect the public health and welfare. "
The study to develop the Section 7(a) report was carried out through a participatory
and consultive process involving a task force. That task force was made up of six task
groups. The functions of these six task groups were to:
iii
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1. Consider legal and institutional aspects of aircraft and airport noise and the
apportionment of authority between Federal, state, and local governments.
2. Consider aircraft and airport operations including monitoring, enforcement,
safety, and costs.
3. Consider the characterization of the impact of airport community noise and to
develop a cumulative noise exposure measure.
4. Identify noise source abatement technology, including retrofit, and to conduct
cost analyses.
5. Review and analyze present and planned FAA noise regulatory actions and
their consequences regarding aircraft and airport operations.
6. Consider military aircraft and airport noise and opportunities for reduction of
such noise without inhibition of military missions.
The membership of the task force was enlisted by sending letters of invitation to a
sampling of organizations intended to constitute a representation of the various sectors
of interest. These organizations included other Federal agencies, organizations repre-
senting state and local governments, environmental and consumer action groups, pro-
fessional societies, pilots, air traffic controllers, airport proprietors, airlines, users
of general aviation aircraft, and aircraft manufacturers. In addition to the invitation
letters, a press release was distributed concerning the study, and additional persons
or organizations expressing interest were included into the task force. Written inputs
from others, including all citizen noise complaint letters received over the period of
the study, were called to the attention of appropriate task group leaders and placed in
the public master file for reference.
This report presents the results of the Task Group 4 effort devoted to the investi-
gation of the status of current and future noise control technology. It also provides a
technical basis for recommending regulations, as proposed by Public Law 92-574.
*
The membership of Task Group 4 was made up of representatives of the Federal
Government, airport operators, airlines, airframe manufacturers, general aviation,
and environmental groups. The task group met six times in Washington, D. C. during
the period February 15, 1973 to June 22, 1973. The members presented information
pertinent to the problem, presented comments on information supplied by other
iv
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members, generally discussed the problem and possible solutions, and reviewed and
commented on draft reports. EPA requested that all data submitted be in writing; all
documents are listed in the References and Bibliography and are available for inspec-
tion in the Airport/Aircraft Study files.
Reference to a specific item in the listing is made by providing the page number and
the group acquisition number of the item being referenced. For example, "Reference
(4. 1-56)" refers to the document numbered 56 on page 4. 1 in the Bibliography. Position
papers of the task group participants are included in Appendix A and the list of partici-
pants is provided as Appendix B.
The conclusions and recommendations of this report are the responsibility of the
Chairman and staff and are based on the information supplied by task group participants
and on consideration of protection to the public health and welfare. The difficult and
controversial subjects of the task group assignment precluded complete agreement
among task group members. EPA sincerely appreciates the wholehearted efforts the
task group members have put forth and without which this report could not have been
prepared.
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CONTENTS
Section Page
1 INTRODUCTION AND BACKGROUND 1-1
Technology Evolution & Development 1-2
Commercial Air Carrier Fleet l-r4
General Aviation 1-6
Vertical Takeoff and Landing Aircraft (VTOL) 1-12
Short Takeoff and Landing Aircraft (STOL) 1-16
Reduced Takeoff and Landing Aircraft (RTOL) 1-17
Aircraft Fleet Size Forecasts 1-21
U.S. Air Carrier Fleet 1-21
U. S. General Aviation Fleet 1-28
U. S. Civil Helicopter Fleet 1-30
2 CURRENT TECHNOLOGY OPTIONS 2-1
Jet Engine Nacelle Retrofit 2-1
JT3D and JT8D Engines 2-1
Other Air Carrier Engines 2-11
General Aviation Jet Engines 2-12
Engine Refan Retrofit 2-13
Background and Program Status 2-13
General Technical Approach and Objectives 2-15
Estimated Results; Noise Reduction 2-19
Estimated Results; Performance Parameters 2-27
Jet Engine Replacement 2-27
Air Carrier Fleet 2-27
General Aviation Fleet 2-27
Aircraft Replacement 2-28
3 FUTURE TECHNOLOGY OPTIONS AND RESTRAINTS 3-1
Component Technology 3-1
NASA Quiet Engine Program 3-1
Sonic Inlets 3-4
Core Engine Components 3-6
Aerodynamics 3-9
Engine Technology 3-19
Air Carrier CTOL Engines 3-23
STOL Engines 3-23
VTOL Engines 3-24
General Aviation Engines 3"26
SST Engines 3-27
4 COST & ECONOMIC ANALYSIS 4-1
The Null Case 4-2
Current Technology Options 4-20
vi
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CONTENTS (Continued)
Section Page
Cost Analysis of Retrofit Alternatives 4-38
Economics of Achieving Various Levels of Cumulative
Noise Exposure 4-40
Future Technology Options 4-57
Annex to Chapter 4 4-58
5 SUMMARY AND CONCLUSIONS 5-1
Current Technology Status 5-1
Future Technology Status 5-2
6 RESEARCH AND DEVELOPMENT RECOMMENDATIONS 6-1
Component Technology 6-1
Power Sources 6-2
Duct Treatment Materials and Technology 6-2
Cabin Noise 6-2
Noise Measurement and Analysis 6-3
Engine and Aircraft Technology 6-3
Subsonic Aircraft 6-3
Supersonic Aircraft 6-3
V/STOL Aircraft 6-4
Helicopters 6~4
General Aviation Aircraft 6-4
Aircraft Design 6"4
New Engine Development 6-5
Operational Procedures 6-5
General 6"5
References and Bibliography **~i
Appendix A Position Papers of Task Group Members A-l
Appendix B Task Group Participants B-l
vii
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LIST OF ILLUSTRATIONS
Figure
1-1 Military-Civil Technology Transfer 1-3
1-2 Noise Reduction Technology Trend (TAKEOFF) 1-7
1_3 U. S. Air Carrier Fleet - Take Off Noise Levels 1-8
1-4 U. S. Air Carrier Fleet - Approach Noise Levels 1-9
1-5 U.S. Air Carrier Fleet - Sideline Noise Levels 1-10
1-6 General Aviation Fleet Size and Gross National
Product (GNP) 1-11
1-7 Current Business Jet Noise Levels 1-13
1-8 Helicopter Hover Noise at 500' 1-15
1-9 QCSEE Noise Goal Related to Current CTOL Technology 1-18
1-10 High Lift Flap Development 1-19
1-11 Typical Powered Lift Concepts 1-20
1-12 U. S. Air Carrier Fleet - Number of Aircraft 1-22
1-13 Worldwide and U. S. Fleet Levels, DC-8 Type (All
Series) 1-23
1-14 Worldwide and U.S. Fleet Levels, DC-9 Type (All
Series) 1-24
1-15 U.S. Fleet Levels; Actual and Projected, 720B & 707
Series 1-25
1-16 U.S. Fleet Levels; Actual and Projected, 727-100 & 200 1-26
1-17 U.S. Fleet Levels; Actual and Projected, 737 Series 1-27
1-18 Turbine Powered General Aviation Fleet (U. S. ) 1-29
1-19 U. S. Civil Jet Aircraft Fleet Size 1-31
1-20 U. S. Civil Helicopter Fleet Size 1-32
2-1 Current and Estimated Nacelle Retrofit Noise Levels-
Sideline 2-4
2-2 Current and Estimated Nacelle Retrofit Noise Levels-
Takeoff 2-5
2-3 Current and Estimated Nacelle Retrofit Noise Levels-
Approach 2-6
2-4 727 Nacelle Retrofit Lower Goal (SAM) Configuration 2-8
2-5 707 Nacelle Retrofit Lower Goal (SAM) Configuration 2-9
2-6 727 Nacelle Retrofit Upper Goal (SAM + JNR)
Configuration 2- 10
2-7 JT3D-3B/JT3D-9 Comparison 2-16
2-8 JT8D-9/109 Comparison 2-17
2-9 Core Jet Noise Reduction 2-18
2-10 Current and Estimated Refan Retrofit Noise Levels-
Approach 2-22
2-11 Current and Estimated Refan Retrofit Noise Levels-
Sideline 2-23
2-12 Current and Estimated Refan Retrofit Noise Levels-
Take Off 2-24
viii
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LIST OF ILLUSTRATIONS (Continued)
Figure Page
3-1 NASA Quiet Engines with Full Suppression 3-3
3-2 Effect of Degree of Fan Suppression on Aircraft Economics 3-5
3-3 Sonic Inlet Research 3-7
3-4 Aircraft Wing Loading vs. Short Field Length 3-12
3-5 High Lift System Noise 3-13
3-6 Aerodynamic Noise Sources 3-15
3-7 Non-Engine Aerodynamic Noise Relative to FAR 36
Approach Noise Limits 3-16
3-8 Military/Commercial Transport Noise Levels -
Take Off 3-20
3-9 Military/Commercial Transport Noise Levels -
Approach 3-21
3-10 Engine Development Cycle 3-22
3-11 Quiet Fan Propulsive System 3-25
4-1 Estimated Number of People Impacted by Aircraft
Noise - 1972 Baseline 4-7
4-2 Estimated Unit Cost for Noise Compatible Land
Use Control 4-15
4-3 Cumulative Land Use Costs 4-18
4-4 Estimated Schedules for Approach Procedures and
Retrofit Implementation 4-23
4-5 Estimated Noise Levels at FAR 36 Measuring Points
(a) Sideline 4-25
4-6 Estimated Noise Levels at FAR 36 Measuring Points
(b) Take Off with Cutback 4-26
4-7 Estimated Noise Levels at FAR 36 Measuring Points
(c) Approach 4-27
4-8 Average Daily Air Carrier Fleet Operations for
1972, 1978 & 1985 - Atlanta 4-29
4-9 Average Daily Air Carrier Fleet Operations for
1972, 1978 & 1985 - LaGuardia 4-30
4-10 Average Daily Air Carrier Fleet Operations for
1972, 1978 & 1985 - Kennedy International 4-31
4-11 Average Daily Air Carrier Fleet Operations for
1972, 1978 & 1985 - San Francisco International 4-32
4-12 Average Daily Air Carrier Fleet Operations for
1972, 1978 & 1985 - Los Angeles International 4-33
4-13 Average Daily Air Carrier Fleet Operations for
1972, 1978 & 1985 - O'Hare 4-34
4-14 Estimated Percent Population Impacted by Aircraft
Noise - 75 L. Contour (40 NEF) 4-36
4-15 Estimated Percent Population Impacted by Aircraft
Noise - 65 L Contour (30 NEF) 4-37
ix
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LIST OF ILLUSTRATIONS (Continued)
Figure Page
4-16 Estimated Total Costs for Seven Retrofit Options
(a) Current Dollars 4-43
4-17 Estimated Total Costs for Seven Retrofit Options
(b) Present Value 1973 (10% Discount Rate) 4-44
4-18 Estimated Total Costs for Noise Protection -
80 L, Contour (45 NEF) 4-49
4-19 EstimaPed Total Costs for Noise Protection -
75 L, Contour (40 NEF) 4-50
4-20 Estimated Total Costs for Noise Protection -
70 L, Contour (35 NEF) 4-51
4-21 Estimated Total Costs for Noise Protection -
65 L, Contour (30 NEF) 4-52
4-22 Estimated Total Costs for Noise Protection -
60 LdnContour (25 NEF) 4-53
LIST OF TABLES
2-1 Estimated Noise Levels for JT3D-9 (Refanned)
Powered Aircraft 2-20
2-2 Estimated Noise Levels for JT8D-109 (Refanned)
Powered Aircraft 2-21
2-3 Estimated Performance Parameters for JT3D-9
(Refanned) Powered Aircraft 2-25
2-4 Estimated Performance Parameters for JT8D-109
(Refanned) Powered Aircraft 2-26
3-1 Flyover Noise Compairson - Four Engine Aircraft 3-4
4-1 Summary of Curfew Costs 4-11
4-2 HUD Acceptability Categories for Proposed Housing
Sites 4-17
4-3 Unit Costs for Noise Retrofit Programs 4-41
4-4 Retrofit Program Costs ($M) 4-42
4-5 Investment Costs for Noise Source Treatment of
Domestic Business Jets 4-45
4-6 Sample Airport Capacity Estimates 4-61
4-7 Estimates of Curfew Induced Incremental Delays
(a) 1974 4-63
4-8 Estimates of Curfew Induced Incremental Delays
(b) 1980 4-64
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SECTION 1
INTRODUCTION AND BACKGROUND
This report reviews the technological developments that have contributed to
the historical growth of the civil aviation industry and looks to the present and
future technology to nurture its continued growth. Future expansion of air trans-
portation is now dependent upon resolving the problem created by its Achille's heel—
aircraft generated noise.
One of the principal avenues available for reducing noise impacted areas
resulting from aircraft operations is by treating the source of the noise—the aircraft
and its contributing components.
The remaining portion of Section 1 reviews how we got where we are and pre-
sents forecasts of where industry is headed in terms of future aircraft types, and
fleet sizes which are demand-oriented. Section 2 addresses the problem of how to
reduce the noise of the existing fleet so that the various elements of the industry,
(e.g., the airport operator, airline operator and the aircraft and engine manufac-
turers) can move ahead on plans for accommodating the projected increasing demand
for air service. The various technical options are discussed in terms of their current
status and anticipated performance levels. Section 3 looks to the next generation of
aircraft. Current aircraft and engine component development programs will provide
the technology for quieter aircraft in the future. The most difficult part of the study
is to predict the cost of doing something as a function of time and benefits to be
obtained. Equally discomforting is the fact that there is a cost tied to doing nothing.
Quantification of the noise reduction options in terms of cost, availability date and
effectiveness are presented in Section 4. While the data presented is not presumed
to be absolute, significant conclusions can be drawn therefrom. Section 5 presents
a concise summary of the key points developed in the preceding four sections of
the report. Finally, specific R&D programs are identified in Section 6 which, if
effected in a continuing aggressive program of timely implementation, will insure
the continued growth and community acceptance of a prime national asset, the
U. S. aviation industry.
1-1
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TECHNOLOGY EVOLUTION & DEVELOPMENT
The present civil aviation system includes a wide variety of aircraft sizes and types
designed to serve the varying needs of each of the market segments; the commercial
air carriers, air taxi and commuters and general aviation. Over the years, the char-
acteristics of these aircraft have undergone periodic changes, with the implementation
of advanced technological developments, which have improved the performance and
operational efficiency of these vehicles.
Technological advances in the civil fleet have historically been applied to the air
carrier fleet initially and then subsequently adopted by other categories of the civil air
system.
Most current commercial aircraft engines are civil derivatives of engines developed
under government funding for military applications as indicated in Figure 1-1. This
technology transfer cycle is still visible in the more recent aircraft and propulsion
developments. The high bypass turbofan engines utilized in the DC-10 transport air-
craft were developed as the direct result of a competitive military engine development
program which was initiated to provide an efficient power plant for a new, large inter-
theatre military transport (C-5). The development of the JT9D high bypass engine (which
powers the B747) was based upon the technology developed under an Air Force-spon-
sored engine demonstrator program, which preceded the C-5 engine development
program. Some of the performance and noise reduction advantages of the high bypass
engine technology has also been passed down to the general aviation fleet. The JT15D
engine powering the Cessna Citation and the Garrett TFE731 planned for the new
Falcon 10 are representative of the use of the high bypass fan technology in this market
arena.
Many cost benefits to both military and commercial users resulted from this evo-
lutionary practice. However, increasing noise and pollution environment constraints
on civil aircraft have introduced a divergent trend in design characteristics which
might make civil derivatives of future military engines less certain or not even
feasible. (See Section 3)
A brief review of the technological progress to date and the resultant effect on
fleet composition and aircraft noise is appropriate here as a prelude to the discussion
of future options.
1-2
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J57/
B52
COMMERCIAL
AIR CARRIER
JT3C (JET) IN 707/DC-8 A"
\
/5 \ ^ #
^* Q"T >J
JTTD
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COMMERCIAL AIR CARRIER FLEET
The initial round of commercial jet aircraft were powered by engines that had been
originally developed for high performance military aircraft (e.g., the 707, 720, and
DC-8 aircraft utilized a modification of the J57 turbojet engine). This meant that the
engine frontal area (or diameter) was small (for minimum drag), thereby limiting the
quantity of air that could be introduced into the engine, which led to high velocity ex-
haust conditions required to develop the necessary thrust. These high exhaust velocities
produced high jet noise characteristics. The initial (and costly) noise abatement
program consisted of adding noise suppressors at the rear of the engine. Various
approaches to the problem were pursued, but the most effective suppression method
involved changes to the jet nozzle. The single nozzle was replaced by a cluster of
small nozzles having the same total equivalent area as the original. This concept
provides some attenuation of the deep-toned rumble of the unsuppressed jet. This
device, however, added weight and decreased performance, which in turn led to
higher operating costs.
The addition of a fan to the basic engine provided additional air at low velocity.
This fan exhaust air either surrounded the primary jet exhaust (as in the JT3D engine),
or the two were mixed in a common nozzle (as in the JT8D engine), to reduce overall
exhaust velocity. Also, more exhaust energy was extracted by the larger turbine,
which was required to drive the fan, thereby reducing the engine core velocity as well.
This resulted in exhaust noise reductions which were an order of magnitude better than
had been demonstrated with the earlier suppressors. While the addition of the fan added
weight to the installation, the thrust and specific fuel consumption were improved so
that the operating costs of the turbofan powered aircraft were appreciably lower than
that of the pure turbojet. Both the JT3D and JT8D turbofan engines were modifica-
tions of existing military turbojets. The JT3D engine was developed for installation
on existing DC-8 and 707 aircraft. The maximum fan diameter and hence the bypass
ratio (ratio of the weight flow of air discharged from the fan-exhaust duct to the
weight flow of air passing through the core engine) on the JT3D were therefore set
by engine-installation considerations as much as the capabilities of the available
technology. The bypass ratio on both the JT3D and JT8D was relatively low, being
approximately 1.4 on the JT3D and 1.0 on the JT8D.
1-4
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Whereas the addition of the fan reduced the exhaust rumble at takeoff, the fan
became a significant new noise source, radiating from the inlet and fan exhaust por-
tions of the engine. Fan noise became predominant at all operating conditions except
takeoff and was particularly noticeable during landing approach.
The addition of suppressors and fans to these relatively inefficient (by commer-
cial aviation standards) engines represent sincere industry attempts to attack the
noise problem at the source during the period from 1958-1965, within the limitations
presented by the non-optimum engine cycles and the physical limitations of the installa-
tions, while trying to respond to the exigencies of the times. Recent technology
developments indicate that additional noise reduction is technically feasible for these
existing systems and these will be discussed in Section 2.
During the same period that the low-bypass fan was being introduced into the
then existing commercial fleet, the engine industry began exploring the characteristics
of high bypass fans aimed at a new generation of jet transports, which would not be
initially constrained by fan size limitations. The results of these studies, and
component development programs, proved conclusively the benefits in performance,
operating cost and noise from this type of propulsion system when applied to high
subsonic transport aircraft.
Fortunately, the Air Force had come to the same conclusion and sponsored a
competitive engine demonstrator program between Pratt and Whitney and General
Electric. Based upon the results of this demonstrator program, the Air Force initi-
ated a design competition for a powerplant to meet their requirements for an inter-
theatre logistics transport. This competition led to the development of the GE TF39
engine, which was the progenitor of the CF-6 engine now powering the DC-10 com-
mercial transport. After losing the Air Force design competition, Pratt and Whitney
designed and developed a new commercial engine (JT9D) that included all of the noise
reduction technology known at that time, based upon the results of their participation
in the engine demonstrator program. Here was the case once more where the com-
mercial aviation industry was provided with new engines as the result of a military
initiated program.
The characteristics of the newest transport aircraft of Boeing, McDonnell-
Douglas and Lockheed (B-747, DC-10, L-1011) have demonstrated dramatic
1-5
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improvements in noise technology {Figure 1-2)* as well as efficiency and productivity,
over those of the first generation jet transports. These aircraft will represent a sig-
nificant portion of the fleet by 1980. The growth and composition change of the U. S.
Fleet, historically and projected, is discussed in a subsequent part of Section 1.
Typical baseline noise levels for the existing air carrier jet fleet are provided
on Figures 1-3 through 1-5 relative to the FAR 36 standard. (See Task Group V
Report for discussion of the implications of the FAR 36 rule.)
GENERAL AVIATION
General aviation is defined as all civil flying that does not require a certificate
of public convenience and necessity issued by the Civil Aeronautics Board. As such,
general aviation contains many different use categories as well as many different
types of aircraft. It varies from personal flying and transportation of personnel and
cargo by business firms in corporate-owned aircraft and by air taxi operators to
special uses of aircraft, such as crop dusting, power and pipeline patrol, and aerial
advertising.
Over the past 15 years, the growth of the U.S. general aviation fleet has closely
paralleled the economic growth of the country as indicated in Figure 1-6. A periodic
surge in the economy has been historically reflected in a surge of new aircraft
procurement in the following year.
As indicated previously, the technological developments that have been introduced
into the air carrier fleet was subsequently adapted to specific segments of the general
aviation fleet. The most obvious has been the development and modification of the
turbojet engine to the low-bypass fan and more recently the introduction of the high-
bypass turbofan concept for application in business aircraft.
The fastest growing segment of the general aviation market is that of the relatively
more sophisticated turbojet/turbofan powered aircraft which are primarily utilized for
more efficient business transportation. Accounting for less than 1 percent of the
general aviation fleet today, industry forecasts indicate a growth to approximately
2.5 percent of the fleet by 1985. These percent numbers are deceptively low—the
*Figure 1-2 cannot be utilized as a predictive tool for future systems. It
merely represents the time-phased trend in aircraft noise reduction for different
classes of aircraft.
1-6
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DbPER
1000#
GROSS
WEIGHT
1.2
1.0
0.8
0.6
0.4
0.2
DC9 10
INCREASING
THRUST/WEIGHT
RATIO DUE TO
ENGINE-OUT
SAFETY
REQUIREMENTS
707/
DCS
LOW BYPASS FAN
A300
(EST.)
747-200
747-100
I
0
1958 1960 1962 1964
1966 1968
YEAR
1970 1972 1974
Figure 1-2. Noise Reduction Technology Trend (TAKEOFF)
1-7
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EPNdB
120
110
X
100
TAKEOFF
(WITH CUTBACK)*
CERTIFICATED
NOISE LEVELS
60 80 100
GROSS WEIGHT (1000 LBS)
200
*NO CUTBACK ON
747, DC10, L1011
400
600 800
Ref.8.2 104
Figure 1-3. U. S. Air Carrier Fleet-Take Off Noise Levels
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APPROACH
EPNdB
120
110
1C
CERTIFICATED
NOISE LEVELS
20
60 80 100
GROSS WEIGHT (1000 LBS)
200
400
GOO
800
Ref. 8.2-104
Figure 1-4. U.S. Air Carrier Fleet - Approach Noise Levels
-------
EPNdB
110
100
SIDELINE
• CERTIFICATED
NOISE LEVELS
60 80 100
GROSS WEIGHT (1000 LBS)
200
747-200B
400
600 800
Ref. 8.2-104
Figure 1-5. U.S. Air Carrier Fleet - Sideline Noise Levels
-------
140 -
20 -
- 400
Figure 1-6. General Aviation Fleet Size and Gross National Product (GNP)
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absolute quantity of aircraft involved is significant, particularly when compared with
the present and projected air carrier jet fleet. (See the following discussion on Air-
craft Fleet Size Forecasts.)
When these aircraft operate out of the major air carrier airports, their current
contribution to the overall noise impact is minimal due to their relatively low opera-
tional utilization at these airports when compared with air carrier fleet operations.
However, many of these aircraft also operate out of smaller suburban airports
with little or no air carrier operations. Here, they represent the dominant aircraft
noise source and may impact quite significantly on the residential community. In
addition, when the noise generated by the air carrier fleet is diminished, the business
jets will contribute more significantly, even at the major airports, unless noise abate-
ment techniques are applied to these aircraft as well.
Figure 1-7 presents the estimated noise levels for the current fleet of general
aviation jet aircraft. The Cessna Citation and Falcon 20 are the only aircraft in the
business jet fleet that have been certificated to the noise requirements of FAR 36,
Appendix C. The Fokker-VFW F 28 at 65000 #GW is currently being marketed as a
short haul transport. It too has been certificated in compliance with FAR 36. At
least one of these aircraft has already been procured by a U. S. industrial firm for
business use.
It is expected that the future expansion of the business jet fleet, (as indicated
earlier), will occur with the introduction of new aircraft powered by turbofan engines
having significantly reduced noise characteristics. However, as in the case of the
commercial carrier fleet, there will still be 1000-1500 of the current type of turbojet
powered business aircraft still operational in the late 1970's and early 1980's.
The current options available for reducing the noise levels of these aircraft are
discussed in Section 2.
VERTICAL TAKEOFF AND LANDING AIRCRAFT (VTOL)
The lifting forces in VTOL aircraft are provided by
1. Rotors, propellers, or fans operating in a horizontal plane.
2. Vertically directed exhaust energy developed by turbine engines, wherein the
lift energy (or thrust) generated is in excess of the gross weight of the aircraft.
1-12
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110
100
0
EPN
110
100
•
\l dB
A
A °
o
\j
A
O
^
0
A A
(V) i ^
A
O
A
O
O
A
A O
G SIDELINE
A APPROACH
FAR 36 X
Q
B
3 CITATION
a
* 0
El FALCON 20
I
2
¥
P
TAKE OFF
| WITH C/B
AR 36
I0
GROSS WEIGHT (000#)
Figure 1-7. Current Business Jet Noise Levels
1-13
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The unique capability provided by VTOL aircraft has been fully demonstrated in
military operations and for a variety of missions. Surveillance, rescue, and trans-
port of men and materials are typical military applications with analogous requirements
in the civil sector. Today, 33 years after the initial demonstration of the first practical
VTOL vehicle (the Sikorsky VS-300), the helicopter remains the only viable VTOL
operational system that has been developed to meet these needs.
The utilization of the helicopter in the general aviation sector has grown by an
order of magnitude since 1955 and is forecast to more than double by 1985 (Figure 1-20
on page 1-32). The vast majority of the current fleet consists of the small (less than
4000 #GW) piston powered type. However, as in the other segments of civil aviation,
the turbine engine has become the primary power source for these aircraft (approxi-
mately two-thirds of the currently produced helicopters are turbine powered).
The principal source of helicopter noise normally is the rotor system rather than
the engine. The high velocity jet noise generally associated with the turbine engine is
not present in a helicopter installation. Much of the exhaust energy developed in the
engine is dissipated by the addition of a "free" turbine stage in the exhaust stream
which absorbs this energy to drive the rotor system. The noise levels of the heli-
copter in hover are in the range of 75 to 105 PNdB @ 500' (Figure 1-8), however, the
unique characteristic rotor "slap" can be a sensitive irritant in a residential commu-
nity. Current efforts to reduce this effect are discussed in Section 3.
The commercial air carrier helicopter fleet has decreased from a peak of 26
vehicles in 1957 to 14 vehicles in 1972. Many abortive attempts were made to develop
and expand the use of the helicopter in commercial passenger service without success.
Stability problems, vibration, and noise have restricted passenger acceptance, and
relatively high direct operating costs (DOC) due to the low speed and payload capa-
bility of those aircraft that have been offered has been the inhibiting factors restrict-
ing their revenue service potential.
The use of auxiliary engines for more efficient lift and propulsion in forward
flight has been demonstrated. Their application would permit higher flight speeds
(250 to 300 mph) and improved operating economics over that of the slower, less
efficient pure helicopter. This class of vehicle has been termed the "compound
helicopter."
1-14
-------
ESTIMATED
O MEASURED
60
56 8 10
GROSS WEIGHT (1000 LBSI
50 60
a
Figure 1-8. Helicopter Hover Noise at 500'
-------
The Army, Air Force, NASA and industry have been pursuing tilt rotor tech-
nology for many years. The tilt rotor concept offers another opportunity for extending
the proven performance capability of the helicopter. Conceptually, the tilt rotor
possesses the best characteristics of both the helicopter and the fixed-wing aircraft.
A joint NASA/Army tilt rotor development program now underway will result in
flight tests of a research vehicle by 1976. The objectives of the program are to sub-
stantiate the technical and operational feasibility of this concept for cruise speeds of
350 to 400 mph. If these tests are successful, development of commercial versions
could follow. Lift fans, retracted rotors, stowed rotors, etc., are additional VTOL
concepts which could yield higher subsonic performance characteristics but additional
development and demonstration testing is required.
The potential benefits to civil aviation due to vertical takeoff and landing capability
are reduced noise impact on the airport community, and reduced airport congestion,
as a result of utilizing small airfields and other landing sites not available to conven-
tional aircraft.
SHORT TAKEOFF AND LANDING AIRCRAFT (STOL)
The current, generally accepted definition of a STOL aircraft is one having the
capability for a maximum payload takeoff and landing utilizing a 2000-foot (or less)
runway. This capability would provide access to essentially all of the public airports
in the U. S. The objective is to relieve congestion at the major hub airports by utiliz-
ing additional suburban sites and, in addition, provide improved service to smaller
communities.
With the restraints being placed on the air system due to the noise characteristics
of the existing fleet, it is apparent that any new air vehicle that is brought into the
system must be compatible with its operating environment. As the runway requirements
and airport size decrease, the noise constraints become more severe since the aircraft
become more closely interactive with the community.
At this time, there is no standard or regulation establishing the noise criteria for
STOL (or for that matter, VTOL) aircraft. A noise goal for the NASA quiet, clean,
STOL, experimental engine (QCSEE) program has been tentatively suggested as 95
EPNdB at 500 feet from the source of the noise. This is a significant technological
1-16
-------
challenge, particularly for high performance vehicles, as indicated in Figure 1-9.
Note that the goal for the QCSEE is approximately 30 EPNdB lower than existing regu-
lations and 9 dB less than was achieved in the NASA Quiet Engine experimental test
program.
In attempts to reduce takeoff distances and landing roll, high lift devices have
been developed and utilized to supplement the aerodynamic lift provided by the wing
surfaces. Figure 1-10 provides an indication of the improved lift capability realized
with the progressive developments in flap design which effectively modified the wing
geometry in low speed flight regimes. These devices obtain their increased lift
capability solely from the free stream air flow.
An additional and effective means for increasing wing lift is the application of
engine power (or energy) to the lifting surfaces. This is currently identified as the
"powered lift" concept. Early development of this theory was applied to propeller
driven air vehicles, wherein the propeller slipstream was directed over the wing and
flap devices. This was termed the "deflected slipstream" concept. This technology
was utilized in the Breguet 941 STOL aircraft development program.
Current technology efforts are directed at employing the deflected slipstream
concept, but utilizing the efflux from turbofan engines, instead of the propellers, as
indicated in Figure 1-11. A more detailed discussion of the status of these potential
propulsive lift options is presented in Section 3.
REDUCED TAKEOFF AND LANDING AIRCRAFT (RTOL)
The limiting runway lengths for reduced takeoff and landing aircraft has been
tentatively identified as between 3, 000 and 4, 000 feet. RTOL capability is important
in order to permit expanded utilization of existing airports, and access to smaller
airports, without incurring the economic penalties associated with much more sophis-
ticated STOL class aircraft. The use of high-lift devices as discussed earlier, or
improved braking or landing system, may be all that is necessary to obtain this
capability. The concept of "overpowering" the aircraft by increasing the engine thrust
or decreasing payload for a given installation may also provide this capability. The
McDonnell Douglas Corporation has indicated in a submission to the Aviation Advisory
Commission that a certified RTOL version of the current DC-9 aircraft could be
available 2 years from go-ahead.
1-17
-------
EPNdB
125
120
115
110
105
100
95
90
-
NOTE: AIRCRAFT
GROSS WEIGHT
= 1 50,000 LBS.
4 (EXCEPT 727 AND DC9
*
Z
o
i-
5
^3
O
LLJ
or
<
z
LU
co
LLJ
CC
0-
ENG.
2-3
ENG.
LL.
O
Q
LLJ
|_
_J
O
Q.
CC
1
X
LU
Z
o
1-
5
rn
LU
QC
<
LL
WHIUH A lit MUI UML
GROSS WEIGHT)
* 1500' SIDELINE FOR
727/DC9 2-3 ENG. AIRCRAFT
LL
o
o
in
O
1—
Q
LU
|—
I
2
QC
X
LU
LL
^
DC
O
rv-
LL
H
Z
LU
DC
DC
O
2100' SIDELINE FOR
4 ENG. AIRCRAFT
C3
0
_J
0
Z
X
o
LU
<
UJ
Z
O
z
UJ
UJ
^
a
CO
z
nrQPP
NOISE GOAL
500 FT SIDELINE
Figure 1-9. QCSEE Noise Goal Related to Current CTOL Technology
1-18
-------
RELATIVE
INCREASED
LIFT
CAPABILITY
2.0
TRIPLE SLOTTED FLAP
&
LEADING EDGE SLATS
DOUBLE-SLOTTED
FLAP
c
FOWLER
FLAP
SPLIT
FLAP
1920
1930 1940 1950
CALENDAR YEARS
1960
Figure 1-10. High Lift Flap Development
1-19
-------
EXTERNAL BLOWN FLAP
AUGMENTOPWING
i
to
o
UPPER SURFACE BLOWING
INTERNALLY-BLOWN FLAP
Figure 1-11. Typical Powered Lift Concepts
-------
AIRCRAFT FLEET SIZE FORECASTS
U.S. AIR CARRIER FLEET
The number of aircraft in the U. S. air carrier fleet, historically and as projected
by the Air Transport Association (ATA) and the Federal Aviation Administration (FAA),
is indicated in Figure 1-12. This figure illustrates the composition of the fleet by
aircraft types, the phenomenal growth of jets during the mid-1960s, the recent cessa-
tion of this growth, and the introduction of the wide-body (747, DC-10 and L1011)
series of jet aircraft. As indicated by the ATA projection, the growth is expected
to resume and be based primarily on the introduction of the wide-body types meeting
the increase in demand and replacing the older narrow-body (707 and DC-8) types of
jet powered aircraft. The FAA projection also indicates a resumption of the growth
of jets; however, this projection, when compared with that of the ATA, indicates
that it will start later and be more rapid in the late seventies. The fleet size and
composition projections have implications relative to possible noise retrofit options
and future airport noise exposure levels; therefore, the historical and projected num-
bers of the major current types are illustrated in greater detail in Figures 1-13
through 1-17.
The number of aircraft of the DC-8 type, including all series of this type, are
illustrated in Figure 1-13. The figure illustrates the worldwide fleet size as a
function of time using three assumptions about the life span of the aircraft. The three
assumptions are:
1. Each aircraft has a fixed structural life of 20 years.
2. Each aircraft has a fixed competitive life of 15 years.
3. Aircraft are retired as a result of analysis of route structures in conjunction
with air service demand forecasts and airline plans and surveys.
The figure also illustrates the U. S. air carrier DC-8 fleet size based upon the
third assumption as provided in Reference 3.4-132 and a projection provided by the
ATA, Reference 13.3-92. The number of DC-8s in the U.S. fleet as of January 1973
as provided by the Pratt and Whitney Aircraft Company in Reference 2.1-67 is also
shown.
1-21
-------
3000 -
i
DC
ATA
FORECAST
9/72
(JETS ONLY)
Figure 1-12. U.S. Air Carrier Fleet - Number of Aircraft
-------
500
40u
to
u
DC
-
X
3
DC
UJ
r
S
300
200
100
KEY U.S. FLEET
D DOUGLAS AIRCRAF^
O ATA
0 P&WA
WORLDWIDE FLEET
20 YEAR LIFE
15YEARLIFE
-— DEMAND FORECAST
WORLDWIDE
FLEET
DATA
Figure 1-13. Worldwide and U.S. Fleet Levels, DC-8 Type (All Series)
-------
1000
KEY U.S. FLEET
D DOUGLAS AIRCRAFT
O ATA
OP&WA
WORLDWIDE FLEET
KEY
20 YEAR LIFE
— .—15 YEAR LIFE
—DEMAND FORECAST
WORLDWIDE
FLEET
DATA
U.S. FLEET
DATA
Figure 1-14. Worldwide and U.S. Fleet Levels, DC-9 Type (All Series)
-------
600
to
01
500
u. 400
<
DC
U
DC
DC
LU
CO
300
200
100
QLdL
1955
ATA PROJECTION (REF 13.3-92)
• 720B
• 707-120B
A 707-320 B/C
PROJECTED LIFE CURVES
PROVIDED BY NASA
(REF. 11.2-380)
ACTUAL -*
707-320B/C
707-1 20B
720B
^-PROJECTED AT
CONSTANT UTILIZATION
NOTES
U.S. FLEET ONLY
FUTURE SALES EXCLUDED
ASSUMED AIRCRAFT LIFE
CAPABILITY - 60,000 HOURS
•L. I N\\ I I
ll"^ I I I I ^l\M I I I I I I I I I I I
60
65
70
75 80
YEAR ENDING
85
90
95
2000
Figure 1-15. U.S. Fleet Levels; Actual and Projected, 720B & 707 Series
-------
to
OS
ui
8
*«
8
- 727-100
<
DC
O
cc
£ 300
cc
Ul
CO
•5.
3
z
200
:±
§
ATA PROJECTIONS (REF. 13.3-92)
^727-100
• 727-200
PROJECTED LIFE CURVES
PROVIDED BY NASA
(REF. 11.2-380)
ACTUAL
727-200
11
1960
65
•*- PROJECTED AT
CONSTANT UTILIZATION
V J
NOTES
FUTURE SALES EXCLUDED
U.S. FLEET ONLY
ASSUMED AIRCRAFT LIFE
CAPABILITY - 60,000 HOURS
» i i i I t 'II
I I I I I I I
70
75 80
YEAR ENDING
85
90
95
2000
Figure 1-16. U.S. Fleet Levels; Actual and Projected, 727-100 & 200
-------
I
to
-q
t 300
DC
0
DC
u. 200
O
DC
Ul
m
5
^ 100
NOTES
ATA PROJECTIONS [ J
/
/
i i t i I i i i i I i /i i I i i i i I i i i I I i i i i I i i l i 1 1 1 1 1 I 1
1955 60 65 70 75 80 85 90 95
YEAR ENDING
— _ _
%
\
\
\
\
i lit il ill
2000
Figure 1-17. U.S. Fleet Levels; Actual and Projected, 737 Series
]
-------
Figure 1-14 illustrates the same information on the DC-9 aircraft type, includ-
ing all series within this type, as provided by the Douglas Aircraft Company, the
Pratt and Whitney Aircraft Company and the ATA in the above cited references.
Figures 1-15 through 1-17 illustrate similar information on the Boeing 707, 727
and 737 series of aircraft, respectively, as provided in Reference 11.2-380. *
U.S. GENERAL AVIATION FLEET
The numbers of turbine powered aircraft in the U. S. general aviation fleet as
provided by the FAA aviation forecast documents are illustrated in Figure 1-18.
Historical or actual data extracted from the FAA documents are provided through 1971.
An insert in the figure illustrates the actual percentage of the total turbine powered
fleet represented by the turbojet and turbofan powered aircraft. As shown, this per-
centage has averaged at slightly more than forty percent since 1965. The FAA fore-
cast for the 1973-1984 period, as provided in Reference 8.5-348, lists only the total
turbine powered fleet numbers. This projection and 40 percent of this projection,
representing the anticipated number of jet powered aircraft based upon the historical
data are also shown in this figure.
The size of the jet powered, general aviation fleet has been estimated and projected
by R. Dixon Speas (Reference 13.3-360), Mitchell Research Associates (Reference
7.1-54) and General Electric (unpublished data). As shown in Figure 1-18, these
projections indicate that the business jet portion of the turbine fleet will represent a
much higher percentage in the future than it has in the past. For comparison, seventy
percent of the total turbine powered fleet as forecasted by the FAA is also shown in
the figure.
If the trend is truly toward jet powered aircraft for this class of aviation, and it
appears that it is, and the numbers will be close to those estimated by the above
cited sources, then the number of jet powered, general aviation aircraft can be
expected to exceed the number of jet powered, air carrier type aircraft in the mid to
late 1970s and possibly be twice as many in the mid 1980s. This comparison is
*Data, subsequently provided by Boeing (3.8-374) indicates only minor differences.
Additional data provided by Boeing (3.10-456) indicates significant changes with
respect to the 727 life span.
1-28
-------
9 -
.
< 5 -
•
TJ/TF = 70%
/ OF FAA
I F'CAST
' TJ/TF AS
%OF FLEET
MITCHELL
ASSOC.
F'CAST
8/21/72
TJ/TF = 40%
OF FAA
F'CAST
Figure 1-18. Turbine Powered General Aviation Fleet (U.S.)
1-29
-------
illustrated in Figure 1-19 and is significant to the formulation of aircraft/airport
noise abatement programs and regulations.
U.S. CIVIL HELICOPTER FLEET
As noted in the previous section, civil use of the helicopter has been growing
steadily and is expected to grow at least as rapidly in the forseeable future. Figure
1-20 indicates the U. S. civil helicopter fleet size (total and turbine powered) as
provided in the FAA forecast for the period 1973 to 1984 (Reference 8.5-348). Another
forecast made by R. Dixon Speas Associates (Reference 13. 3-360) is also shown. The
projection developed by Speas in 1970 appears to be an extension of a rate of growth
that was prevalent in the short period between 1966 and 1969.
1-30
-------
6 -
ACTUAL
cc
u
oc
o
QC
D
COMMERCIAL
AIR CARRIER
MITCHELL
ASSOCIATES
(8/72)
FAA AND
MITCHELL
ASSOCIATES
(9/72)
/ BASED ON
(PROJECTED PASS.
V DEMAND
GENERAL
AVIATION
I L_
ATA FORECAST (9/72)
•ASSUMING 60% OF
TURBINE POWERED A/C
FLEET FORECAST is
TURBOJET/TURBOFAN
J L
54
58
62
66
70
YEAR-END
74
78
82
86
Figure 1-19. U.S. Civil Jet Aircraft Fleet Size
-------
8700 IN 1980
CO
to
5000 -
4000 -
DC
LU
_
o
o
_l
LU
X
LL
O
3000 -
£ 2000 -
1000 -
54
FAA
FORECAST
9/72
86
Figure 1-20. U.S. Civil Helicopter Fleet Size
-------
SECTION 2
CURRENT TECHNOLOGY OPTIONS
The present state-of-the-art in aircraft technology can provide several alterna-
tives for modifying the current civil jet aircraft fleet, in order to further reduce the
community impact of aircraft-generated noise.
The development of improved light-weight, low-cost, efficient sound absorption
materials provides the potential for relatively simple nacelle and engine acoustical
treatment.
The demonstrated noise reductions achieved with advanced technology high bypass
fans has led to the possibility of modifying the low bypass fan engines that are predom-
inant in the air carrier fleet today with a higher bypass capability.
Replacement of the engines in current aircraft, or even replacement of the air-
craft itself, with available improved technology systems is also being considered.
It is probable that no single alternative represents a noise panacea. An optimum
course of action will undoubtedly be represented by some combination of these options.
JET ENGINE NACELLE RETROFIT
JT3D and JT8D ENGINES
In May 1967, NASA contracted with the McDonnell Douglas Corporation and the
Boeing Company to investigate nacelle noise control modifications for operational
Douglas and Boeing transports powered by JT3D turbofan engines. The NASA pro-
gram successfully demonstrated by flight tests in 1969, conceptual feasibility of
nacelle modifications for controlling both approach and takeoff noise of JT3D propelled
aircraft.
In June 1971 the FAA initiated a nacelle noise control project directed to retrofit
of the current fleet of narrow body aircraft. This project extended the NASA program
to include research and development of takeoff and approach noise control for both
JT3D and JT8D propelled aircraft. The purpose of this project is to provide test
data to assist in determining whether certain classes of turbofan propelled airplanes
in the current fleet can be modified for meaningful noise reduction in a feasible
2-1
-------
manner. Feasibility relates to three key instructions contained in Public Law 92-574;
that is, the noise abatement methods must be technologically practicable, economically
reasonable, and appropriate for the particular type of aircraft, aircraft engine, appli-
ance, or certificate to which it will apply. The effort is directed to providing acousti-
cal treatment, designed to conform to specified noise reduction goals, that is flight
worthy, flight weight, and capable of being certificated. The acoustical treatment
may be any hardware or mechanical device, applied, either singly or combined, to
the inlet and primary and secondary exhausts that will either absorb sound or other-
wise effect a noise reduction at the FAR 36 measurement positions.
The project is being implemented by means of three separate contracts with
appropriate airframe manufacturers. The first is with Boeing Wichita on 707 aircraft,
the second with Boeing Seattle on 727 and 737 aircraft, and the third with Douglas on
DC-9 aircraft. In addition, all three prime contractors have subcontracts with Pratt
and Whitney on engine compatibility testing; Boeing Wichita has a subcontract with
Douglas on 707/DC-8 nacelle generality studies; and Douglas has a subcontract with
Rohr on fabrication and ground testing of DC-9 nacelles. The FAA, therefore, has
most aspects of nacelle retrofit feasibility investigations for JT3D and JT8D aircraft
covered by the airframe, engine, and nacelle manufacturers most involved with the
narrow-bodied civil aircraft fleet.
The FAA has established a task force to direct and monitor the progress of the
retrofit feasibility contracts. The task force consists of representatives from the
research and development, regulatory, and airworthiness services of the FAA. It is
most important that the latter area be thoroughly covered to insure that a judgment of
the feasibility of noise abatement retrofit modifications is based upon production hard-
ware and commercial operations that will not compromise safety in any way.
The progress of the FAA nacelle retrofit project has been excellent. The first
contract was initiated in June 1971 and the last one is scheduled for completion in
December 1973, a total span of only two and one half years. The work includes
ground testing of JT3D and JT8D production and modified nacelles and flight testing
of 707, 727, and DC-9 aircraft installed with both production and modified nacelles.
It is anticipated that all models of JT3D and JT8D propelled aircraft can be analyzed
for modified nacelle noise and propulsion performance and installation cost based
upon the results of the nacelle retrofit project.
2-2
-------
The results of the FAA nacelle retrofit project will produce noise, performance,
and cost data for one or more nacelle retrofit options for each of the 707, DC-8,
727, 737, and DC-9 type aircraft. That is, the entire narrow bodied fleet of JT3D
and JT8D propelled aircraft will have at least one option to be considered for retrofit
application. The options with the minimum complexity and least cost are those that
will enable the aircraft to conform to the specified noise levels of FAR Part 36. The
effects of the minimum options will result in a significant reduction in airport com-
munity noise exposure, particularly for approach operations.
The nacelle options with the maximum complexity, those denoted in the contrac-
tual requirements as the upper goal configurations, have the capability of decreasing
the noise to levels considerably below the requirements of FAR Part 36, and represent
the maximum state-of-the-art for nacelle retrofit. The minimum retrofit options
have a negligible effect on aircraft performance and, if implemented, would insure
that the older narrow bodied commercial aircraft would comply with the FAR Part 36,
Appendix C, noise criteria, as do the newer wide bodied aircraft, with no appreciable
degradation in range, field length requirements, and direct operating costs. However,
the maximum retrofit options, in addition to costing more per shipset, would introduce
substantial degradation in performance, but all of these performance losses are not
necessarily irrevocable. Uprating the airframe for loading and the engine for thrust
(e.g., JT8D-9 to JT8D-15) will increase the range and reduce the required field
length to values approaching those of the baseline production version.
The noise reduction expected to be realized at the FAR 36 measuring points by
nacelle modifications are shown in Figures 2-1 through 2-3 (8. 2-72 and 8.3-120). *
The nacelle options with the minimum complexity contain sound absorption material
(SAM) only, and the options with the maximum complexity contain both SAM and some
sort of jet noise reducer (JNR). The nacelle retrofit options for SAM have been
completed for the 737 and 727 aircraft and the values shown in the Figures are FAR 36
certificated levels for these aircraft. In addition, the nacelle retrofit option for
*Although additional inputs have recently been received from various sources
(3.6-411, 3.7-412, 3.10-450, and 3.9-408), the data contained therein indicated
inconsistencies, therefore Figures 2-1 through 2-3 have not been modified. The
values in the figures, however, are representative of the noise levels of the indicated
aircraft types, whereas the inconsistencies in the data can be attributed, at least in
part, to variations in specific aircraft models, engine models, power settings, flap
settings, etc.
2-3
-------
120
-
DC
1
111
K
:
z
c
.
.
u
U
110
- FAR PART 36 LEVELS
100
•
'
1 I
1. DC-9-32
2. 737-200 ADV.
3. 727-200
4. DC-8-61
5. 707-320B
O BASELINE
D SOUND ABSORPTION MATERIAL (SAM)
O SAM + JET NOISE REDUCER
A WIDE-BODY AIRCRAFT
I
I I I II I
- FAR PART 36 LEVELS- 10 dB
6. L-1011
7. DC-10-10
8. DC-10-40
9. 747-100
10. 747 200
,
50 70 100 200
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
300
500
700
1000
Figure 2-1. Current and Estimated Nacelle Retrofit Noise Levels - Sideline
-------
120
110
x
•-
a
~
3
_
;
z
_
_
>
.
L.
_
.
LI
•
L
_
100
1. DC-9-32
2. 737-200 ADV.
3. 727-200
4. DC-8-61
5 707-320B
WITH
CUTBACK
6. L-1011
7. DC-10-10
8. DC-10-40
9. 747-100
10. 747-200
FAR PART 36 LEVELS
WITHOUT
CUTBACK
FAR PART 36 LEVELS - 10dB
O BASELINE
D SOUND ABSORPTION MATERIAL (SAM)
O SAM 4 JET NOISE REDUCER
A WIDE-BODY AIRCRAFT
70 100 200
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
300
500
700
1000
Figure 2-2. Current and Estimated Nacelle Retrofit Noise Levels - Takeoff
-------
120
tc
39
a
s
-
_
110
100
i i i i i i
1. DC-9-32
2. 737 200 ADV.
3. 727-200
4. DC-8-61
5. 707-320B
FAR PART 36 LEVELS
- FAR PART 36 LEVELS-10 dB
6. L-1011
7. DC-10-10
8. DC-10-40
9. 747 100
10. 747200
O BASELINE
D SOUND ABSORPTION MATERIAL (SAM)
O SAM + JET NOISE REDUCER
A WIDE-BODY AIRCRAFT
100
200
300
BOO
700
1000
MAXIMUM AIRCRAFT WEIGHT. 1000 LBS.
Figure 2-3. Current and Estimated Nacelle Retrofit Noise Levels - Approach
-------
SAM + JNR has been completed for the 727 aircraft and the levels shown were measured
in accordance with FAR Part 36. The levels shown for the DC-9 are measured values
reported by the manufacturer and those for the DC-8 and 707 are the manufacturers'
estimates. Both the DC-9 and 707 eventually will have SAM + JNR treatment, but the
estimates are not sufficiently firm at this time to include them in the Figures.
It is interesting to note that retrofit of the narrow-bodied aircraft with SAM
results in FAR 36 noise levels comparable to those of the wide-bodied aircraft.
Futhermore, all SAM retrofit aircraft meet or exceed the Appendix C noise-level
requirements of FAR Part 36, except for the DC-8-61 at the takeoff point. The FAA
prototype nacelle on the 707-320B achieved approximately 11 EPNdB noise reduction
as shown in Figure 2-2. An 8 EPNdB noise reduction is depicted in Figure 2-2 for the
SAM treatment on the DC-8-61 aircraft. To continue investigations of SAM retrofit,
the FAA has funded McDonnell Douglas, through a subcontract with Boeing Wichita, to
study the problems associated with installing the Boeing nacelle on short- and long-duct
versions of turbofan-powered DC-8 aircraft.
Examples of typical SAM treatment for JT8D and JT3D engine aircraft are shown
in Figure 2-4 and 2-5. For 727 aircraft, the treatment is minimal; the noise reduc-
tion benefits are negligible for sideline and takeoff but significant on approach, and
the costs and performance losses are so modest that it is unreasonable not to include
such treatment on all new aircraft. For 707 aircraft, the treatment is much more
extensive; the noise reduction benefits are substantial at all three measuring positions
but especially dominant at approach, the performance losses are very small, and the
costs are significant but not necessarily unreasonable from a cost effectiveness view-
point.
*
Figure 2-6 illustrates the SAM + JNR treatment for 727 aircraft. It is clear that
this is a complex system that enables nacelle retrofit to accomplish substantial noise
reduction for sideline and takeoff with negligible reduction at approach beyond that
accomplished by SAM alone. The performance losses and costs are large if the
treatment is applied to an existing aircraft type. However, performance recovering
techniques (upgrading the engine and airframe) can overcome much of the loss but at
considerable increase in cost. The SAM + JNR treatment is a noise abatement retrofit
option that results in substantial benefits, is capable of being certificated for air-
worthiness, but does not appear to be viable because of the large cost and performance
2-7
-------
PERFORATED SHEET
PRODUCTION NACELLE
to
I
oo
TAILPIPE TREATMENT
INLET TREATMENT
P&WA BG 19
ENGINE TREATMENT
TREATED NACELLE
Figure 2-4. 727 Nacelle Retrofit Lower Goal (SAM) Configuration
-------
NOSE DOME
FAN COWL
NOSE COWL
TT
to
CD
SIDE COWL
3/4 FAN DUCT
T
1 r~ 1
1 1 '
1 1
1 '• 1
1 ! !
J kx
! !
• I
i i
7
*-u._
70 SQ. FT. OF
ACOUSTIC TREATMENT
FAN REVERSER
171 SQ. FT. OF
ACOUSTIC TREATMENT
SLEEVE
PLAN VIEW
ACOUSTIC TREATMENT
Figure 2-5. 707 Nacelle Retrofit Lower Goal (SAM) Configuration
-------
MIXED HOT ENGINE AIR
AND SECONDARY AIR
SECONDARY
INLETS CLOSED
IN CRUISE
MIXED
SECONDARY AIR
AND ENGINE AIR
Figure 2-6. 727 Nacelle Retrofit Upper Goal
(SAM + JNR) Configuration
2-10
-------
degradation. Nevertheless, it is available if the need arises and does represent the
maximum state of the art of nacelle noise abatement retrofit. Noise reduction retrofit
beyond what can be achieved by SAM alone, probably can best be accomplished by
engine modifications; i.e., refan.
In summary, the FAA retrofit feasibility project presents a number of nacelle
retrofit options for consideration in reducing the noise level of the narrow bodied civil
aircraft fleet. These options must be carefully considered with respect to installation
cost, operating cost, and cost of alternatives. The alternatives include any possible
future options such as the new front fan, fleet replacement, as well as the option of
doing nothing and accepting such public initiated local airport regulations as night
curfews, aircraft type restrictions (power plant, number of engines, gross weight,
etc.) preferential runway usage, and restrictions on the expansion of existing airports
and the development of new airports.
OTHER AIR CARRIER ENGINES
The JT3D and JT8D engines power two thirds of the current air carrier fleet.
Of the remainder, approximately 20 percent are powered by reciprocating engines and
turboprops which are not being considered for nacelle retrofit. The pure jet 707,
DC-8 and 880 (approximately 150 aircraft) are scheduled to be retired from the fleet
by the end of the decade and no consideration is being given to the development of retro-
fit kits for these aircraft. The BAG 111 and the 747's delivered prior to December
1971 are expected to remain in the fleet well into the 1980's; therefore, potential
nacelle retrofit options for these aircraft are discussed below.
British Aircraft Corporation, BAG 111
The BAG 111 is powered by the low bypass Rolls Royce (RR) Spey engine. As
indicated in Figures 1-3 through 5, these aircraft currently do not meet the FAR 36
noise standards. A joint program between BAG and RR has been initiated to develop
retrofit kits for the BAG 111 enabling the aircraft to meet the FAR 36 standard (with
tradeoff). The kit includes a six-chute suppressor nozzle, an acoustically lined 40-inch
jet pipe extension, acoustically lined bypass duct and intake. A development kit will
be flight tested early in 1974 with production kits planned for early 1976 availability,
The delta weight of the kit is approximately 418 Ib. with an estimated performance
penalty of 1 percent loss in T.O. thrust and 3.3 percent increase in SFC.
2-11
-------
Boeing 747
Early models of the 747-100 (delivered prior to December, 1971) were not subject
to the FAR 36 Appendix C noise requirements. Later models of the 747 have been
certificated to these requirements (See Figures 1-3 through 5). A joint Boeing/P&W
noise reduction program is currently underway to determine the potential for further
noise reduction for the early 747's as well as for future growth versions. Initial test
results indicate additional inlet noise reduction is possible with the addition of splitter
rings. Current research effort on improved acoustic materials, providing higher
effectiveness at reduced weight, is a potential option for future engine growth programs.
(Ref 3.1-1)
McDonnell Douglas (DC-10) and Lockheed (L 1011)
All models of these aircraft have been certificated well below the requirements of
FAR 36. However, similar R&D activity, as indicated above, has been initiated for
these aircraft which will also provide the potential for noise reductions for future
growth engine programs.
GENERAL AVIATION JET ENGINES
Approximately 20 percent of the aircraft in the general aviation jet fleet (repre-
sented by two aircraft — the Falcon 20 and the Cessna Citation) are powered by mod-
erate bypass turbofan engines and have been certificated in accordance with the FAR 36
requirements. The remaining 80 percent are powered by turbojet or very low bypass
turbofan engines (with noise characteristics similar to that of the turbojet).
The Gulfstream II, the largest aircraft in this class, utilizes a version of the
Spey engine having a bypass ratio of 0. 64. The takeoff and sideline noise levels are
in excess of the FAR 36 standards (Figure 1-7). Grumman, in concert with Rolls
Royce, has defined a program to develop a noise suppression kit for the Gulfstream II
aircraft, utilizing hardware developed by RR for the F 28 and BAC 111 aircraft, which
is expected to meet the FAR 36 requirement. A prototype flight test is scheduled for
the last quarter of 1973 with a certification flight test approximately 1 year later.
Production kits could be available by mid-1975. Acoustic linings are not included in
the program at this time but are being considered as backup, if necessary.
2-12
-------
The rest of the aircraft in the fleet are powered by small (3000 to 3500 Ib. thrust)
turbojet engines that are extremely compact engines.
Since small engines are less tolerant of disturbances to the basic cycle, small
size in itself can be a problem with regards to the application of sound absorption
materials (SAM) in the engine nacelle. Since this type of acoustic treatment is con-
cerned only with the audible frequencies, and since turbomachinery, combustion noise,
fan multiple pure tones, etc., fall generally into the same frequency ranges regardless
of engine size, SAM treatments fabricated of resonator cavity type materials will not
vary substantially in thickness from one engine to another. As a result, the weight and
costs associated with small engine SAM treatments will undoubtedly represent a larger
share of the total propulsion system installation than those for large engines. Further,
a higher overall penalty to airplane performance will result, not only due to the extra
weight but also to the increased nacelle drag and engine inlet blockage.
For those aircraft that are marginally shy of meeting the FAR 36 standards
(Learjet, for example) a modified exhaust nozzle may be all that is necessary to meet
the current standard. Such a program is being investigated at this time with the
potential to certify the Learjet to the FAR 36 noise requirement with a redesigned
exhaust nozzle.
A noise suppression kit has been developed for the BH125-600 aircraft. Develop-
ment flight test is scheduled for June 1973, with the objective of meeting the noise
requirements of FAR 36 by July 1974 for new production aircraft.
For the Jetstar, Sabreliner and Commodore, the performance penalties associ-
ated with the amount of acoustical nacelle treatment that would be required to enable
these aircraft to meet the FAR 36 noise standards may deteriorate their operational
effectiveness to an intolerable level. There are, however, other options available to
these aircraft. (See Page 2-27.)
ENGINE REFAN RETROFIT
BACKGROUND AND PROGRAM STATUS
This noise source control option is significantly different than those previously
discussed in this chapter inasmuch as it involves modification and replacement of
2-13
-------
certain engine, as well as nacelle, components. The most significant, but not the
only, engine component to be replaced is the bypass fan; thus the program is referred
to as "refan".
The refan program, as established under NASA sponsorship in August, 1972,
benefits from, and is based upon, both engine and noise technology developed since
1968. At that time, when it became apparent that efficient and effective jet noise
reduction could be achieved best through reduction of the primary jet exit velocity,
the Pratt and Whitney Aircraft Division (P&WA) began their studies on the JT3D engine.
Variations of this basic engine are used on the Boeing 707 and the McDonnell Douglas
DC-8 series of aircraft. This engine, as opposed to the JT8D, was investigated first
as it was the more conservative design and therefore had the greater possibility of
doing additional work which is fundamental to the refanning concept.
Early parametric studies of potential single-stage and two-stage fans showed that
the refan requirements could be satisfied by either two-stage fans of moderately larger
diameter or single-stage fans with a greater increase in diameter. The initial engine
studies resulted in the JT3D Configuration m, which was studied by the two aircraft
manufacturers as part of the nT Research Institute (IITRI) Study in 1969. This con-
figuration had a larger diameter two-stage fan, which increased the engine length and
installed weight. Although this engine provided a moderate reduction in jet noise,
there was no improvement in performance and it was not considered an acceptable
configuration at that time. Study of the refanning of the JT3D engine continued with
internal funding on an intermittent basis until 1972. During the period 1968 to 1972,
P&WA studied 10 possible configurations of this engine. The direct studies also bene-
fitted from the P&WA JT9D engine (powerplant for the Boeing 747 aircraft) develop-
ment as well as an FAA sponsored study of low, medium, and high, fan tip speed noise
characteristics. The ninth configuration of the JT3D studied by P&WA had an increased
diameter single-stage fan and no inlet guide vanes. This configuration formed the basis
for the NASA sponsored refan program when proposed.
Prior to initiation of the NASA program, it was determined that, with modification,
the JT8D could also be refanned. This engine is used on the various models of the
Boeing 727 and 737 and the McDonnell Douglas DC-9 aircraft. Within the initial scope
and funding of the NASA refan Program (Reference 11.1-186), Phase I contracts
were let for design and analysis of the engine and nacelle modifications with three major
2-14
-------
contractors: Pratt and Whitney Aircraft, a Division of United Aircraft Corporation;
The Boeing Company; and the Douglas Aircraft Company, a Division of McDonnell
Douglas Corporation. Small contracts were also let with American Airlines and United
Airlines for consulting work to assure that the modifications being considered incor-
porated as many requirements of the user airlines as possible.
In January, 1973, program funding curtailment forced limiting the scope of the
program to only one engine type. The joint NASA/DOT/FAA decision was to proceed
with the JT8D rather than the JT3D. The basic reason given for this choice was that
the JT8D-powered aircraft will have a larger impact on the aircraft noise exposure
in the 1980's.
As of this writing, the program to develop a refan kit for the JT3D powered
aircraft is not being actively pursued. As far as can be determined, the
technical/engineering approach is sound and of low risk, the economic reasonableness/
unreasonableness has not been developed, and the ground and flight test to demonstrate
flight worthiness and safety will not be performed. The refanned engine design had
been designated the JT3D-9. The significant differences between this engine and the
JT3D-3B, from which it was derived are shown in Figure 2-7. A similar compar-
ison of the refanned JT8D-9, currently designated as the JT8D-109, is shown in
Figure 2-8.
GENERAL TECHNICAL APPROACH AND OBJECTIVES
As briefly mentioned earlier, the concept of refanning requires starting with an
engine that was conservatively designed in order to extract additional work. This is
further explained by P&WA in Reference (2.1-74), "to lower the primary jet noise by
reducing the primary jet velocity without losing thrust requires that more of the pri-
mary engine's gas stream energy be converted into the low velocity bypass fan stream,"
(as shown in Figure 2-9). "This conversion can be accomplished by either increasing
the fan pressure ratio, or the bypass flow or by increasing both. Increasing the bypass
airflow is the more desirable route because it also provides increased total engine
thrust and reduced fuel consumption. This route is feasible since both the JT3D and
JT8D low pressure turbines have the capability of doing more work to absorb more
primary gas stream energy. Furthermore, the gains in fan design technology since
the initial design of these engines support the feasibility of new fans that would absorb
the additional low turbine work."
2-15
-------
JT3D-3B
JT3D-9 RELATIVE TO JT3D-3B
DIAMETER [FLOW PATH) + 6.4 INCHES
LENGTH + 0.7 INCHES
WEIGHT + 400 POUNDS
Figure 2-7. JT3D-3B/JT3D-9 Comparison (Reference 2. 1-74)
-------
to
JT8D-109
JT8D-109 RELATIVE TO JT8D-9
+12 INCHES
+ 14.17 INCHES
+ 562 POUNDS
DIAMETER
LENGTH
WEIGHT
Figure 2-8. JT8D-9/109 Comparison (Reference 2.1-74)
-------
10
M
oo
INCREASING
FAN WORK
PRIMARY
JET
REQUIRES
GREATER
WORK EXTRACTION
BY LOW TURBINE
REDUCES
ENERGY
REMAINING
IN PRIMARY
EXHAUST
Figure 2-9. Core Jet Noise Reduction (Reference 2.1-74)
-------
While reforming is primarily directed toward reducing the primary jet noise,
redesign details, such as number of stages, spacing between the rotating and stationary
elements, numbers of rotor blades, and stator vanes, are also studied in order to
minimize the turbomachinery noise portion of the spectrum. After this has been
accomplished, nacelle modification and treatment with sound absorbing material is
added in order to further reduce the noise levels.
The refan Program, as sponsored by the NASA, takes the above described
multi-faceted approach to engine and nacelle retrofitting with the following program
objectives"... through development of retrofit kits (demonstrate) that the noise pro-
duced by narrow-body fleet can be reduced to 5 to 10 EPNdB below FAR-36, while
retaining demonstrated engine reliability and maintainability, causing no
degrading of aircraft performance or safety and could be accomplished at an acceptable
fleet retrofit cost."
ESTIMATED RESULTS; NOISE REDUCTION
The NASA and the two aircraft manufacturers, Boeing and Douglas, have made
estimates of the noise levels associated with each of the various aircraft considered
to be possible candidates for a refan retrofit. In every case, the estimated noise
levels are those for the FAR Part 36 positions and conditions with the aircraft
powered by the refanned engine. In some cases, estimated noise levels for more than
one nacelle treatment or configuration were developed and reported. A compilation of
the estimates from reports* available to the task group is provided in Tables 2-1 and
2. These estimates and those being used in the DOT aircraft retrofit cost effective-
ness analysis, (Reference 8.5-355), have been combined to provide a range of esti-
mated noise levels for the five most representative aircraft. The estimates and noise
levels normally associated with the baseline aircraft are shown for comparison in
*Figures 2-10 through 2-12 and Tables 2-1 through 2-4 are based on data provided in the
references cited in the tables. More recent information (References 3.6-411, 3.7-412,
3.10-456, 2.4-454 and 11.2-398) indicate small differences in acoustic data from those
listed in the tables and provided in the figures, as well as some variability of data
between the submitting sources. However, the data presented in the figures and tables
are considered representative of the noise trends for the refan program. Firmer
noise performance figures will be established as the program progresses into ground
and .flight tests.
2-19
-------
CO
&
o
AIRCRAFT
TYPE AND
SERIES
DC-8-61
DC-8-54F
DC-8-51
DC-8-62
DC-863
707-320B/C
707-12QB
SJT3D
Powered
ACFT
NUMBER OF
ACFT IN
1973 FLEET
(REF. 2.1-87 )
U.S. WORLD
66 87
24 51
46 95
17 64
47 102
242 437
103 111
69 93
603 1040
SOURCE
OF
DATA
NASA
McO-D
i
McD-D
McD-D
McD-D
McD-D
I
NASA
Boeing
Boeing
Boeing
DEGREE
OF
TREATMENT
*
Maximum
Intermediate
Minimum
Intermediate
Intermediate
Maximum
Maximum
Minimum
«
Maximum
1 intermediate
Minimum
Intermediate
Intermediate
SIDELINE
BASE- FAR RE FAN
LINE PART36 ACFT
103 10S.E 94
103 106.2 93
i i 96
t I 96
104 106.1 97
104 105.8 97
103 106.3 96
102 106.4 93
* * 95
107.5 106.5 94
191.9
92.1 '
92.7
107.5
107.5
NOISE LEVELS IN EPNdB
TAKEOFF
BASE- FAR RE FAN
LINE PART36 ACFT
116 103.6 102
I I 107
T T 107
103.4 106
110 102.4 102
113 103.8 102
115 104.1 103
* * 104
115.0 104.0 99.5
I I 99.7
f t 100.6
110.0
108.5
TAKEOFF W/CUTBACK
BASE- FAR • REFAN
LINE PART36 ACFT
117 103.5 95
116 103.6 98
1 1 '°2
f T 103
115 103.4 101
109 102.4 95
112 103.8 97
114 104.1 98
* t 101
113 104.0 95
114 104.0 94.8
i 1 B5''
1 I 96.6
108 -
105.5
APPROACH
BASE- FAR REFAN
LINE PART36 ACFT
117 105.5 98
117 106.2 96
i 1 10°
t T 104
118 106.1 100
117 10S.8 99
114 106.3 95
114 106.4 96
} * 100
119.5 106.5 98
120.5 106.5 102.2
1 1 103.0
f I 107.6
118
117.5
DATA
REFERENCE
11.1-186
3.4-13S
1
3.4-135
3.4-135
3.4-13S
3.4135
11.1-186
3.3-123
I
3.3-123
3.3-123
NOTE' DIFFERENT DEGREES OF TREATMENT ARE NOT PHYSICALLY THE SAME FROM TYPE-
TO-TYPE AND MAY NOT BE THE SAME FROM SERIES TO SERIES WITHIN A TYPE.
NOT SPECIFIED
TABLE 2-1: ESTIMATED NOISE LEVELS FDR JT3D-9 (REFANNED) POWERED AIRCRAFT
-------
to
I
to
AIRCRAFT
TYPE AND
SERIES
DC-9-30
DC-9-32
1
DC-9-10
DC-920
DC-9-40
727200
727-100
727-1 00 C/O.C
737-200
737-200 C/QC
737-100
2JT8D
Powered
ACFT
NUMBER OF
ACFT IN
1973 FLEET
(REF, 2.1-67 )
U.S. WORLD
286 479
95 133
0 10
0 24
264 332
300 397
125 161
166 248
12 33
0 29
1248 1846
SOURCE
OF
DATA
NASA
McD-D
1
NASA
Boeing
I
NASA
Boeing
DEGREE
OF
TREATMENT
.
Maximum
Intermediate
Minimum
•
Maximum
Intermediate
Minimum
•
*
NOISE LEVELS IN EPNdB
SIDELINE
BASE- FAR REFAN
LINE PART36 ACFT
101.5 103.5 92
102.0 103.1 92
1 93
\ * 94
102.0 104.5 92
99.9 104.4 84.9
I 1 89.9
\ I 90.9
104 103.5 92
101.1 103.5 92.5
TAKEOFF
BASE- FAR REFAN
LINE PART36 ACFT
_ _ __
103 95.6 92
1 i 11
— ~~ ~
107.4 99.0 92.4
1 97'4
t t 97.4
— — —
_ _ _
TAKEOFF W/CUTBACK
BASE- FAR REFAN
LINE PART36 ACFT
97 96 84
97 95.6 88
1 1 s
102.0 100 88
100.0 99.0 87.0
I I 89.0
I » 89.0
96 96.5 84
96.7 96.5 85.5
APPROACH
BASE- FAR REFAN
LINE PART36 ACFT
108 103.5 95
108 103.1 97
I 1 '°°
| | 102
109.5 104.5 96
108.2 104.4 98.2
I I 98.2
t » 100.2
108 103.S 95
108.9/ 103.5 100
110.9
DATA
REFERENCE
11.1-186
3.4-136 '
i
11.1-186
3.8-243
t
11.1-186
3.1-1
NOTE: DIFFERENT DEGREES OF TREATMENT ARE NOT PHYSICALLY THE SAME FROM TYPE-
TO-TYPE AND MAY NOT BE THE SAME FROM SERIES-TO-SERIES WITHIN A TYPE.
NOT SPECIFIED
TABLE 2-2: ESTIMATED NOISE LEVELS FOR JT8D-109 (REFANNED) POWERED AIRCRAFT
-------
I 9
I S
1 9
120
110
CO
111
100
y 90
80
70
20
1. DC-932
2. 737-200 ADV.
3. 727 200
4. DC8-61
5. 707 320B
FAR PART 36 LEVELS
FAR PART 36 LEVELS - 10 dB
O BASELINE
MAX)
/REFAN ESTIMATE
WIN.)
A WIDE-BODY AIRCRAFT
11
fl
30
50 70 100 200
MAXIMUM Al RCRAFT WEIGHT. 1000 LBS.
300
6. L 1011
7. DC 10-10
8. DC 1O40
9. 747-100
10. 747 200
500
/()<)
1
1000
Figure 2-10. Current and Estimated Refan Retrofit Noise Levels - Approach
-------
120
i
i':
'•-
110
<
1
u
I
I
I •
ii
II'
I
Ml
o
ll'
I
:i
- FAR PART 36 LEVELS
100
: 0
0
!0
1. DC-9-32
2. 737-200 ADV.
3. 727-200
4. DC-8-61
5. 707-320B
I I
I TIT TTFl
1
0
I r_
FAR PART 36 LEVELS 10 dB
O BASELINE
-MAX}
/REFAN ESTIMATE
-MIN.J
A WIDE-BODY AIRCRAFT
6. L-1011
7. DC-10-10
8. DC-10-40
9. 747-100
10. 747-200
J 1
to
50 70 100 200
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
300
500
700
1000
Figure 2-11. Current and Estimated Refan Retrofit Noise Levels - Sideline
-------
120
i 9
i S
ii
as
I
uu
u
a
in
a
in
u
uu
110
100
BO
/,.
WITH
THRUST
CUTBACK
1. DC-932
2. 737-200 ADV.
3. 727-200
4. DC-8-61
5. 707 320B
_ FAR PART 36 LEVELS
- FAR PART 36 LEVELS-10 dB
to
0
WITHOUT
THRUST
CUTBACK
O BASELINE
REFAN ESTIMATE
-WIN.)
A WIDE-BODY AIRCRAFT
J I I I I I I I I
6. L-1011
7. DC-10-10
8. DC-10-40
9. 747 100
10. 747 200
100
200
300
500
700
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
1000
Figure 2-12. Current and Estimated Refan Retrofit Noise Levels - Takeoff
-------
to
I
CO
cm
AIRCRAFT
TYPE AND
SERIES
DC-8-61
DC-8-54F
DC-8-51
DC .8-62
OC-8^3
707-320B/C
707-120B
7208
EJT3D
Powered
ACFT
NUMBER OF
ACFT IN
1673 FLEET
IREF 2 VE7I
U.S. WORLD
65 87
24 51
46 95
17 64
47 102
242 437
103 111
69 93
603 1Q40
SOURCE
OF
DATA
McO-D
1
McD-D
McD-D
McD-0
McD-D
»
NASA
Boeing
i
Boeing
Boeing
DEGREE
OF
TREATMENT
Maximum
Intermediate
Minimum
Intermediate
Intermediate
Maximum
Maximum
Minimum
Maximum
Intermediate
Minimum
Intermediate
Intermediate
BASELINE
INST.
TAKEOFF
THHUST
(Ibt.l
14.J20
I
14,120
14.120
13.875
13.875
16.720
!
REFAN
Afn
<%l
+4.8
+3.4
+5.9
+3.4
+ 3.4
+6.7
+6.7
+7.4
+8.8
+ 8.6
+8.6
+8.7
BASE-
LINE
SFCCR
-------
to
I
to
05
AIRCRAFT
TYPE AND
SERIES
009-32
1
1
OC-9-10
DC-9-20
DC-9-40
727.200
727-100
727-100C/QC
737-200
737-200C/OC
737-100
EJTSD
PowerKJ
ACFT
NUMBER OF
1973 FLEET
U.S. WORLD
286 479
95 133
0 10
0 24
264 332
300 397
125 161
166 248
12 33
0 Z9
1248 1848
SOURCE
OF
DATA
McD-O
1
NASA
Boeing
Boeing
DEGREE
OF
TREATMENT
Maximum
Intermediate
Minimum
.
Maximum
Intermediate
Minimum
TAKEOFF
THRUST
lib.)
„
12.200
12.200
12,200
12,700
I
REFAN
l%1
_
-3.3
+ 1.3
+6.7
6.7/10.0
+5.4
+5.1
+7.7
BASE-
LINE
CSFC
_
0.862
0862
0.862
0.83
1
REFAN
ACSFC
IX)
_
+7.7
+3.9
-1.0
•3.4/+2.4
-2.8
0
-1.6
B/L
OPER.
EMPTY
WEIGHT
Iklb)
„
58.59
58.59
58.59
99.0
J
AOEW
_
+8.1
+6.2
1 +4.1
+2.0/4.1
+4.9
+4.5
+3.8
B/L
MAX.
TAXI
WEIGHT
_
109.0
109.0
109.0
__ •
~
AMTW
(X)
_
0
0
0
_
-
BASELINE
FIELD
LENGTH
(ft.)
_
7,000
7.000
7,000
8,370
I
AFL
_
- 1.4
-13.6
-17,0
-3.5/-S.4
-12.9
-12.2
-15.0
BASELINE
RANGE
(nm)
_
1000/2000
1000/2000
1000/2000
1,355
1,015
J
—
An
W
_
-10.0M5.0
- 5.01-10.0
0/-2.5
../-20
- 7.9
- 9.8
4.9
-160
RECERT
TAKEOFF
WEIGHT
(Ibl
_
_
_
-
182.5
108.3
RECEBT
AR
-
_
_
-
0
+ 14.0
+ 11.4
+ 14.0
+ 3.1
DATA
REFERENCE
3.4-136
|
I
11.1-186
3,8-243
I
3.1-1
NOTE: DIFFERENT DEGREES OF TREATMENT ARE NOT PHYSICALLY THE SAME FROM TYPE-TO-TYPE AND
MAY NOT BE THE SAME FROM SERIES-TO-SERIES WITHIN A TYPE.
•NOT SPECIFIED
TABLE 2-4: ESTIMATED PERFORMANCE PARAMETERS FOR JT8D-109 (REFANNED) POWERED AIRCRAFT
-------
Figures 2-10 through 12 for the approach, sideline and cutback takeoff operations,
respectively. The range of estimates for a "refanned" aircrMt includes all levels of
nacelle treatments considered from all of the available sources.
ESTIMATED RESULTS; PERFORMANCE PARAMETERS
In conjunction with the noise levels, NASA and the two aircraft manufacturers have
also made at least a preliminary assessment of the performance impact of various
retrofits associated with refanning for the various aircraft. An attempt to collect and
compile data indicative of the effect on various performance parameters has been made
and these data are tabulated in Tables 2-3 and 2-4 for the JT3D and JT8D powered
aircraft, respectively.
JET ENGINE REPLACEMENT
AIR CARRIER FLEET
Replacing the low bypass fan engines in the air carrier fleet (JT3D, JT8D, Spey
MK 511) with characteristically quieter high bypass engines is not a viable current
technology option. There are no engines available in the thrust classes required. The
NASA Quiet Engine Program (discussed in Section 3) effectively demonstrated the
capability for noise reduction in an experimental engine test program at thrust levels
comparable to those of the JT3D and JT8D, but, the engine hardware that was utilized
was not flightworthy nor was it intended to be.
However, even if a new engine development program were initiated to provide a
quieter high-bypass fan engine, the option of replacing the current engines with a new
engine would be prohibitive in cost particularly in view of the limited life that would be
remaining in these aircraft. (Reference 7.1-25.) The modification program could
not begin until late in the decade after the engine development and certification
program was completed.
GENERAL AVIATION FLEET
There are currently several small turbofan engines that can be considered for
possible retrofit in existing turbojet aircraft. One such program has already been
announced, the replacement of the JT12 turbojet engines currently in the Jet star with
2-27
-------
the moderate bypass Garrett 731 turbofan. It is estimated that not only will the noise
level of the re-engined Jetstar comply with the FAR 36 requirements but the range/
payload characteristics will be significantly enhanced.
The Lear jet has been test flown with the Garrett 731 engine, providing still another
retrofit option possibility. The General Aviation Division, Rockwell Corp. is proceed-
ing with the development of a turbofan-powered Sabreliner with the CF 700 engine
(used on the Falcon 20) which could offer a retrofit possibility for the existing Model 60
and 70 Sabreliners.
In addition to the Garrett 731 and the GE CF 700 engine, the Lycoming ALF502D
and the UAC-Canada JT15D turbofan engines are available for possible retrofit.
Some of these engines are also being evaluated as possible replacement engines in
turboprop installations.
AIRCRAFT REPLACEMENT
In addition to the technical options cited above, accelerated retirement of the noiser
aircraft with their equivalent capacity maintained by accelerated procurement of the
new technology, quieter widebodies has been suggested as an alternate means of reducing
aircraft noise.
However, this too is an extremely costly option. As indicated in Reference
7.1-99, the cost of replacement of the JT3D fleet alone would represent an invest-
ment of 6 to 8 billion dollars. This does not take into account any additional procure-
ment that may be required to meet the forecasted growing demand for air service
nor does it consider the residual value remaining in both the aircraft and the world
wide stock of spare parts inventory which must be scrapped.
In the case of the business jet owner, aircraft replacement may be a viable option.
The improved range/payload characteristics of the new turbofan powered aircraft
(due primarily to the major reduction in fuel requirements) may provide adequate
incentive for the individual or corporate owner to upgrade his aircraft equipment.
The aircraft replaced, however, may still require a nacelle modification or engine
replacement program if it is sold to another U.S. operator. The cost of a used air-
craft with acoustical modifications would still be significantly lower than the cost of
a new aircraft, which could lead to a new market for these aircraft.
2-28
-------
SECTION 3
FUTURE TECHNOLOGY OPTIONS AND RESTRAINTS
Diminution of aircraft noise will be a continuing objective as new, more advanced
vehicles are introduced into the civil aviation fleet. It is anticipated that the standard
of noise acceptability will be steadily reduced as the developing technology demonstrates
the feasibility of so doing.
This section of the report addresses the current developments in both airplane and
engine component technology, as well as advanced engine concepts, which will largely
determine the potential for significant reduction in aircraft noise in the years ahead.
COMPONENT TECHNOLOGY
NASA QUIET ENGINE PROGRAM
The NASA Quiet Engine Program was initiated about 5 years ago with the objective
of developing engine noise reduction technology and demonstrating in engine tests the
combined effect that this technology would have on reducing engine noise. An additional
objective was to determine the impact on airplane economics resulting from the meas-
ures necessary to reduce the noise.
Two "engines" were built and tested during the program, in which two basically
different fan designs were evaluated. To obtain a major cost saving, both engines used
the CF-6 engine core, and for this application it is oversized; therefore, the engines
were not flight weight. A high-bypass ratio engine was chosen to reduce jet velocity
and, consequently, jet noise. A number of features were incorporated to reduce fan
noise production. A relatively large rotor-stator spacing of two rotor chords was
employed to reduce fan discrete frequency noise. A choice of rotor tip speeds was
available for the fan design. Low tip speed fans have been found to produce less noise,
while high tip speed fans can improve airplane economics by reducing engine weight,
but they require additional noise suppression to achieve equally low noise output. Both
approaches were evaluated in this program. Finally, a noise governed optimum ratio
of number of fan stator to rotor blades was employed (2. 25 to 1). In addition to design
features aimed at low fan noise production, the fan noise can be reduced further by the
3-1
-------
addition of sound absorbing liners to the inlet and outlet ducts. This was also investi-
gated on the experimental engines.
A cross section of quiet engines A and C with full fan acoustic treatment applied is
shown in Figure 3-1. Also shown are some of the important performance and design
characteristics of the engines. Both engines were designed to produce 22,000 pounds
of thrust, and this puts them in the thrust class of the JT3D engines used in the DC-8
and 707 type aircraft. Engine C, the high-speed engine, has a single-stage fan with a
design fan tip speed of 1550 ft/sec, while engine A, the low-speed engine, has a single-
stage fan with a tip speed design point of 1160 ft/sec.
This program has been of great importance in determining the tradeoffs associated
with performance and noise reduction. The first results of this highly successful pro-
gram were reported in 1972. The program goal of a noise level reduction of 15 to 20
EPNdB below the levels of the 707/DC-8 long range transport aircraft was exceeded
(Table 3-1). These results clearly indicate that the potential for lower noise levels
of future engines, and aircraft, is excellent. It has been estimated that the fan tech-
nology demonstrated in the Quiet Engine Program would, in a new engine scaled to
the thrust level of the current high bypass engines, yield a 5-to-6-dB reduction in
fan generated noise compared with the current engines.
In relating the performance improvements to be expected with the technology devel-
oped in these advanced fan concepts, an economic analysis was performed for an assumed
new trijet of approximately 200,000 Ib. gross weight. The results of the study, using
flight type engine designs based upon the experimental data developed for engines A and
C, is provided in Figure 3-2. Changes in direct operating cost (DOC) utilizing un-
suppressed engine "C" technology as the base, is plotted against aircraft noise level
relative to FAR-36 noise regulations for both the high-speed and low-speed engine
designs. The curves shown for each engine represent various degrees of fan acoustic
treatment starting with an unsuppressed case at the lower end of the curves and ending
with wall treatment plus three inlet and two exhaust splitters at the upper end. The
higher speed engine is more economical (-2.5 percent DOC) in an unsuppressed condi-
tion because the high engine speed allows the number of turbine and compressor stages
to be reduced, thereby reducing engine weight. However, it produces more noise, as
stated previously. The knee in the curves (where DOC begins to increase rapidly with
noise reduction) results from increased engine weight and engine pressure losses, that
accrue as acoustic splitters are added to the fan inlet and exhaust ducts. As a result,
3-2
-------
ENGINE A
OS
09
ENGINE C
FAN PRESSURE RATIO
BYPASS RATIO
THRUST, LB
ENGINE CORE
FAN TIP SPEED, FT/SEC
ENGINE A
1.5
6.1
22,000
CF-6
1160
ENGINE C
1.6
5.1
22,000
CF-6
1550
Figure 3-1. NASA Quiet Engines with Full Suppression
-------
TABLE 3-1
FLYOVER NOISE COMPARISON - FOUR ENGINE AIRCRAFT
TAKEOFF APPROACH
EPNdB
DC-8 116 118
FAR-36 104 106
Baseline Quiet Engine A 97 98
Quiet Engine A with
Acoustic Nacelle 90 89
the low speed engine (A), even though it is a basically less efficient engine, is more
economical as lower noise levels are reached. The cost of obtaining a noise level of
FAR-36 minus 10 EPNdB, using the A-type engine, is seen to be about 4 percent in
DOC for this particular study. These results are not necessarily typical and must be
determined for each aircraft/engine installation.
It is obvious, however, that to progress beyond the FAR-36 minus 10 EPNdB noise
levels economically, a vigorous noise reduction technology program is required. Ad-
vances in noise source reduction and improved suppression efficiency are areas of major
importance for future technology programs. The fan and possibly the turbine as well as
core engine noise are candidates for source noise reduction programs. In addition,
the non-engine aerodynamic noise may preclude the realization of further benefits
from engine source noise reduction, particularly in the aircraft approach mode. This
noise contribution must be identified and resolved. Additional discussion relative to
the technology programs addressing the above limitations are presented in subsequent
portions of this section. Improvements in suppression technology are needed to increase
acoustic treatment effectiveness so that less treatment will be required for a given noise
reduction and also to reduce the weight per unit area of treatment by incorporating new
materials or fabrication concepts or both.
SONIC INLETS
The NASA Quiet Engine Program established fan design concepts which indicated
that significant reductions in fan-generated noise was achievable in future engines.
3-4
-------
12
200,000-LBTRI-JET; 1800 NAUTICAL MILES
CO
QE-A TECHNOLOGY
. —— QE-C TECHNOLOGY
10
ADOC, %
SPLITTERS
3 INLET & 2 EXHAUST,
DUCT WALLS
UNSUPPRESSED
I
1 EXHAUST SPL
SPLITTERS
1 INLET &1 EXHAUST
FAR 36 -5 -10
NOISE LEVEL, A dB
Figure 3-2. Effect of Degree of Fan Suppression on Aircraft Economics
-15
-------
Treating the nacelle inlet with sound absorption materials (SAM) reduces the external
propagation of whatever noise is generated.
An additional noise reduction concept that may replace or supplement the use of
SAM is the sonic (or choked) inlet which is essentially a reflective type of device.
The simplest explanation of its operation is that if the steady flow within a duct has
obtained sonic velocity then a sound wave cannot propagate against this flow. This im-
plies that this principle can be applied only when the sound is propagating against the
steady flow. In an actual inlet, however, the mechanism is much more complicated
than that implied previously. There will be continuous reflections of the sound wave
caused by the varying duct diameter and steady flow Mach number. Radial and trans-
verse velocity gradients also exist which will refract the sound waves away from the
axial direction where they can be swept back from the inlet by the steady flow. Experi-
mental data indicates a steady increase in suppression as the average inlet Mach number
approaches one.
A collaborative NASA/General Electric Company parametric study on choked inlets
is underway. The work involves both acoustic and aerodynamic measurements of a
family of 19 different inlet configurations which should provide significant inlet quadrant
noise suppression. The tests are being accomplished on a 12-inch diameter fan, and
the hardware represents elements of variable geometry cowl and center-body systems.
Particular attention is being given to measurements of inlet flow profiles in order to
make direct correlations with both the internal and external inlet noise fields.
Figure 3-3 shows two of the choked inlet concepts under study in the current
program. The concept is simple but there are difficult practical problems to be solved
before adequate technology is available.
The mechanical complexity, structural integrity, and weight of the inlets must be
reduced as well as airflow distortions and large losses in total pressure.
In FY 1974, some of the more promising sonic inlets will be tested on a full-scale
two-stage fan rig to measure both acoustic and aerodynamic performance. Full scale
acoustic tests will be performed with two different sonic inlets added to Quiet Engine C.
CORE ENGINE COMPONENTS
As discussed previously, much progress has been made in commercial jet engine
noise reduction since its inception, approximately 15 years ago.
3-6
-------
CO
3 POSITION TRANSLATING CENTERBODY
J
APPROACH
TAKEOFF
CRUISE
2 POSITION CENTERBODY WITH
RADIAL VANES
VANE POSITION FOR
TAKEOFF AND CRUISE
VANE POSITION FOR
APPROACH
TAKEOFF AND APPROACH
CRUISE
3 POSITION TRANSLATING CENTERBODY
2 POSITION CENTERBODY WITH
RADIAL VANES
1.00r-
~i 40
.8 .9
INLET THROAT MACH NUMBER
1.0
INLETS IN
CRUISE
POSITION
INLETS IN
TAKEOFF OR
APPROACH POSITIONS
Figure 3-3. Sonic Inlet Research
-------
All of the noise control advancements, from the pure turbojet to the high-bypass-
ratio turbofan engines, were the result of technology developments for rotating machin-
ery (fan component) and/or sound absorption materials. No comparable advancements
have been experienced for the core engine noise of the high-bypass-ratio engines in
current production. Rotating machinery and sound absorption noise control technology
have continued to advance to the point where further progress may be ineffective unless
the core engine noise is controlled as well. As visualized now, core engine noise is
the floor which establishes the limit of effectiveness of the current noise control state
of the art as it pertains to aircraft engines.
The FAA is currently sponsoring a Core Engine Noise Control Program, the pur-
pose of which is to provide theoretical and experimental data to assist the designers in
developing future technology aircraft capable of conforming to lower noise levels than
are now required by FAR Part 36. The effort is directed to identifying, evaluating,
and controlling the component noise sources inherent in the core engine (the gas
generator).
Core engine noise is defined as the noise produced by the gas generator portion of
the gas turbine engine either solely or as influenced or amplified by the fan discharge,
tail pipe, and other portion of the exhaust system. Core engine noise is assumed to
radiate only in the aft engine quadrant, and its sources may be generated either upstream
or downstream of the tail pipe exit plane. Core engine noise does not include com-
pressor generated noise radiating from the engine inlet nor fan generated noise radi-
ating from either the engine inlet or exhaust ducting. It may, however, include com-
pressor generated noise transmitted downstream through the engine flow passages or
*
fan generated noise enhanced by interaction with the core engine noise or gas stream.
The factors under investigation that cause or influence the component noise sources
of the core engine include but are not limited to:
* Jet Exhaust Stream. Historically, the jet noise has been defined by the quad-
rapole concept leading to the classical velocity to the eighth power law, with
the absolute level at any given velocity dependent upon various influences
upstream of the engine tail pipe such as geometry, roughness, turbulence scale,
etc. Are the assumptions valid for subsonic flow? Can the influences upstream
of the tail pipe be quantified ?
3-8
-------
• Turbine. Does the turbine generate noise in a similar manner as the com-
pressor and fan, and can compressor and fan noise reduction techniques be
successfully applied to turbines? What are the effects of rotating stall, hot
spots, and other flow irregularities on noise generation?
• Compressor. Can the compressor have any significant contribution or influ-
ence on the noise transmitted or generated within the core engine ?
• Combustor. What contributions do the combustion equipment and process make
to the noise field? Are combustion screech and rumble significant?
• Discontinuities in the Flow Passages. Is there significant dipole or monopole
noise generation from such discontinuities as linkages, orifices, constrictions,
and bends in the core engine flow passages?
• Interaction of the Core Engine Exhaust and Fan Duct Streams. Can the combi-
nation of the two exhaust streams generate a significant noise component? Is
noise from either the fan or core engine amplified by the other ? Is some
resonant condition set up in the tail pipe?
• Noise Radiation from the Engine Casing. Are engine casings designed to have
adequate sound transmission loss capability? Can significant structure borne
sound be transmitted to and radiated from the casing?
In addition to the FAA program on core noise investigations, NASA and DOD are
undertaking complementary research efforts relative to their unique requirements.
Formal and informal interagency discussions preclude 'the possibility of redundancy
among the various programs.
AERODYNAMICS
The principal source noise abatement activity to date has been concentrated on
attempts to reduce engine generated noise for a given size aircraft. Additional source
noise control may be possible if the aircraft is treated as a system where each element
of the system is designed to provide minimum overall aircraft system noise. Some
examples of this concept follow.
3-9
-------
Wing Design
Supercritical Wing
Application of supercritical wing technology to the design of new aircraft could
result in reduced noise, as a secondary effect.
Conventional airfoils are designed for operational efficiency over a limited per-
formance range. At flight speeds beyond the design capability of the airfoil, generally
identified as the critical flight speed, excessive drag and buffeting are experienced.
The supercritical wing is configured to operate beyond the normal Mach number limits
that have constrained conventional wings. The potential benefits of the application of
supercritical wing technology to civil aircraft are:
• More efficient cruise performance when operating at high subsonic Mach
numbers, by delaying the onset of transonic drag rise.
• Its use can result in reduced wing structural weight, thereby permitting
increased payload or increased fuel capacity for greater range.
For a given range/payload design, the gross weight of the aircraft would be reduced,
requiring smaller engines, which for the same state of technology would result in lower
noise. Design studies of the effects of supercritical wing technology to the B-l bomber
program showed an 11 percent reduction in gross weight for the specified mission.
The recent Advanced Technology Transport studies utilized supercritical wing
technology in developing the efficient performance characteristics of the near sonic
commercial transport designs. This technology is equally applicable to the business
jet aircraft currently operating in the general aviation fleet. William Lear, developer
of the Lear jet, is planning to demonstrate a supercritical wing on a Lear jet aircraft
in 1973.
Asymmetric Wing
Wind tunnel tests at the NASA Ames Research Center of an elliptical, asymmetric
(or oblique) wing for efficient low supersonic or high transonic performance has pro-
duced some dramatic initial results. Studies and model testing of this unconventional,
radical design indicated better noise, performance, and structural characteristics than
for the variable swept wing configuration. Tests to date have been limited to experi-
mental wind tunnel and small radio-controlled flying models. Additional development
3-10
-------
effort is required, particularly full scale demonstration testing, before the preliminary
data can be validated.
Study results also indicated that the oblique wing configurations incur less cost for
a given level of noise reduction.
High-Lift Devices
As indicated in Section 1, continuing developments in wing flap design have
effected significant improvement in aerodynamic lift capability over the years. Current
activity is directed at the evaluation of various "powered-lift" concepts in an attempt
to meet the requirements of potential future short takeoff and landing aircraft (STOL).
To serve the high-density short haul need, and still prove profitable, these air-
craft must also approximate the productivity, cruise speed and economy, and ride com-
*
fort of the CTOL transports. The latter considerations dictate relatively high wing
loadings (80 to 110 Ibs/sq. ft.). Hence, the desired low-speed performance requires
maximum lift values well in excess of those achievable with the most effective aero-
dynamic high lift systems.
To generate these high-lift values, propulsive energy must be applied to augment
the aerodynamic wing lift.
The powered lift effort presently is being concentrated on three principal types
(See Figure 1-11):
1. The augmentor wing (AW).
2. The externally blown flap (EBF) with engines located under the wing (UTW).
3. The EBF with engines located over the wing (OTW).
Figure 3-4 provides some indication of the performance characteristics of the
powered lift jet systems as compared with the typical, present day, turboprop STOL
transport aircraft.
The steep ascent and descent Hight paths, made possible by these high lift devices,
is expected to reduce the extent of the noise impact on the community. However, the
effect of the higher engine thrust requirement, combined with the induced noise gener-
ated by the exhaust gas and flap interaction (Figure 3-5), needs to be determined by
full scale testing in an operationally viable system in order to more completely evalu-
ate the overall system noise.
3-11
-------
WING
LOADING,
LB/FT.2
120
100
n
60
EXTERNALLY
BLOWN FLAP
40
20
A BREGUET
'— 941
MECHANICAL
FLAP-DEFLECTED
SLIPSTREAM
A
DHC-7
DHC-5
/\ DHC-6 (TWIN-OTTER)
i
1500
2000 2500
LANDING FIELD LENGTH, FT.
Figure 3-4. Aircraft Wing Loading vs. Short Field Length
3-12
-------
WING SLOT
JET NOISE
FAN & COMPRESSOR
NOISE
r
CASE NOZZLE
RADIATED EXIT PLANE
NOISE TURBULENCE
NOISE
FAN&
TURBINE
NOISE
EJECTOR
JET NOISE
EJECTOR
EXIT PLANE
TURBULENCE NOISE
(a) AUGMENTOR WING SYSTEM NOISE
FAN & COMPRESSOR
NOISE
FLAP SCRUBBING
NOISE
WING SCRUBBING
NOISE
SLOT FLOW
NOISE
FLAP TRAILING EDGE
TURBULENCE
NOISE
CASE NOZZLE
RADIATED EXIT PLANE
NOISE TURBULENCE
NOISE
FAN
& TURBINE
NOISE
FLAP JET
NOISE
(b) EXTERNALLY BLOWN FLAP NOISE
Figure 3-5. High Lift System Noise
3-13
-------
As discussed earlier, the development of the high-bypass fan (bypass ratio of
5 or 6:1) provided large reductions in noise for the conventional transport aircraft.
In order to meet the anticipated noise limitations for high performance STOL air-
craft, much higher bypass engines may be required. The higher the bypass, for a
given thrust, the lower the jet velocity. This low exhaust velocity will not only reduce
the engine jet noise but will also minimize the flap interaction noise in these high
lift systems.
External Flow
The approach noise of an aircraft is currently dominated by the high frequency
noise produced by the engines.
Advances have been made in the technologies of quieter engine design and the
acoustic treatment of engine installations to attenuate engine-generated noise. Con-
siderable payoff is expected on future aircraft/engine combinations designed from
the beginning for very low noise. This has encouraged predictions that noise at the
standard FAR 36 noise measuring points can be reduced 10 dB, or more, per decade
starting immediately. However, recent studies and flight tests of large commercial
airplanes strongly indicate that we now face an airframe noise constraint for at least
the approach condition, with flaps extended, below which additional noise reduction
would be difficult even if the airplane had no engines.
Airframe noise is defined as the noise generated by an aircraft in flight from
sources other than the engine, auxiliary power units, and machine accessories. Air-
frame noise or aircraft nonpropulsive noise sources, as illustrated in Figure 3-6,
thus include noise generated by airflow over the fuselage, wings, nacelles, flap
systems, landing gear struts, wheel wells, etc.
Measured and predicted aerodynamic approach noise data are presented in Figure
3-7. The trend of the points has a slightly greater slope than the FAR 36 minus 10
EPNdB curve, which indicates that the aerodynamic noise effect becomes more criti-
cal as gross weight is increased.
The most controlling parameters in aerodynamic noise generation are flap angle
and aircraft velocity. The turbulence and, therefore,, aerodynamic noise, varies with
flap angle but depends to a large extent on the flap design. The landing velocity change
results in a change in EPNdB proportional to velocity to the fourth power. This
3-14
-------
:..
I
,--
'
TRAILING VORTICIES FlSELAGE
AND WAKES
BOUNDARY LAYER
NOSE GEAR WHEEL
WELL AND DOORS
FLAPS, SLATS, ETC.
MAIN GEAR WHEEL
WELL AND DOORS
Figure 3-6. Aerodynamic Noise Sources
-------
120
CO
1
00
T3
Q.
UJ
Ui
5
z
Q
UJ
o
DC
UJ
Q.
UJ
no
100
90
20
"T ~r
A MEASURED C-5
T 1 1—T
CONVENTIONAL TRANSPORTS
(PREDICTED)
FAR 36
FAR 36 MINUS 10
I I I
T—i—ru
i
i i i
30
50
70 100 200
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
300
500
700
1000
Figure 3-7. Non-Engine Aerodynamic Noise Relative to FAR 36 Approach Noise Limits
-------
characteristic should be considered when appraising the effectiveness of alternative
approach and landing procedures. For example, in a decelerating approach the air-
craft would not only have low engine noise but would be clean, i. e., have low drag,
and therefore low aerodynamic noise until its final deceleration close to touchdown.
Just prior to touchdown the aerodynamic noise would be the same as for a constant
speed approach. However, during the final deceleration phase the aircraft would have
a high flap angle and higher than touchdown velocity and therefore higher than a con-
stant speed approach aerodynamic noise.
Decreasing engine noise to levels near or under the aerodynamic noise level would
have essentially no effect on further total aircraft noise reduction, unless the aero-
dynamic noise itself is reduced.
A program to understand and reduce the nonpropulsive noise is underway at NASA.
These studies will provide information relative to the identification and location of air-
frame noise sources; the manner in which noise varies as a function of angle of attack,
local air velocity, turbulence levels, separated flows, etc.; improved prediction
methods; and approaches to noise alleviation. A flight test program is planned to
better understand the relationship between aerodynamic noise and engine noise and the
different types of noise abatement approaches (the steep slope, the two-segment ap-
proach, the curved ground track, and decelerating approach).
Helicopter Rotors
It has been generally accepted (Ref. 3. 6-195) that for the turbine-powered rotary-
wing aircraft, sources of the most annoying sound, are:
1. Rotor blade slap
2. Tail rotor rotational noise
3. Main rotor broadband and rotational noise
4. Turbine engine noise
5. Transmission noise
Blade slap and rotor rotational noise are unique to the helicopter and will be briefly
discussed in the following paragraphs along with the potential means for reducing their
noise impact.
3-17
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Blade Slap
With its characteristic acoustic signature, blade slap can occur in many regimes
of flight. In high-speed forward flight, blade slap is usually due to the compressibility
phenomena occurring on the advancing blade of the helicopter rotor. Studies indicate
that in this case, the impulsive noise can be attributed to the rapid drag rise of the
advancing blade tip, coupled with Doppler effect. "Banging" in hover, and low-speed
regimes of flight, are probably caused by interaction of the tip or rolled-up vorticies
from the preceding blades with the oncoming blades.
Reduced tip speeds, which lessen the strength of the interacting trailing vortex
and reduce the blade tip Mach number, combined with special blade design character-
istics (e. g,, blade loadings and tip design), will tend to suppress blade slap. Increas-
ing the number of blades to provide the same lift capability at reduced rotor speeds
can also contribute to reduced noise.
Rotational Noise (main and tail rotors)
In a physical sense, rotational noise and blade slap have much in common. In
both cases, there is an element of interaction between wake vortices and the blade.
Thus, blade slap (in other than high-speed regimes of flight) may be considered as a
particular case of strong manifestation of that interaction. For this reason, many of
the means suggested for blade slap suppression, especially through modification of
the vortex structure and wake geometry (e.g., special blade tips, increase in the
number of blades) could also be beneficial for the reduction of rotational noise.
Reduction in rotor tip speed is the primary parameter in reducing helicopter noise.
However, in a pure helicopter configuration, a key determinant of the forward flight
speed capability of the vehicle is the rotor tip speed. Generally, higher flight speeds
are associated with higher tip speeds. This establishes a tradeoff between noise
reduction and helicopter performance and economics.
However, if the rotor is not required to provide forward flight capability (as in a
compound helicopter configuration), the tip speed for optimum hovering flight tends to
be lower, and therefore more compatible with reduced noise.
3-18
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ENGINE TECHNOLOGY
In Section 2, engine source noise was discussed in the context of available near
term options for reducing the noise of current engines and aircraft.
The longer range goal is to reduce the FAR 36 noise limits by 5 to 10 EPNdB.
This can be most efficiently accomplished by source noise control in new engines by
dedicated attention to this requirement when the inital designs are laid down.
The basic technology that would permit the development of advanced engines and
aircraft, with noise levels approximately 10 dB below the FAR 36 standard has been
demonstrated, as pointed out earlier in the discussion of the NASA Quiet Engine Pro-
gram. Unfortunately no engine development program which could apply the lessons
learned in the NASA program to an operationally viable system has resulted from
this activity. While it may be interesting or comforting, from a purely R&D perspec-
tive, to have demonstrated the capability for lower noise, unless this technology
results in a practical application, the expenditure of time and money is worthless.
The Air Force Advanced Turbofan Engine (ATE) development program could be
the catalyst that would utilize the demonstrated technology of the NASA Quiet Engine
Program. Such an engine development program would provide, as it has in the past,
the basis for a new, quieter engine for the next generation of commercial aircraft.
Figures 3-8 and -9 indicate the variations in noise levels for comparable mili-
tary and commercial aircraft utilizing similar technology propulsion systems. It is
apparent that significant noise reductions can be achieved in the commercial deriva-
tives, where they are not constrained by the tactical performance requirements
associated with a military application. Commercial derivatives of the ATE would
conceivably provide similar noise reduction potential.
Since the propulsion system development generally represents the longest lead
time requirement in a new aircraft program, any delay in the development of advanced
propulsion technology will impact on the eventual operational availability of new,
advanced aircraft systems. Figure 3-10 illustrates a typical engine development
cycle. If new quiet aircraft are to be operational in the fleet by 1980, an advanced
quiet engine development program must be initiated no later than late 1973 or early
1974. On the other hand, a quiet STOL engine technology program is only just being
initiated. The technology (as stated earlier) is not yet in hand and a 3-year experimental
3-19
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130
U
i '-•
:
DO
_
a
in
•
Ui
,n
Q
in
i •
Q
ill
i
U i
120
110
100
90
80
(1) WITH SAM
(2) REPRESENTATIVE
4 ENGINE MILITARY
CTOL AIRCRAFT
(W/O SAM)
FAR 36 MINUS 10
C5A
20
!G
POTENTIAL
COMMERCIAL
APPLICATION
(WITH SAM)
I I
50 70 100 200 300
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
500
700
1000
Figure 3-8. Military/Commercial Transport Noise Levels - Takeoff
-------
I
Q
i
.
'
1) WITH SAM
REPRESENTATIVE
4 ENGINE MILITARY
CTOL AIRCRAFT
(W/0 SAM)
POSSIBLE
AERODYNAMIC
NOISE FLOOR
(SEE FIG. 3-7)
FAR 36 MINUS 10
POTENTIAL
COMMERCIAL
APPLICATION
(WITH SAM)
30
D
70 100 200
MAXIMUM AIRCRAFT WEIGHT, 1000 LBS.
300
500
700
1000
Figure 3-9. Military/Commercial Transport Noise Levels - Approach
-------
1985
1980
YEARS
TO
OPERATIONAL
STATUS 12
10 8
A A-
-A A
ENGINE
DEMONSTRATOR
PROGRAM
INITIATE
COMPONENT
TESTING
A A A
FIRST
FLIGHT
OPERATIONAL
INITIATE
DEVELOPMENT
CERTIFI-
CATION
EXPLORATORY
DEVELOPMENT
TECHNOLOGY
BUILDING
BLOCKS
ADVANCED
DEVELOP-
MENT
ENGINEERING
DEVELOPMENT
PRODUCTION
Figure 3-10. Engine Development Cycle
3-22
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(demonstration) program is being pursued by NASA (see following Section on STOL
engines). It is not likely that an advanced technology quiet STOL turbofan engine
program can become fully operational before 1983.
The following discussion presents some of the new engine options and their cur-
rent status.
AIR CARRIER CTOL ENGINES
Industry and Government projections indicate that new, modern technology engine
types are needed to power next generation CTOL (conventional takeoff and landing)
long haul and intermediate range transport aircraft by the end of this decade. Previous
testimony by industry and Government at special aeronautics hearings of the Subcom-
mittee on Advanced Research and Technology, House of Representatives committee on
Science and Astronautics, in January 1972 indicated that some kind of government
support and encouragement is needed for the development of one or more new engine
types within the current "thrust gap" between about 10,000 and 40,000 pound thrust,
particularly around the 25,000 pound thrust level.
Both General Electric and Pratt and Whitney have indicated that engines in this
class could be available by 1978. The CFM 56 (GE) and the JT10D (P&W) engines
when packaged in optimally designed and treated nacelles, would produce noise signa-
tures compatible with the FAR 36 minus 5-10 EPNdB objective. These designs are
based on demonstrated hardware developments. The CFM 56 core gas generator
utilizes the technology incorporated in the B-l engine, which is under development for
the Air Force. The fan component reflects the results of the NASA Quiet Engine test
program and the CF-6 program. The P&W JT10D draws on the technology developed
for the JT9D engine.
STOL ENGINES
The Quiet, Clean Short-Haul Experimental Engine (QCSEE) Program is a major
element in NASA's quiet powered-lift propulsive technology program. It is being under
taken to establish the technology base for very quiet propulsion systems, designed for
installation in powered-lift STOL aircraft. As discussed earlier, the blown flap, powe
lift concept will probably require a very high bypass ratio power plant in order to mini
mize the flap interaction noise, as well as providing adequate flow for increased lift.
3-23
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The.prop-fan, (Figure 3-11) developed by the Hamilton Standard Division of
the United Aircraft Corporation, provides one method for developing this capability.
The prop-fan is basically a very high-bypass, low-tip speed fan that can be matched
to existing core engines to provide the propulsive requirements (thrust, bypass ratio,
etc.) of any subsonic aircraft type. The engine thus conceived will have characteris-
tically low noise levels due primarily to the high-bypass ratios possible (BPR of 15-30)
and the low fan tip speeds (600 to 800 feet per second).
Prop-fan engines have been included as part of the initial QCSEE preliminary
design studies. The QCSEE program is not directed towards the development of an
engine for flight and the experimental engine .resulting from QCSEE will not be flown.
The QCSEE program provides for close cooperation and coordination with the Air
Force in their development of the Advanced Turbofan Engine (ATE) demonstrator.
The possibility exists for the core gas generator of the ATE to be compatible with both
the military requirement as well as for the more stringent potential commercial STOL
application.
VTOL ENGINES
For nonrotary wing high speed VTOL aircraft, the propulsion system concepts
vary from lift fans (as demonstrated in the Army XV-5 program), deflected thrust
engines (as in the Marine Harrier aircraft), to direct lift turbo jets or turbofans (the
German DO-31).
For commercial applications, the only serious studies to date have been developed
utilizing lift fan systems. Demonstration flights of the DO-3.1 yielded a noise level of
135 EPNdB at 500 feet. Harrier noise levels are reported as 120 PNdB at 500 feet.
Recent studies by Rockwell International, McDonnell, and Boeing indicated that
in the 1980 to 85 time period a 100,000 pound gross weight, 100 passenger VTOL trans-
port powered by advanced technology engines and lift fans would be able to meet a
95 EPNdB criterion at 500 feet. Using existing engines and current lift fan technology,
a research aircraft could be built by 1978 that would develop a noise level of approxi-
mately 99 EPNdB's at 500 feet.
3-24
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-
(
Figure 3-11. Quiet Fan Propulsive System
-------
GENERAL AVIATION ENGINES
There are several new engine, as well as new engine concept, programs currently
in development which could find future homes in the high performance business air-
craft or helicopter market.
Turbofan Engines
• Garrett ATF 3 at 5000 pounds of thrust is in development for the Air Force.
Military qualification is scheduled for the 1974 time period. Commercial
availability would follow, if there is a market. The noise levels of this
engine would meet the current FAR 36 standard.
• TURBOMECA Astafan IV is a French developed fan engine of 2250 pounds
thrust with a bypass ratio of approximately 8.0. Initial engine tests took
place in June of 71. Estimated noise levels are well within the FAR 36
requirement.
• TURBOMECA LARZAC at about 3000 pounds thrust is a low-bypass, low
pressure ratio fan engine. Studies of the engine in a small (13,500 pound
gross weight) business jet indicated noise levels well below the requirements
of FAR 36. U.S. license for the engine is held by Teledyne CAE.
• Teledyne - CAE participation in the Air Force ATEGG (Advan?ed Turbine
Engine Gas Generator) program has provided a core gas generator that, when
matched with an appropriate fan, could lead to an engine in the 3000-5C-00
pound thrust class. A certificated fan engine could be available in the 1978-80
time period.
Rotary Engines
Curtiss Wright has been exploring the potential of the Wankel-type rotary engine
for light aircraft and helicopter applications. The benefits claimed for this engine are
low noise and emissions as well as better maintainability and reduced weight, particu-
larly when compared with the reciprocating engine. Flight tests of the engine in both
fixed wing and helicopter installations have been initiated.
3-26
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Prop-fan Engines
The characteristics of the prop-fan concept discussed earlier are equally appli-
cable to the light aircraft market where the fan can be matched to the power output
of the reciprocating engine. Small turboshaft engines and the rotary-type engine
discussed above are also core engine possibilities for the prop-fan concept.
SST ENGINES
The cancellation of the U. S. development of a commercial supersonic transport
was due to several factors, only one of which was the high noise levels to be expected.
The basic design parameters of the Concorde SST, which will be entering revenue
service in 1975, were essentially frozen in the mid-1960's, prior to the need for noise
certification of new aircraft. Even then, noise control was of significant concern to
the manufacturers. The noise levels of the Concorde, at its service entry date, will
be comparable to the contemporary straight jet and low-bypass, long range, subsonic
aircraft. It is technologically infeasible to reduce the noise levels of the Concorde to
meet the current FAR 36 Appendix C requirement.
A variety of engine cycles can be considered for possible future supersonic trans-
port aircraft. However, the jet exhaust velocities tend to be considerably
higher than those for subsonic aircraft. As a consequence, the jet noise for these
engines, being a primary function of jet velocity, is much louder than for those used
in subsonic CTOL aircraft. Although the fan for supersonic aircraft engines generally
operates at low-bypass ratios and high pressure ratios with resultant high noise, the
unsuppressed jet due to its high velocity is the dominant noise source. There is,
therefore, a need to suppress jet noise in order to render supersonic transport air-
craft acceptable to the community. As the jet noise is suppressed, the fan noise and
core (internal) noise may become dominant. Noise attenuation means for these noise
sources are similar to those applied to the current subsonic engines.
The use of variable-cycle engines has been proposed in order to help reduce the
jet noise. NASA has contracted with the General Electric Company and Pratt and
Whitney to perform analyses of propulsion systems suitable for a second-generation
supersonic transport aircraft. A major goal of the work is to examine systems that
can meet severe noise constraints, not only those of today but the possibly more
stringent ones of the future. The engine contracts are coordinated with more general
3-27
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studies of the complete airplane design being performed by the Boeing, Lockheed, and
Douglas airplane companies under contract to Langley Research Center. The Langley
contracts will study the technology problems and design tradeoffs for the integrated
airframe/engine combination, including such operational constraints as engine noise
limits.
The overall objective of the Advanced Supersonic Technology program is to provide
an expanded supersonic technology base in the technical areas critical to:
1. Future advanced military supersonic cruise aircraft.
2. Assessment of the impact of present and future foreign civil supersonic aircraft.
3. Future consideration for an environmentally acceptable and economically viable
supersonic transport.
3-28
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SECTION 4
COST & ECONOMIC ANALYSIS
In recent years, the public's tolerance to aircraft and airport noise has diminished,
giving rise to widespread complaints and in some cases legal action. Some recent
court decisions possibly have exposed airports to legal liability. If the present noise
levels continue, public opinion and concerted action will continue to limit new airport
development, extension of existing facilities, commercial flight frequencies, arrival
and departure time windows, aircraft types, and runway choices. The effects of such
action may seriously impair the financial stability of the airline and aerospace indus-
tries.
The general economic question addressed is which combinations of noise impact
reduction options are the most economically efficient for achieving various levels of
cumulative noise exposure? Of corollary interest is the determination of the financial
implications to the affected institutions if no national airport noise reduction program
is undertaken.
The set of options of interest in this report are those which reduce source noise;
consequently, the issue to be resolved is what economically efficient role can source
noise reduction options play in reducing the noise environment around the nation's
airports.
The implications and costs associated with some expected legal and administra-
tive actions that might occur if no coordinated federal airport noise reduction program
is forthcoming are initially analysed. Subsequently, the financial consequences of
achieving several levels of cumulative noise around airports are then developed,
aasuming no source reduction options are utilized. Using these data, the economic
implications of utilizing source noise reduction options are then projected. * Finally,
a qualitative sensitivity analysis of the results is undertaken, primarily in recognition
These investigations are on a cost-effectiveness and not a cost benefits basis. This
situation is primarily due to the fact that although the benefits of the air transportation
system are known and dollar estimates exist, reliable data on the benefits of noise
reduction to the public are not available.
4-1
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of the fact that the data used herein will most likely become obsolete subsequent to
the release of this study. Accordingly, the data presented here should be viewed as
only providing a relative measure of the costs and effectiveness associated with the
options investigated.
Each of the current technology source treatment options discussed in previous
sections can be combined to offer a number of basic strategies. Some of the types of
strategic alternatives investigated are discussed in the subsequent text. The first
and perhaps least expensive basic approach, although they are not source options, is
to change aircraft operating procedures. ** At the other end of the expense and schedule
spectrum is replacement of the existing narrow body fleet with new aircraft employing
advanced jet aircraft noise reduction technology. Adoption of the latter approach
would provide markedly quieter aircraft beginning in the early 1980's. The forced
obsolescence of the then existing narrow bodied fleet would produce significant airline
industry writeoffs on the order of billions, equipment certificate payment default
problems, and additional billions of dollars in outlays for new aircraft.
Modification of the engines in existing narrow bodied aircraft with advanced noise
•i
technology engines (refan) could possibly be accomplished earlier. Both the write-
off and the new outlay requirements should be relatively less and performance gains
might further offset some of the cost.
Another approach is to provide new modified low noise nacelles, including engine
treatment, for the existing narrow bodied fleet. This approach provides relatively
early noise reduction opportunities at relatively low write-off and new outlay require-
ments.
THE NULL CASE
The null case condition assumes that no source abatement options are utilized.
Several situations and their contribution towards alleviating the airport noise environ-
ment will be examined under this condition. These situations are;
1. The courts adopting a policy of allowing a recovery of noise damages by
any person exposed to high noise environments.
**The costs and effectiveness of these options are discussed in Ref. 10.4-426.
4-2
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2. The adoption of a national night-time curfew.
3. Increasing the use of capacity limitation agreements between airlines.
4. Implementing land use and receiver treatment alternatives.
In this section, the viewpoint is adopted that although airports are an essential
part of the community they serve, and its economic environment, the benefits to the
community largely represent redistribution of economic activity rather than the crea-
tion of new activity (8.5-103). As such, regional transfers balance out at the national
level; consequently, the regional impacts of each situation will not be examined. This
is not to say that the regional impacts are insignificant, rather the impacts can be
examined on a national level.
The interest group relationships that the subsequent analysis uses as a frame of
reference are such that ultimately, the consumer of transportation services will pay,
either directly or indirectly, for the cost of resolving the aircraft/airport/community
noise environment conflict problem. More specifically, the public affected by high
noise levels around airports is the primary interest group whose actions are demand-
ing a solution to the aircraft/airport noise problem. The litigation this group has
initiated, their demands for curfews and quotas and their denial of local funding author-
ity at the voting booths all translate into increased costs of delivering the transporta-
tion services of the air mode to a community. In the free enterprise pricing system,
one of the interest groups must pay these increased costs how these costs are
passed on will be discussed in the subsequent text.
Litigation awards are costs initially incurred by the airport operators. Depending
on the operator's contractual arrangements with the airlines, the operators will
attempt to pass these costs on to its customers, the airlines, as soon as possible.
Regardless of these contractual arrangements, there will be a lag between the time
when the operator must pay out the awards and when the operators can recover the
amount of the awards. It should further be recognized that although awards for dam-
ages are made, this does not preclude the operator instituting curfews, quotas, etc.,
in an attempt to defer future litigation or in response to political pressure, the estab-
lishment of noise exposure standards, etc.
4-3
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Not only are litigation costs ultimately passed on to the airlines, when the lease
arrangement permits, but the airlines also incur costs associated with the curfews,
etc. The costs of delays, diversions, and cancellations which result from curfews,
quotas and aircraft type restrictions are directly incurred by the airlines. Off-setting
these costs would be a commensurate increase in passengers carried per trip result-
ing from carrying the same volume of customers over a shorter daily operating time;
span. In other words, assuming a constant demand level, airport operator initiated
schemes to reduce the airport/community noise problem can result in increased
profits and productivity of airline activity which are, in turn, offset by costs of delays,
diversions, etc.
Within this action/reaction loop the CAB is the determining body as to whether,
and when, litigation and these other costs are passed on to the users. Again, there
is a perceived time lag between the incurrance of costs and when such costs can be
recouped. The CAB in allowing tariff adjustments to pass on the described costs will
have taken an action which can theoretically affect user demand for air transportation
services. That is, by passing along the increased costs of operator actions to the
users, the demand for transportation services will be affected. Such a result tends
to have a negative effect on airline profits and productivity.
As superficially discussed, the action/reaction relationships began with the
impacted public's legal and/or political reactions to high noise exposures. Such action
in turn stimulates airport operators to take administrative actions which affect air-
line economics. Given such effects the CAB can agree to tariff adjustments which
allow the airlines to defray such increased cost. These tariff adjustments can theo-
retically affect the demand for air travel services. Now, if the public does not perceive
a significant change in the noise environment/ they could, in turn initiate additional
actions which again trigger the reaction chain. As described, this reaction chain is
degenerate or self defeating in that only solutions to local airport/community noise
problems may result, i. e. there is no national solution. The net result is the alloca-
tion of resources in an inefficient manner (e. g., resources to satisfy a particular
community as opposed to those necessary to effect a national solution.
It should be expected that the impacted public will increasingly attempt to take
actions resulting in increasing costs of delivering air transport services. One should
also note that the longer the time between tariff adjustments via CAB actions, the
4-4
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greater will be the pressure on the industry's cash flow. It is conceivable that this
pressure will result in further disrupting the delivery of services (e. g., via insuffi-
cient operating funds or curtailment of credit lines, where such a situation can lead
to curtailment of flights, cancellations, etc., which in turn affects the competitive
positions of the airlines as a function of route structure). Therefore, the speed with
which costs are passed on is seen to be a key factor in assessing the feasibility of
implementing any noise reduction alternative. In the following section, estimates of
the magnitudes of costs of the various public and locally legislated actions are
developed.
The Cost of a Judicial Alternative*
One incentive to lower noise around airports is the threat of a lawsuit against an
airport and an adverse judgment. The policy of allowing a recovery of noise damages
by any person exposed to high noise annoyance, if it were to prevail in the courts,
would have an economic impact that would depend on when the policy prevailed and
what noise abatement policies were in effect at the time. Actions brought to date
have had only limited success and awards have usually been small lump sums when
awarded. Additional damages in such cases are only awarded if noise levels sub-
stantially increase. Therefore, the same amount of noise can continue indefinitely
once compensation has been paid. Obviously, there is no incentive to decrease noise
levels after compensation.
Compensation payments, then, will not solve the noise environment problem;
furthermore, with the setting of public health and welfare criteria, additional actions
may have to be taken to protect the public. This suggests that litigation costs are
only one element of a total cost to achieve *a cumulative noise environment. In addi-
tion, dollars for this element are absorbed locally and divert resources from a national
solution.
The measure of damages normally is based upon the difference between the
property value before and after the high noise levels began. Traditionally, the amount
of the damages is ascertained by the use of expert appraisers, with the court often
*In this section only lawsuits against airports are considered. Condemnation proceed-
ings by airports against real estate holders to create clear zones are not discussed.
The magnitudes of money involved can also run in the hundred of millions.
4-5
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splitting the difference or using average values of the evidence introduced. Recently,
however, there have been instances of the courts at least considering technical data.
In a recent case the Federal Court for the District of Connecticut used a geometric
formula derived from an article in the Appraisal Journal (10.4-271).
A California court has gone so far as to consider the Noise Exposure Forecast
value for the property in question. Although the amount of the award was not based on
the actual NEF exposure, the Court did use the concept to identify which pieces of
property were eligible to plead for recovery (10.4-425). In light of these instances
it is not unreasonable to anticipate the courts at some future date basing damages on
a formula similar in concept to that used in this latter case.
Extending this rationale to past court award history which, incidentally, has only
occurred in exposure contours of 40 NEF and above, the formula used to calculate
potential damage is $53 per person per unit change in NEF value. *
Using the demographic data developed by Task Group 3 efforts, Figure 4-1 was
developed. Shown in this figure is the estimated national 1972 population within each
NEF contour generated by aircraft/airport activity. No attempt will be made to fore-
cast population changes with time for this distribution. Since the award history is
relevant for levels of 40 NEF and above, only those people currently exposed to such
levels appear to have the best chance of successful suit. Based on the national popula-
tion by noise exposure level, it is estimated that there are some 1.5 million people
exposed to such levels. If one assumes a perfect information transfer to this popula-
tion, it is reasonable to expect that the total population within such contours will seek
legal relief. Assuming further that each person receives legal relief, then the level
of potential damage awards in 1973 dollars, is calculated to be approximately 300
million dollars. Court costs should also be added to this potential damage estimate.
It should be recognized that this estimate is based on past court proceedings.
Where public health and welfare noise exposure standards as established by the EPA,
an entirely new dimension of litigation approaches could envolve and result in even
more litigation awards. Since the incidence of this type of litigation is by airport, it
then follows that those airports with the most severe noise problems face the highest
potential legal costs and social and political pressures.
*This number was developed by dividing the national average of people per household
(3.8) into the historical average of court awards per unit change in NEF (10.4-271).
4-6
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CUMULATIVE NOISE EXPOSURE, NEF.
30
35
50
.•
'
20
-;
u
B
:
; •
a
LL
)
-'-•
10
g
QL
i r
I I
CUMULATIVE
NOISE
EXPOSURE
Ldn
60
65
70
75
80
81
ESTIMATED
EXPOSED
POPULATION
X10-6
16.0
7.5
3.4
1.5
0.2
0.0
70 75
CUMULATIVE NOISE EXPOSURE, Ldn.
i'.!
Figure 4-1. Estimated Number of People Impacted
by Aircraft Noise-1972 Baseline
-------
If an aggressive, national airport environmental noise abatement policy is followed,
there is less chance that the courts will liberalize awards. If any awards are granted,
they will be relatively small. If abatement policies are not pursued, it is more likely
that the courts will act, that they will act sooner, and that there will be correspond-
ingly higher damage awards. This is just one basis, i. e., the avoidance of perceived
potential damage costs, on which the relative attractiveness of other strategy alterna-
tives could be determined.
The Cost of a National 10 P. M. -7 A. M. Curfew
Faced with such magnitudes of potential damage awards, it is possible that if a
source noise reduction program is not adopted on a Federal level, airport operators
will take independent action to avoid and/or reduce the amounts of potential damage
awards. One of the most dramatic actions that can be taken is the imposition of a
night-time curfew. As soon as it is apparent that no Federal program will be under-
taken, it is assumed that the operators will undertake independent actions resulting
in a national curfew and maintain it until effective noise reduction alternatives become
available. * The assumption is made that the curfew will be instituted in 1974 and
maintained until at least 1980 when quieter aircraft could become available. Because
there is little factual data available on the costs of curfews, the implications of this
policy alternative requires more detailed analysis than the preceding alternatives to
develop at least a minimum cost impact estimate and a perspective as to whether
public convenience will be adversely affected.
The impact of a curfew can be broken down into the following areas:
• Impact on passenger service
• Impact on air cargo service
• Impact on mail and express
• Impact on maintenance and repair activities
• Impact on international operations
*Underlying this assumption are the further ones that the operators of the airports are
the owners such that the Burbank ruling is satisfied and also that the FAA allows such
actions to occur. Further details on the Burbank ruling may be found in Ref. 10.4-425.
4-8
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Actually, there are some airports where no curfew would be needed or where
less restrictive limits could be imposed. The transfer of some maintenance and
freight operations to these airports would lessen the economic loss to an area, if, and
only if, the noise exposure at these airports does not increase as a result of the acti-
vity transfers. The detailed-analysis of the costs incurred by category may be found
in an annex at the end of this chapter. (See Page 4-59)
The Noise Reduction Effectiveness of a Curfew
Most techniques for measuring the cumulative effects of aircraft operations over
time place a heavier annoyance weighting on nighttime operations than those during
the day. The Cumulative Noise Forecast method considers a flight between 10 p. m.
and 7 a. m. to be as intrusive as would a higher multiple of daytime flights. As a
result, the elimination of these heavily weighted night operations through the imposi-
tion of a curfew yields a dramatic reduction in L, levels with a corresponding de-
crease in the land area within any given L, contour.
Applying the mathematics of L^ construction to the assumptions used in deter-
mining curfew costs (i. e., 15 percent of the present total operations occur during the
proposed curfew period, 1/3 of the cancelled flights could be shifted to non-curfew
hours and 1/3 could be rescheduled with new aircraft), calculations show that a 10 p.m.
to 7 a. m. curfew would result in a 5 to 6-dB reduction, which in turn would reduce
the land area exposed to any L, level by approximately 60 percent. Since the assump-
tion that 15 percent of the present total operations occur during the curfew period is
based on national statistics, a further verification of this estimate was made. The
weighted average percentage of night time operations at twelve of the nation's most
active and noise impacted airports was found to be 11 percent. Using L, mathemat-
ics, a curfew implementation at these airports would result in an average 3 dB environ-
mental noise reduction at each airport which in turn would reduce the land areas
exposed to any L, level by approximately 35 percent (10.4-441). Such impacted area
reductions are significant and it follows that if such a curfew were implemented,
potential damage costs would then be reduced proportionally. This reduction would
be in addition to any other noise abatement technique employed and would
be based on the total land area exposed at the time of the curfew's implementation.
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Summary of Curfew Costs and Institutional Effects
The curfew investigation found that a national curfew implementation would affect
maintenance, mail and express, air cargo and passenger operations. The major
impacts on the national airline system are the costs associated with the additional
delay times. Airline operating costs can also be affected through the purchase of
additional aircraft, and the hiring of crews to fly them, so as to make up the capacity
lost by the inability to move or pre-position aircraft at night. The effects on cargo,
assuming the shippers can adjust their schedules, are the relatively small loss of
business. The effects on mail and express may be such that public convenience would
be affected if the peak volume periods for mail processing cannot be shifted to meet
the departure and delivery requirements of a national curfew. A summary of the
estimated curfew induced costs are shown in Table 4-1. Finally, by implementing
a national curfew, the airport operators are able to avoid a significant portion of the
estimated potential damage awards and the costs required to protect public health and
welfare once such standards are promulgated.
In retrospect, it does not appear that litigation awards will provide sufficient
market incentive to trigger a national curfew. This follows from the very low success
rate to date in such litigation. The real incentive to implement curfews will stem
from the execution of the Noise Control Act provisions and the share of land use costs
that airport operators must incur if no source abatement technology is transferred to
the active civil fleet.
Capacity Limitation Agreements
In recent years, the CAB has approved several agreements between airlines
competing on the same route whereby each airline reduces its flight frequency along
the subject route. Under such agreements the amount of equipment necessary to
service the route and its user volume is less, as are the airlines' costs. The finan-
cial results of these agreements have been dramatic in that significantly higher profits
have been realized, by each participating airline, relative to the same user traffic
levels which existed before the agreements.
Understandably, the question then arises as to what extent can the frequency of
flights within the national network be reduced so as to provide some national noise
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TABLE 4-1. SUMMARY OF CURFEW COSTS
MILLIONS OF 1973 DOLLARS
YEAR
1974
1975
1976
1977
1978
1979
1980
DELAY
TIMES
(000 MINUTES)
5139.8
5353.4
5567.4
5781.2
5995.1
6208.9
6422.7
TOTALS
AIRLINE OPS.
COST INCREASE
(1)
7.30
7.83
8.40
9.06
9.73
10.54
11.37
64.23
AIRLINE LOST
CARGO REVS.
(2)
3.77
4.13
4.51
4.92
5.37
5.87
6.22
34.79
AIRLINE
DELAY COSTS
(3)
39.06
40.68
42.31
43.93
45.56
47.18
48.81
307.53
USER
DELAY COSTS
(4)
36.06
37.56
39.06
40.56
42.06
43.56
45.06
283.92
TOTAL
(5)
86.19
90.20
94.28
98.47
102.72
107.45
111.46
690.77
SOURCE: REF 8.4-182
4-11
-------
relief around airports ? The answer to this question is little or none at all! This
follows from the apparent industry viewpoint of a conservative system in operation. *
Given a national level of capacity, then if less capacity is carrying more users in one
portion of the system, the remaining capacity can be re-allocated among the other
routes. Therefore, if the same frequency of flights to maintain this capacity occurs,
then the national noise problem is not changed significantly. What may change are the
levels around some airports where some might decline while at others, receiving
greater numbers of flights, the levels may increase.
Where such agreements may be of utility to the airlines is in offsetting the 5 per-
cent additional capacity requirement created by the implementation of a nation curfew.
If this could be offset, then the operating costs shown in column (1) of Table 4-1 may
be avoided by the airlines. There would also be some reduction in this industry's
demand for fuel. To date, there are not sufficient data to analyze this possibility.
Implementation of Land Use and Receiver Treatment Alternatives
Only one of the legal and administrative response areas (i. e., a national curfew)
so far investigated will result in a reduction of the general noise environment around
the nation's airports. ** Given the promulgation and enforcement of a national noise
exposure standard, and the situation where no source abatement technology is trans-
ferred to the exposure civil aviation fleet, the only completely effective alternatives
to public protection are noise compatible land use control options. ***
The responsibility for exercising land use control options are shared by the air-
port operators and the Federal, State and local governments depending upon the size
*This is the essence of competing airline responses in CAB hearings, where the
assertions are made that excess capacity taken off one route is dumped on another.
**It is acknowledged that aircraft operational procedures, when implemented, will
reduce the NEF contours and the amount of population exposed to aircraft activity
generated high noise environments. However, these procedures will not completely
protect the nationally impacted public. It is in this sense that the term completely
effective is used.
***In setting the noise exposure standard, it has been assumed that technological
practicability, safety and economic reasonableness relative to all of the options
available to achieve the desired levels, have been considered. Thus the discussion
here is in the context that land use and receiver treatment options are feasible under
the considerations discussed.
4-12
-------
of the noise impacted areas and the political jurisdictions that control its welfare.
Implementation of this type of alternative can require the removal of population from
areas of noise exposure greater than the public health standard, the noise reduction
treatment of private and public structures in the areas where noise affects public
welfare, and the denial via zoning restrictions of any current and future land use
developments that are not compatible with the noise environment.
New airport development shall be assumed to occur only if noise compatible land
uses occur concurrently. For airports already in existence, the costs of zoning
restrictions precluding already planned development will not be estimated. The esti-
mate to be developed is the cost of protecting people in areas where the noise environ-
ment exceeds the public health and welfare standards. The type of protection employed
must result in an environment that is not in violation of these standards.
The Unit Cost Curves
The Task Group 3 report (10.4-427) indicates that persons exposed to exterior
cumulative noise levels (L, ) of 80 dB or above are exposed to a significant risk of a
decrease in hearing acuity. Persons exposed to exterior L, levels of 75 through 80
dB are subject to extreme annoyance from the intrusion of noise and the effects such
intrusion has on their daily activities. The degree of annoyance decreases with cor-
responding decreases in L, . An exterior L, of 60 dB is apparently the threshold
where activity interruption is not significant enough to generate substantial numbers
of complaints.
Using these levels as a guideline, the rule of public protection employed in the
cost calculations is that every person exposed to L = 60 dB or greater must be
dn
protected. Actions taken to reduce a person's environment to this level, or less,
range from relocation to insulating structures.
For levels of L, of 80 dB or greater, no structures treatment technologies are
feasible (12.2-291). The only feasible land use alternative is the conversion of the
existing land uses to those which are noise compatible. In a study for the Aviation
Advisory Commission (Reference 7.1-99) just such an estimate was developed for the
costs of converting incompatible land uses within L, = 80 dB around 11 airports.
The estimate, developed in 1972 dollars, was $16,000 per person relocated. The
4-13
-------
cost consisted of acquiring all incompatible land uses, relocating the people at no
expense to them, razing the structures and packaging the land into noise compatible
land use parcels. Consequently, most of the infrastructure costs of neighborhoods
were captured in this effort. There are, however, several shortcomings in using
this estimate. First, the 80 L, contours under which this estimate was developed
were for the year 1985. The current 80 L, contours are larger and contain more
people and incompatible land uses. Secondly, no allowance was made in the develop-
ment of this estimate for the recovery of the conversion investment. This was primar-
ily due to the lack of information on the timing and sales rates that could reasonably
be expected. Assuming that the same infrastructure relationships more or less obtain,
then although larger land areas are currently involved the conversion costs per person
will remain relatively stable. Making an allowance for investment recovery, it is
assumed that 50 percent of the property acquisition costs (1/3 of the total conversion
costs) can be recovered during the time period of interest. These assumptions result
in a 1973 dollar estimate of $10,000 per person relocated and will be used in this
analysis.
For levels of L, less than 80 dB there exist structure treatment technologies
which, if implemented, will insure that noise intrusion will not affect the daily activi-
ties of the public inside the treated structures (12.2-291). It should be noted that
implementating structure treatment technologies makes no provisions for the effect of
noise on the outdoor environment, i. e., it requires the impacted public to remain
inside acoustically treated homes to avoid the annoyance caused by aircraft operations.
Consequently, estimates developed from the structure technologies approach are con-
servative in the welfare sense that all public activities should not be affected by noise
intrusion. The average treatment cost utilized has been put on a per capita basis to
facilitate computations. In 1973 dollars the levels per person used were $2500 per
person for 13-17 dB reductions, $1400 per person for 8 to 12 dB reductions and $500
per person for 3 to 7 dB reductions.
Using the data presented above, the lower curve shown in Figure 4-2 has been
constructed. It represents the minimum land use and receiver treatment costs per
person per unit (dB) of cumulative noise exposure. Use of this curve does not allow
for public choice, when it is applicable, of having one's structure soundproofed or
4-14
-------
HUD ACCEPTABILITY CATEGORIES
hi
CLEARLY
ACCEPTABLE
•^ to.
NORMALLY
ACCEPTABLE
« to.
NORMALLY
UNACCEPTABLE
•« to.
CLEARLY
UNACCEPTABLE
to.
' •>
«
I
':
O M
o o>
3<-t-
S
T3 3
- w
en c*
CUMULATIVE NOISE EXPOSURE, NEF
QC DC
O UJ
LL 9
EXTREME
ANNOYANCE _
•
Ldn
60
65
70
75
80
UNIT COST
1000$
PER PERSON
MAX
0
1.0
2.5
5.0
10.0
MIN
0
0.5
1.4
2.5
10.0
65 70 75
CUMULATIVE NOISE EXPOSURE, Ldn
-------
choosing to leave the high noise environment at no cost. * The upper curve has been
developed to present a more probable outcome of having the public choose its protec-
tion techniques. Its construction assumed that all persons severely annoyed in the
population exposed to L, levels of 75-80 dB would choose to relocate at a cost of
on
$10,000, the rest of the exposed population will choose to remain in the area and have
their dwellings soundproofed. Between the L, range of 65-75 dB only one half of the
annoyed population will choose to relocate. Finally, at L, =30 dB, none of the people
annoyed will choose to relocate. Included on this figure are the HUD acceptability
categories. A fuller explanation of these may be found in Table 4-2.
Baseline Land Use and Receiver Treatment Costs
Supplied with a set of unit cost curves, the estimated national distribution of pop-
ulation exposed to various levels of noise in 1972, and the percentages of exposed
populations that are annoyed, ** one can develop a national estimate of the costs to
protect the public from noise pollution using only land use and receiver treatment
options. Exercising these data, the total cost of this option is estimated to be in the
range of 21 to 31.5 billions of 1973 dollars. How these costs cumulate by cumulative
exposure level are shown in Figure 4-3.
Summary of the Null Findings and Implications
Several possible implications of a strategy of not implementing source noise
reduction technologies have been examined. It has been estimated that potential liti-
gation awards could total $300 million 1973 dollars. However, the realization of such
an award level would require some fundamental changes in the law currently utilized
in such litigation. As this likelihood is small, then the expected actual awards should
also be small. In addition, the incidence of such awards first falls on the airport
operator who may or may not be able to pass these costs on to the airlines. The
*It should be noted that not all persons exposed to high noise environments are annoyed.
In general, the higher the noise environment, the greater will be the percentage of
exposed population annoyed. For a complete discussion see the report of Task Group
3 (10. 4-427).
**See summary table in section 4-G of the Task Group 3 Report. (Ref. 10.4-427)
4-16
-------
TABLE 4-2. HUD ACCEPTABILITY CATEGORIES FOR PROPOSED
HOUSING SITES
Clearly Acceptable:
Normally Acceptable:
Normally Unacceptable:
Clearly Unacceptable:
i
the noise exposure is such that both the indoor and
outdoor environments are pleasant.
the noise exposure is great enough to be of some
concern but common building construction will
make the indoor environment acceptable, even for
sleeping quarters, and the outdoor environment
will be reasonably pleasant for recreation and play.
the noise exposure is significantly more severe so
that unusual and costly building constructions are
necessary to ensure some tranquility indoors, and
barriers must be erected between the site and
prominent noise sources to make the outdoor
environment tolerable.
the noise exposure at the site is so severe that the
construction costs to make the indoor environ-
ment acceptable would be prohibitive and the
outdoor environment would stilt be intolerable.
4-17
-------
C
LU
CO
35
30
§ 20
15
-
80
CUMULATIVE NOISE EXPOSURE, NEF
40 35 30
75 70 65
CUMULATIVE NOISE EXPOSURE, Ldn
Figure 4-3. Cumulative Land Use Costs
';
4-18
-------
ability to pass through such costs is a function of the type of lease each airport
operator has with the airlines.
This litigation spectre is only one of the pressures that an airport operator would
be under. Perhaps, just as important are the local, political, and social pressures
currently being exerted. In addition, the 1972 Noise Control Act, as its provisions
are being implemented will establish environmental noise exposure standards which
the operator will at some point in time be required to comply with. Under such a set
of pressures and circumstances, it is reasonable to expect the airport operator,
knowing that source reduction technology will not be implemented, to take independent
actions to reduce the extent of the airport/community noise environment problem.
One of the actions an operator may take is to institute a night-time curfew. The
implications of such independent actions when they amount to a national 10:00 p. m. to
7:00 a.m. curfew on aircraft flights have also been examined. Although the cost
estimate developed is admittedly conservative, the estimated total six year cost of
such a curfew is approximately $700 million. Slightly over half of this cost is initially
incurred by the airlines, the remainder is incurred by the users. This estimate was
developed under the assumption that airline users could adjust their transportation
requirements to schedules that comply with the curfews. Where this structural res-
ponse is not valid, the costs of the curfew are understated. However, the effective-
ness of a national curfew is estimated to result in a 35 to 60 percent reduction in the
land areas exposed to high noise environments.
A cursory examination of whether increasing approval of capacity limitation
agreements would help alleviate the noise environment problem around airports
revealed that this trend would not be very effective for this problem. It could, how-
ever, aid airlines to earn higher profits and reduce the operating fuel requirements
of this industry.
Since the airport operator can also be a paying partner in the land use options to
alleviate the subject problem, estimates of these options were also developed. The
total cost range of a land use and receiver treatment option to achieve a L^ = 60 dB
environment has been estimated to be $21 to 31.5 billion. Although the extent of the
operator's participation in this option has yet to be determined, it should be expected
4-19
-------
that it will be significant and provide the real incentives for the operators to take
actions to reduce the noise environments around their respective airports.
Given the magnitude of the costs associated with some of the possible responses
to a decision not to implement source noise reduction technology into the current civil
aviation fleet, a more rational solution to this conflict problem must be identified.
CURRENT TECHNOLOGY OPTIONS
The objective of the following analysis is to investigate whether transferring
current noise reduction technology into the civil fleet of this nation would have more
desirable financial and economic results in achieving various cumulative noise levels,
than those developed in the previous discussion. Initially, commercial and general
aviation fleet modification strategies, resulting in reduced noise impacts around air-
ports, are developed from the available options. Estimation of the costs and noise
impact effectiveness associated with each strategy are then generated. From these
data the economics of achieving various cumulative noise levels are developed for
each fleet modification strategy. *
The Relationship of the Options to Fleet Modification Strategies
The four basic technology options available during the time period of interest
(1973-1985) are the nacelle retrofit, engine refan retrofit, engine replacement and
aircraft replacement. These latter two options are not investigated here for the
commercial fleet because of the scarcity of effectiveness data and their high program
costs. The remaining options, nacelle and engine refan retrofits, may be used
individually or in combination on various types of aircraft in the commercial airline
fleet. They may also be used in conjunction with aircraft operational procedures.
Time plays an important role because of the dynamics of change both with respect
to fleet mix and numbers of operations. Given the fact that the new high-bypass ratio
engine aircraft are quieter than existing narrow-body aircraft, and that presumably
future aircraft will be even quieter, the expected long run trend is for reduction in
*The data and findings of Ref. 8.5-355 are used extensively in this study.
4-20
-------
airport noise. This trend has not been reflected in the null case just discussed as it
was examined from the viewpoint of short term potential public reactions in the pre-
vious section.
Understandably, the timing of the commercial aviation retrofit programs will
have a significant impact on the overall effectiveness of the program relative to the
public protection requirements. Schedules developed in Ref. 8.5-355 for retrofit
implementation were based upon current and proposed regulatory actions and the
status of the ongoing FAA and NASA research programs. These schedules are real-
istic but do not represent a commitment on the part of the Government to any specific
regulatory or program action. For this analysis the schedules are:
• Nacelle retrofit on all JT8D engine aircraft starting in early 1975 and
JT3D engine aircraft starting in late 1975, all airplanes completed by
July 1, 1978.
• Refanned engine retrofit on all JT8D engined aircraft starting near the
end of 1976, complete by December 31, 1979.
• Refanned engine retrofit on all JT3D engine aircraft starting near the
end of 1977, complete by December 31, 1980 (included for comparative
purposes only. Program support discontinued by the Government in
January, 1973).
• Operational change in 1973, 3000 foot approach altitude until intercept
of a 3 glide slope.
• Operational change starting in mid-1974 and completed by the end of
1978, 3000 foot approach altitude until intercept of a 6 glide slope
to 1,200 foot transition to a 3° glide slope by 800 foot altitude.
Seven combinations of the commercial aviation SAM and RE FAN retrofit options
were analyzed. They were:
1. SAM 8D — Retrofit all JT8D engined airplanes with
acoustically treated nacelles.
2. SAM 3D — Retrofit all JT3D engined airplanes with
acoustically treated nacelles.
3. SAM 8D/3D — Retrofit all JT3D and JT8D engined airplanes
with acoustically treated nacelles.
4-21
-------
4. RFN 727/ — Retrofit the B-727 with refanned engines and
SAM rest the other JT3D and JT8D engined airplanes
with acoustically treated ancelles.
5. RFN 8D — Retrofit the JT8D engined airplanes with
refanned engines; including aircraft produced
with "quiet" nacelles prior to start of refan
retrofit.
6. RFN 8D/ — Retrofit the JT8D engined airplanes with
SAM 3D refanned engines and the JT3D engined air-
planes with acoustically treated nacelles.
7. RFN 8D/3D — Retrofit all JT3D and JT8D engined airplanes
with refanned engines.
It was further assumed that all aircraft produced after the start of the retrofit
program would be produced with the appropriate engine/nacelle configuration to keep
newly produced airplanes at the same level as the retrofit airplanes. Figure 4-4
depicts the schedule start and completion times for each option during the time period
of interest.
As discussed in Sections IV-1 and 2 of this report, the jet powered aircraft in the
general aviation fleet are expected to increase in number at a much more rapid rate
than those in the air carrier fleet. New aircraft introduced into this fleet will, in
general, probably take advantage of the operating economics associated with the
turbofan engines and, therefore, also produce less noise. However, a major portion
of the existing fleet is powered by turbojet or very low bypass turbofan engines. Noise
suppression kits, including modified exhaust nozzles and sound absorbing materials,
and/or engine replacements for the existing aircraft are being considered. Specific
considerations are detailed in Section IV-2 of this report. For the purposes of this
study, it is assumed that each type of general aviation aircraft will have the appropri-
ate retrofit option implemented by 1978 such that it complies with the current FAR-36
requirements.
Retrofit Effectiveness Measure
Retrofit effectiveness can be measured in a number of different ways: noise
reduction at a given set of points on the ground; reduction in the size of the noise
footprint for a single takeoff and landing; reduction in the noise impacted population
around airports using some criterion measure which incorporates the noise effect
4-22
-------
72
JAN 72
74
76
78
80
74
76 78 80
CALENDAR YEARS
82
82
84
86
300073°
APR.
3000V6°/38
APPROACH
SAM
JT8D
SAM
JT3D
REFAN
JT8D
REFAN
JT3D
84
86
Figure 4-4. Estimated Schedules for Approach Procedures
and Retrofit Implementation
4-23
-------
of all aircraft operating at that airport. This latter criterion measure (reduc-
tion in impacted population) is used to judge program effectiveness.
Data Inputs
The baseline aircraft noise levels, the FAR 36 limits and the retrofitted aircraft
noise levels used in this analysis are summarized in Figures 4-5 through 4-7 for the
JT3D and JT8D powered aircraft under study by the FAA and NASA contractors. The
\
FAR 36 data are for aircraft flying at maximum gross takeoff weights. The data for
the FAA nacelles with sound absorption material (SAM) are based upon flight tests
(B-707, B-727, B-787, DC-9) or analytical studies (DC-8). Recent flight test data
for the Boeing 707 with acoustically treated nacelles have not been fully analyzed,
but give high confidence to ground test estimates. A range of data has been presented
for the NASA Refan Program since the effort to date is basically analytical and has
not progressed to the point where a final configuration (engine and nacelle) can be selected.
The refanned JT3D aircraft (707 & DC-8) are included, although Government
funding for this program has been terminated. At the present time the maximum refan
treatment used in this analysis has been dropped by the NASA program and the more
probable configuration is the minimum refan. The maximum and minimum refan
reductions are also depicted in the above cited figures.
Analysis Approach
Given these various sets of noise output data, the-important question then is how
noisy will the airport environments be under relatively realistic operating conditions;
i. e., a mix of takeoff profiles and aircraft types. Six airports were analyzed in con-
siderable detail with respect to forecasted operations by aircraft type, aircraft flight
procedures and airport runway/flight track utilization. The analysis of the six airports
assumed maximum acoustical treatment for refan.
The analysis for each airport included the establishment of the present airport
configuration, including land area (and boundaries), the heading, length and layout
of usable runways, a summary of operational facilities pertinent to the airport's
current and future operations and capacity including NAVAIDS and taxiways.
4-24
-------
to
01
30 85 90 95 100 105 110 11!) 12
BOEING
707
DOUGLAS
DC-8
BOEING
727
BOEING
737
DOUGLAS
DC-9
FAR 36 1 .
BASELINE 1
SAM 1
REFAN l^^^l
FAR 36 1
BASELINE 1
SAM 1
REFAN t^SSSd
FAR 36 1
BASELINE
SAM
REFAN |KS^
FAR 36 1
BASELINE 1
SAM 1
REFAN IsSSS^
FAR 36 |
BASELINE
SAM
REFAN fc^^
80
85
90 95 100 105 110
EFFECTIVE PERCEIVED NOISE LEVEL, EPNdB
115
120
Figure 4-5. Estimated Noise Levels at FAR 36 Measuring Points.
(a) Sideline.
-------
bo
80
BOEING
707
DOUGLAS
DC-8
BOEING
727
BOEING
737
DOUGLAS
DC-9
85
80
85
90
95
100
105
110
115
120
FAR 36 I
BASELINE |
SAM I
REFAN
vVxVVVVVVVvSI
FAR 36 1
BASELINE 1
SAM l~
REFAN
^v^SS^^^S^Sl
FAR 36
BASELINE J
SAM
REFAN b^sSSNSNSNM
FAR 36
BASELINE
, SAM |
R/F fc^SS^^
FAR 36 |
BASELINE )
SAM |
R/F KS^SSSSSSSS
90 95 100 105 110
EFFECTIVE PERCEIVED NOISE LEVEL, EPNdB
115
120
Figure 4-6. Estimated Noise Levels at FAR 36 Measuring Points.
(b) Takeoff with Cutback.
-------
I
to
-q
BOEING
707
DOUGLAS
DC-8
BOEING
727
BOEING
737
DOUGLAS
DC-9
an 85 90 95 100 105 110 115 12
S
^S
£
FAR 36 I
BASELINE 1
SAM
REFAN l^SSNSSNS>^l
FAR 36 I
BASELINE I
SAM
REFAN R^^^3
' FAR 36 L
BASELINE I
SAM I
REFAN ts^Ss^^^l
FAR 36 I „
BASELINE I
SAM
REFAN
\\>>>\VO\XSNI
FAR 36 I
BASELINE I
SAM I
REFAN
^^^^1
0 85 90 95 100 105 110 lib i
D
20
EFFECTIVE PERCEIVED NOISE LEVEL, EPNdB
Figure 4-7. Estimated Noise Levels at FAR 36 Measuring Points.
(c) Approach.
-------
The statistic used to describe noise exposure around an airport is the Noise
Exposure Forecast (NEF). NEF is determined by the noise levels of the individual
airplanes and the total number of movements into and out of the airport. For this
analysis, the number of aircraft movements representative of an average day based
on an annual estimate have been established for each airport. The annual average
day has been used because:
• NEF contours are not absolute measurements but are intended for
comparative purposes. Therefore, the operational information
utilized in developing the contours is correctly based on averaged
conditions. Noise measurements made at any one time (say, over
a period of a few days) may be thought of as representing a
"snapshot" of the situation at that time rather than the long-term
average of the NEF contours.
• NEF contours are relatively insensitive to small changes in traffic
volumes.
• Total airport activity is relatively stable over periods lasting
several months.
Assuming that a major portion of business jets flights are into or out of large
airports, then the noise reduction impacts of these craft will be masked by commer-
cial airline activity. However, if no modifications were made to these aircraft
which now exceed the current FAR-36 levels, then regardless of what alternative is
implemented for the commercial fleet, the business jet fleet would contribute more
significantly to the noise impacted environment. Consequently, modification of each
element of the civil aviation fleet not in compliance with the existing FAR-36 levels is
assumed in this analysis since it is not only equitable but the most efficient way to
reduce the noise environments around all classes of airports.
The estimated average daily operations used for the year 1972, 1978 and 1985
by major airplane categories at the six analysis airports (Atlanta, LaGuardia, Kennedy,
San Francisco, Los Angeles and O'Hare) are summarized in Figures 4-8 through 13.
To reiterate, aircraft retrofits with either acoustically treated nacelles or refanned
engines are intended, primarily, to alleviate the problems associated with noise around
existing airports and not future airports. Future airports are expected to be built with
4-28
-------
10
12
to
to
B-707& 1972
DC-8 1978
1985
B-727, 1972
B-737& 1978
DC-9 1985
2. 3, &4 1972
ENGINE 1978
WIDE BODY 1985
1972
OTHER 1978
1985
1
1
1
1
1
1
r
TOTAL AVG.
YEAR DAILY OPS.
1972 1160
1978 1231
1985 1847
1
1
1
1
1
1
1
1
1
l
1
1
1
I
468
AVER AGE DAILY OPERATION X 10-2
10
12
Figure 4-8. Average Daily Air Carrier Fleet Operations
for 1972, 1978 & 1985—Atlanta
-------
10
12
CO
0
B-707& 1972
DC-8 1978
1985
B-727, 1972
B-737& 1978
DC-9 1985
2, 3&4 1972
ENGINE 1978
WIDF RnnY 1QB5
OTHER 1972
1978
1985
1
1
1
1
1
TOTAL AVG.
YEAR DAILY OPS.
1972 790
1978 826
1985 1001
1
1
1
zn
.
1
,
,
1
1
1
468
AVERAGE DAILY OPERATIONS X 10-2
10
12
Figure 4-9. Average Daily Air Carrier Fleet Operations
for 1972, 1978 & 1985-LaGuardia
-------
W
0 2 4 6 8
B-707 & 1972
DC-8 1978
1985
B-727, 1972
B-737& 1978
DC-9 1985
2, 3&4 1972
ENGINE 1978
WIDE BODY 1985
1972
OTHER 1978
1985
(
• 1
• 1
1
1
1
1
1
1
1
I
TOTAL AVG.
YEAR DAILY OPS.
1972 883
1978 1001
1985 1206
,
b
| , .
i
1
i
10 12
1
D2468
•
10 12
AVERAGE DAILY OPERATIONS X 10'2
Figure 4-10. Average Dally Air Carrier Fleet Operations
for 1972, 1978 & 1985—Kennedy International
-------
10
CO
to
B-707& 1972
DC-8 1978
1985
B-727, 1972
B-737& 1978
DC-9 1985
2, 3&4 1972
ENGINE 1978
WIDE BODY 1985
1972
OTHER 1978
1985
"~l
1
1
IT1
i
1
i
~1
i
=1
i
i
i
T
YEAR
1972
1978
1985
I
1
TOTAL AVE.
DAILY OPS.
717
835
1118
1
1
12
0 2 4 6 8
AVERAGE DAILY OPERATIONS X 10'2
Figure 4-11. Average Daily Air Carrier Fleet Operations
for 1972, 1978 & 1985-San Francisco International
10
12
-------
I
w
03
n 24 6 8
B-707& 1972
DC-8 1978
1985
B-727, 1972
B-737& 1978
DC-9 1985
2, 3&4 1972
ENGINE 1978
WIDE BODY 1985
1972
OTHER 1978
1985
1
1
1
1
1
1
=>!
1
1
TOTAL AVG.
YEAR DAILY OPS.
1978 1120
1985 1318
1
,
1 | f , .
1
1
I
1
02468
10 12
I
10 1
AVERAGE DAILY OPERATIONS X TO'2
Figure 4-12. Average Daily Air Carrier Fleet Operations
for 1972, 1978 & 1985-Los Angeles International
-------
10
12
CO
B-707& 1972
DC-8 1978
1985
B-727, 1972
B-737& 1978
DC-9 1985
2, 3&4 1972
ENGINE 1978
WIDE BODY 1985
1972
OTHER 1978
1985
1
— i —
1
-^
i
i
i
I
TOTAL AVG.
YEAR DAILY OPS.
1972 1591
1978 1656
1 QQ£ O1 1 1
1
1
1
1
ID
i
i
i
i
02468
I
i
i
10 1;
AVERAGE DAILY OPERATIONS 10'2
Figure 4-13. Average Daily Air Carrier Fleet Operations
for 1972, 1978 & 1985-O'Hare
-------
noise as one of the design criteria taking into account the noise levels of aircraft
expected to be in use when the airport is operational. One objective of this study is
to determine if source abatement technology, if applied, will reduce the total cost of
achieving various cumulative noise levels. The major impact of aircraft noise has
been on the people residing under or adjacent to the various flight tracks; therefore,
reduction in the number of people living in noise impacted areas is the major criterion
for assessing the effectiveness of any noise abatement effort. A major sub-objective
of this analysis effort has been to estimate the number of people currently residing in
noise impacted areas, the expected number adversely impacted in the future if there
were no retrofit or change in operational procedures, and the change in the number of
people impacted if a retrofit program and/or operational changes are implemented.
Population estimates are based on the 1970 census. No attempt was made to forecast
population changes for future years.
Analysis Results
Estimates of the population residing within the noise impacted areas for each of
the airports in the analysis have been generated for the two operational alternatives
and the seven retrofit options. These estimates are for 1972 (the baseline year) and
the year the modification option was completed, assuming no change in population
from the 1970 census estimates.
The curves of Figures 4-14 and 15 show the population effects of the baseline "do
nothing" case, plus the effects of two retrofit options and modified landing procedures
on population impacted by noise for the six airports studied. The relative effectiveness
of the noise reduction alternatives is highly sensitive to the airport being analyzed.
Some general tendencies, however, can be derived from the figures. When combined
with two-segment approach, either the SAM or the Refan 8D/SAM3D retrofit will
reduce the population exposed in the L, = 65 dB and 75 dB contours. With the JT8D
refan/SAMSD option, the reduction in population exposed to L, = 65 dB region is
significantly greater than that achieved by SAM. The extent to which this tendency
will be modified by shifting to the minimum refan acoustical treatment should be
determined by further analysis. One other factor should be reiterated: the SAM
nacelle is currently in production or has been flight-tested on the B-707, B-727, B-737,
and DC-9; the JT8D refanned engine and modified nacelle data is based upon engineering
4-35
-------
100
90
80
70
2-SEGMENT
APPROACH
60
SAM 8D/3D —
& 2-SEG. APR.
\
0 50
tr
40
30
20
10
NOTE: The results attributed to the individual
modifications, at their respective completion
dates, are consistent with the DOT study (8.5-
355). However, the depicted straight' line
assumption between program initiation and
completion does not reflect the modification
rate utilized in the referenced study and,
therefore, should not be used to estimate
intermediate results.
REFAN 8D-
SAM3D
& 2-SEG. APP.
JAN 73
74
75
76
77
YEAR
~-
80
Figure 4-14. Estimated Percent Reduction in Population Impacted
by Aircraft Noise—75 L Contour (40 NEF)
4-36
-------
100
.
JAN 73
^
^
^^
^
SAM 8D/3D ~
& 2-SEG APR.
NOTE: The results attributed to th
_ modifications, at their respective co
dates, are consistent with the DOT <
355). However, the depicted straigf
assumption between program initial
_ completion does not reflect the moc
rate utilized in the referenced study
therefore, should not be used to est
intermediate results.
BAS
/
1
e individual
tudy (8.5-
)t line
ion and
Jification
and,
mate
ELINE
r~ 2~s
^^C^ AP
V
\
EGMENT
PROACH
^^«
^>
\
REFAN 8D — -*\
SAM 3D \
& 2-SEG. APP. \
\
\
\
77
YEAR
Figure 4-15. Estimated Percent Reduction in Population Impacted
by Aircraft Noise—65 L Contour (30 NEF)
4-37
-------
analyses; and the exact configuration and degree of acoustical treatment is yet
to be decided; therefore, data presented are subject to significant variation until
further work is accomplished.
The difference in program timing will have an effect as to when the noise reduc-
tion can be achieved. As can be seen in the baseline case of Figures 4-14 and 15 there
will be a reduction in the number of people in the L, = 65 dB and 75 dB contours
between 1972 and 1978 with normal attrition and replacement of the current fleet of
JT3D aircraft and new production of JT8D engined aircraft which meet FAR 36 (the
Boeing 727 and 737 airplanes have been certificated in compliance with the FAR 36
noise requirements). The assumption has also been made that the population density
around the airports will not change between the 1970 census data and 1978. This
latter assumption depends upon proper land use planning to prevent continued
encroachment in the vicinity of the airports. Such an influence is currently beyond
the control of the airport operator.
There will be further reductions if the two-segment approach is implemented
starting in mid-1974*
COST ANALYSIS OF RETROFIT ALTERNATIVES
The Commercial Airlines
To determine the impacts of these various fleet modification strategies on airline
industry economics, several assumptions must be made on how the economy is expected
to perform and whether the industry will become more efficient during the time period
of interest. In general, the DOT studies from which this analysis has been performed
assumed that the economy would continue to grow at a rate of 4 percent real growth
per annum. In addition, an industry average flight load factor of 55 percent was
assumed to be reached by 1978.
From these assumptions, existing FAA, CAB and ATA traffic demand esti-
mates were used as bases for estimating passenger and cargo traffic growth on an
annual or specific future year basis. Given the productivity of each type of aircraft,
their respective numbers in the current fleet and individual airline equipment
retirement and acquisition plans, estimates of the fleet mix at points in time are
made. Given these data, the candidate fleets which would be affected by each
4-38
-------
retrofit alternative are then identified. Note should be taken here that fleet mix
estimates developed as described above will necessarily be different than that which
would obtain if industry economics were such as to preclude early retirement due
to the high cost of capacity replacement or the cost of capital in the private market.
This situation of delayed retirement of the noisier aircraft in the fleet was not inves-
tigated in this analysis.
Evaluation of the cost of proposed noise reduction programs is based on specific
data derived from the FAA and NASA studies. Because these studies are at different
stages of completion, the accuracy of the cost estimates will vary between programs.
For this reason the costs discussed here, particularly with respect to the Refan
Program, are preliminary and are subject to change as the research programs near
completion. Nevertheless, the relative order-of-magnitude estimates of the retrofit
costs can be used at this point to compare the cost effectiveness of the various program
alternatives.
Alternative programs for noise reduction have been evaluated in terms of total
cost of the investment required to develop, certificate and install these selected
modifications on all candidate aircraft, plus the marginal operating costs associated
with the modification over the time period, and for the varying number of candidate
aircraft subject to the program.
Analysis of future costs must also take into account all likely losses incurred by
virtue of the retrofitting program. Among these are opportunity costs resulting from
loss of revenue due to forced idleness of the equipment during installation and main-
tenance of noise reduction kits, and lost productivity from changes in performance,
weight or fuel consumption. The impact of any potential lost productivity of retrofit
aircraft which could result from changes in performance, weight, or fuel consumption
have been considered by assuming that the available-ton-miles produced in any given
time period will be unchanged either by increasing the number of airplanes flown per
day or the utilization rate of each airplane for each retrofit alternative. Therefore,
no revenue will be "lost;" however, the cost of providing the fixed level of produc-
tivity may be significantly altered by retrofit. An approximate measure of the cost
impact of lower productivity has been developed by applying the changes in unit direct
operating costs over the additional flight hours, additional aircraft miles or additional
4-39
-------
trips necessary to produce the original level of available ton miles. Shown in Table
4-3 are the retrofit unit costs per aircraft.
Table 4-4 summarizes the retrofit program costs by element, both in current
dollars and present value discounted to 1973 at a. 10 percent discount rate. Figures
4-16 and 17 show the total program cost in both current and present value. Minimum
and maximum estimates have been derived based upon a range of refan retrofit cost
and performance changes. Uncertainty in the estimate of number of aircraft to be
retrofitted and the unit cost per aircraft is bounded by a plus and minus in these
estimates. As has been previously noted, NASA has dropped the maximum refan
treatment from its JT8D refan research program. In addition, funding for the JT3D
refan program has been dropped. To this extent one should expect the performance
effects estimated here to diminish and/or program costs to increase.
The Business Jet Portion of the General Aviation Fleet
Since the current business jet fleet will still be operating during the time period
of interest, those aircraft which currently cannot satisfy FAR 36 requirements are
the candidate set of aircraft for the nacelle, modified nozzle or re-engine alternative.
For those aircraft yet to be manufactured, the assumption is made that these aircraft
will conform to the current FAR 36 requirements. Given this set of conditions, then
the retrofit or re-engine investment per aircraft type would be as shown in Table 4-5..
Shown in this Table are the total investment requirements by aircraft type and for the
total fleet.
It should be noted that the total business jet fleet investment requirements are
significant. In the case of the Re-engine option however performance and operational
benefits will be realized and, under a ceteris paribus activity level assumption, these
business jet operators will realize a savings.
ECONOMICS OF ACHIEVING VARIOUS LEVELS OF CUMULATIVE NOISE EXPOSURE
The objective of the following analysis is to utilize the cost and effectiveness
results of the previous discussion to determine if a mix of source noise reduction
techniques and land use alternatives can result in a more equitable and less costly
program of achieving various levels of cumulative noise.
4-40
-------
TABLE 4-3. UNIT COSTS FOR NOISE RETROFIT PROGRAMS*
S.A.M. REFAN
Sound Absorption New Front Fan
Aircraft Material with S.A.M.
JT3D Engines
B-707's $930,000 $1,900,000
DC-8's $770,000 $2,300,000
JT8D Engines
B-727's $169,000 $1,400,000
B-737's $ 202,000 $ 1, 000, 000
DC-9's $175,000 $1,100,000
* Installed cost per aircraft, including spares
(1973 dollars).
Source: Reference 8. 5-355
4-41
-------
TABLE 4-4. RETROFIT PROGRAM COSTS ($M)
Current Dollars
00
Program
SAM8D
SAM 3D
SAM 8D/3D
REFAN 727/
SAM Others
REFAN 8D
REFAN 8D/
SAM 3D
REFAN 8D/3D
Investment
164.4
290.7
455.1
1,065.0
1,121.0
1,411.8
1,652.7
Minimum Estimate
Change Lost
in Cash Lost Produc-
D.O.C. Time tivity
25.0
58.0
83.1
249.9
339.0
397.1
456.3
25.4
11.8
37.2
36.6
24.4
36.2
33.3
7.4
55.9
63.3
111.7
189.3
245.2
205.3
Total
Retrofit
Cost
222.2
416.4
638.7
1,463.2
1,673.7
2,090.3
2,347.6
Investment
222.5
393.4
615.9
1,440.8
1,516.7
1,910.0
2,236.1
Present Value, $1973 (10% Discount
Maximum Estimate
Change Lost
in Cash Lost Produc-
D.O.C. Time tivity
25.0
58.0
83.1
493.1
756.7
814.8
945.7
Rate)
Minimum Estimate
SAM8D
SAM 3D
SAM 8D/3D
REFAN 7277
SAM Others
REFAN 8D
REFAN 8D/
SAM 3D
REFAN 8D/3D
112.5
193.2
305.7
673.5
687.1
880.3
1,015.0
10.9
25.4
36.3
101.4
132.5
157.9
180.4
17.4
7.9
25.3
23.4
15.0
22.9
20.5
3.2
24.8
28.0
46.9
73.5
98.3
80.0
144.0
251.3
395.3
845.2
906.1
1,159.4
1,295.9
152.2
261.4
413.6
911.3
929.7
1,191.0
1,373.2
10.9
25.4
36.3
197.2
295.9
321.4
373.7
25.4
11.8
37.2
36.6
24.4
36.2
33.3
Maximum
17.4
7.9
25.3
23.4
15.0
22.9
20.5
7.4
55.9
63.3
587.7
1,004.4
1,060.3
1,126.7
Estimate
3.2
24.8
28.0
234.3
392.2
417.0
443.1
Total
Retrofit
Cost
280.3
519.1
799.5
2,558.2
3,302.2
3,821.3
4,341.8
183.7
319.5
503.2
1,366.2
1,632.8
1,952.3
2,210.5
-------
I
t£"
CO
0.5
1.5
2 2.5 3
BILLIONS OF DOLLARS
4.5
Figure 4-16. Estimated Total Costs for Seven Retrofit Options
(a) Current Dollars
-------
0.5
1.5
it
2.5
3.5
4.5
0.5
1.5
2 2.5 3
BILLIONS OF DOLLARS
3.5
4.5
Figure 4-17. Estimated Total Costs for Seven Retrofit Options
(b) Present Value 1973 (10% Discount Rate)
-------
TABLE 4-5. INVESTMENT COSTS FOR NOISE SOURCE
TREATMENT OF DOMESTIC BUSINESS JETS
Aircraft
Type
BH125-400
-600
Commodore
1121
1123
Gates-Lear
24D
25B/C
26
Grumman
II
Jet Star
1329
Sabreliner
60
70
INVESTMENTS (1973 Dollars x 106)
Est. Costs/Aircraft
U.S.
Fleet
Qty
142
134
81
113
124
63
Engine
Set
Costs
_
-
.210
.210
.210
-
-
.340
-
Install-
ation
Costs*
_
-
.150
.150
.150
-
.
.150
-_
Re-
engine
Costs
_
—
0.360
0.360
0.360
-
1.350
.490
-
Re-
trofit
Costs
0.100
0.100
—
-
. 150**
-
-
TOTALS
Costs/U.S. Fleet
Re-
engine
Costs
v
—
48.3
29.2
-
167.4
30.8
275.7
Re-
trofit
Costs
14.2
17.0
-
.
-
31.2
Fleet
Costs
14.2
48.3
29.2
17.0
167.4
30.8
306.9
* Assumed $75,000/engine installation (Ref. 7.1-54)
** Cost estimate based upon BAC-111 and F-28 Data (Ref. 3. 8-367)
4-45
-------
It has been found that the introduction of source abatement technology will
reduce the noise impacted population around airports due to the shrinkage of NEF
contours. However, the impacted population or noise reduction effectiveness of
any of the alternatives varies as a function of time. This is due to the different time
periods for the start and completion of a specific program, and the varying effect of
changes in the fleet mix between retrofitted airplanes, unmodified airplanes and new
airplanes. As a measure of effectiveness the maximum impacted reduction achieved
by retrofit has been selected. Implicit in this selection is the assumption that public
policy would not permit the noise problem to grow once noise reduction had been
attained. Various policy alternatives to attain this objective are currently being
explored in the DOT.
The results of the six airports analyzed in these effectiveness terms may be
generalized from Figures 4-14 and 15. The "no change" alternative has an effective-
ness of about 20 percent; i. e., changes in the fleet mix alone will result in an average
20 percent reduction in the population within the 30 or 40 NEF at no additional cost for
noise abatement. Implementing the two-segment approach would increase the effective-
ness to about 25 percent in the 30 NEF area, and to about 40 percent in the 40 NEF
area. Retrofitting all of the JT3D and JT8D engined airplanes with acoustically
treated nacelles and using a two-segment approach will increase this effectiveness
further to about 30 percent in the 30 NEF area and about 60 percent in the 40 NEF
area and, as shown in Figure 4-16 and 17, at a current dollar total program cost of
some $600 to 800 million (present value of $400 to 500 million in 1973 dollars).
Similarly, retrofitting all JT8D engined aircraft with refanned engines, and all JT3D
engined aircraft with acoustically treated nacelles and flying a two-segment approach
will have an efficiency of over 80 percent in the 30 NEF area, and about 75 percent
in the 40 NEF area, at a current dollar total program cost of $2.1 to 3.8 billion
(present value of $1.2 to 2.0 billion in 1973 dollars). These effectiveness levels
indicate that the 31.5 billion dollar maximum estimate to protect the 1972 impacted
public to L, = 60 dB using land use options only, can be significantly reduced as
shown subsequently in Figures 4-18 through 22. However, one should recall that the
numbers cited in the Refan cases are optimistic both from a performance and cost
standpoint, and some adjustment may be required as firm figures are developed.
4-46
-------
Translation of the Six Airport Effectiveness Results
To translate the general findings to the national impacted population distribution,
the following procedure was followed. By assuming that the six airport effectiveness
results reasonably reflect what can be expected on a national basis and normalizing
the six airport results to a percentage reduction of the baseline population, one can
develop an annual relationship between effectiveness per option and calendar year.
Shown in Figures 4-14 and 15 are the percent population impacted variations by
year, for two of the options, for the L, = 65 and 75 dB levels. Basically, because
of the static population aspect of the baseline case, population shrinkage in any
contour is the result of that contour itself shrinking. Assuming that all other L,
contours also shrink proportionately as the Lj = 65 and 75 dB contours vary by
option, by year, then these results become transferable to any impacted population
distribution.
For this analysis, a static national estimate of the impacted population distribu-
tion by L, level (see Figure 4-1) has been assumed and this distribution is utilized
to estimate the remaining population impacted in the following manner. The two
data points indicating baseline percentage population reductions for an option, also
represent two points on the resulting national population distribution curve. To
construct an entire option curve, the assumption was made that the original curve
shape represented the relationship between population impacted and cumulative noise
exposure. Therefore, a symmetric shift of the original curve form was performed
and the population impacted per L, level was tabulated. This process was performed
for every option investigated.
Retrofit Influence on Total Achievement Costs
Recall that the rule employed in the cost calculations is that every person
exposed to L, = 60 or greater must be protected to that level. On this basis a
land use and structure treatment unit, cost curve (Figure 4-2) waS applied to the
baseline national impacted population curve to develop the estimate range of 21 to
31.5 billions of 1973 dollars to achieve an L, = 60 dB environment in 1973.
Since, with the passage of time and/or the implementation of an operational or
source abatement option, the impacted population decreases, then it also follows that
4-47
-------
the 1973 dollar cost of achieving this or any other level will diminish. However,
the operational and/or retrofit program costs must be added to the land use and
treatment costs to accurately reflect the total costs of achieving a desired cumulative
noise environment. Shown in Figures 4-18 through 22 are such total costs for each
five unit increment of L, or NEF level. The top bar in each figure portrays the
an
1973 land use only option, the reduction of these costs as the baseline situation occurs,
and the effects on achievement costs of also implementing 6 /3° approach procedures. *
One should also note that the retrofit program completion dates are included to illus-
trate that there do exist differences in the duration, or waiting period, before the
impacted public could expect relief via the transfer of source abatement technology
to the operating civil aviation fleet.
One will find, upon inspection of these figures, that the implementation of any
source abatement technology will exclude the national population around airports from
being exposed to 80 L, levels and above. One will also find that the implementation
of any source abatement technology will reduce the total L, = 60 dB achievement costs
by at least 13 billions of 1973 dollars. Again, in reviewing these figures, one is
cautioned that the Refan total protection costs are subject to revision upwards as more
refined data on expected performance and unit costs are developed.
On the basis of the rational use of resources, it is apparent that source abatement
technology should be implemented into the active civil aviation fleet.
Sensitivity Analyses
As previously mentioned, the assumptions and basic data supporting this analysis
are subject to variations and revisions. To determine if the conclusions of the analysis
would change if such actions took place, a sensitivity analyses of some of the key
variables must be undertaken.
*Recall that the procedure for determining population reductions was a symmetric
shift of the population distribution curve such that the new curve passes through the
Ldn = 65 and 75 dB point estimates. However, operational procedure effectiveness
in high noise environments (L^^SO dB) is non-existent or small, primarily because
these procedures only redistribute energy. Consequently, on Page 4-49, no popu-
lation reduction credit is given to the two-segment approach.
4-48
-------
1978 1
1978 2
1978 3
1979 4
1979 5
1979 6
1980(+) 7
SAM 8D
0.5 1 1.5
(2) (3)
LAND USE ONLY
2 + 3 =1973 (NULL)
2 = 1978 (NULL)
2 =1978 (2 SEG.) See'Footnote on Page 4-48.
2.5
SAM 3D
SAM 8D/3D
TECHNOLOGY
COSTS
LAND USE
COSTS
MAX
P
MAX
MIN
NOTE: ADD 67 MILLION
DOLLARS FOR TWO
SEGMENT APPROACH
REFAN 727
& SAM OTHERS
^SS^^NS^^ REFAN 8D
REFAN 8D
^^^^^^ * SAM3D
REFAN
8D/3D
0.5 1 1.5
BILLIONS OF 1973 DOLLARS
2.5
Figure 4-18. Estimated Total Costs for Noise Protection—
80 L . Contour (45 NEF)
4-49
-------
10
12
14
1978 1
1978 2
1978 3
1979 4
1979 5
1979 6
1980H-) 7
1
1
4 SAM 8D r
jj» SAM 3D 1
Yf SAM 8D/3D i
HP r-
J
rJ:
Y//f^ REFAN 8D ,
1
<%
ijp
••^•^^^H
^ 1
r
J REF
&S>
REFA
i
2
2
1
EFAN >
SAMO
^
AN8D
\M3D
N8D/2
'27
THERS
D
i
1 +
1 +
i
NOT
DOL
SEG
SOURC
TECHIS
COSTS
L
C
3 |
3
.AND
2 + 3
2
E: AD
LARS
VIENT
:E
OLOG
AND-U
DSTS
JSEC
= 1
= 1
= 1
D67
FOR
APPR
Y
SE
)N
9;
97
97
M
TV
O
LY
3(NU
8(NU
8(2S
ILLIO^
VO
ACH
y////A
n
-U
-L)
EG.)
\
3 M>
Ml
] M;
M\
\X
N
\X
N
4 6 8 10
BILLIONS OF 1973 DOLLARS
12
14
Figure 4-19. Estimated Total Costs for Noise Protection-
75 L Contour (40NEF)
4-50
-------
1978 1
1978 2
1978 3
1979 4
1979 5
1979 6
19801+) 7
0
1 1 1
5 10 15 20 25 3<
I I I I
Ml
1 | 2 | 3 1
1 1 2 | 3 |
SAM8D
SAM 3D
' SAM 8D/3D
'% I]
f
X/vvJ
Wr\
MM
I
1
1
" ' I REFAN 7
& SAM O'
1 ' REFAIS
^J REFAN 8D
& SAM 3D
•^ REFAN 8D/3I
1 1 II
1
j
27
FHERS
8D
D
1 1 1 1
LAN
1 +2 +
1 +2
1
NOTE:
DOLL/
SEGME
SOUF
TECH
COS1
LA
CO
1
ID USE ONLY
3 = 1973 (NU
- 1978 (NU
= 1978(281
ADD67MILLIC
VRS FOR TWO
ENTAPR
INOLOGY IXX
S t^
IMD USE
5TS
1
LL)
LL)
EG.
N
Itfft MAX
<4\ MIN
HMAX
MIN
1 1
10 15 20
BILLIONS OF 1973 DOLLARS
25
30
Figure 4-20. Estimated Total Costs for Noise Protection—
70 Ldn Contour (35 NEF)
4-51
-------
10
15
20
25
30
1978 1
1978 2
1978 3
1979 4
1979 5
1979 6
1980{+) 7
i i.rr
in—~—T
SAM 3D
LAND USE ONLY
1+2 + 3 = 1973 (NULL)
1+2 = 1978 (NULL)
1 = 1978 (2 SEG.)
SAM 3D
SAM 8D/3D
REFAN 727
& SAM OTHERS
J REFAN 8D
REFAN 8D
& SAM 3D
REFAN 8D/3D
NOTE: ADD 67 MILLION
DOLLARS FOR TWO
SEGMENT APPROACH
SOURCE
TECHNOLOGY
COSTS
LAND-USE
COSTS
MAX
MIN
rp
MAX
10 15 20
BILLIONS OF 1973 DOLLARS
25
30
Figure 4-21. Estimated Total Costs for Noise Protection—
65 L, Contour (30 NEF)
4-52
-------
1978 1
1978 2
f
1978 3
1979 4
1979 5
1979 6
1980(+) 7
SAM 8D
SAM 3D
SAM 8D/3D
10
15
20
25
30 32
T~^~i—3—r
| REFAN 727
J & SAM OTHERS
REFAN 8D
REFAN 8D
& SAM 3D
REFAN 8D/3D
1
LAND USE ONLY
1 + 2 + 3 =1973 (NULL)
1+2 = 1978 (NULL)
1 = 1978 (2 SEG.)
I
NOTE: ADD 67 MILLION
DOLLARS FOR TWO
SEGMENT APPROACH
SOURCE
TECHNOLOGY
COSTS
LAND-USE
COSTS
1
\
MAX
MIN
MAX
10 15 20
BILLIONS OF 1973 DOLLARS
25
30
Figure 4-22. Estimated Total Costs for Noise Protection—
60 L, Contour (25 NEF)
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One of the basic assumptions made was that no further population encroachment
occurred in currently noise impacted areas around the nation's airports. In reality,
one should expect that such encroachment will occur until local governments actually
come to grips with the noise pollution problem and implement effective land use con-
trols. The effects of such encroachment are increases in noise impacted populations
and increases in the costs of achieving any desired level of cumulative noise exposure.
This is one argument for a timely adoption of an integrated environmental noise
reduction program if the costs of achievement, are to be reasonable.
If the impacted population distribution curve were changed, then the effectiveness
and costs of the various options examined would change. If the change were symmetric,
the land use cost component would change accordingly. The relative results would still
obtain; however, a stopping point may be created. If the change were non-symmetric
then a re-evaluation of each option may be required.
The other key variables, which can influence this study's findings are the
following:
• the number of aircraft to be retrofit;
• the availability dates of the retrofit kits;
• the estimated source noise reductions resulting from the retrofit; and
• the cost of the kits.
The number of aircraft to be retrofit has both program cost and effectiveness
implications. Total retrofit program costs would increase if the number of aircraft
to be retrofit were greater than that used in this study. The effectiveness of an
expanded fleet retrofit for either technology would be approximately that estimated
in this study if not greater. This follows from the fact that when the narrow bodied
portion of the commercial fleet is retrofit with SAM technology, their resulting
noise output levels are reduced to those comparable to the 747, DC-10, and L-1011.
The activity levels at airports, under a constant capacity offered assumption, may
increase slightly due to the requisite capacity substitution from wide bodies to narrow
bodies. However, the resulting cumulative noise levels around airports would not
change proportionally, but logarithmically. Retrofit of narrow bodies with Refan
technology would make these retrofit aircraft quieter than the wide bodies. It
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therefore follows that the Refan retrofit fleet would have relatively quieter aircraft
operating than that used in this study; consequently, the effectiveness of this type of
retrofit program would be greater than that employed in this analysis.
The remaining variables of availability, noise reduction performance and costs
of the retrofit kits have little uncertainty associated with them for the SAM tech-
nology. This situation is primarily due to the fact that this technology is flying in
current production aircraft and flight demonstration tests have been made of a kit
for one type of aircraft not currently in production. The chance of a slip in the
availability schedule of more than six months, from that used in this study, is felt
to be rather small. If such a slip occurred, the result would be that there would be
a delay in the achievement of any given cumulative noise level. * Significant changes
in the levels of noise reduction performance of SAM retrofit kits are not expected
essentially for the same reasons cited previously. The costs of SAM retrofit kits
can change as a result of production decisions. Such cost changes will vary total
retrofit program costs accordingly.
The uncertainty associated with kit availability, noise reduction performance,
and kit costs for the Refan technology are relatively greater than that associated
with SAM retrofit. The reason being that this technology is now in the engineering
design phase where the design has yet to be fixed, fabricated, and flown. If there is
a slip in the availability of Refan kits the general result would again be a delay in the
achievement of cumulative noise levels around the nation's airports and the attendant
inflation of achievement costs. If there were to be a reduction in Refan noise reduc-
tion performance from that used in this study, there would be an increase in the land
use component of achievement costs. Essentially, in this situation the relative attrac-
tiveness of Refan vis-a-vis SAM would decrease and the achievement costs of Refan
would tend towards those of SAM. Changes in the Refan kit costs would have the same
general effect as those sited for SAM.
*It should be noted here that the longer it takes to achieve reductions in L^ = 75 dB
and above, the greater could be the frequency of local litigation for damages. As
previously discussed this could result in a diversion of resources from those
necessary to achieve national airport cumulative noise levels.
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Considering the differences in the key program variables between the SAM and
Refan retrofit alternatives it is apparent that there is a significant risk in a singular
decision to key an airport noise reduction program to the Refan program. The more
prudent approach appears to be to initiate such a program with the SAM retrofit and
have Refan retrofits when the kits become available. Under this mixed strategy,
source reduction relief will occur at the earliest possible dates and the maximum
costs of the program are known.
Summary of the Economics of Achievement
In terms of the economic question of which combinations of options are the most
efficient to achieve a desired cumulative outdoor noise environment level, the follow-
ing findings can be stated.
« The costs of transferring aircraft source noise abatement technology into the
civil aviation fleet are always less than the costs of achieving cumulative noise
without such transfers.
• Transferring the aircraft source noise reduction technology into the civil
aviation fleet alone cannot eliminate the outdoor noise environment problem
around the nation's airports.
• Source technology cannot be fully implemented into the civil aviation fleet
until 1977 at the earliest, and path technology by 1978; however, intermed-
iate relief can occur before this period by the effective exercising of fleet
operational procedures, airport operator options and local government land
use options. Such intermediate relief must occur, especially the curtailment
of further encroachment of population around airports, if the costs of achieve-
ment are to be kept at a minimum.
• The problem of equitable treatment of populations residing near large mili-
tary airports although not addressed here cannot be ignored and appropriate
remedies and costs will have to be developed.
The Alternative Impacts on the General Economy
Given the situation that the alternative of not changing current aircraft/airport
activity procedures will ultimately cost the airport operators, airlines, and users
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billions of dollars, it is then reasonable to assume that an economically rational solu-
tion to the aircraft/airport noise impact problem will evolve. This solution will most
likely consist of a mixed strategy of retrofitting, airport operations optimization, land
use programs and possibly some removal of impacted populations. Necessarily,
retrofitting will create an additional demand for capital goods, labor and materials.
Also the costs of retrofitting will ultimately have to be borne by the users of the air
transportation system. Since the air network system is not now reflecting the economic
and social costs of noise in its tariffs, the resulting rise in tariffs or business cost
pass through to recover the costs of an integrated noise reduction program will have
demand effects of the revenue of the airlines and the activity levels of general aviation.
In addition, if fewer people fly because of higher tariffs, then it follows that relatively
less money is spent in the regional destination economy.
In essence, the implementation of the rational noise abatement alternatives will
have demand creating and diminution effects. What these effects are on a national
basis as well as on a regional impact basis must be investigated to insure that the
selected program is also one which creates the least undesirable economic impacts.
Finally, the achievement of cumulative noise levels around the nation's airports
will require international cooperation due to the high level of foreign flag air carrier
activity at a number of domestic airports. Questions as to whether, and how, these
nations can comply with the domestically developed schedule of achievement, how
requisite investment and operating expenses enter into their cost functions, and
whether such increased achievement costs will be passed through or used as a compet-
itive advantage, must and will be addressed in the subsequent rulemaking study effort.
FUTURE TECHNOLOGY OPTIONS
Although the component and engine technologies discussed in Section III have high
potential for significant noise reductions, their associated production costs are not
really understood at this time. Consequently, the costs associated with these options
are primarily research and development costs. When more definitive development
plans are provided, order of magnitude estimates of their cost implications can be
developed.
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ANNEX TO CHAPTER 4
THE IMPLICATIONS OF A NATIONAL CURFEW
Introduction
During the course of the task group meetings on which this report is based, one
airport noise reduction option continually created controversy. This was the imple-
mentation of curfews by airport operators. The basic question was to what extent the
curtailment of night time flights would effect the operations and users of the national
air transportation system.
What is reported here is a basic analysis of all elements of the problem. The key
assumption made, primarily due to the lack of valid data, was that the users of the air
transportation network could re-arrange their schedule requirements to those offered
after the curfew implementation at little cost. Necessarily, this assumption is optimis-
tic; consequently, the results of the analysis as reported here should be viewed as the
minimum which would obtain if a national curfew were implemented.
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The Cost of a National 10 P.M.-7 A.M. Curfew
Faced with significant magnitudes of potential damage awards and/or land use
costs, it is possible that if a source noise reduction program is not adopted on a Federal
level, airport operators will take independent action to avoid and/or reduce the amounts
of potential damage awards. One of the most dramatic actions that can be taken is the
imposition of a night-time curfew. As soon as it is apparent that no Federal program
will be undertaken, it is assumed that the operators will undertake a national curfew
and maintain it until effective noise reduction alternatives become available. The
assumption is made that the curfew will be instituted in 1974 and maintained until at
lease 1980 when quieter aircraft could become available. Because there is little
factual data available on the costs of curfews, the implications of this policy alterna-
tive requires more detailed analysis than the preceding alternatives to develop at
least a minimum cost impact estimate.
The impact of a curfew can be broken down into the following areas:
* Impact on passenger service
• Impact on air cargo service
• Impact on mail and express
• Impact on maintenance and repair activities
• Impact on international operations
Actually, there are some airports where no curfew would be needed or where less
restrictive limits could be imposed. The transfer of some maintenance and freight
operations to these airports would lessen the economic loss to an area," if, and only if,
the noise exposure at these airports does not increase as a result of the activity
transfers.
Impact on Passenger Service
Using the Official Airline Guide, a survey was made of the arrival patterns of
passenger aircraft at several airports across the country, including Los Angeles
International. Only about 15 percent of passenger aircraft movements occur between
10 P. M. and 7 A.M. and, of that number, about half are within an hour of the curfew
limits i.e. 11 P.M. and 6 A.M. The assumption is made that at least one-third of the
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curfew affected flights could be rescheduled to arrive or depart during noncurfew
hours. This rescheduling of flights will lead to increased congestion and delays in the
national aviation system. The remainder of the flights affected cannot effectively be
rescheduled; therefore, this would represent an overall decrease in airline industry
flight activity of about 10%. An assumption is made that half of this activity will not
be replaced and that the passengers will travel on noncurfew flights. This will result
in an increase in the noncurfew flight load factor. Such a situation would tend to increase
airline profits while at the same time expose these additional passengers to the additonal
airport congestion and delays previously mentioned. To replace the remaining 5%
of affected aircraft movements, the airlines would have to buy new equipment to
compensate for decreased aircraft utility and scheduling flexibility, (e. g. pre-position-
ing for next day flights). The corresponding increase in fleet size would not only add
to airport delay and congestion but also raise airline annual depreciation costs over
presently planned industry expenditures by 5 percent. Since depreciation represents
about 10 percent of the total industry operating costs, the change in overall industry
operating cost because of the additional aircraft would be 0. 5 percent.
Additional flight crews would be needed to operate these new aircraft. Since crew
costs represent about 13 percent of the total operating costs, the required increase in
crews (corresponding to the 5 percent increase in the number of aircraft) would raise
the overall operating costs 0.65 percent (13 percent of 5 percent). Based on these
figures, the total increase in fleet operating costs, due to this compensating activity
caused by a 10 p. m. to 7 a. m. curfew would then be the sum of the 0.5 percent
depreciation increase and the 0. 65 percent crew cost penalty for which there is no
offsetting profit!
To estimate the costs of congestion and delays the viewpoint was taken that
although 95 percent of the original capacity is maintained, this capacity is offered
over a much shorter operational period due to the imposition of a daily 9-hour curfew.
To maintain this capacity over a shorter time period, a "virtual" 10 percent increase
in operations per hour will occur. This increase will result in additional aircraft,
passenger and cargo delays. Since delays are inherent in the airline system, this
will represent an increase over and above what the system would consider normal.
Shown in Table 4-6 are airport capacity or operations estimates for a sample of
airports for which delay data were available. The historical operations data shown
in column 2 were taken from Reference 7.1-175. The estimated 1985 capacities of the
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TABLE 4-6. SAMPLE AIRPORT CAPACITY ESTIMATES
AIRPORTS
O'HARE
JFK
LAGUARDIA
ATLANTA
LOS ANGELES
NEWARK
MIAMI
SAN FRANCISCO
PHILADELPHIA
WASHINGTON NAT'L
ST. LOUIS
1971 CAPACITY
(000 OPERATIONS/YEAR)
617
344
258
385
413
184
250
297
186
215
187
EST. 1985 CAPACITY
(000 OPERATIONS/YEAR)
700
395
300
530
471
237
323
383
240
277
241
PERCENT
ANNUAL
GROWTH
1.0
1.0
1.0
2.4
1.0
1.9
1.9
1.9
1.9
1.9
1.9
PERCENT
OF TOTAL
DELAYS
IN 1969
13.7
10.6
6.9
5.9
3.7
3.7
4.1
2.8
3.1
2.9
1.7
TOTAL:
59.1
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sample airports were either taken directly from Reference 7.1-99 or estimated by
assuming the same capacity growth rate for those airports in the cited reference
similar to the sample airports. The delay data were taken from Reference 8.5-103.
From these data, estimates of the curfew induced incremental delays were developed.
Shown in Table 4-7 are thebe estimates for the year 1974. The basic approach to
developing these estimates was to estimate the normal capacity of each sample airport
by compounding the annual capacity growth rate from the year of interest (1974). A
"virtual" 10 percent increase in capacity was then applied to develop the curfew in-
duced flight activity level at each airport. Using an annual delay versus annual
airport activity figure from Reference 8. 5-103, delay times were estimated for each
airport. Assuming that the relative shares of percentage of total delays remain con-
stant for each airport, the net curfew induced delays were extrapolated to a national
number. Shown in Table 4-8 are the delay estimates for the year 1980. From these
two tables, the delay times associated with each intervening year can be estimated
under a uniform growth assumption. Multiplying these delay times by the respective
airline and passenger delay costs from Reference 8.4-182, yields the airline and user
cost impacts shown in Table 4-1. (See Page 4-11)
Impact on Air Cargo Service*
Since approximately 50 percent of air cargo moves in passenger aircraft, the
impact of a curfew on this portion of the business would be included in the passenger
service calculations. The remaining 50 percent moves in all-cargo aircraft which
fly almost exclusively at night.
It is difficult to estimate the impact on system economics if a curfew required
a rescheduling of these aircraft since the combination carriers themselves (other
than exclusive air cargo carriers) have little feel for the value of cargo business.
The traditional service pattern of overnight delivery is such that there is a large
influx of shipments into the freight terminals after the close of business of shipper
firms. The resulting congestion often exceeds the ability of the freight facility to
handle the shipments. Additional people must be employed (at evening rates) for
these peaks and must be paid a full day's wage even if they are needed only for a few
hours. (This reduces the productivity of employees in the air cargo industry to about
* The major portion of this discussion has been taken from Reference 10-271.
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TABLE 4-7. ESTIMATES OF CURFEW INDUCED INCREMENTAL DELAYS
(a) 1974
i
Oi
co
AIRPORTS
O'HARE
JFK
LAGUARDIA
ATLANTA
LOS ANGELES
NEWARK
MIAMI
SAN FRANCISCO
PHILADELPHIA
WASHINGTON NAT'L
ST. LOUIS
1974 CAPACITY
(OOOOPS./YR.)
636
355
266
410
426
195
265
307
197
228
198
CURFEW INDUCED
1974 CAPACITY
(OOOOPS./YR.)
700
391
293
451
469
215
292
338
217
251
218
NORMAL
DELAY TIME
(000 MINUTES)
960
550
410
625
660
295
410
470
295
350
300
CURFEW
INDUCED TOTAL
DELAY TIME
(000 MINUTES)
1600
820
600
960
1200
395
600
680
395
520
400
NET CURFEW
INDUCED DELAY
(000 MINUTES)
640
270
190
335
540
100
190
210
100
170
100
TOTAL:
2845
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TABLE 4-8. ESTIMATES OF CURFEW INDUCED INCREMENTAL DELAYS (b) 1980
AIRPORTS
O'HARE
JFK
LAGUARDIA
ATLANTA
LOS ANGELES
NEWARK
MIAMI
SAN FRANCISCO
PHILADELPHIA
WASHINGTON NAT'L
ST. LOUIS
1980 CAPACITY
(OOOOPS./YR.)
676
376
283
474
452
218
296
352
220
255
222
CURFEW INDUCED
1980 CAPACITY
(OOOOPS./YR.)
743
414
311
522
497
240
326
387
244
281
244
NORMAL
DELAY TIME
(000 MINUTES)
1100
580
420
710
700
330
460
525
330
390
335
CURFEW
INDUCED TOTAL
DELAY TIME
(000 MINUTES)
1750
910
680
1300
1250
495
690
810
495
580
500
NET CURFEW
INDUCED DELAY
(000 MINUTES)
650
330
260
590
550
165
230
285
165
190
165
TOTAL:
3580
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1/lOth of that in the trucking industry.) After the peak, the facilities stand nearly idle
until the next evening. As a result of this cyclic peaking, then idle, capacity at least
one-half of the costs of moving air freight are for ground handling. Because of such
activity cycles, night-time operations are at least part of the reason for this loss.
Thus, the carriers themselves would prefer to transfer a large part of their cargo
activities to day hours to spread the traffic flow and make better use of manpower and
facilities. With the advent of the widebodied jets with their large cargo compartments,
the airlines are now able to move more freight during the day on scheduled passenger
flights. In fact, the use of such "belly" capacity can greatly improve the profitability
of passenger flight and offset the low-load factors often experienced on widebodied
aircraft.
For all these reasons, the elimination of all-cargo flights at night might actually
improve the financial performance of the air system rather than create additional
costs. However, the airlines contend that all-cargo service cannot be evaluated apart
from overall system cargo service because the existence of freighters, properly
marketed, generates traffic for the total fleet. Often more traffic will be delivered
for a freighter flight than can be accommodated so the overflow moves as belly freight
on passenger flights. Also, once a shipper has stopped to make one delivery, he may
use the same airline to ship additional goods to other places rather than go to other
terminals. On the other hand, airlines argue that night-time capacity will be required in the
future because of the rapid expansion of the air cargo business (as indicated by the 400 per-
cent increase in the overall volume of domestic air freight from 1960 to 1970 and the
even greater growth rate for all-cargo aircraft traffic).
It is impossible to evaluate the importance of these factors or to predict how they
might change if all-freight aircraft were still available but required to fly by day.
Rather than attempt to quantify the effects of a curfew on shipments by examining the
carrier's performance, it may be useful to examine the needs of the shipper.
Air cargo shipments can be placed in three distinct categories:
1. routine non perishable planned traffic;
2. routine perishable traffic that is time-sensitive, but its movement
planned in advance; and
3. emergency traffic which is unplanned and highly time-sensitive.
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A curfew would have little effect on the first two, since day freighter service could
be planned as an alternative. Also, since these types of shipments can be anticipated .
and containerized more easily than unplanned emergency traffic, they represent lower
cost to the airlines. Thus, a marketing thrust can be anticipated in the direction of
high-density, high-volume regular movements with a corresponding de-emphasis on
emergency cargo.
The real impact of a curfew on air cargo movements is on the emergency ship-
ments. It is assumed that 50 percent of all air freight is emergency traffic or at
least perceived to require emergency shipment by the shipper. It can further be
assumed that most of these shipments are not perishable, since a shipper of perish-
able goods would normally anticipate and plan his shipments in advance. Therefore,
under these assumptions a few hours' delay in most "emergency" traffic will result
primarily in inconvenience, not spoilage.
The emergency market can be divided into two geographic markets—one where
alternate service by truck exists, and one where it does not. If truck service is a
viable alternative, then most emergency shipments probably already move by truck
because the cost is about half that of air service. Assuming an average speed of 50
miles per hour for trucking, a pick-up made at 5 p.m. could be delivered anywhere
within a 750-mile radius by 8 a. m. the next morning. Assuming a 500-mph speed
for aircraft, a jet could also provide overnight service in this market if it could
depart before 8:30 p.m. (in order to arrive before the 10 p.m. curfew is enforced).
If the plane could not depart until 7a.m. the next morning, it still would provide
faster service than the truck for distances beyond 850 miles (the distance of an over-
night truck drive plus the additional distance the truck could travel in the two hours
necessary for the plane to overtake it). Over greater distances, aircraft would have
a clear speed advantage. Therefore, much of the emergency traffic that moves by air
today would still go by air since there is little alternative. The difference would be
that shipments would not arrive as quickly as they do today.
The major problem would be for emergency shipments moving east since time
zone changes decrease the apparent speed of aircraft. To arrive on the east coast
before 10 p.m. a flight would have to leave the west coast before 2 p. m. (5-hour
flight plus 3-hour time zone change). This would essentially preclude any shipments
that could not be picked up from the shipper before 10 or 11 a. m. Alternatively, it
would be possible for a plane to depart the west coast at 10 p. m., delay one hour in
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flight and arrive on the east coast at 7 a. m. (5-hour flight plus 1-hour in-flight
delay plus 3-hour time zone change). This would increase the cost of such a flight
by 20 percent because of the hour delay, but the cost could be passed along to the
shipper if he really desired next-day delivery.
Failing either of these two options, the shipper would have to wait for a 7 a.m.
departure the next morning, arriving on the east coast at 3 p. m. with little likelihood
of delivery until the following morning. With these alternatives in mind, the shipper
would probably become more conscious of which shipments were really emergency
and which were not, paying the premium for overnight service only when it was
justified.
Summarizing these effects:
1. The 50 percent of air cargo that presently moves in passenger
aircraft would not be affected by a 10 p. m. to 7 a. m. curfew.
2. Assuming 50 percent of the remaining air cargo is perceived as "emer-
gency" traffic then 50 percent of the freighter traffic presently moving
at night is non-emergency and could be diverted to day flight.
3. The 50 percent emergency traffic moving at night is 25 percent
of the total air cargo traffic. In most cases, next day delivery
could still be achieved by either getting the goods to the airport
in time for a precurfew departure or by settling for a mid-day
delivery the next day, based on a post-curfew departure. Since
the shipper has little alternative, he would still use air service
for most of these shipments although it would not be as con-
venient as without the curfew.
4. The greatest impact on traffic is on shipments moving from the
west coast to the east coast. Assuming that half the total air
cargo moves north-south and half moves east-west, then only
half of the 25 percent (or 12. 5 percent) of the total traffic
that represents emergency shipments moves in the cross-
country direction. The half of this that moves.east to west is
much less sensitive to curfew effects. Of the remaining
traffic moving west to east, perhaps only half is transconti-
nental. The rest is distributed at lesser distances and there-
fore capable of mid-day delivery on the next day after shipment.
Therefore, only 3.125 percent of the total air cargo traffic
(transcontinental eastbound emergency traffic presently moving
in night freighters) could be severely restricted by a curfew.
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5. However, this 3.125 percent of the traffic could still move on an
overnight freighter by paying a 20 percent premium. Assuming the
-0.7 elasticity used for passenger traffic (which is not unreasonable
since "emergency" traffic is relatively insensitive to price changes),
14 percent (-0.7 x 20 percent rate premium) of 3.125 percent would
be lost. Thus the total air cargo traffic loss attributable to a curfew
would be 0.4375 percent.
6. Since domestic air cargo shipments provide about 6.5 percent of
total air system revenues, this traffic loss would decrease revenues
by . 028 percent (6.5 percent x . 004375). Based on total system
revenues estimated in Reference 8.4-214, these lost revenues are
estimated as shown in Table 4-1.
Impact on Mail and Express
Mail traffic represents about 3.3 percent and express about 0.4 percent of total
system revenues, approximately half that of cargo. Following a similar type of
analysis, the impact of a curfew on air system costs and revenues due to changes
in the carriage of mail are very small. * Here, however, public convenience may be
more important.
Most of the country could still receive one-day delivery from other areas if the
postal service were to shift its delivery service to afternoon, allowing most north,
south and westbound flights to leave at 7 a. m. and arrive in time to distribute the
mail. In lieu of this, a change in postal pickups could allow earlier sorting and
delivery to planes in time to depart early evening and still arrive in time for night
sorting and next-morning distribution of mail. In short, a great deal of the incon-
venience could be minimized by revised pickup and delivery services.
The worst case, as with cargo, is overnight service from the west coast to the
east coast. But again, premium service could be available on departures just prior
to the start of the curfew.
Banks would perhaps be hurt most by delayed express deliveries. It has been
estimated that a curfew would cost New York banks $34.8 million per year in lost
interest because of delays in handling transactions between banks, the Federal
Reserve and the bank clearing houses. It can be assumed, however, that much
*Note that an implicit assumption has been made that the peak volume periods for
mall processing can be shifted to coincide with the curfew restrictions.
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of this loss could be regained by earlier processing by using computers or hiring addi-
tional personnel, so that shipments could be made on earlier flights. The cost of
these measures would be considerably less than the potential loss of interest and
actually benefit the regions involved by higher employment.
Impact on Maintenance and Repair Activities
In a recent airport curfew case in California, the district court opinion spent some
time discussing the potential impact of a curfew on maintenance and repair activities,
concluding that considerable cost increases would result. * However, it is doubtful
whether this would really occur. About 2 percent of all present flights are non-revenue
operations connected with maintenance, training or movements to reposition equipment.
Most of these are planned well in advance, however, so those influenced by a curfew
could be eliminated by schedule changes. In addition, because of the high reliability of
present jet aircraft, most maintenance is done on an as-needed basis. Many airports
are already equipped to do various minor repairs and backup aircraft are available if
major repairs require an empty flight to a repair base. Thus the unnecessary duplicate
facilities feared by the court either already exist or are really not needed. In either
case, the additional aircraft purchases required as a result of rescheduling passenger
service would provide enough flexibility to alleviate many of the scheduling and plan-
ning problems associated with maintenance activities.
Impact on International Operations
Many major foreign airports have instituted nighttime curfews on aircraft opera-
tions. Typically, these curfews are in effect during 11 p. m. through 6 a. m., local
time. Due to these curfews, the departure and arrival windows of flights to and from
these foreign airports, and U. S. airports, have shrunken to approximately 17 hours a
day. However, public convenience; i. e., the ability of a traveling public to travel when
it wishes, apparently has not been diminished significantly by the imposition of these
curfews.
What must now be determined are the effects on the aircraft activity windows
and the attendant impacts on public convenience of instituting a U. S. curfew between
* 318 F. Supp. 914 (C. D. Cal. 1970)
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10 p.m. and 7 a.m. Flights to and from JFK and SFO to Paris, France and Tokyo,
Japan were analyzed for the curfew effects on both passenger and cargo freighter
operations.
On passenger flights from JFK to Paris, the departure window shrinks from
17 hours to approximately 8 hours. However, on checking the flight schedules of two
domestic airlines on this route, not one daily scheduled passenger flight would be
eliminated! The departure window on flights from the West Coast to Paris shrinks
similarly from 17 hours to 8 hours. Again, for these same airlines, no currently
scheduled daily flight would eliminated.
If a U. S. curfew were implemented, then for flights from Paris to JFK, the window
shrinks from 17 hours to approximately 15 hours. Understandably, not one currently
scheduled passenger flight would be affected by this curfew. For flights from Paris
to the West Coast of the U. S. the window shrinks to 11 hours. Again, no currently
scheduled flights would be affected.
Flights from JFK and the West Coast to Tokyo currently have 16 and 17 hour
departure windows, respectively. The adoption of a U.S. nighttime curfew will
decrease these departure windows by no more than two hours. Daily flight schedules
for a domestic and foreign flag carrier were analyzed to ascertain whether any
currently scheduled daily flights would be cancelled. Again it was found that no
currently scheduled flights of these two airlines would be cancelled or re-scheduled
as a result of implementing a U. S. night curfew on airport activity. With the
implementation of a national curfew the windows on flights from Tokyo to the West
Coast and JFK will decrease, respectively, to approximately 12 and 10 hours. How-
ever, no flights of the airlines investigated would be cancelled.
Assuming that daily flight schedules reasonably reflect the public's travel require-
ments, it appears that international passenger traffic between the U. S. and the two
foreign airports considered would not be affected by the implementation of a national
curfew. If one further assumes that these foreign airports are gateways for a major
portion of European and Far Eastern travel, it would appear that a significant share
of the currently scheduled international traffic would not be affected by the implemen-
tation of a U. S. nighttime curfew. With the advent of the tourist season, this finding
may change somewhat.
4-70
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The passenger arrival and departure windows stated above also obtain for the pure
cargo freighter activity. On reviewing the U. S. freighter departure schedules of the
subject airlines it was found that every flight would be affected. Each flight was found
to be in violation of the U. S. curfew by roughly 2 hours. It would not be unreasonable
to expect that such flights could be rescheduled to depart earlier, thereby reducing the
impact of the curfew. However, due to the recent devaluations of the dollar, export
cargo traffic or volume should be expected to increase. *
The increase in this export volume may be such that additional freighter flights
are necessary. Given this situation and the advent of the tourist season, it then
follows that more daily international flights will occur. Such increased activity in
turn will result in departure and arrival delays and flight diversions. As no interna-
tional delays and diversion data are available and also that the extent of the tourist
and export/import cargo effects of the devaluation has yet to be determined, then the
effects of a national curfew on international traffic cannot be monetized at this time.
However, from the currently scheduled flight activities, if they represent travel and/
or shipping desires, it appears that implementation of a national curfew will not
cause catastrophic structural dislocations in international patterns of air transport
user requirements.
The Noise Reduction Effectiveness of a Curfew
Most techniques for measuring the cumulative effects of aircraft operations over
time place a heavier annoyance weighting on nighttime operations than those during the
day. The Cumulative Noise Forecast method considers a flight between 10 p. m. and
7 a. m. to be as intrusive as would a higher multiple of daytime flights. As a result,
the elimination of these heavily weighted night operations through the imposition of a cur-
few yields a dramatic reduction in L, levels with a corresponding decrease in the
land area within any given Ldn contour.
Applying the mathematics of L calculations to the assumptions used in deter-
mining curfew costs (i. e., 15 percent of the present total operations occur during the
proposed curfew period, 1/3 of the cancelled flights could be shifted to non-curfew
hours and 1/3 could be rescheduled with new aircraft), calculations show that a 10 p.m.
* Conversely, import cargo volume should at least stabilize if not decrease.
4-71
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to 7 a. m. curfew would result in a 5 to 6-db reduction, which in turn would reduce
the land area exposed to any L^ level by approximately 60 percent. * Potential damage
costs would then be reduced proportionally. This reduction would be in addition to any
other noise abatement technique employed and would be based on the total land area
exposed at the time of the curfew's implementation. It should be mentioned here that
the exposed population distribution (Fig. 4-1) upon which the damage award costs were
calculated shifts downward with the passage of time due to the natural retirement of the
noisier aircraft and the introduction of relatively quieter aircraft into the fleet.
Summary of Curfew Costs
As shown, a national curfew implementation would affect maintenance, mail and
express, air cargo and passenger operations. The major impacts on the national
airline system are the costs associated with the additional delay times. Airline
operating costs are also affected through the purchase of additional aircraft, and the
hiring of crews to fly them, to make up the capacity lost by the inability to move
aircraft at night. The effects on cargo are the relatively small loss of business. A
summary of these costs is shown in Table 4-1. Finally, by implementing a national
curfew, the airport operators are able to avoid a significant portion of the estimated
potential damage awards and the costs required to protect public health and welfare
once such standards are promulgated. In retrospect, it does not appear that litigation
awards will provide sufficient market incentive to trigger a national curfew. This fol-
lows from the very low success rate to date in such litigation. The real incentive to
implement curfews will stem from the execution of the Noise Control Act provisions and
the share of land use costs that airport operators must incur if no source abatement
technology is transferred to the active civil fleet.
*Ref. 10.4-441 found that for twelve of the nation's most severly noise impact air-
ports, the areas for any L, level would decrease approximately 35 percent.
4-72
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SECTION 5
SUMMARY AND CONCLUSIONS
The degree of aircraft source noise reduction is time-dependent and based upon
an effective program of technological development and demonstration.
The current state-of-the-art has progressed to the point where there are tech-
nology options available, which can be initiated immediately, to reduce the noise
generated by the civil jet aircraft fleet. Other development programs indicate the
potential for greater noise benefits at some later date at greater cost.
An optimum solution to the aircraft noise problem is a comprehensive, dedicated
program taking advantage of current techniques and technologies for near term noise
relief and providing assurance that future generations of transport aircraft will be
less obtrusive to the airport neighbor.
In the context of achieving a goal of a certain level of cumulative noise exposure,
it has been found that the cost of introducing currently available noise reduction tech-
nology into the civil aviation fleet is always less than the cost of achieving such levels
not utilizing this technology. Therefore, on a rational use of resource basis, retrofit
of state-of-the-art technology into the civil aviation fleet must be an integral part of
any comprehensive program of cumulative noise reduction around airports.
CURRENT TECHNOLOGY STATUS
The present FAA noise standard, FAR 36, Appendix C, essentially put an upper
limit on the generation of noise for newly certificated aircraft. However, the major
portion of both the commercial air carrier fleet and the jet powered segment of the
general aviation fleet exceed those limits. These aircraft are expected to continue
to represent a dominant part of the inventory into the 1980's, thus masking the noise
improvements being realized by the newer, quieter widebodied jets.
Demonstrated current technology can provide the means to bring all of these
aircraft under the noise "umbrella" of FAR 36. This could be accomplished by the
1977 to '78 time period if an enforced noise abatement program is initiated immediately.
5-1
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Meeting the present requirements of FAR 36 should not be interpreted as being
the ultimate in noise reduction. The noise levels identified therein were based upon
the technology available at the time of issuance of the rule. Present and future tech-
nological developments will permit a lowering of the allowable source noise level
(See Task Group 5 Report).
FUTURE TECHNOLOGY STATUS
The NASA Experimental Quiet Engine Program successfully demonstrated the
feasibility of realizing significant reductions in source noise in future engine
developments. The capability now exists within industry to produce advanced-
technology engines and transport aircraft with source noise levels approximately
5 to 10 EPNdB below the current FAR 36 requirement. With appropriate incentives
and funding, these vehicles could be operational by 1980.
The same degree of noise reduction has not been demonstrated for the smaller
engines that are compatible with the business jet aircraft requirement. Comparable
research and development in noise abatement concepts for this class of engines and
aircraft has not been accomplished.
Further reductions in engine-generated noise may have limited effectiveness,
since it appears that a noise floor, due to external aerodynamic flow, is present
during the approach and landing pattern. This is due to the relatively dirty, flaps
down, wheels down, configuration in which the flow over these appurtenances has
been estimated to generate a noise level of approximately FAR 36 levels minus
5 to 10 EPNdB.
New propulsion system concepts, particularly for RTOL and STOL-type aircraft,
are in the early stages of development. Very high-bypass fans, such as the prop-fan
concept, are currently being evaluated for future air carrier and general aviation
type aircraft. Aircraft component developments, such as blown flaps, quieter heli-
copter rotor systems, while requiring additional development and demonstration
testing, are all designed to provide a reduced future noise environment.
A continuing, but accelerated, technology research and demonstration program
is imperative to provide early implementation of advanced concepts in source noise
abatement.
5-2
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SECTION 6
RESEARCH AND DEVELOPMENT RECOMMENDATIONS
The discussions in Sections 2 and 3 illustrate that extensive noise source
research and development work has been and continues to be conducted by Government
and industry. It is clear that considerable state-of-the-art technology is available
for immediate application and that significant R&D effort is in progress for near-
future utilization. Most of the R&D costs to date have been borne by the Federal
Government, but not all. Industry has recognized that noise is an inhibiting factor
to the promotion, encouragement, and development of civil aeronautics and has con-
tributed substantial in-house funding to noise control. If the current and near-future
source noise abatement technology were fully exploited, the noise exposure would
drastically decrease, and a great deal of the noise impacted airport neighborhoods
would experience welcome relief.
The R&D conducted to date, however, is by no means complete. New and more
efficient aviation systems are needed and are under consideration. These systems
may introduce noise characteristics and special problems that have not yet been
adequately investigated. More R&D is required if civil aviation is to continue to
grow and at the same time drastically reduce its noise emissions. The costs of the
necessary R&D probably cannot be borne by the aviation community alone. The
Federal Government, in order to ensure that civil aviation continues to be a viable
national asset without jeopardizing the public health and welfare, must assume the
R&D leadership, both in funding and technical direction, to the extent necessary for
industry to continue on its own.
Research and development recommendations for aircraft noise control are well
documented in a Society of Automotive Engineers Aerospace Information Report (SAE
AIR 1079), and those relevant to this report are included in the following paragraphs.
COMPONENT TECHNOLOGY
The following research areas relating to components or systems have general
application to a wide variety of aircraft and engine types.
6-1
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POWER SOURCES
Engine and auxiliary power unit (APU) noise is generated by:
• Rotating components such as fans, compressors, turbines, propellers,
rotors, and gears.
• Airflow interactions with such internal components as struts, vanes,
surfaces, and burners.
• Accessories
• Mixing of exhaust jets with the ambient air.
Investigation is required to identify the mechanisms of noise generation in each
case, to relate the noise of the various sources parametrically to operational vari-
ables, to establish reliable procedures for determining the relative strengths of the
various sources, and to develop effective and practical methods of noise reduction.
DUCT TREATMENT MATERIALS AND TECHNOLOGY
This technology relates to the application of sound absorbing materials to the
interior passages of the airflow ducts of all types of jet engines, to reduce the noise
propagating in the ducts and thus minimize the noise radiated from the nacelles.
Additional work is needed to optimize the acoustical, mechanical, and aero-
dynamic properties of the sound absorptive materials and the duct lining configura-
tions. Of particular importance is the development of general methods for predicting
the acoustical performance of duct treatment for specific applications and the limit
of effectiveness governed by self noise (aerodynamic flow).
CABIN NOISE
It has become customary to specify the airplane cabin noise environment in terms
of overall sound pressure level (OASPL) and a speech interference level (SIL). The
OASPL normally represents the low frequency end of the spectrum, and the SIL repre-
sents the medium to high frequency end. The use of OASPL and SIL has, in some
cases, been shown to be an unsatisfactory means for indicating cabin acoustical accept-
ability. Investigation into more satisfactory forms of passenger cabin and crew com-
partment noise criteria is needed to provide a basis for guiding fuselage wall and
interior acoustical design.
6-2
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NOISE MEASUREMENT AND ANALYSIS
Continuing review and improvement of noise measurement and analysis instru-
mentation and procedures is needed to keep pace with regulatory and monitoring
requirements. Among items that should receive immediate attention are analyzer
characteristics and procedures for defining tones in aircraft noise, integration times
for analyses of flyby noise measurements, specification of test sites, and method
of correction for ground plane effects.
ENGINE AND AIRCRAFT TECHNOLOGY
The following research areas are pertinent to particular types of aircraft and
their propulsion systems.
SUBSONIC AIRCRAFT
• Engine compressor and fan noise generation, prediction, and reduction.
• Engine duct treatment technology.
• Development of prediction and reduction techniques for medium (1000 to
2000 ft./sec.) and low velocity (below 1000 ft./sec.) jet exhaust noise
including flight (relative velocity) effects.
• APU noise prediction and control.
• Aircraft interior noise criteria and evaluation.
• Subjective response to flyby, ramp, and interior noise.
SUPERSONIC AIRCRAFT
• Development of prediction and reduction techniques for high velocity (above
2000 ft./sec.) jet exhaust noise including afterburner operations and flight
(relative velocity) effects.
• Sonic boom generation, propagation, and effects.
• Sonic boom abatement operational techniques.
• Subjective reaction, particularly related to low frequency noise and sonic
booms and to associated vibrations.
• Cabin noise prediction and evaluation for supersonic cruise.
6-3
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V/STOL AIRCRAFT
• Prediction of noise characteristics of integrated lift-propulsion systems.
• Prediction of noise characteristics of variable camber, including
shrouded, propellers.
• Prediction of noise characteristics of deflected jet streams.
• Subjective reaction, particularly relating to low frequency noise and long-
time exposures.
• Cabin noise reduction.
HELICOPTERS
• Main-rotor noise generation, prediction, and reduction.
• Rotor/rotor and rotor/propeller interaction effects.
• Cabin noise reduction.
GENERAL AVIATION AIRCRAFT
• Engine exhaust muffler technology.
• Noise reduction for slow-turning multiblade propellers.
• Engine mechanical and intake noise reduction.
• Cabin noise reduction.
AIRCRAFT DESIGN
The development of new structural design concepts to lower aircraft gross weight
for a given mission, improve aerodynamic efficiency for better aircraft performance,
and optimize engine placement should be investigated for beneficial effects on noise
exposure.
In future aircraft designs, consideration should be given, in the preliminary design
stage, to those components and design parameters that would permit more extensive
use of preferential runways under high crosswind and gust conditions.
6-4
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Airframe noise, defined as the noise generated by an aircraft in flight from
sources other than the engine, auxiliary power units, and machine accessories,
is the floor that establishes the limit of effectiveness of the current noise control
state-of-the-art for aircraft during approach operations. Additional research and
development is needed on noise generated by airflow over fuselage, wings, nacelles,
flap systems, landing gear struts, wheel wells, etc., in order to provide data to
assist designers in developing future technology aircraft capable of conforming to
lower noise levels than are now achievable.
NEW ENGINE DEVELOPMENT
The NASA Quiet Engine Program provided the technology to permit the develop-
ment of quieter engines for the next generation of commercial transports. Since the
propulsion system is the longest lead time component for a new aircraft system, its
development must be initiated now if new quieter aircraft are to be introduced into
the fleet by 1980. Direct support of a new commercial engine development program
or, as an alternative, accelerated development of the Air Force ATE program, from
which commercial derivatives will be developed, is strongly recommended as a tool
for future aircraft noise control.
OPERATIONAL PROCEDURES
Study of the optimization of takeoff and landing operations for noise minimization
should continue, with attention given to such items as takeoff cutback procedures,
optimum flap settings, optimum speeds, and approach path alternatives. In parallel,
it is necessary to develop specialized instrumentation for use on board aircraft or on
the ground to enhance the noise abatement procedures. A detailed discussion of the
noise reduction benefits associated with the use of modified operational procedures
is covered in the Task Group 2 report.
GENERAL
The DOT/NASA Joint Office of Noise Abatement (JONA) has begun the development
of an integrated long-range plan for aircraft noise abatement research and develop-
ment which covers the following subject matter:
1. Community Acceptance
6-5
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2. Existing CTOL Aircraft
3. Advanced CTOL Aircraft (Including SST)
4. General Aviation Aircraft
5. Powered Lift Aircraft (STOL, RTOL, and VTOL)
6. Basic Noise Research
7. Aircraft Systems Analysis
The plan, while still in the formative stage, appears to be sufficiently comprehensive
to cover all important aspects of aircraft noise control for the foreseeable future.
Complementary to the long range plan, NASA has created a new Aircraft Noise
Prediction (ANOP) Office, initiated an Aircraft Noise Prediction Program (ANOPP),
and established a technical advisory group of Government personnel from DOD, DOT,
EPA, HUD, and NASA. The purpose of these actions is the development of accurate
prediction techniques for noise generated by aircraft. This is essential in evaluating
community impact of new modified aircraft systems as well as for screening aircraft
and engine component and system concepts to guide research efforts aimed at noise
reduction. Predictions will be developed in such forms as peak noise levels and
spectra, noise time histories, noise "footprint" contours and as various measures of
community impact.
The most effective use of technology to achieve maximum noise control is in the
design and development of new aircraft systems. Consequently, noise abatement
research and development (both for source control and flight procedures) must continue
to be adequately funded to insure that these new aircraft systems evolve with the cap-
ability for substantially less noise impact than exists for current aircraft. The JONA
Long Range Plan and the NASA ANOP Office, if adequately funded and staffed, has the
potential for accomplishing this objective.
6-6
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REFERENCES AND BIBLIOGRAPHY
-------
TABLE OF CONTENTS
Item Categories page
1.0 Airport Operators/Owners 1.1
2.0 Aircraft Engine Manufacturers 2.1
3.0 Aircraft Manufacturers 3.1
Jf.O Airlines if.1
5.0 Individuals 5.1
6.0 Environmental Groups 6.1
7.0 Federal Government: Aviation Advisory
Commission 7.1
8.0 Federal Government: DOT/FAA 8.1
9.0 Federal Government: DOD 9.1
10.0 Federal Government: EPA 10.1
11.0 Federal Government: NASA 11.1
12.0 Federal Government: U.S. Misc. & Foreign 12.1
13.0 Professional And Trade Groups 13.1
1^.0 Regulatory and Legislative Considerations 14.1
15-0 State And Local Governments 15.1
R-i
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1-0 AIRPORT OPERATORS/OWNERS
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
58 J. D. Reilly, Ltr: "Noise Rules for Supersonic
Transport," AOCT, 6 March 1973.
60 C. A. Moore, "Presentation to the Board
of Airport Commissioners of Management's Re-
commendation for Airport Regulations and Policies
Designed to Reduce the Noise Contours at Los
Angeles International Airport," Los Angeles
Department of Airports, 20 December 1972.
6l N. Ewers et al, "Results of an Area Wide
Noise Monitoring System," Presented to the
Acoustical Society of America, Date unknown.
8? J. D. Reilly, Ltr: "Response to ANPRM 73-3
Docket No. 12531*-/' Airport Operators Council
International, 7 March 1973-
187 R. J. Bresnahan, "Effectiveness of the ECOLOG I
Noise Monitoring System Installed at Orange
County Airport as a Noise Abatement Tool,"
Orange County Airport, 16 March 1973-
191 G. J. Bender, Jr., Ltr: "Two Segment Approach Procedure
and Wake Turbulence," Boston-Logan International
Airport, l6 March 1973-
278 Resolution No. 7^83, Los Angeles International Airport
Board of Airport Commissioners. Subject: "Aircraft
Sound Description System (ASDS)," 20 Dec. 1972.
352 Pamphlet: "What is Massport Doing about Airport Noise,"
Mass. Port Authority, Date Unknown.
287 Press Release: Five-Point Program to Alleviate Airport
Noise; Los Angeles Department of Airports, 20 Dec 1972.
288 Resolution No.7^6?: Resolution Adopted Five-Point
Program to Alleviate Airport Noise; Board of Airport
Commissioners, Los Angeles International Airport,
20 Dec 1972.
R-l.l
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1.0 AIRPORT OPERATORS/OWNERS (CONT'D)
MASTER
FILE .
NO. BIBLIOGRAPHIC CITATION
289 ' Resolution No.7^8^: Resolution Affirming Support of
Parts of Joint Policy Statement Issued by Airport
Communities; Board of Airport Commissioners, Los Angeles
International Airport, 20 Dec 1972.
290 Resolution No.7^8^-A: Resolution Recommending the
Adoption of Appropriate Legislation to Effect Stronger
Methods of Compatible Land Use in the Surrounding
Communities; Board of Airport Commissioners, Los Anp;elen
International Airport, 20 Dec 1972.
392 "Los Angeles International Airport-Environmental Impact
Study" Phase I Report. Northrop Corporation for the
Los Angeles Department of Airports, Jan 17, 197^.
Clifton A. Moore, Ltr. with Enclosure, "Comments on
Draft Reports by Task Groups on Airport Noice",
Department of Airports, City of Los Angeles,
29 June 1973.
. Louis Achitoff, Ltr. with Enclosure, "Comments with
Respect to Task Group 4 and 5 Reports", The Port
Authority of New York and New Jersey, 29 June 1973.
"Ontario International Airport Environmental Impact
Study" Volume 1-Executive Summary; Volume 2-Air
Pollution and Related Studies; Volume 3- Aircraft
Noise Studies; Volume '4-Biological and Related
Studies; Volume 5-Economic Studies. Northrop Corporation
for the Los Angeles Department of Airports, June 1973.
"Ontario International Airport: Draft Environmental
Impact Statement; Pursuant to Section 102(2)(c),
Public Law 91-190" Northrop Corporation for the
Los Angeles Department of Airports, June 1973-
"Draft Environmental Impact Statement Pursuant to
Section 102(2)(c) Public Law 91-190" Submitted by
Board of County Road Commissioners Wayne County,
Michigan to Department of Transportation, Federal
Aviation Administration, April 1973-
R-1.2
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2.0 AIRCRAFT ENGINE MANUFACTURERS
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
2 "Noise Reduction Programs at Pratt and Whitney
Aircraft," Presented to the Environmental
Protection Agency Aircraft/Airport Noise Study
Task Group 4, 28 February 1973, (Rev) Ik Mar '73.
15 W. G. Cornell, "Selective Bibliography of General
Electric Reports on Aircraft Noise Research and
Development," Submitted to EPA Aircraft/Airport
Noise Study Task Group U, 27 February 1973.
67 U. S. and International Commercial Jet Transport
Fleets, Pratt and Whitney Aircraft, February 15, 1973
Ik W. E. Helfrich, "Noise Reduction Program at Pratt
& Whitney Aircnft," Presented to the Environmental
Protection Agency, Pratt & Whitney Aircraft,
February 28, 1973-
8l W. G. Cornell, "Supplementary Bibliography of General
Electric Reports and Papers," General Electric, 15 Mar'73.
82 W. G. Cornell, Ltr: "ANPRM 73-3," General Electric,
15 March 1973.
93 "Supersonic Transport Noise Reduction Technology
Program—Phase II," Report No. DOT-FA72WA-289<>,
Aircraft Engine Group, General Electric Quarterly
Progress Report, 1 December thru 28 February 1973.
12U "Preliminary Engine Definition and Characteristics
of the JT3D Quiet Engine," Pratt and Whitney,
September 14, 1972.
125 "Preliminary Engine Definition and Characteristics
of the JT8D Quiet Engine," Pratt and Whitney,
October lkf 1972.
126 "Final Phase I Engine Definition and Characteristics
of the JT3D--9 Engine," Pratt and Whitney, 14 Dec '72.
38? W. E. Helfrich, Ltr. "Core Engine Noise Levels for
JT8D Refan Engine," Pratt and Whitney Aircraft,
6 June 1973.
L.G. Dawson and T. D. Sills, "The Changing Environment
and Propulsion", Presented to the 13th Anglo-American
Aeronautical Conference, London (k-8 June 1973)i
Rolls-Royce (1971) Limited.
R-2.1
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2.0 AIRCRAFT ENGINE MANUFACTURERS (COM"D)
MASTER
FILE
HO. EIBIIOGRAPHIC CITATION
127 "Supplement 1 to Preliminary Engine Definition and
Characteristics of the JT8D Quiet Engine," Pratt
and Whitney, December 22, 1972.
134 "Preliminary Engine Definition and Characteristics
of the JT8D-100 Quiet Engine," PWA 1*671, Pratt
. . and Whitney, February 12, 1973-
306 M. C. Steele, 'Yiewgr^phs and Reference Material
Used in Presentation to EPA/ONAC Aircraft Noise
Task Group k," Garrett-Airesearch ^ April 197^.
170 VJT8D-100 Series: Current Performance Data,"
Pratt and Whitney Aircraft, 8 February 1973-
17^ W. G. Cornell, Ltr: "Comments on Various FAA Re-
gulatory Notices on Aircraft Noise," General
Electric, 2 April 1973-
197 "Visuals in Support of Presentation on Small Quiet
Engine-Nacelle-Airplane Program," Airesenrch Division
of Garrett Corporation, 18 April 1973-
198 "Visuals in Support of Presentation on Airssearch
Propulsion Engines," Airesearch Division of Garrett
Corp, 18 April 1973.
199 "Visuals in Support of Presentation on Effect of
Noise Regulations Program Schedule," Airesearch
Division of Garrett Corp., 18 April 1973.
200 "Visuals in Support of Presentation on Combustion
Noise and Emissions," Alresearch Division of Garrett
Corp., 18 April 1973.
201 "Visuals in Support of Presentation on Turbine
Noise Control, " Airesearch Division of Gsrrett
Corp., 18 April 1973-
202 "Visuals in Support of Presentation on Mechanical
Noise," Airesearch Division of Garrett Corp., 18
April 1973-
. J. N. Krebs, Ltr. "Views', on Aircraft Noise Regulations",
General Electric Co., 22 May 1973.
R-2.2
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2.0
AIRCRAFT ENGINE MANUFACTURERS (COKT'D)
MASTER
FILE
N0- BIBLIOGRAPHIC CITATION
203 "Visuals in Support of Presentation on V/STOL
Rotary Propulsion Study, "Airesearch Division of
Garrett Corp., 18 April 1973.
^ 'Visuals in Support of Presentation on Dual Bvoass
Turbofan Engine Concept," Airesearch Division of
Garrett Cbrp., 18 April 1973.
220 "Aircraft Engine Noise Reduction at Airesearch,"
Airesearch Division of the Garrett Corp., April 1973.
261 Comments On FAA Project Report, "Noise Certification
Rule for Quiet Short Haul Category Aircraft," Hamilton
Standard, 27 April 1973.
26if Comments On FAA Project Report, "Propeller Driven Aircraft
Noise Type Certification Standards," Hamilton Standard,
27 April 1973.
258 F- B- Metzger et al, "Noise Characteristics Of Quiet
Propellers For STOL Aircraft, Purdue Noise Conference,
15 July 1971.
259 F. B. Metzger et al, "New Low-Pressure-Ratio Fans for
Quiet Business Aircraft Propulsion, SAE Business Aircraft
Meeting, Wichita, 3-6 April. 1973.
2^° F. B. Metzger et al, "Low-Pressure-Ratio Fan Noise
Equipment and Theory," Journal for Engineering and
Power, January 1973.
356 W. E. Helfrich, Ltr. with Position Paper Related to Task
Group 4 Efforts, Pratt & Whitney Aircraft, 15 May 1973.
357 W. E. Helfrich, Ltr. with Position Paper Related to Task
Group 5 Efforts, Pratt & Whitney Aircraft, 11 May 1973.
365 "Q-FAN"; Report No.SP06A?2, Hamilton Standard Division
of United Aircraft Corp, Sept 1972.
375 E. G. Ratering and C. L. Walker, "General Motors
Statement Before the Environmental Protection Agency
Task Force on the Aircraft/Airport Noise Study," Detroit
Diesel Allison Division of General Motors, 21 June 1973-
R-2.3
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2.0 AIRCRAFT ENGINE MANUFACTURERS (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
"Visual Aids in Support of Oral Report on JT8D Refan
Program" Pratt and Whitney Aircraft, 25 July 1973.
R-2.4
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3 -0 AIRCRAFT MANUFACTURERS
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
1 V. L. Blumenthal, W. S. Huntington, J. M.
Streckenbach, "Noise-Reduction Research and
Development - 1972 Progress," Boeing Document
D6-60199, March 1973.
13 V. L. Blumenthal, R.E. Russell, J. M.
Streckeribach, "Summary Noise Reduction Research
and Development," Boeing Document D6-60146, November
1971-
1^ V. L. Blumenthal, J. M. Streckenbach, R. B. Tate,
"Aircraft Environmental Problems," AIAA Paper No.
73-5 AIAA 9th Annual Meeting and Technical Dis-
play, Washington, D.C., 8-10 January 1973.
k R. E. Pendley, "Noise Retrofit of DC-8 and DC-9
Airplanes," Presented to Subcommittee on Advanced
Research and Technology, House of Representatives
Committee on Science and Astronautics, Douglas
Aircraft Co., 19 January 1972.
7 "DC-9 Engine Noise Reduction Programs," Douglas
Aircraft Co. Report MDC-J4358, 5 January 1973-
8 A. L. McPike, "The Generation and Suppression of
Aircraft Noise," Douglas Aircraft Co. Report
710304, No Date.
9 R. E. Pendley, "Review of Programs Dealing with
Reduction of Subsonic Transport Noise at the
Source," Douglas Aircraft Co. Paper 5799, Presented
to Air Transport Association of America, Chicago,
Illinois, 26 May 1970.
10 A. L. McPike, "Evaluation of Advances in Engine
Noise Technology," Douglas Paper 5^31> Presented
to Eleventh Anglo-American Aeronautical Conference,
Royal Aeronautical Society, London, England,
8-12 September 1969.
R-3.1
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3.0 AIRCRAFT MAMUFACTURERS (CONI'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
11 P. E, Pendley, "Technical and Economic Feasibility
of Developing Hacelle Modifications to Reduce Fly-
over Noise of DC-8 and DC- 9 Airplanes," Douglas
Aircraft Co. Paper 583^, August 1970.
32 A. L. McPike, "Community Noise Levels of the DC-10
Aircraft," J. Aircraft Vol.9» No. 8, August 1972.
5 J. S. Gibson, "Non-Engine Aerodynamic Noise Tech-
nology and Impact," Lockheed-Georgia Co. Information
Brief, 21 February 1972.
6 J. S. Gibson, "V/STOL Noise Technology and Design
Considerations," Lockheed-Georgia Co. Information
Brief, 22 February 1972.
17 N. Shapiro, J. F. Schulert, "Improved Airport/
Community Noise Environment vith the New L-1011
Tri jets, " AIAA Paper No. 69-801, AIAA Aircraft
Design and Operations Meetings, Los Angeles,
California, 14-16 July 1969.
18 N. Shapiro, "Community Noise Levels of the L-1011
Tristar Jet Transport," Acoustical Society of
America, Buffalo, N. Y., 18-21 April 1972.
19 H. Drell, "Impact of Noise on Subsonic Transport
Design," Society of Automotive Engineers Paper
700806, Los Angeles, California, 5 -9 October 1970.
20 J. R. Thompson, M. J. T. Smith, "Minimum Noise
Pod Design," Society of Automotive Engineers
Paper 700805, Los Angeles, California, 5-9 October
1970.
21 N. Shapiro, G. J. Healy, "A Realistic Assessment
of the Vertiport/Community Noise Problem," J.
Aircraft, Vol. 5, No. U, July-August 1968.
22 N. Shapiro, J. W. Vogel, "Noise Certification of
a Transport Airplane," Inter-Noise 72 Proceedings,
Washington, D.C., k-6 October 1972
R-3.2
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3-0 AIRCRAFT MANUFACTURES (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
23 J. R. Thomson, N. Shapiro, "The Effect of
Temperature Inversions of Flyover Noise
Measurements," Symposium on Atmospheric Acoustic
and Noise Propagation, National Bureau of Standards,
Gaithersburg, Md., 27-29 September 1972.
28 "Concorde: Airport Noise andl Silencing Programme,
Annex 1, Test Facilities," SNIA , SNECMA, BAC
and Rolls Royce Limited, October 1972.
78 J. S. Gibson, "The Ultimate Noise Barrier—Far
Field Radiated Aerodynamic Noise," Lockheed-Georgia,
k October 1972.
88 H. W. Withington, "Response to ANPRM 73-3,
Docket No. 12531*, " Boeing Commercial Airplane
Company, 28 February 1973.
89 A. L. McPike, "Response to ANPRM 73-3, Docket
No. 12531*," McDonnell-Douglas, 1 March 1973.
90 A. L. McPike, "Copies of View Graphs Used in
Presenting A New Aircraft Noise Rating Concept,"
McDonnell-Douglas, 22 March 1973-
91 A. L. McPike, "The Relative Importance of Take-
Off, Sideline and Approach Noise," McDonnell-
Douglas, 22 March 1973.
96 A. L. McPike, * A Suggested Alternative Approach to
Controlling the Noise of the Fleet," McDonnell-
Douglas, 22 March 1973-
122 "707/JT3D -9 Refan Nacelle and Airplane Inte -
gration Definition," D3-9039-1, Boeing, November
10, 1972.
123 "707/JT3D-9 Refan Nacelle and Airplane Integration
Definition, D3-9039-1, Boeing, Second Submittal
January 15, 1973-
128 "DC-8 Series 6l Engine and Nacelle/Airframe Inte -
gration Definition," Report MDC J5731, McDonnell-
Douglas , November 10, 1972.
R-3. 3
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3.0 AIRCRAFT MANUFACTURERS (CONT'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
129 "DC-8 Series 6l Engine and Nacelle/Airframe Inte -
gtation," Report MDC J5731A., McDonnell-Douglas,
January 8, 1973.
130 "DC-8 Series 63 Engine and Nacelle/Airframe Inte -
gration Definition," Report MDC J5732, McDonnell-
Douglas, November 10, 1972.
131 "DC-8 Series 63 Engine and Nacelle/Airframe Inte -
gration Definition," Report MDC J5732A, McDonnell-
Douglas, January 8, 1973.
132 "Preliminary Retrofit and Economic Analysis,"
Volume I Economic Analysis, Report MDC
McDonnell-Douglas, January 8, 1973.
133 "Preliminary Retrofit and Economic Analysis,"
Volume II Retrofit (Trade Study) Analysis,
Report MDC J5734-2, McDonnell-Douglas, January 8, 1973-
135 "JT3D Final Engine and Nacelle/Airframe Integration
Definition," Report MDC J5735, McDonnell-Douglas,
March 15, 1973.
136 . "DC-9-32 Engine and Nacelle/Airframe Integration
Definition," Report MDC J5733, -McDonnell-Douglas,
March 15, 1973-
Ito R. A. Fuhrman, Ltr: "Response on Docket No. 1253^,
Notice No. 73-3," Lockheed-California Co., 27
February 1973.
142 H. Drell, Ltr: "Comments on Information Brief
on Aircraft Noise Control Options and Methods
of Exploiting Technology," Lockheed -California
Co., 30 March 1973-
151 W. R. Dunbar, "DC-8 Noise Reduction Studies" Me
Donnell-Douglas , 2 April 1973.
152 "DC-9 Engine Noise Reduction Programs" McDonnell
Douglas, 5 January 1973.
153 "The Integration of Quiet Engines with Subsonic
Transport Aircraft, " McDonnell-Douglas, 1 August
1969.
R-3.4
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3-0 AIRCRAFT MANUFACTURERS. (COHT'D)
MASTER
BIBLIOGRAPHIC CITATION
159 V. L. Blumenthal, Ltr: Some General Comments
and Recommendations Pertaining to Task Group
4 Activities, Boeing, 2 April 1973.
161 D. R. Hawes, C. R. Cox, "Noise Reduction Possi-
bilities for a Light Helicopter," Bell Helicopter
Co., Date Unknown.
1^2 C. R. Cox, "Subcommitte Chairman's Report to
Membership on Aerodynamic Sources of Rotor
Noise," Presented to the 28th Annual National
Forum of the American Helicopter Society, Wash.,
May 1972.
163 C. R. Cox, "Flying Neighborly - How to Operate
the Light Helicopter More Quietly," Bell Helicopter,
Date Unknown.
164 C. R. Cox, "VTOL Noise," Presented at EPA.ONAC Alrcraft/
Airport Noise Task Group 4 Meeting, 3 April 1973.
178 V. L. Blumenthal, Ltr: (v/Attachments) "Thoughts
on the Existing Aircraft Noise Regulation and
Planned Regulatory Actions," Boeing, 2 April 1973.
184 G. I. Martin, Ltr: (with enclosures) "AIAA Response
to FAA Noise Rule Making Dockets," AIAA, 9 April 1973.
190 J. S. Gibson, "Technical Brief: Status of the Aircraft
Non-Engine Aerodynamic Noise Problem," Lockheed-
Georgia Co., 5 February 1973-
193 H. Sternfeld, Jr.; E. Hinterkeuser, "Effects of
Noise on Commercial V/STOL Aircraft Design and
Operation," Presented at AIAA 5th Annual Meeting
and Display, Vertol Division of the Boeing Co.,
October 1968.
395 Ronald G. Schlegel, Ltr: "Position Paper Related
to VTOL Aircraft Noise Rules", Sikorsky Aircraft,
Division of United Aircraft Corp., 2 July 1973.
R-3.5
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3.0 AIRCRAFT MANUFACTURERS (COMT'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
F. H. Duke, W.E. Hooper, "The Boeing Model
Advanced Technology Helicopter Program," Presented
at the 27th Annual National V/STOL Forum of the
Helicopter Society, Vertol Division of the Boaing
Company, May 1971.
195 W. E. Stepnievski, F. H. Schmitz, "Possibilities
and Problems of Achieving Community Noise Acceptance
of VTOL, " Presented to 8th Congress of the International
Council of the Aeronautical Sciences, Vertol Division
of the Boeing Company and the Army Air Mobility Lab.,
August 1972.
196 N. B. Hirsh, H. W. Ferris, "Design Requirements for
a Quiet Helicopter, " Presented at the 28th Annual
National Forum of the American Helicopter Society,
Aircraft Division of the Hughes Tool Co., May 1972.
212 "Summary: 707-727-737-7^7 Noise-Reduction Activities, "
Report D6- 4o6l3-B, The Boeing Commercial Airplane
Company, March 1973.
211 N. B. Hirsh, H. W.Ferris, "The Hughes OH-6A Quiet
Helicopter Program, " Hughes Helicopter, A Division
of Summa Corp., Undated.
208 W. H. Barlow et.al., "OH-6A Phase II Quiet Helicopter
Program, " USAAMRDL Report 72-29, Prepared for Eustis
Directorate of U. S. Army Air Mobility Research and
Development Laboratory, Hughes Tool Company, Sept. 1972.
206 E. G. Hinterkeuser, H. Sternfeld Jr., "Subjective
Response to Synthesized Flight Noise Signatures of
Several Types of V/STOL Aircraft, " Vertol Division
of the Boeing Co. NASA CR Report CR-1118, Undated.
205 "Visuals in . Support of Presentation on 737/T-U3A Noise
Reduction Program, " The Boeing Company, 30 March 1973 .
kOO E. J. Whitehead, "program on Ground Test of Modified
Quiet Clean JTJD and JT8D Engines in Their Respective
Nacelles; DC-9 Series 32, Engine and Nacelle/Airframe
Integration Definition", Report MDC J5733A, Douglas
Aircraft Company, 23 May 1973 (Second Submittal).
A,. L. McPike, Ltr: "Additional Comments on Task
Group k Report of an Editorial Nature", Douglas
Aircraft Company, 29 June 1973.
R-3.6
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3.0 AIRCRAFT MANUFACTURERS (COHT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
221 "Noise Abatement Takeoff Procedure Recommended
for Commodore Jet 1123* Israel CAA Approved
Flight Manual, 26 Nov. 1971.
226 C. R. Cox, Ltr: (including enclosures), Corrected
Visual of Air Speed vs Sideline Noise and "Fly
Neighborly-How to Operate the Medium Helicopter
More Quietly," Bell Helicopter, 12 April 1973-
227 J. S. Gibson, "Information Brief - V/STOL Noise
Technology and Design Considerations," IB 7302,
Lockheed-Georgia Company, 9 March 1973 (Rev.).
228 J. S. Gibson, "Information Brief-Non-Engine Aero-
dynamic Noise Technology and Impact," IB7301,
Lockheed-Georgia Company, 6 April 1973 (Rev.).
219 H. 3ternfeld, Jr., E. G. Hinterkeuser, "Acceptability
of VTOL Aircraft Noise Determined by Absolute Sub-
jective Testing," NASA CR-2C43, Vertol Division of the
Boeing Company, 10 Jan. 1972.
217 "An Investigation of Noise Generation on a Hovering
Rotor: Partll," Vertol Division of the Boeing Company,
Nov. 1972.
216 F. H. Schmitz et.al., "A Comparison of Optimal and
Noise Abatement Trajectories of a Tilt-Rotor Aircraft,"
Vertol Division of the filing Company, Jan. 1972.
230 "FAA 727 Quiet Nacelle Retrofit Feasibility Study -
Contract DOT-FA71WA-2637," Wichita Division of the
Boeing Company, Date unknown.
231 "Feasibility and Initial Model Studies of a Coanda/
Refraction Type Noise Suppressor System," Report
03-9068, Wichita Division of the Boeing Company,
January 1973-
A. L. McPike, Ltr: "Comments on Draft Report and
Operations of EPA Task Group V1, Douglas Aircraft
Company, 29 June 1973
A. L. McPike, Ltr: "Comments on Draft Report and
Operations of EPA Task Group 5", Douglas Aircraft
Company, 29 June 1973-
R-3.7
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3.0 AIRCRAFT MANUFACTURERS (CONT'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
286 H. Brell, Ltr: (with enclosure),"Lockheed-California
Company/Rolls-Royce Position Belated to the Potential
for further Engine Noise Reduction, Lockheed-Calif.
Company, 25 April 1973.
30*4- J. Vogel, Ltr:(with enclosures), "Sideline Noise
Measurements," Lockheed-California Company, 1 May 1973.
374 V.L.Blumenthal, Ltr. "Additional Comments on Draft
Reports" Boeing Commercial Airplane Company, 20 June 1973-
330 "Contract DOT-FA71WA-2628, FAA JT3D-707 Quiet Nacelle
Program Summary," Boeing-Wichita, 7 May 1973.
246 R. E. Russell, Ltr. w/attachments, "Data on Operational
Procedures as Requested in EPA Letter of 12 April 1973,"
Boeing Commercial Airplane Group, 20 April 1973-
338 "Concorde: Airport Noise and Silencing Programme,"
SNIA, SNECMA, EAC and Rolls Royce limited, Oct. 1972.
339 "Concorde: Airport Noise and Silencing Programme;
Annex 3> The Economic Aspects of Silencing Concorde,"
SNIA, SNECMA, BAC and Rolls Royce Limited, Oct. 1972.
3^0 "Concorde; Airport Noise and Silencing Programme;
Annex 2, Manufacturers Further Studies of Noise Re-
duction," SNIA, SNECMA, EAC and Rolls Royce Limited,
Oct. 1972.
367 "BAG - 111 Ifoise Reduction Programs, " British Aircraft ,
Corp. (USA), 29 May 1973-
M. G. Wilde, Ltr. with ."Recommendations of the Con-
corde Manufacturers to the EPA Relating to the Regulation
of Concorde Noise, " BAC, 17 May 1973.
243 ",'?7 JT8D-109 Re fan Nocr-lle and Airplane
tioti Definition", Preliminary Submit tul D-6'f0882,
Boeing Commercial Airplane Company, ': April 1973-
R-3.8
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3'° AIRCRAFT MANUFACTURERS (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
K. P. Rice, "Program on Ground Test of Modified,
Quiet, Clean JT3D and JT8D Engines in Their
Respective Nacelles; JT3D/JT8D REFAN Preliminary
Economic Study" Report No. D6-40982, Boeing
Commericial Airplane Company, April 1973.
K. P. Rice, "Program on Ground Test of Modified,
Quiet, Clean JT3D and JT8D Engines in Their
Respective Nacelles; 707/JT3D-9 REFAN Nacelle,
Engineering Summary Report" Report No. D3-9107,
Boeing Commercial Airplane Company, April 10, 1973.
K.' P. Rice, "Program on Ground Test of Modified,
Quiet,. Clean JT3D and JT8D Engines in Their
Respective Nacelles; Phase I, 737, JT8D-109 REFAN
Nacelle and Airplane Integration Definition"
Report No. D6-32569» Boeing Commercial Airplane
Company, June 22, 1973.
s
K. P. Rice, "Program on Ground Test of Modified,
Quiet, Clean JT3D and JT8D Engines in Their
Respective Nacelles; Phase I, 727, JT8D-109 REFAN
Nacelle and Airplane Integration Definition"
Report No. 06-^1170, Boeing Commercial Airplane
Company 1 June 1973.
Bernard D. Brown, Ltr. "Confirming Currency of
Documentation Supplied to the Task Group",
British Aircraft Corporation (U.S.A.) Inc., 2 July '73.
Bernard D. Brown, Ltr. "Position Paper Related to
EPA Aircraft/Airport Noise Study Report", British
Aircraft Corporation (U.S.A.) Inc. for Concorde
Project Director, BAC-CAD on behalf of the four
Concorde Manufacturers, 2 July 1973-
408 V. L. Blumenthal, Ltr. w/Attachments: "Boeing
Commercial Airplane Company Position on Task
Group k, Noise Source Technology and Cost Analysis
Including Retrofitting", Boeing Commercial
Airplane Company Letter 6-7270-1-Wt, 29, June 1973-
409 V. L. Blumenthal, Ltr.: "Boeing Commercial Airplane
Company Position on Task Group 5, Review arid
Analysis of Present and Planned FAA Noise Regulatory
Actions and Their Consequences Regarding Aircraft
and Airport Operations" Boeing Company Letter
No. 6-7270-1-^55, 29 June 1973-
R-3,9
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3.0 AIRCRAFT MANUFACTURERS (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
Ronald G. Schlegel, "Position on VTOL Noise
Certification", Sikorsly Aircraft, 20 July 1973-
D. L. Hiatt, M. B. McKaig, et.al., "72? Noise Retrofit
Feasibility; Vol. Ill: Upper Goal Flight Testing and
Program Summary" FAA-RD-72-ifO, III, Boeing Commercial
Airplane Co., June 1973-
450 "Visual Aids in Support of an Oral Report on Contract
DOT-FA71WA-2628, FAA JT3D-707 Quiet Nacelle Program",
Boeing Commercial Airplane Company, 25 July 1973*
V?1 "Visual Aids in Support of an Oral Report on Contract
DCT-FA71WA-2637, FAA 727 Quiet Nacelle Retrofit
Feasibility Study", Boeing Commercial Airplane
Company, 25 July 1973.
452 "Program on Ground Test of Modified Quiet Clean JT3D
and JT8D Engines in Their Respective Nacelles: Visual
Aids in Support of an Oral Report on Phase I Results",
Douglas Aircraft Company, 25 July 1973.
"Visual Aids in Support of Oral Report on a Retrofit
Feasibility Program", Federal Aviation Administration,
25 July 1973-
"Visual Aids in Support of Oral Report on Long Eange
Noise Measurements" Boeing Commercial Airplane Company,
25 July 1973.
"Visual Aids in Support of Oral Report on Refan Retrofit
Program Status" Boeing Commercial Airplane Company,
25 July 1973.
R-3.10
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AIRLINES
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
56 J. T. Davis, Ltr: "Comments on FAA Rules and
Proposals," Delta Airlines, 9 March 1973.
73 P. A. Soderlind, Ltr: "Northwest Airlines Noise
Abatement Procedures," Northwest Airlines, 2*f
November 1970.
270 "Flight Standard Bulletin No. 3-70: Revised
Standard NWA Takeoff," Northwest Airlines, Inc.,
5 October 1970.
267 R. E. L. Carmichael, Ltr: (with enclosures)
"Regarding PSA Policies Involving Noise Abatement
During Arrivals and Departures," Pacific Southwest
Airlines, 28 March 1973.
268 J. R. Tucker, "Takeoff Flight Path Studies," Air
California, 1 March 1973.
269 "Special DCA Noise Abatement Procedure," Flight
Operations Manual, United Air Lines, 25 Feb. 1972-
333 J. T. Davis, Ltr: "Comments on Draft Report
Task Group 5, 5 May 1973," Delta Air Lines,
16 May 1973-
334 J. T. Davis, "Visualt; in Support of Comments on
Draft Report Task Group 5, 5 May 1973," Delta Air
Lines, 16 May 1973-
R. W. Rummel, Ltr. with Enclosure titled "Airlines and
t'.ie Energy Crisis", Trans World Airlines, 23 May 1973-
R-4.1
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5.0 IMDIVIDUALS
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
41 H. P. Kelly; Ltr: "Nosie Problems at Oftet-
Locka Airport," 12 February 1973-
47 R. Gegauff; Ltr: "Noise Problems at Logan
Airport," 2 March 1973.
372 J. C. Bohonis; Ltr: "Suggestions for Aircraft/
Airport Noise Study Report," 17 April 1973-
373 E. E. Farman; Ltr: "Aircraft Noise" 12 May 1973-
381 W. H. Rodgers, Jr. Ltr with Copy of Chapter from
Author's Book Titled "Corporate Country",
8 June 1973.
R-5.1
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6.0 ENVIRONMENTAL GROUPS
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
12 Lloyd Hinton, "Aircraft Noise as a Continuing
National Problem," Proceedings of International
Conference on Transportation and the Environment,
Ho Date.
16 J. Tyler, "Source Abatement Technology," Submitted
to EPA Aircraft/Airport Noise Study Task Group 4,
28 February 1973.
27 J. Hellegers, L. Hinton, N. McBride, C. Lerza,
J. Conroy, Envir
-------
6.0 ENVIRONMENTAL GROUPS (CONT'D)
MASTER
FILE
MO. BIBLIOGRPAHIC CITATION
29k L. Hinton; Ltr: "Questions Related to FAA's
Understanding of Authority to Regulate Airport
Noise," N.O.I.S.E., k May 1973.
293 L. Hinton; Ltr: "To Mr. Phillip T. Cummings, Asst.
Counsel, Committee on Public Works, United States
Senate, N.O.I.S.E., 4 May 1973-
295 J. Tyler, L. Hintonj Press Release Related to
Aircraft Noise Reduction Demonstration at Dulles
Airport on 7 May 1973, N.O.I.S.E., 7 May 1973.
325 J. Scaffetta; Ltr: "Concern over SST Noise Pollution,
Member of Friends of the Earth, 15 March 1973.
J. M. Tyler. L. Hinton, "Comments on Drbft Reports of
Task Group h and 5," NOISE, 15 May 1973.
L. Hinton, Ltr: "Findings and Recommendations Re-
lated to "Adequacy of FAA Flight and Operational
Noise Controls," NOISE, 27 April 1973.
358 L. Hinton, J. Tyler, Ltr: "Comments and Recommenda-
tions for Draft No. 1, Chapter 3 of the Report to
the Congress," NOISE, 18 May 1973-
3?>9 J. F. Hellegers, Ltr. "Capacity Limitation
Agreements," Environmental Defense Fund, 31 May 1973-
393 Lloyd Hinton and John Tyler, Ltr: "Position Paper
Belated to Task Group 5 Report", N.O.I.S.E,
30 June 1973-
39^ Lloyd Hinton and John Tyler, Ltr: "Position Paper
Related to Task Group h Report", N.O.I.S.E,
30 June 1973-
R-6. 2
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7.0 FEDERAL GOV'T; AVIATION ADVISORY COMMISSION
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
25 "The Long Range Needs of Aviation, "Report of
the Aviation Advisory Commission, 1 January 1973-
52 The Long Range Needs of Aviation: "Technical
Annex to the Report of the Aviation Advisory
Commission," Vol I, January 1973.
53 The Long Range Needs of Aviation: "Technical
Annex to the Report of the Aviation Advisory
Commission," Vol II, January 1973-
99 "Aircraft Noise Analysis for the Existing Air
Carrier System," Report No. 2218, Contract No.
CON-AAC-72-12, Bolt, Beranek and Newman for
the Aviation Advisory Commission, 1 September 1972.
5^ "Impact of Business Jets on Community Noise
Exposure," Proj. Report No. 2222, Bolt, Beranek
and Newman for the Aviation Advisory Commission
21 August 1972.
117 "Classification of Airport Environs by Airport/
Community Land Use Compatibility," Back & Sterling,
Inc. for Aviation Advisory Commission, 28 Jan '72.
118 "Cost Estimates for Removal of Residental and
Related Land Use Near Selected Airports," Back &
Sterling, Inc. for Aviation Advisory Commission,
25 August 1971.
175 "A Model and Methodology for Estimating National
Land Use Removal Costs," The Decision Information
Group, Inc., For the Aviation Advisory Commission,
k August 1972.
R-7.1
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8.0 FEEBtAL GOV'T: DQT/FAA
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
29 L. Simpson, R. C. Khovles, J. B. Feir,
"Airline Industry Financial Analysis with
Respect to Aircraft Noise Retrofit Programs ,"
R. Dixon Speas Associates, N. Y., January 1973.
2k. D. C. Gray, "Results of Noise Surveys of Seventeen
General Aviation Type Aircraft," Federal Aviation
Administration Report No. FAA-EQ-73-1, Dec '72.
37 "Draft: Environmental Impact Statement for Policy
Changes on the Role of Washington National Airport
and Dulles International Airport," Prepared by
the Federal Aviation Administration, 31 January
1973.
7° Working Paper No. 10: "Aviation Cost Allocation
Study; Allocation of Airport and Airway System
Costs," Office of Policy Review, Department of
Transportation, December 1972.
48 "Noise Abatement Procedures," Federal Aviation
Agency, November 1960.
J*9 R. L. Faullin, :The Status of International
Noise Certification Standards for Business
Aircraft," Department of Transportation,
6 April 1973, NBAA Meeting.
50 "Noise Abatement Rules: Amendment 91-46 to
FAR," Federal Aviation Administration, 4 Dec'67.
68 J. D. Wells et al, "An Analysis of the Financial
and Institutional Framework for Urban Transporta-
tion Planning and Investment," Study S-355,
Contract No. DAHC15-67-C-0011, Department of
Transportation, June 1970.
69 Working Paper No. 8: "Aviation Cost Allocation
Study, Design Rationale for a General Aviation
National Airspace System," Office of Policy
Review, Department of Transportation, July 1972.
R-8.1
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8.0 FEDERAL GOV'T; DOT/FAA (00111*0)
MASTER
FILE
DO. HLBIIOGRAPHIC CITATION
71 Working Paper Mo. 18; "Aviation Cost Allocation
Study, The Price Elasticity of Demand for General
Aviation," Office of Policy Review, Department
of Transportation, December, 1972.
72 D. L. Hiatt et. al., "727 Noise Retrofit Feasi-
bility; Vol. Ill: Upper Goal Plight Testing and
Summary," Report Bo. FAA-RD-72-JK), III., Federal
Aviation Administration, January, 1973-
(PRELIMINARY).
100 "Project Report: Noise Certification Rule for STOL
Category Aircraft," FAA, 18 January 1971.
101 "Aviation Cost Allocation Study: Overview of Cost
Allocation Methodologies; Working Paper No. 1,"
Office of Policy Review; Dept. of Transportation,
January 1972.
102 "Aviation Cost Allocation Study: Working Paper
No. 15; Socio - Economic Approach to Benefits
of the Airport and Airway System, " Office of
Policy Review, Dept. of Transportation, Dec'72.
2Ok W. C. Sperry, "Information Brief on Bibliography
on Aircraft Certificated Noise Levels," Preliminary
Data Compiled by FAA/AEQ-20, 21 December 1972.
1O5 W. C. Sperry, "Information Brief on Bibliography
of FAA Aircraft Noise Reports," 18 August 1972.
107 W. C. Sperry "Information Brief on Current and
Estimated Noise Levels for Major U. S. Aircraft
Series," FAA, 2 December 1972.
108 W. C. Sperry. L. A. Ronk "Information Brief
on Boeing 707-320B Aircraft Noise," FAA, 25
January 1972.
109 L. A. Ronk, T. N. Cokenais, W. C. Sperry,
"Information Brief of EPNL Contour (Footprint)
Comparison of Noise Abatement Retrofit Options
for 707-320B Aircraft," FAA, 11 January 1973-
110 L. A. Ronk, T. N. Cokenais, W.C. Sperry,
"Information Brief of EPNL Contour (Footprint)
Comparison of Noise Abatement Retrofit Options
for 727-200 Aircraft," FAA 22 December 1972.
R-8.2
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8.0 FEDERAL GOV'T; DOT/FAA (CONT'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
1H T. N. Cokenais, "Information Brief on Computer
Programs for the Evaluation of EPNL Contours
for Approach Operations," FAA, 19 September 1972.
112 L. A. Ronk, "Information Brief on Computer Programs
for the Evaluation of EPNL Contours for Takeoff
Operations," FAA, 11 September 1972.
113 L. A. Ronk, T. N. Cokenais, W. C. Sperry," Infor-
mation Brief on EPNL Contours and Enclosed Areas
for 727, DC-9, and 707 Aircraft," FAA, 1 May 1972.
11^ L. A. Ronk, W.C. Sperry, T. N. Cokenais, "Infor-
mation Brief on Takeoff and Approach Noise for
Boeing 727 Aircraft," FAA, 8 January 1973.
116 W. C. Sperry, L. A. Ronk, T. H. Cokenais, "Infor-
mation Brief on Prediction of Aircraft Noise Levels
for Planning Purposes/" FAA, 7 September 1971.
119 "Part 91: General Operating Flight Rules; Civil
Aircraft Sonic Boom," Federal Register Vol. 38,
No. 59, 28 March 1973-
120 W. C. Sperry, "Information Brief on Current and
Estimated Noise Levels for Major U.S. Aircraft
Series,1 FAA, 2 December 1972.
iVf W. C. Sperry, "Information Brief on Federal Aviation
Administration Noise Abatement Research and Development,"
FAA, 22 December 1972.
148 W. C. Sperry, "Information Brief on FAA Aircraft
Noise Research," FAA, 6 December 1972.
1^9 W. C. Sperry, "Information Brief on Analysis of
Aircraft Sound Description System (ASDS)," EPA,
2 April 1973.
J07 "A Study of the Magnitude of Transportation Noise
Generation and Potential Abatement: Vol. I - Summary,"
OST-ONAC-71-1, Department of Transportation, Nov'70.
"A Study of the Magnitude of Transportation Noise
Generation and Potential Abatement: Vol. VII -
Abatement Responsibility," OST-ONA-71--1, Dept. of
Transportation, November 1979.
R-8.3
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8.0 FEDERAL GOV'T; DOT/FAA (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
213 "Airline Economic Impact Computer Model: Vol. I -
Detailed Discussion," FAA-EQ-72-^, I, Federal Aviation
Administration, Department of Transportation, June
1972.
182 "Airline Economic Impact Computer Model. Vol II -
Appendix, Detailed Data Tables," FAA-BQ-72-4,II,
Rohr Industries, Inc. and Mitchell Research
Associates for the Department of Transportation,
June 10.72.
286 J. E. Cruz, "Aircraft Sound Description System -
Background and Application" Final Report FAA-EQ-73-3,
Office of Environmental Quality, FAA, March 1973.
DRAFT "Noise Standards for Newly Produced Airplanes of
Older Type Designs" Federal Aviation Administration,
Draft Regulation, July 1973.
185 C. R. Foster, Memo and Fnclosure; "Report of the
U. S. Delegation to the ICAO Committee on Aircraft
Noise, Third Meeting," 5 March 1973.
207 "Arrival and Departure Handling of High Performance
Aircraft," DOT/FAA Advisory Circular No. AC 90-59,
28 February 1972.
222 Hews Article: "FAA Uncertain of Authority in Regulating
SST Noise," Aviation Daily, 18 April 1973.
l65 H. Safeer, "Visuals on Airport Noise Reduction Forecast,"
Presented to EPA/OHAC Aircraft/Airport Noise Study
Task Group 4, Meeting No. k, 3 April 1973.
"Proposed FAA Maximum Allowable Noise Levels to be Required
for Certification of Future Aircraft," Enclosed with Ltr.
by Joseph D. Blatt, i September 1966.
H. B. Safeer Ltr: (with enclosures) "Summary of Effects of
Retrofit on Population for Six Airports and Program Costs,"
30 April 1973.
R-8.4
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8.0 FEDERAL GOV'T; DQT/FAA (CONT'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
"Economic Impact of Implementing Acoustically
Treated Nacelle and Duct Configurations Applicable
to Lov_By-Pass Turbofan Engines, " Report FAA-NO-
70-11, Prepared for Dept. of Transportation, Federal
Aviation Administration by Rohr Corporation, July 1970.
Claude S. Brinegar, Ltr: "Regarding the Assignment of
DOT Personnel to Work with EPA in Meeting EPA Responsi-
bilities under Sections 7, 17, and 18 of the Noise
Control Act of 1972, " Department of Transportation,
5 April 1973.
252 J. F. Woodall and Advisors, "Aircraft Development Serrice
Proposal for FAA Noise Certification Criteria," 1 February
1968.
25k I. H. Hoover, "Aircraft Noise Certification Alternatives,"
Ltr: Aircraft Industry Manufacturers, Operators,
and Consultants, 3 October 1967.
103 "Aviation Cost Allocation Study: Working Paper No. 9;
Benefits," Office of Policy Review, Department of
Transportation, October. 1972.
31*8 "Aviation Forecasts Fiscal Years 1973-198U," Dept. of
Transportation, Federal Aviation Administration,
Sept. 1972.
355 H. B. Safeer, Tech. Memo. "Aircraft Retrofit - A Cost
Effectiveness Analysis," Dept. of Transportation, 18
May 1973-
391 "Land Use Control Strategies for Airport Impacted Areas
Report No. DOT-FA71WA-2579, Urban Systems Research
and Engineering, Inc for the Federal Aviation
Administration, Oct. 1972.
' "The New Aviation Taxes", E. C. Bulletin No. ?0-2,
Office of Aviation Economics, Federal Aviation
Administration, July 1970.
R-8.5
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8.0 FEDERAL GOV'T: DOT/FAA (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
^39 Project Report: "Newly Produced Airplanes of
Older Type Designs - Proposed Application of
FAR 36 Noise Standards (NPRM 72-19, Docket No.12064),
Before July 1972.
Project Report: "Aircraft Noise Certification
Rule for Transport Category Aircraft" 2*f Sept. 1968.
' "A Study of the Magnitude of Transportation Noise
Generation and Potential Abatement: Vol.III-
lirport/Aircraft System Noise," OST-ONA-71-1,
3ept. of Transportation, Nov '70.
Carole S. Tanner, Ray E. Glass, "Analysis of
Operational Noise Measurements in Terms of Selected
Human Response Noise Evaluation Measures", FAA-RD-
71-112, December 1971.
"Visual Aids in Support of Oral Report on Retrofit
Study" R. Dixon Speas, 25 July 1973.
"Visual Aids in Support of Oral Report on the
Airport Noise Reduction Forecast Program", Wyle
Laboratories, 25 July 1973.
R-8.6
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9-0 FEDERAL GOV'T; DOD
MASTER
FILE
NO. EEBIZOGRAPHIC CITATION
75 P. A. Shahady, "Department of Defense Noise
Research Programs Source Noise Abatement
Technology," Department of Defense, Air
Force Aero Propulsion Labs, 21 March 1973.
192 N. J. Asher et.al., "The Demand for Intercity
Passenger Transportation by VTOL Aircraft,"
Institute for Defense Analysis, Aug. 1968.
335 P. A. Shahady, "U. S. Air Force Noise Research,"
Presented to EPA Aircraft/Airport Noise Study
Task Group k, 16 May 1973.
336 W. S. Blazowski et al, "The Aircraft Engine and the
Environment," Air Force Aero Propulsion laboratory,
16 May 1973.
337 R. P. Burns, "Noise Pollution Control in the U.S.
Navy," Naval Air Propulsion Test Center, 16 May 1973.
363~ F. H. Schmitz, "Rotary Wing Acoustic Research,"
Ames Directorate, U. S. Army Air Mobility R & D
laboratory, l6 May 1973.
350 R. W. Young, "Material for Report on Aircraft/Airport
Noise," Submitted to EPA Task Group 3, Department
of the Navy, 3 May 1973-
R-9.1
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lfi.0 FEIERAL GOV'T; EPA
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
£6 W. C. Sperry, "Three Point Measurement Concept for
STOL Noise Certification," Information Brief,
2 October 1972.
31 W. C. Sperry, "Aircraft/Airport Noise Report
Study. Meeting No. 1 of Task Groups k and 5 -
Summary^" EPA/ONAC, 27 February 1973.
to L. A. Plumlee, (EPA) M.D.; Ltr: "Police Helicopters,"
Noise'and Utilization, 22 February 1973.
^5 J. C. Schettino, Ltr: "DOT Participation in Aircraft/
Airport Noise Report Study," EPA/ONAC, 7 Mar'73.
59 W. C. Sperry, "Minutes of Meeting No. 2, Aircraft/
Airport Noise Report Study - Task Groups 4 and 5, "
EPA/ONAC, Ik March 1973-
84 A. F. Meyer, Jr., Memo: "Comments on AKPRM on
FNL," 19 Mar'73.
86 W. C. Sperry, "Information Brief on Fleet Noise
Level Methodology," EPA, 19 March 1973.
97 W. C. Sperry, "Summary Minutes of Aircraft/Airport
Noise Report Studyj Meeting No. 3 for Task Groups
4 and 5 with Enclosure," EPA/ONAC, 26 March 1973.
98 W. C. Sperry, "Information Brief on Aircraft Noise
Control Options and Methods of Exploiting Technology,"
EPA/ONAC, 24 March 1973- (Rev. 23 April 1973)
115 W. C. Sperry, "Aircraft Noise Exposure: Background,
Methodology and Comparisons," FAA, 24 September '71.
121 "Information Brief on Aircraft Equipment Growth and
Future Trends," Aviation Week and Space Technology,
19 March 1973.
139 "Information Brief on Aircraft and Engine Specifi-
cations, " Aviation Week and Space Technology,
19 March 1973.
R-10.1
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10.0 FEDERAL GOV'T; EPA (CONT*D)
MASTER
FILE
NQ. BIBLIOGRAPHIC CITATION
Betsy Amin-Arsala, Memo: "Concept of Airport
Certification, G.tf.U./EPA, 30 March 1973.
"REFAN: Promising Technology, Uncertain Future,"
Article from Aerospace daily, 23 March 1973.
179 w- c- Sperry, "Summary Minutes of Aircraft/Airport
Noise Report Study; Meeting No. k for Task Groups
k and 5 with Enclosures," EPA/ONAC, 10 April 1973-
180 R. S. Bennin, "Information Brief on Framework for
Airport/Aircraft Regulations," EPA/ONAC Task
Group 5, 5 April 1973-
22k W. D. Ruckelshaus; Ltr: (with enclosures),
"Indicating Response to Concern Expressed
by Ms. K. W. Hemer, Constituent of Hon. W. G.
Magnuson," EPA, 2 April 1973-
308 J. C. Schettino; Ltr: "In Reply to Mr. William
M. Cooper, Jr., Citizens for Conservation,"
EPA, 19 April 1973-
377 H. J. Nozick, Information Brief on Noise Exposure
Forecast (NEF) Areas and Land Clearance Costs at
Twelve Air Carrier Airports for Six Fleet Configurations
'O985 Operations), EPA, 9 April 1973,.
2l*l W. C. Sperry, Memo: "ICAO Activity, can/3," EPA,
20 Mar 1973.
285 Draft #1: Chapter 3: Operations Analysis, Environmental
Protection Agency Aircraft/Airport Noise Report of
Task Group 2, 5 May 1973-
39 A. Meyer, Jr., Memo: "Information Regarding Depart-
ment of Transportation Consultations and Participation
in the Aircraft and Airport Noise Study - Noise Con-
trol Act of 1972," EPA/ONAC, 6 March 1973.
376 H. J. Nozick, Information Brief on Business Jet
Identification and Estimated Noise Levels, EPA,
6 April 1973.
R-10.2
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10.0 FEDERAL GOV'T; EPA (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
271 "An Evaluation of Policy Alternatives for Airport
Noise Abatement," Joseph Vittek Jr., March Ik, 1973,
A supporting document for George Washington University
I«gal and Institutional Analysis of the Noise Control
Act of 1972.
299 DRAFT: "Impact Characterization" Report of Task
Group 3 of the Aircraft/Airport Noise Study, 10 May 1973.
300 DRAFT: "Report on Aircraft Noise Source Technology
for Environmental Protection Agency Aircraft/Airport
Noise Report Study," EPA Task Group 4, 5 May 1973.
301 DRAFT: "Report on Noise Regulatory Actions by the
Federal Aviation Administration for Environmental
Protection Agency Aircraft/Airport Noise Report Study,"
EPA Task Group 5, 5 May 1973.
302 DRAFT: "Section VII. Bibliography and References
for Task Group k Draft Report and Task Group 5 Draft
Report," EPA Aircraft/Airport Noise Report Study, 5
May 1973.
257 "The Economic Impact of Noise," NTID 300.14, U.S.
Environmental Protection Agency, 31 December 1971
327 J. C. Schettino, Ltr: Reply to Mr. Jerry Scaffetta's
letter of 15 March 1973, EPA, Undated
3^7 A. Meyer, Jr., Ltr: to FAA "EPA Comments ANPRM 73-3,
Civil Airplane Fleet Noise (FNL) Requirements," EPA,
2 February 1973.
31*9 B. Amin-Arsala, "Relevant Data on Starrett City Develop-
ment Project, Brooklyn, New York," Submitted to Task
Group 5 on 16 May 1973, G.W.U., 18 April 1973-
356 P.P. Back, "Information Brief on Relationships and Data
Requirements for Analysis of Aircraft Source Noise
Abatement Options," EPA, 11 April 1973-
R. L. Randall, "Information Brief on the U. S. Supreme
Court's Decision in the Burbank Case," EPA,
31 May 1973.
R-10.3
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10.0 FEDERAL GOV'T; EPA (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
"Legal and Institutional Analysis of Aircraft and
Airport Noise and Apportionment of Authority Between
Federal, State and Local Governments", NTH) 73.2,
Environmental Protection Agency, July 1973.
"Operations Analysis Including Monitoring, Enforcement,
Safety, and Cost" NTID 73.3, Environmental Protection
Agency, July 1973.
"Impact Characterization of Noise Including Implications
of Identifying and Achieving Levels of Cumulative
Noise Exposure" NTID 73.^, Environmental Protection
Agency, July 1973.
Jf28 "Noise Source Abatement Technology and Cost Analysis
Including Retrofitting" NTID 73.5, Environmental
Protection Agency, July 1973.
"Review and Analysis of Present and Planned FAA Noise
Regulatory Actions and Their Consequences Regarding
Aircraft and Airport Operations" NTID 73-6,
Environmental Protection Agency, July 1973*
"Military Aircraft and Airport Noise and Opportunities
for Reduction Without Inhibition of Military Missions"
NTID 73.7, Environmental Protection Agency, July 1973*
"Report to Congress on Aircraft/Airport Noise" Report
of the Administrator of the Environmental Protection
Agency in Compliance with the Noise Control Act of 1972,
Public Law 92-57^" NEC 73.1, Environmental Protection
Agency, July 1973-
Larry A Ronk, "Information Brief on Land Use Costs to
Provide Noise Impact Protection at Various Noise
Exposure Levels for Various Retrofit Options"
Environmental Protection Agency, 15 June 1973*
kj>2 Randall L. Hurlburt, "Information Brief on Noise
Problems at 19 Large Hub Airports", Environmental
Protection Agency, 30 June 1973»
438 W. C. Sperry & D. C. Gray; "Information Brief on
Project Reports" EPA, 19 July 1973-
Randall L. Hurlburt: "Information Brief on Night
Operations at Airports", EPA, 19 July 1973-
R-10. 4
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10.0 FEDERAL GOV'T; EPA (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
"Public Health and Welfare Criteria for Noise"
NOD 73.1, Environmental Protection Agency,
27 July 1973.
R-10. 5
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11.0 FEDERAL GOV'T: NASA
MASTER
FILE
»0. BIBLIOGRAPHIC CITATION
3 "Aircraft Noise Reduction Technology, " A Pre-
JJLninary NASA Report to the Environaental Pro-
tection Agency for the Aircraft/Airport Moise
Study," W. H. Roudebush, 28 February 1973.
V* J. J. Kramer, Ltr: "Footprint Calculation Procedures
in REFAN Program," NASA, 5 March 1973.
51 "NASA REFAN Program" Presented to Task Group 4 of
A/A Noise Report Study by J.J. Kramer, 28 Feb'73.
79 C. Ciepluch, "Visuals Presented, by Carl Ciepluch,
NASA's Quiet Engine Program," 21 Mar'73.
167 "Viewgraphs for Review of NASA Quiet Engine
Program" Presented to EPA/ONAC Aircraft/Airport
Noise Report Study Task Group k, Meeting No. 3,
21 March 1973.
186 "Aircraft Noise Reduction Technology," Presented
to the EPA for the Aircraft/Airport Noise Study,
NASA, 30 March 1973-
209 G. C. Smith, "Publications and Presentations of the
Acoustics Branch, Loads Division, NASA-Langley
Research Center," NASA, 31 Dec. 1972.
210 "Human Response to Noise-Publications and Presen-
tation, " Acoustics Branch, Langley Research Center,
NASA, 15 Dec. 1972.
229 "Statement of R. P. Jackson, Associate Administrator
for Aeronautics and Space Technology, NASA before
the Subcommittee on Aeronautics and Space Technology,
Committee on Sciences and Astronautics, House of
Representatives," April 1973-
F. B. Metzger, et al, "Analytical Parametric Investi-
gation Of Low Pressure Ratio Fan Noise," NASA CR-2188,
March 1973.
R-ll. 1
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11.0 FEDERAL GOV'T; NASA (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
237 "Statement of Boy P. Jackson, Associate Adm. for
Aeronautics and Space Technology, NASA before the
Committee on Aeronautics And Space Science," United
States Senate, April 1973*
277 M. H. Waters et al. "Shrouded Fan Propulsors for
light Aircraft, SAE Business Aircraft Meeting, Wichita,
3-6 April 1973.
378 B. J. Clark, Ltr. with Enclosure; "FAR 36 and CTOL
Engine Noise Levels Extrapolated to 500 - Foot
Sideline for 150,000-Pound G. W. Aircraft", NASA
Lewis Research Center, 23 May 1973-
380 J. J. Kramer; Ltr. with Enclosures, "Data Related to
Refan Program and Fleet Sizes", NASA Hqs., 2k May 1973.
3lfl W. H. Roudebush, Ltr. "Task Group 4 Draft Report,
Aircraft Noise Source Technology," NASA, 15 May 1973.
3te W. H. Roudebush, Ltr. "Task Group 5 Draft Report,
Envrionmental Noise Regulatory Actions by the FAA, "
NASA, 15 May 1973.
398 William H. Roudebush, Ltr with Enclosures: "Comments
On and Corrections to the Task Group k Draft Report",
NASA, 28 June 1973.
R-11.2
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12.0 FEDERAL GOVERNMENT... U.S. Misc. & Foreign
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
106 "Status of the Federal Aircraft Noise Alleviation
Program as of July 1, 1967 and Recommendation for
Updating and Improving the Program," Report of the
Program Evaluation and Development Committee (PEDC),
1 July 1967.
183 M. R. Segal, "Aircraft Noise: The Retrofitting
Approach," 72-76 SP, Congressional Research
Service, Library of Congress, 28 March 1972.
189 J. H. Ogonji, S. Loo, "Noise Effects and Problems
of Control; Selected, Annotated References 1966-
1972," Congressional Research Service, Library
of Congress, 15 Jan. 1973.
223 S. N. Goldstein, "Environmental Noise Quality-
A Proposed Standard and Index," The Mitre Corp.
for the Council on Environmental Quality, Mar '71.
225 J. V. Tunney, Ltr: "Concern Over EPA Effort under
Noise Control Act of 1972 and Interest in Public
Hearings," U.S. Senate, 14 February 1973-
"Alleviation of Jet Aircraft Noise Near Airports,
a Report of the Jet Aircraft Noise Panel," Office
of Science and Technology, March 1966.
250 International Conference on the Reduction of Noise
and Disturbance Caused by Civil Aircraft, London,
November 1966.
253 Fifth Air Navigation Conference, International Civil
Aviation Organization, Montreal, Canada, November-
December 1967.
R-12.1
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12.0 FEDERAL GOVERNMEWT-MISCELLANEOUS U. S. AMD FOREIGN (CORT'D)
MASTER
FILE
NO. BIBLTOGRPABIC CITATION
329 "Action Against Aircraft Noise: Progress Report 1973,"
A Department of Trade and Industry Publication, 1973.
291 "Aircraft Noise Impact - Planning Guidelines for Local
Agencies" Prepared for Department of Housing and Urban
Development by Bolt, Beranek and Newman and Wilsey and
Ham. Nov. 1972.
21*7 Federal Aviation Act of 1958 (Public Law 85-726) 23
August 1958.
21*8 "Title IV - Noise Pollution of the Clean Air Act
(Public Lav 91-60lf).
3^3 "Social and Economic Impact of Aircraft Noise,"
OECE, 13 April 1973.
385 C. W. Graves, Ltr; Review and Position on Task Group 5
Report, Assistant Secretary for Community Planning
and Management, Department of Housing and Urban
Development, 1 June 1973.
Clifford W. Graves, Ltr. with Enclosure "HUD Comments
on Recommendations on the EPA Task Force on Aircraft/
Airport Noise Problems", Dept. of Housing and Urban
Development, 29 June 1973.
"Noise Assessment Guidelines; Technical Background",
Report No. TE/NA 172, Dept. of Housing and Urban
Development, 1972.
"Views of the Department of Commerce Concerning EPA's
Aircraft/Airport Noise Report Study", General Counsel
of the Department of Commerce, 19 July 1973-
R-12.2
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23-0 PROFESSIONAL AMD TRADE GROUPS
MASTER
FILE
HO. BIBIIOGRAPHIC CITATION
te K. D. Kryter, I*r: "Participation in Aircraft/
Airport Boise Report Study," Acoustical Society
of America, 12 February 1973.
^3 W. W. Long, Ltr: "Participation in Aircraft/
Airport Noise Report Study," Institute of Noise
Control Engineering, No Date.
62 J. A. Nammack, Ltr: "State Lave as Belated to
Land Use Control," National Association of State
Aviation Officials, 16 March 1973.
150 L. P. Bedore, Ltr: "NBAA Noise Abatement Programs,"
National Business Aircraft Association, Inc.,
26 March 1973.
171 C. P. Miller; Ltr: "Statement on Proposed Noise
Standards for Propeller-Driven Aircraft," AOPA,
29 March 1973.
188 L. P. Bedore, Ltr.: "Recommended Changes to NBAA
Noise Abatement Program," National Business Aircraft
Assoc., Inc., 10 Nov. 1972.
255 K. G. Harr,, Ltr: "To FAA(KcKee ), with "Aerospace
Industries Report on Aircraft Noise Certification,"
5 December 1967.
266 W. A. Jenson, "ATA Flight Operations Committee Re-
commended Takeoff Procedures-Effective Date: 1 Aug.
1972," Operations Memorandum No. 72-6U, Air Transport
Association of America, 12 June 1972.
332 W. B. Becker: Ltr. with Attachments "Comments Upon
Review of Task Group 3 Draft Report," ATA, 10 May 1973-
R. G. Flynn: Ltr. with Attachments "Comments on Draft
Report of Task Group 2," 11 May 1973.
Report of the Tnird Meeting of the Committee on Aircraft
Noise (CAN), Montreal, 5 to 23 March 1973, International
Civil Aviation Organization (ICAO), 23 March 1973.
L. Bedore, Memo: "Definition of General Aviation,"
NBAA, 17 May 1973.
R-13.1
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23.0 PROFESSIONAL AND TRADE GROUPS (CONI'D)
MASTER
TJTT.in
NO. BIBUOGRIFHIC CITATION
160 "Retrofit Costs," Compiled by Anen Dallas, ATA
31 March 1973*
166 V. B. Becker, "In the Matter of Boise Standards,
Aircraft Type Certification; Docket No. 9337,
Notice 69-1," ATA, U June 1969.
172 A. W. Dallas, Ltr: "Fleet Mix," ATA$ 28 March 1973.
176 "Compilation of ATA's Original Responses to
Various Noise Regulation Proposals," Com-
piled by A. Dallas, Presented to Aircraft/Airport
Noise Report Study, Task Group 5, 5 April 1973*
177 C* F- VonKann, "Statement before the Senate
Aviation Subcommittee on Aircraft Noise, Los
Angeles," ATA, 30 March 1973*
236 "Standard Method of Estimating Comparative Direct
Operating Costs of Turbine Powered Transport
Airplanes," Air Transport Association of America,
Dec. 1967.
235 R. R. Shaw, Ltr: "Declining Invitation to Partici-
pate in Aircraft/Airport Noise Study Task Force,"
International Air Transport Association, 10 April '73 <
236 G. Fromm, "Value of Aviation Activity," Prepared for
the Air Transport Association by Data Resources,
Inc., January 1973*
239 "Comments on Aviation Cost Allocation Study
Working Paper NoA-An Airport and Airway System
Cost Base: FAA,DOD,NASA and DOT-OST," ATA Staff,
Undated.
2^0 "ATA Comments on Public Benefits Portion of
Aviation Cost Allocation Study, Working Paper
#9, Benefits," ATA Staff, Undated.
371 Working Papers from the Third Meeting of the
Committee on Aircraft Noise (CAN), Montreal,
5 to 23 March 1973, International Civil Aviation
Organization (ICAO), 23 March 1973.
396 Roger G. Flynn, Ltr. with 3 enclosures: "Principal
Positions Related to Task Group 5 Report dated
1 June 1973"j Air Transport Association, 2 July '73«
R-13.2
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PROFESSIONAL AMD TRADE GROUPS(CONT'D)
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
33 "Noise Retrofit - Existing Airplanes Powered
by JT3D and JT0D Engines," ATA Staff Study.
March 1972.
55 C. F. VonKann, Ltr: "Response to Docket No.
1253^: Notice No. 73-3," Air Transport
Association, 2 March 1973.
359 L. Bedore, Memo: "Definition of General Aviation,"
NBAA, 17 May 1973.
326 "Aircraft Noise_Research Needs", AIR No. 1079,
Society of Automotive Engineers, Inc., May 1972.
92 "Estimated Number of Jet (Non-Propeller) Air-
craft in the Scheduled U. S. Airplane Fleet
(ATA Members) as of 30 June 1972, ATA, l Sept '72.
360 "The Magnitude and Economic Impact of General
Aviation, 1968-1980," A Report Prepared for the
General Aviation Manufacturers' Association (QAMA)
by R. Dixon Speas Associates, February 1970.
155 "NPRM 69-1, Economic Impact Study," Airplane
Ferformace and Operating Economics, Vol. I,"
AIA/ATA, May 1969.
156 "NPRM 69-1, Economic Impact Study, Airline
System Economic Impact, Vol. II," AIA/ATA,
May 1969.
157 "NPRM 69-1, Economic Impact Study, Exhibit II,
Legal Considerations," AIA/ATA, May 1969.
158 "NPRM 69-1, Economic Impact Study, Exhibit III,
Detail Comments on Proposed Noise Standards;
Aircraft Type Certification," AIA/ATA, May 1969.
390 G. I. Martin, Ltr. "Concern Over Conduct of
EPA Aircraft/Airport Noise Study" Aerospace
Industries Association of America, Inc., 25 May 1973^
R-13. 3
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13.0 PROFESSIONAL AND TRADE GROUPS (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
399 J. Donald Reilly, Ltr with Enclosure: "Comments
on Task Group IV and V Draft Reports", Airport
Operators Council International, Inc, 2 July 1973-
A- w- Dallas, Ltr. "Principal Positions Related
to Task Group 4 Report dated 1 June 1973",
Air Transport Association, 2 July 1973-
"General Aviation Manufacturers Association
Comments on the Draft Report on Noise Source
Abatement Technology and Cost Analysis Including
Retrofitting for Environmental Protection Agency
Aircraft/Airport Noise Report Study-Task Group k"
General Aviation Manufacturers Association
(GAMA), 20 June 1973.
"General Aviation Manufacturers Association
Comments on the Draft Report on Review and Analysis
of Present and Planned FAA Noise Regulatory Actions
and Their Consequences Regarding Aircraft and
Airport Operations for EPA-Task Group 5"
General Aviation Manufacturers Association
(GAMA), 20 June 1973.
if 16 Gene I. Martin, Ltr. with Enclosure, "Comments on
the Conduct of the Aircraft/Airport Noise Study",
Aerospace Industries Association of America, Inc.,
2 July 1973-
^20 Clifton F. von Kann, Ltr. "Expression of ATA's
Interest in EPA's Aircraft/Airport Noise Studies",
Air Transport Association, 3 July 1973.
^37 "Statement of William B. Becker, Assistant Vice
President for Operations, Air Transport Association
at the Environmental Protection Agency Conference,
June 21, 1973" ATA, 21 June 1973.
"Positions on the Issues Contained in the Report on
Review and Analysis of Present and Planned FAA Noise
Regulatory Actions and Their Consequences Regarding
Aircraft and Airport Operations" Submitted to the
Environmental Protection Agency by the General
Aviation Manufacturers Association, 20 June 1973-
R-13.4
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13.0 PROFESSIONAL AND TRADE GROUPS (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
"Positions on the Issues Contained in the Report
on Noise Source Abatement Technology and Cost
Analysis including Retrofitting" Submitted to
the Environmental Protection Agency by the General
Aviation Manufacturers Association, 20 June 1973*
R-13. 5
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REGULATORY COMSIDERATIOHS
MASTER
FILE
BO. TITLE IDEHTIF. DATE
Control t Abateanent of PL 90-411 21 Jul 68
Aircraft Noise & Sonic
Boom
Hoise Standards: Aircraft PAR PART 36 21 Hov 69
Type Certification
312 ffivil Aircraft Sonic Boom HPRM 70-16 10 Apr 70
Civil Supersonic Aircraft AHPRM 70-33 4 Aug 70
Hoise Type Certification
Standards
Civil Airplane Hoise Re- AHPRM 70-44 30 Oct 70
duction Retrofit Require-
ments
33-5 Hoise Type Certification & HPRM 71-26 13 Sep 71
Acoustical Change Approvals
ATA Flight Operations Com- ATA ops. 12 Jun 72
mittee Recommended. Takeoff Memo. 72-64
Procedures
Mewly Produced Airplanes of HPRM 72-19 7 Jul 72
Older Type Designs
318 Three Point Measurement Con- Information 2 Oct 72
cept For STOL Hoise Certi- Brief
fication
319 Civil Aircraft Fleet Hoise Draft HPRM 8 Hov 72
Level (FHL) & Retrofit Re-
quirements
320 Amendment To Federal Aviation Project 21 Hov 72
Regulations To Provide For A Report
Takeoff Hoise Control Operat-
ing Rule
321 Civil Airplane Fleet Hoise AHPRM 73-3 24 Jan 73
(FHL) Requirements
322 Propeller Driven Aircraft Project 22 Jan 73
Hoise Type Certification Report
Standards
R-14.1
-------
REGULATORY CONSIDERATIONS (COMT'D)
MASTER
FILE
BO. TTTLE IPEHTIF. DATE
323 Hoise Certification Rule Project 29 Dec 72
for Quiet Short Haul Report
32U Part 91: General Operat- Part 91 28 Mar 73
ing and Flight Rules; Civil
Aircraft Sonic Boom
242 Criteria for Implementation final Draft 20 Mar 66
of Jet Noise Abatement Take- Advisory
off Profile Circular
256 Noise Standards: NPRM 69-1 3 Jan 69
Aircraft Type Certification
281 Federal Aviation Act PL 85-726 23 Aug 58
of 1958
282 National Environmental PL 91-190 1 Jan 70
Policy Act of 1969
283 Noise Pollution and Abate- Title IV
ment Act of 1970 PL 91-60^
284 Noise Control Act of 1972 PL 92-574 27 Oct 72
279 Code of Federal Regulations,
Aeronautics and Space, Parts
1 to 59, 60 to 199, 200- ,
Revised 1 Jan 72
280 Aeronautical Status and Related
Material, Civil Aeronautics Board,
Revised • . 1 Jun 70
353 "Airport and Airway Development Act of
1970 and Airport and Airway Revenue Act
Of 1970," 21 May 70
R-14.2
-------
15-0 STATE AND LOCAL GOV'TS
MASTER
FILE
HO. BIBLIOGRAPHIC CITATION
31* "Title h: Subchapter 6: Noise Standards,"
Department of Aeronautics, State of Cali-
fornia.
35 "Section 21669.5: Construction; Application;
Duration," Public Utilities Code, State of
California.
36 "Preamble: The City of New York Noise Control
Code (Local Law 57)," 12 October 1972.
63 Resolution No. 6598: A Resolution of the
City Council of the City of Inglewood, California,
Regarding Civil Airplane Fleet Noise Requirement,
27 February 1973-
6k Press Release: Related to Restrictions of Use
at Oakland International Airport, 9 March 1973-
66 California Laws Relating to Aeronautics, Calif.
Department of Aeronautics, Rev. 2 (6-72).
(
65 N. C. Yost, Deputy Attorney General, Ltr: "Air-
port/Aircraft Noise Report Task Force Effort,
State of California.
38 R. T. West on, "Congressional Intent: Re. Section
7(b) of the Noise Control Act of 1972; Compari-
son of Criteria Established in the 1968 and 1972
Acts for the Promulgation of Federal Aircraft
Noise Regulations," March 1973-
76 C. Gaulding, R. T. West on, "Comments on the
ANPRM on FNL, Docket No. 12534, Notice No. 73-3,"
Commonwealth of Pennsylvania, 27 February 1973-
80 "Resolution Related to ANPRM on FNL, Docket No.
1253U, Notice 73-3," City of Los Angeles, 27
February 1973-
388 "A Report of the Ad Hoc Committee Studying the
Impact of Aircraft Noise from Dulles International
Airport on Fairfax County," Dept. of County
Development, Fairfax County, Va., Feb 1972.
R-15.1
-------
15.0 STATE AND LOCAL GOY'TS (CONT'P)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
83 R. H. Quinn, "Comments Re: Proposed Fleet Noise
Requirements for Civil Airplanes d*f CFR 121),"
Department of the Attorney General, Mass.,
2 March 1973.
R. Hurlburt, "A Complete Analysis of the Costs and
Benefits of a Quiet Engine Retrofit Program,"
City of Inglewood, 15 January 1971.
A. H. Colman, "Aircraft Noise Abatement Alternatives,"
City of Inglewood, September 1971.
232 "Testimony of Mayor Merle Megell, Inglewood,
California," Presented to the Aviation Subcommittee
of the United States Senate Commerce Committee,
30 March 1973.
265 "Resolution No. 7^67- A Five Point Plan for Airport
Noise Abatement," Board of Airport Commissions,
Los Angeles International Airport, 20 Dec. 1972.
Jhk "Supporting Information for the Adopted Noise
Regulations for California Airports," Final
Report to the California Department of Aeronautics,
Report No. WCR ?0-3(R), Wyle Laboratories, 29 Jan '71.
397 John S. Moore, Ltr: "Comments on Aircraft/Airport
Noise Study Task Force", Illinois Environmental
•Protection Agency, 20 June 1973-
351 B. J. Lockheed, Ltr: "Comments on Chapter J>:
Operations Analysis Task Group 2," City of
Los Angeles, Dept. of Airports, 8 May 1973.
2^5 M. Mergell; Ltr: "City of Inglewood's Support
of EPA Aircraft/Airport Noise Study Task Force,"
City of Inglewood, 26 March 1973.
382 M. S. Spelman, Ltr. "Comments on Possible Aircraft Jet
Engine Noise Research," Malcolm S. Spelman Associates,
Aviation Consultants to Nassau County, N.Y., k May '73-
383 H. L. Diamond, Ltr. "Participation in EPA Task Force",
Department of Environmental Conservation, State of
New, York, 25 April 1973.
R-15.2
-------
15.0 STATE AND LOCAL GOV'TS (CONT'D)
MASTER
FILE
NO. BIBLIOGRAPHIC CITATION
John S. Moore; "Position Statement for Illinois
Environmental Protection Agency", State of Illinois,
July 1973.
R-15.3
-------
APPENDIX A
POSITION PAPERS
OF
TASK GROUP MEMBERS
Note: Throughout the development of this report, and especially during
the review of the two published drafts, the chairman and staff continually
solicited two types of information from the task group membership. First,
written comments and critiques, as well as additional data, were requested
of all and submitted by most active participants. This information has been
helpful in the refinement of this final report. All of the submissions, com-
ments and critiques are contained in the list of references and bibliography,
and a copy of each is preserved and maintained, available to the public, in
the task group master file. Second, position papers in which the members,
representing their various interests, would state their position relative to
the issues, independent of the conclusions and recommendations stated in
this report, were solicited. Those position papers are included in this
appendix.
-------
AEROSPACE INDUSTRIES ASSOCIATION Or AMERICA. INC.
1725 DE SAI.FS STREET. N "JV., WASHINGTON. O C 2CO30TFL 3472315
July 2, 1973
Dr. Alvin F. Meyer
Deputy Assistant Administrator for
Noise Control Program
Environmental Protection Agency
1921 Jefferson Davis Highway
Room 1115
Arlington, Virginia 20460
Dear Dr. Meyer:
At the invitation of the Administrator, Environmental Protection
Agency, several AIA member companies participated in your Aircraft/
Airport Noise Study. A study task force, divided into six study
groups, lias assisted in developing respective parts of the report
required by the Noise Control Act of 1972. Because of the pace
of task group activities and broad scope of information and data
being assembled, it was not possible for AIA to develop and submit
positions as the study progressed.
We are deeply concerned over the conduct of the study and
desire to provide the following comments on this matter:
a. The total subject of aircraft noise conttrol, including
standards, retrofit or phaseout of existing aircraft,
cumulative noise exposure, operating procedures and
definition of health and welfare is exceedingly complex
and involved. We are concerned that the five month
period available did not allow sufficient time for EPA
to assemble a team, let contracts, and accomplish the
work necessary to complete the study in a entirely
satisfactory manner. Furthermore, this short time nade
it impossible for the task group members to adequately
analyze the findings of the contractors or comment
on the work to date in any detail.
b. Because of the diverse backgrounds, expertise and
interests of the task group members, little attempt
was made to determine consensus or majority opinions on
the multitude of questions discussed in the meetings.
Many of the conclusions and recommendations developed
by Task Group Chairmen were in fact not even covered in
the meetings. Consequently, the final reports should
not be represented as the conclusions and recommendations
of the task groups. They are, more realistically, the
opinions and individual views.of the Task Group Chairmen
A-l
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Dr. Alvin F. Meyer -2- July 2, 1973
which in some important instances do not reflect the
arguments and facts presented by the members.
c. The AIA supports efforts to review the existing noise
standards for new aircraft designs and to strengthen
them. The successful introduction of resulting quietei:
aircraft into the fleet is critically dependent on
Federal action to insure that these aircraft once
certificated as complying v ith the applicable standards
shall have the right to operate at all airports, where
they meet airworthiness requirements. It is essential
that airport operators be preempted from prescribing
restrictions which would prevent such certificated
aircraft from operating .-.t their airports. The
necessity for federal preemptions does not conflict
with the use of noise abatement operating procedures.
However, it is essential that the operational
procedures and required aircraft equipment be FAA
prescribed for reasons of safety of operation, pilot
training and equipment interchangeability. Any
other course which permits individual airport
authorities to specify unique requirements will
lead to chaos and will be counterproductive to
the intent of Public Law 92-574.
.d. In general, we find that the cost analysis approach
taken by EPA was inadequate. For example, the cost
analysis on curfews would suggest that night time
curfews offer a very efficient means of reducing
noise exposure areas on per dollar cost basis.
In fact, the adverse economic impact resulting from
disruption to overseas travel and from aircraft being
other than where needed for the following day's
flights would be severe and was not properly considered.
Another example is in the case of land use studies
where more factual data is needed in place of
oversimplified extrapolations. We are convinced
that the economic analyses must be completely re-
examined before any meaningful conclusions can be
drawn.
e. While AIA is not in a position to disagree with the
general approach taken to rate noise exposure using
the dBA unit, we strongly question the selection of
the specific values of 80 for hearing damage and 60
as the ultimate goal for annoyance or disturbance
criteria in the Ldn scale. The data presented does
not adequately substantiate the selection of these
levels. The implication and impact of these limits
is far reaching. Such limits require substantiation
prior to their selection.
A-2
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Dr. Alvin F. Meyer -3- July 2, 1973
f. The FAA noise regulatory actions recommended by the
Task Group Chairmen contai a number of elements with
which AIA is not in agreem it. These disagreements
will be discussed at the time issue of subsequent
regulatory notices.
The AIA recognizes the extent of the noise problem and the
need for progress in alleviating it impact on. the environment.
We agree that regulations and proceures relating to operations
and compatible land use are necessary to assist in reducing noise
exposure. We also agree with the nf-ed for continued research to
reduce noise at the source and provide operating procedures to
reduce, noise exposure for airport neighbors. We concur with the
need to provide financing for research, equipment development,
implementation of noise control measures, and land acquisition.
In closing, we do want to commend the EPA Task Group Chairmen
for their diligent efforts under difficult circumstances. We
urge your consideration of our concerns discussed above.
This letter revises AIA letter of May 25, 1973 to you.
It is submitted in request to your appeal at the EPA hearings
on June 20, 1973 at the Department of Commerce Auditorium,
Washington, D. C. for all previous submittals made to EPA on
the study subject be reviewed and revised not later than
July 2, 1973. As reflected in our statement at the hearing on
June 20, 1973, it is requested that this statement be included
in the record of all study groups.
Very truly yours,
AEROSPACE TECHNICAL COUNCIL
Associate Director
Civil Aircraft Technical Requirements
GIM:ssf
cc: John Schettino - EPA
EPA Task Group Chairmen (6)
A-3
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ft ' " v COMMERCIAL AIRPLANE COMPANY
P.O. Box 3707 Seattle, Washington 98124
June 29, 1973
6-7270-1-444
Mr. W. C. Sperry
Office of Noise Abatement and Control
Environmental Protection Agency
Washington, D. C. 20460
Subject: Boeing Commercial Airplane Company Position on Task Group 4,
"Noise Source Abatement Technology and Cost Analysis
Including Retrofitting11
References: 1) Boeing Letter 6-7270-1-442, V. L. Blumenthal to
R. L. Hurlburt.
2) Boeing Letter 6-7270-1-443, V. L. Blumenthal to
H. E. von Gierke.
3) Boeing Letter 6-7270-1-445, V. L. Blumenthal to
W. C. Sperry..
Dear Bill:
In response to the request made by Mr. John Schettino in his letter of June 25, 1973,
the Boeing Commercial Airplane Company wishes to include only this letter (with
attachments) in the final report of Task Group 4. References 1, 2 and 3 contain our
position letters for Task Groups 2, 3 and 5.
In some of the Task Group draft reports it clearly states that the conclusions and
recommendations are the responsibility of the chairman. We endorse this position
and agree with it completely as being the only reasonable and fair manner in which
such reports could be written. Because of the variety of opinions espoused in the
Group discussions, and because generally no formal attempt was made to obtain a
consensus, we would suggest that any inference of unanimity of opinion be
expurgated.
Attachment 1 contains our letter to you dated April 2, 1973, but revised to include
later information. Note that we have now included our latest estimate of 707 Quiet
Nacelle availability date, delivery rate, and approximate pricing.
The comments that follow pertain to the 1 June 1973 Task Group 4 Report, but are
written in general terms rather than specific comments to that document.
A DIVISION OF THE BOEING COMPANY
A-4
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-2 -
Mr. W. C. Sperry 6-7270-1-444
3. In numerous instances airplane noise values are presented. Please note
that the 747-100 airplane type is shown at its pre-December 1971 levels.
The correct 747-100 noise levels for airplanes currently being delivered
should be presented as
747-100 (Post-December 1971)
Takeoff (No Cutback) 107
Approach 107/105
Sideline 99
2. Attachment 2 is one chart and three graphs to update Boeing airplane
fleet projections from those provided on June 22. These data include
aircraft sold plus firm options only. However, we anticipate continued
sales of all our present product lines into the 1980 to 1985 period.
3. Options for nacelle retrofit are discussed in the Task Group 4 Report.
The report describes the FAA Quiet Nacelle contract and states that
two or more nacelle retrofit options have been developed under FAA
contract for each airplane. This is not completely correct. For example,
the 737 quiet nacelle option, developed on Boeing funds, will enable
the 737 to meet FAR 36. We know of no additional quiet nacelle option
for this airplane. Likewise, mention is made of a SAM + JNR treatment
option for the 707 that will eventually be available. We are not aware
of work currently in progress on such a configuration.
4. The general philosophy is expressed that, ultimately, the consumer of
transportation services will pay the total cost of noise reduction. It is
not clear why only the air transport consumer must bear this burden.
It is broadly acknowledged that at least part of the growth of the noise
problem is due to encroachment around airports of new residential areas.
It seems that perhaps consideration should be given to having the interest
groups who will receive the benefits of noise reduction share in its cost,
as well as all the benefactors of air transportation, including the air
traveler.
5. We encourage the EPA to conduct studies such as is outlined in the Task
Group 4 report under the heading of Cost and Economic Analysis. The
endorsement of this approach stems from our belief that the magnitude
of the consequences of a recommendation for a compatible land usage
criterion (e. g., 80 or 60 L, ) must be thoroughly understood before a
recommendation can be macte, or adopted, as a national standard.
A-5
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Mr. W. C. Sperry 6-7270-1-444
Although we endorse the general approach and methodology used in the
study, we do have extreme concern with the study as reported to date.
As we have stated in our comments on the Task 3 effort (reference 2),
we do not believe that sufficient data are available to establish defin-
itive maximum values of community noise exposure. Notwithstanding
this weakness, and assuming that the data used in the study are correct,
the Task 4 report establishes a national noise problem extent of
between 2 and 31 billion dollars. Not only is the magnitude of this
problem specif ication staggering, but the variation of cost liability
between the selection of L, 80 and 60 (roughly 29 billion dollars) shows
the leverage associated witn the selection of community criteria. We
believe this magnitude and variability of dollar exposure clearly points
out the need for an accurate and comprehensive study.
The implication of retrofit hardware selection, depending upon the
criterion used, is also worthy of comment. For L, 80, the study
results show JT8D SAM retrofit as the minimum cost solution. Using
L, 60 as the criterion, refan for both JT3D and JT8D fleets results in
lowest system cost. More realistically, SAM JT3D and JT8D retrofit
(technology that is currently being developed) still results in an 11 to 18
billion dollar national liability based on the unsupported Task 3 goal of
60 L - „ Task Group 5 further implies that the residual problem should
be solved by restricting operations and land purchase. It is our opinion
that more study is required to investigate how this is to be accomplished,
and the associated consequences.
In addition, the results of the study present questions that we are
unable to resolve. For example, SAM retrofit of only the JT8D fleet
(in conjunction with two-segment approach) appears as effective as
nacelle retrofit of the JT3D fleet. The dollar reduction shown for JT8D
retrofit implies perhaps a 30 to 50 percent reduction in NEF area. Our
studies do not reflect anything like this. From a recent Boeing study,
for a domestic short haul airport with no JT3D powered airplanes, SAM
retrofit of all JT8D powered airplanes resulted in a NEF 25 area reduc-
tion of about 3 percent, with a NEF 45 area reduction of about 15 percent.
For any airport with JT3D airplanes mixed in, it would seem that even
less effect would be observed due to nacelle retrofit of only the JT8D
powered airplanes.
We are also concerned with the data upon which much of this study is
based. Although we appreciate that every effort was made to obtain the
best data available, within the study time constraints, this need not
A-6
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-4 -
Mr. W. C. Sperry 6-7270-1-444
imply that the data were valid enough to base decisions of the magnitude
implied in the Task Group 4 report. We believe that noise data are now
becoming available, through the FAA Noise Definition and NASA Contracts,
that will hopefully contain reasonably consistent information upon which
to base such a study. Further, the selection of only six airports, several
of which are dominated by surrounding water, may understate the scope
of the problem. It could well be that the extent of the problem is far
greater than 31 billion dollars if the airports selected were more typical
of inland airports. If the information in Task Group 4's report is to be
used as the basis to make major decisions such as retrofit configuration
selection, and to establish community acceptability criterion, we strongly
recommend the following:
* That the details of the study methodology and data used be
completely reviewed so that a thorough understanding and
endorsement of its contents can be obtained.
* If required, a re-run of the study should be conducted when a
more consistent and solid data base is available.
Finally, there is the question of who pays. The range of retrofit costs
quoted is from 280 million to over 4 billion dollars. It is probably con-
ceivable that a fare increase could pay part of this cost, thereby passing
part of the expense to the air traveler. There is no way that the air
transportation industry can pay the total system costs ranging to 31
billion dollars or more. We urge that this aspect be thoroughly
considered before final recommendations are drafted.
It has been our pleasure to participate in the Task Force effort. In these meetings
we have attempted to present our knowledge of the present state of the art in the
various facets of aircraft noise reduction. In addition we have attempted to identify
those areas where adequate decision-making knowledge was lacking. We hope that the
EPA will carefully review the various inputs received from the Task Force partici-
pants, separate fact from fantasy and desire, and establish its recommendations
for future rule making on technically proven concepts. Only in this manner can
A-7
-------
progressive steps be taken to reduce aircraft noise and, at the same time, avoid
costly mistakes which this nation can ill afford.
The EPA is to be congratulated for its success in completing a Study of this
magnitude in the short time available.
Very truly yours,
BOEING COMMERCIAL
AIRPLANE COMPANY
A-*^^
V. L. Blumenthal
Director, Noise and Emission
Abatement Programs
Attachments:
Letter 6-7270-1-361 dated April 2, 1973 (Revised
June 29, 1973)
Chart and (3) curves revised June 28, 1973
A-8
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COMMERCIAL AIRPLANE GROUP
April 2, 1973
6-7270-1-361
Revised 29 June 1973
Mr. W. C. Sperry
Environmental Protection Agency
Washington, D. C. 20460
Dear Bill:
The following are some general comments and recommendations pertaining
to Task Group 4 activities.
As part of the effort to attain a compatible airport/aircraft community
noise environment The Boeing Company has recognized the need to control
aircraft noise at the source. To this end the Company has developed,
and 1s providing, production configurations that fully comply with FAR
36, Appendix C, noise criteria for all models of the 727, 737 and 747
airplanes.
Information related to the pricing and scheduling of retrofit kits for
these airplanes 1s shown on Attachment 1. Details on noise reductions
and weight and range penalties associated with the modifications are
presented in the report, D6-60199 "Noise-Reduction Research and Develop-
ment 1972 Progress," already provided to the Task Group. That paper
also includes a detailed discussion of our noise reduction activities
and provides the major portion of our comments.
We are currently in the final stages of an FAA/Boeing co-funded program
to design, develop, fabricate, and flight test a quiet nacelle for model
707 aircraft. The flight test program, now complete, was necessary to
substantiate the estimated acoustic and airplane performance of this
installation and to assist in identifying design changes needed to
achieve an acceptable configuration. Continued coordination with the
airlines to ensure a reliable, maintainable design is a prerequisite to
firm pricing and scheduling of kit availability. We currently estimate
completion of this work in the third quarter of this year, but have
included current estimates of availability and price on an attachment to
this letter.
A-9
Attachment 1 to 6-7270-1-444
-------
Attachment 1 to 6-7270-1-444
Mr. W. C. Sperry 6-7270-1-361
Page Two
Alternate means of noise reduction, by modifying those engines powering
707, 727 and 737 aircraft, have recently received considerable attention.
Studies started by Boeing, and subsequently sponsored by NASA in August
1972, were aimed at determining the feasibility of noise reduction on
JT3D and OT8D powered airplanes by replacing the two-stage fans with
larger diameter single-stage fans. Work accomplished to date indicates
that these refan concepts are potentially very attractive.
We would recommend that the recently cancelled JT3D program be re-instated
and that adequate funding be provided to both JT3D and JT8D programs to
ensure technical viability.
Source noise reduction must be complemented by other methods of reducing
community noise if a "noise compatible" airport environment is to be
achieved. In order to fully exploit available options for shrinking
noise affected land area in the vicinity of airports, it is recommended
that the government take immediate steps to increase the ILS glide slopes
to the maximum extent practical. In addition, it is recommended that the
government, after appropriate and successful review of the two-segment
approach as outlined in the comments submitted for Task Group 2, initiate
and promulgate plans to install the necessary compatible ground equipment
associated with the two-segment approach concept selected. No ground
equipment installation can be undertaken by industry and the door will
generally remain closed to these two options unless and/or until the
government responsibility is discharged.
It is hoped the information provided in our "Noise Reduction R&D Progress"
report and the above comments provide constructive and useful assistance
to Task Group 4.
Sincerely,
BOEING COMMERCIAL
AIRPLANE COMPANY
Vaughn L. Blumenthal
Director, Noise and Emission
Abatement Programs
Attachment
A-10
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AVAILABILITY AND PRICING OF RETROFIT SHIPSETS
(D
Attachment to
6-7270-1-361
Revised 29 June 1973
INITIAL DELIVERY DATE
Boeing
P&W
AVAILABILITY
Possible Delivery
Rates
Boeing
P&W
707
IstQtr.
1975 (2)
10/Mo.,
2nd Qtr.
1976 (2)
AIRCRAFT TYPE
727 737
10 Mo. After
Go-Ahead (3)
10 Mo. After
Go-Ahead (3)
15 Mo. After
Go-Ahead (4)
33/Mo., 11
Mo. After
Go-Ahead (3)
14/Mo., 11
Mo. After
Go-Ahead (3)
130 Engine
Treatments/
Mo., 21 Mo.
After Go-Ahead (2)
747
9 Mo. After
Go-Ahead
5/Mo., 9 Mo.
After Go-Ahead
APPROXIMATE PRICING
Boeing Nacelle, $ 720,000
Spares (5) 43,000
P&W
Spares (5)
Installation 40,000
80,000
4,800
65,600
16,800
7,200
135,000
8,000
43,800
11,200
3,500
250,000
1,200
NOTES: (1) All information is per shipset except where otherwise specified.
(2) Assuming continuous funding.
(3) Assumes material availability. An additional 9 months flow t.me may be
required for material procurement.
(4) May be required for DC-9 also.
(5) Boeing estimate of additional spare parts required.
A-ll
-------
NUMBER OF BOEING LBPR FAN JETS (SALES AND OPTIONS 5/9/73)
YEAR
58
59 60
61
62 63 64 65 66 67 68 69 70 71
72 73
74 75
TOTAL WORLD
(Cumulative)
707
727
737
TOTAL U.S.
(Cumulative)
' 707
727
737
5 31 43 87 127 155 189 248 328 444
6 99 206 336 490
2
5 25 31 48 80 97 125 158 208 287
6 88 184 279 385
1
551
649
107
341
526
69
609
764
219
379
622
143
623
819
255
381
656
144
629
849
285
381
662
146
632
892.
307
381
682
642 656 658
978 1030 1052
323 340 343
739 755 759
Revised June 28, 1973
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-------
General Aviation
Manufacturers Association
Suite 1215
1025 Connecticut Ave., N.W.
Washington, D. C. 20036
(202) 296-8848
GENERAL AVIATION MANUFACTURERS ASSOCIATION
POSITIONS ON THE ISSUES
CONTAINED IN THE REPORT
ON
NOISE SOURCE ABATEMENT TECHNOLOGY AND
COST ANALYSIS INCLUDING RETROFITTING
FOR
ENVIRONMENTAL PROTECTION AGENCY
AIRCRAFT/AIRPORT NOISE REPORT STUDY
TASK GROUP 4
June 20, 1973
A-16
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The General Aviation Manufacturers Association has been pleased to contribute
to the work of Task Group 4. Specific ccvnments on the report are as
follows:
The unit I^n and allowable magnitude to protect public health and welfare
is described by Task Group 3. It is assumed that Task Group 4 should
orient itself to this new measure and base its recommendations on the
feasibility of industry to comply. It is not clear to GAMA what rela-
tionship the new measure has to existing regulations (FAR Part 36 or
the pending ICftO/FAA regulations) and, indeed, how the new measure could
be utilized by a regulatory body. Since I
-------
NOISE CONSIDERATIONS IN THE DESIGN OF
TURBOPROPULSION ENGINES FOR
GENERAL AVIATION
73-210222 May 10, 1973
1.0 INTRODUCTION
Small turbopropulsion engines, such as those used in general
aviation aircraft, typically produce little noise that is significantly
different from that produced by larger engines. Thus, often the tech-
niques used to mitigate or attenuate the sounds from the large com-
mercial aircraft engines are thought to be applicable also to small
engines. The smaller size of the engines used by business and general
aviation aircraft, however, imposes unique constraints on performance,
weight, and cost that preclude the direct application of these methods
and materials without considerable adaptation. In some instances,
weight or volume limitations may be so severe that radically new ap-
proaches are required if the engines and their installations are to
meet acceptable low-noise emission standards.
This document discusses the significant design and operational
features of small turbopropulsion aircraft engines as they are re-
lated to the acoustical qualitites of these engines. Several specific
acoustical problems unique to small engines and their installations
are discussed, and four areas requiring further research are identi-
fied.
2.0 MECHANICAL AND AEROTHERMODYNAMIC DESIGN
Unquestionably, every aircraft engine design represents a com-
promise among the various technical disciplines involved. Aerodynamic
elegance may be sacrificed for producibility and cost; mechanical
73-21C222
Page 1
A-18 *
-------
ruggedness may be derated to achieve acceptable weight; and each of
these factors, as well as others, may be compromised for a lower engine
noise level. However, among those features of greatest concern to
turbopropulsion engine manufacturers are those that directly influence
performance and integrity riuce those factors also influence aircraft
costs and safety.
The basic performance cycles for turboprop, turboshaft, turbo-
jet, and turbofan engines arc the sair.a regardless of engine size. How-
ever, small aircraft, as a class, operate over broad ranges of cruise
speeds arid altitudes, as shewn in Figure 1. Small engine designs
include a corresponding broad range of cycle variations to meet the
aircraft flight requirements. Thus, the large variety of business
and general aviation aircraft types, coupled with the broad range of
operating conditions, requires that the small engine manufacturer be
prepared to analyze and respond to a much larger number of engine/
aircraft cycle optimization problem statements than manufacturers of
the larger commercial engines. Therefore, to provide engines optimized
for each operational requirement, the smtll engine manufacturer must
be prepared to introduce a larger number of engine configurations
into the time-consuming and expensive design-develcpment-certification-
production cycle.
Figure 2 shows the AiResearch TFE731-2 Engine that: was designed
for a sea-level thrust of 3500 pounds ana compares it to a typical
larger turbofan engine. Although such small turbopropulsion aircraft
engines are generally less complex, their small size can impose
problems that can ultimately result in air-raft performance, weight,
and cost penalties.
The factors that influence the integrity of an engine include
the choice of materials, predetermination of failure modes, redundancy
of functions, etc. In this regard, while the smaller engines are
generally less complex in their operation and installations than engines
i3-210222
Page 2
A-19
-------
used on commercial aircraft, they must still meet/ for example, the
.same regulations regarding bird ingestion as the large engines. A
4-pound bird entering the inlet of a 5000-pound thrust turbofan
engine imposes a relatively much greater potential for damage to
that engine than to a 40,000-pound-thrust engine. As a result, the
mechanical strength of small engines required to pass bird-ingestion
tests must inevitably exceed the minimum performance and life require-
ments.
Because small engines are less tolerant of disturbances to the
cycle, the effects of blade clearances and other leakage paths are
more critical. This fact requires that extra attention be given to
manufacturing tolerances, thermal growth and distortion effects, and
internal air distribution passages.
Compromising designs to accommodate extra structural integrity,
manufacturing with extra precision to minimize the effects of leakages,
designing aerothermodynamic components to achieve higher cycle effi-
ciencies, and anticipating and responding to the broad operating
requirements of a multiplicity of aircraft types are extraordinary
requirements that have been accepted and met by small engine manufac-
turers while still producing engines of competitive cost and efficiency.
To these requirements, low noise must now be added.
3.0 ACOUSTIC IMPLICATIONS OF ENGINE SIZE
From the above discussion, it will be noted that there are both
similarities and dissimilarities between large and small turbofan
engines. However, even the similarities in engine .design and operation
often lead to differences in approach to acoustical suppression. For
instance, most modern turbofan engines for subsonic applications (re-
gardless of size) operate within the same general regimes of fan tip
speed and exhaust velocity. Thus, much of the radiated acoustical
power from any size engine falls within the same part of the audible
73-210222
Page 3
A-20
-------
frequency spectrum. Unfortunately, this range (1000-4000 Hz) generally
overlaps both the critical speech interference frequencies and those
associated with maximum annoyance. Thus, the manufacturers of small
engines are faced with eliminating or attenuating sounds within much
the same frequency ranges as the manufacturers of the large engines.
However, much ofvthe technology developed (a great deal of it at govern-
ment expense) for attenuating large turbofan engine noise employs mate-
rial constructions whose thickness, weight, and cost are wavelength
(and thus frequency) dependent. Figure 3 shows a typical quieted air-
craft propulsion engine utilizing resonative attenuation in a concen-
tric splitter ring within the inlet and longitudinal splitters in the
fan exhaust duct. If treatment tuned to 2000 Hertz were applied to
both sides of each splitter, the splitters would be about 3 inches
thick. Therefore, a ring designed for use in a 6-foot-diameter turbo-
fan engine inlet might take up only about 6 percent of the inlet area
(an important consideration in calculating the drag and performance of
the engine), while the identical splitter construction designed for
the same frequency when employed on a small turbofan would block 23
percent of the area. The weight and. cost penalties are also propor-
tionally larger for the same treatment.
There are other acoustic problems in quieting small-sized engines.
Combination-tone ("buzz-saw) noise, for instance, is the result of
the interaction of shock waves from the supersonic portion of each
fan blade. This interaction is the result of inlet flow distortions
and nonuniformity of the repetitive blades. Both are easier to con-
trol in the design and manufacture of the larger engines and components.
Product safety and integrity also play an important part in limit-
ing the direct application of the large engine acoustic technology.
Anti-icing and foreign-object-damage criteria become more critical
constraints within small turbopropulsion engines because of the thin-
ner blades and higher rotational speeds employed. The FAA-required
4-pound-bird ingestion test mentioned above would also uniquely
73-210222
Page 4
A-21
-------
influence the design of splitters and their installation hardware in
small engines, since there is physically less structure available for
support without assuming a disproportionate weight penalty. It is also
necessary to ensure that foreign objects cannot become lodged in the
smaller passages.
While commercial transport category aircraft certainly make more
noise individually than business and general aviation planes, the
latter fleets are roughly 20 times the size of the transport category.
Further, they are dispersed more widely across the country and often
employ suburban airfields that do not have the industrial and commer-
cial buffer zones often possessed by the larger metropolitan fields.
Therefore, the continued use of small, unquieted aircraft has the
potential to create a more widespread adverse community reaction.
It should also be recalled that a very large, percentage of the
general aviation fleet consists of propeller-driven aircraft. In all
likelihood, barring government restriction or intervention, these .
classes of aircraft will continue to grow in number and, as the commer-
cial fleets are quieted, will grow in acoustic importance at an even
faster .rate.
What is therefore necessary to solve these and other related
acoustical problems of small aircraft is a definitive program to in-
corporate the applicable portions of previous (large engine) noise-
reduction studies and to develop new and more appropriate solutions
to the unique general aviation problems. In each case, it will be
necessary to observe practical limits of weight, space, and cost.
4.0 RESEARCH REQUIREMENTS
According to the Joint DOT/NASA Civil Aviation Research and
Development Policy Study, between $20 and $25 million were spent
73-210222
A-22
-------
Some work was performed on sonic inlets for large quiet-engine
applications, but they did not find general use because of the bulk
required to control such a device on a large engine. However, some
version of the sonic inlet may be practical for small engine installa-
tions.
Attenuating devices that do not depend upon the resonance of air
columns, but rather upon mechanical or electrical resonances, might be
more practical for eliminating low frequencies in small engines.
4.3 Research Is Required into Effective Regulatory Practices and
Their Interaction with Cost and Performance Tradeoffs
Many NASA, DOT, and FAA studies have been funded for investigating
the effect that various proposed noise rules, units, etc., would have
upon the economics of the commercial airline industry. Some additional
similar efforts are needed to assess the cost and performance impacts
of various rule-making activities. For instance, a small engine that
was designed to make a high blade-passage frequency would benefit from
a FAR Part-36-type rule where the measuring points are at relatively
large distances from the aircraft during takeoff, since the higher
frequencies attenuate at an exponentially higher rate than low frequen-
cies. However, some of the schemes being discussed for bringing the
measuring points closer in would negate that advantage and might force
the manufacturer to adopt some other engineering feature. Obviously,
the goal should be the definition of a fair and consistent rule that
would protect the public interest without artificially penalizing
anyone.
4.4 Research Is Required into Means for Reducing Noise Emissions
from Propeller-Driven Aircraft
NASA has conducted research in this area for several years; how-
ever, more definitive noise and performance tradeoff studies are
73-210222
Page 7
A-23
-------
required for general aviation-type propellers and engines. Again, the
type of noise rule that is to be promulgated will affect the types of
solutions to be recommended.
Most current general aviation propellers are manufactured with use
of the same materials, designs, and processes employed 20 to 50 years
ago. The advent of composites and other space-age technologies offers
the promise of constructions that are less controlled by material
strengths and yield points and more by aerodynamic' and acoustic con-
siderations. Scalloped, notched, and slotted blades that a few years
ago were only laboratory curiosities because of cost and/or, strength
limitations are now more practically within the reach of most general
aviation operators. However, specific programs are required to clearly
set down the design and performance guidelines, as well as to identify
the potential benefits.
4.5 Research Results Should Be Substantiated in an Engine-Nacelle
Test Bed
The separate and combined results of the above research efforts
should be adequately demonstrated in a nacelle-engine environment.
A-24
73-210222
Page 8
-------
AIRCRAFT CRUISE SPECTRUM
> £U U)
I >a I
to (t) K)
W M
\D O
10
-
CRUISE SPEED,
KNOTS
CRUISE ALTITUDE,
FEET
600
500
400
300
200
100
50,000
40,000
30,000
20,000
10,000
0
-PCOMMERCIAL
AIRCRAFT
SPEED
GENERAL AVIATION
AND BUSINESS AIRCRAFT
103 10* io5 1Q6
TAKEOFF GROSS WEIGHT, LB
COMMERCIAL
JET AIRCRAFT
ALTITUDE
GENERAL AVIATION-
AND BUSINESS AIRCRAFT
MS 3072-4
103 104 105
TAKEOFF GROSS WEIGHT, LB
FIGURE 1
-------
SMALL ENGINES ARE DIFFERENT
Ql U>
IP I
(D to
H
MO
O N)
to
to
TFE731-2
|-«-53 IN.
DFAN = 28 IN.
CF6-6
190 IN.
p£*?"Efr
^- C^
liiU-j *,-'-•--
-^^|--..,
3500 LBT
MS 3022-6
FIGURE 2
-------
TURBOFAN ENGINE NOISE CONSIDERATIONS
:
10
- !
PRIMARY
EXHAUST
FAN (SECONDARY).
EXHAUST
FAN DUC1
SPUTTER
CENTER BODY
CONCENTRIC RING
NOSE COWL INLET
FIGURE 3
-------
GENERAL® ELECTRIC
COMPANY
CINCINNATI, OHIO 45215
AIRCRAFT ENGINE GROUP
22 May 1973
Dr.Alvin Meyer
Environmental Protection Agency
401 M Street, N. W.
Washington, D. C.
Dear Dr. Meyer:
In reference to discussions at the meetings of the EPA Aircraft/Airport
Noise Study Task Force, the views of the Aircraft Engine Group of General
Electric on aircraft noise regulations c-an be briefly summarized as
follows:
1. FAR 36 (as issued on 23 November 1969) has been effective in
stimulating noise reductions. For example, new wide-bodied
aircraft have been certified at or below Appendix C levels.
2. We suggest the promulgation of the subsonic CTOL Fleet Noise
Rule we proposed in our comments on ANPRM 73-3, sent to the
FAA Rules Docket on 12 March 1973, rather than a series of
separate, incomplete and possibly conflicting regulations. For
example, we favor regulations which would require all newly-
produced aircraft to comply with FAR 36 at reasonable dates,
depending on the aircraft type. The suggested Fleet Noise Rule
would accomplish this. We do not favor regulations which would
require all of the current fleet of older types of aircraft now in
service to be retrofitted with nacelle acoustic treatment or
refanned engines. The suggested Fleet Noise Rule would promote
some retrofit of some aircraft types, depending on the particular
airline operator's constraints.
A proper Fleet Noise Rule would allow an airline a decreasing
"noise quota" with time, out into the 1980 period. We believe
that such a method would offer the airline operators maximum
flexibility to control noise through a combination of off-loading,
operating procedures, retrofit and fleet replacement in the most
economic and practical way for each airline and aircraft type.
It is important to note in this connection that most airline fleets
use a mixture of twq three, and four engine aircraft across a
wide range of different stage lengths and numbers of operations.
A-28
-------
Dr. Alvin Meyer
22 May 1973
Page Two
We suggest promulgation of an FAA regulation of the generic
type of the Fleet Noise Level (FNL) proposed by FAA in ANPRM
73-3, but with important modifications proposed by General
Electric, as follows:
a. The noise measure in such a rule should be weighted to
give considerable incentive to airlines to acquire aircraft
having noise levels significantly below Appendix C levels.
This was not the case with the noise measure proposed in
ANPRM 73-3.
b. Rather than the interim nature of the FNL rule of ANPRM
73-3, which would terminate in 1978, we suggest a rule
with a number of "gates" at specified times, requiring
aircraft "on-the-average" to get half-way-down to FAR 36
by some date, down to FAR 36 by a later date, and down to
levels below FAR 36 by some still later date. The noise
Levels shown on the attached figure are suggested as typical
certification levels for new aircraft in the late 1970's,
based on our views of possible noise reduction, available
technology and economic reasonableness, over the wide
range of aircraft types covered. The suggested approach
noise levels are for the flap settings used in normal
operating practice, rather than the maximum flap settings
as required currently in FAR 36. The use of normal flap
settings is a -worth-while noise abatement operating procedure
in itself.
It should be noted that separate certification rules will be
required for supersonic transport aircraft and for quiet short-
haul aircraft, due to the different characteristics of these
aircraft types.
It is also suggested that FAR 36 bemodified to encourage
the use of two-segment approach procedures, by specification
of an additional special reference point, such as a 3 l/2nm
approach point, and maximum allowable noise levels at this
point. If this method were used, the FAR 36 tradeoff pro-
visions should be maintained at the normal three reference
points only.
EPA has proposed airport regulations as such. The cognizant
authority for such regulations should be a Federal agency, in order
to assure that this vital and integral part of the national transportation
system is not adversely compromised by local piece-meal actions.
Therefore, such definitive Federal pre-emption of airport noise
A-29
-------
Dr. Alvin Meyer
22 May 1973
Page Three
regulations should be a part of the proposed action in order to
afford equitable treatment for all airport users, including airlines.
Appropriate FAA noise source control and aircraft path control
regulations should separately provide final "design requirements"
for manufacturers, as FAR 36 has done in the past.
4. An increased level of .aircraft noise reduction research and
development is needed in the following areas:
a. Development of noise technology for advanced CTOL,
engine/air craft systems which emphasize reduction
of the economic penalties of lower noise, i. e. , lower
cost, weight and performance losses.
b. Identification of improved measures of airport community
noise annoyance for aircraft operations making noise
equal to or less than required by FAR 36.
c. Determination of aircraft-alone noise levels and
identification of means to control this noise source.
General Electric has been active in aircraft noise reduction since the
middle 1950's, in both the civil and military aircraft areas. Substantial
progress has been made, as evinced by the civil fleet introduction of the
new wide-bodied aircraft, which are much quieter than their predecessors.
We believe that Federal aircraft noise regulations and additional research
and development of the types suggested above will achieve further reductions
in airport community noise exposure.
Very truly yours,
J. N. Krebs
attach.
A-30
-------
CERTIFICATION LEVELS FOR NEW AIRCRAFT IN THE LATE 1970's TIME PERIOD
TAKEOFF
3.5 N. Mi. from
Brake Release
SIDELINE
0.35 N. Mi.
(4 Engine A/C)
0.25 N. Mi
(Less than 4 Engines)
110
100
EPNL
110
100
EPNL
.
-
-
-
—
E
=
0
10
/
/
/
/
/
100
y
/
/
jf
/
/
6UO
... FAR 36
PROPOSED
/ TAKJ-IOFF
LIMIT
1000
Maximum Takeoff Gross Weight
(1000 Ib.)
-
—
-
-
—
-
-
—
0
*3
0
^f^
'"
LOO
^"
JU
-
-
-
FAR 36
PROPOSED
SIDELINE
LLMIT
000
Maximum Takeoff Gross Weight
(1000 Ib.)
APPROACH
1.0 N. Mi. from
Threshold
COMMUNITY APPROACH
3.5 N. Mi. from
Threshold
110
100
EPNL
90
BO
:
FAR 36
PROPOSED
APPROACH
LIMIT
PROPOSED
COMMUNITY
APPROACH
LIMIT*
30 60 100
300 600 1000
Maximum Takeoff Gross Weight
(1000 Ib.)
*Based on O'/V Two-Segment Approach with 600 ft. Intercept
A-31
-------
Environmental Activities Staff
General Motors Corporation
General Motors Technical Center
Warren, Michigan 48090
July 25, 1973
Mr. William Sperry, Chairman
Task Group 4
Aircraft/Airport Noise Study
Environmental Protection Agency
Room 1102F
Crystal Mall Building
1921 Jefferson Davis Highway
Arlington, Virginia 20460
Dear Mr. Sperry:
In a discussion with Mr. Curt Walker we agreed to change page 2 of this
submission to reflect an emphasis on our position relative to the issues
rather than to the Task Group Report.
Attached is our revised submission. Thank yon very much for the opportunity
to comment on this important area of environmental noise control.
Sincerely, /
E. G. Ratering, Director
Vehicular Noise Control
Attachment
cc: Mr. C. L. Walker
Detroit Diesel Allison Division, GMC
A-32
-------
Genera! Motors Statement
Before the
Environmental Protection Agency Task Force
on
The Aircraft/Airport Noise Study
Submitted By
Edv/in G. Ratering
Director, Vehicular Noise Control
Environmental Activities Staff
General Motors Corporation
and
Curtis L. Walker
Section Chisf, Noise Reduction
Detroit Diesel Allison Division
General Motors Corporation
June 21, 1973
A-33
-------
General Motors Statement
Mr. Chairman, my name is Curtis L. Walker/ Section Chief, Noise Reduction
Research, Detroit Diesel Allison Division, General Motors. We appreciate the opportunity
to comment upon the problems we see in the study of aircraft noise reduction.
Detroit Diesel Allison manufactures the commercial aircraft engine, Model 501
turboprop, for use in Electros and Convair conversions. Consequently we are concerned
with the noise reduction objectives being considered for aircraft engines.
We appreciate the problem that faces the Task Groups, due to the short time which
Congress allotted to the Environmental Protection Agency to carry out the Aircraft/A;rpcrt
Noise Study. Therefore, we will submit brief comments on those areas under Task Group
consideration wherein our experience and testing has given us competence.
As a preface to our comments, may I establish for the Group two facts:
(1) Our Model 501 turboprop engine is a significantly quieter engine
than a contemporary turbofan engine used in an aircraft of the
same gross weight, viz., the Electro compared with the DC9-30.
A noise footprint making this comparison between the Electra and
DC9-30 is attached as Figure 1. We believe that the Electra
will meet any reasonable noise emission requirement.
A-34
-------
-2-
(2) If, as a result of the EPA studies, reduction of general
aviation aircraft noise is required, then there are several
turboshaft engines which are available which are quieter
than comparable reciprocating engines. One of these
turboshaft engines is the Allison 400-horsepower Model 250,
which is currently in widespread helicopter use.
During the pest seven years at Detroit Diesel Allison, we have been doing
research in the aeroacoustics of advanced high-bypass engines. This effort has made
it necessary for us to construct a unique test facility which is devoted to fan noise
research. As a result of this effort, we believe that technology does exist for further
noise reduction below that currently specified in FAR 36. Moreover, our studies
of commercial derivatives of our current advanced technology core engines indicate
that some noise reduction below current regulatory limits would involve a relatively
straightforward engineering and development effort. We would like to caution,
however, that reductions in the range of 10 EPNdB or more below those levels
currently specified in FAR 36 will be difficult to achieve. Indeed, such reduction
may require significant technological advancements in order to avoid appreciable
aircraft performance penalties.
A-35
-------
The exact degree of improvement1 which may be available without such performance
penalties is impossible to predict at this time. However, the possibilities for noise reduction
through currently available technology are indicated by the calculated footprint for a
commercial derivative of the Advanced Medium STOL Transport (AMST), which is shown
at two typical bypass ratios in Figure 2 (also attached).
Finally, Detroit Diesel Allison Division is greatly concerned that an adequate amount
of lead time be allowed in developing engine improvements of the type we are discussing
today.
Our experience in the development of aircraft engines leads us to the conclusions
we have depicted on the chart attached as Figure 3. As you can see, it is our judgment- that
even v/hen the technology is at hand to accomplish a specific objective, it is likely to take
several years of further development and qualification before such technolgoy has been
incorporated into the final aircraft so that it can enter the market as a production
aircraft. In other words, the phrase "immediately available solutions" in the aircraft
field means that several years of additional testing are still required before translation
to flying hardware is likely to be completed.
This concludes my prepared statement. At this time, we will attempt to ansv.or
satisfactorily any questions that you may wish to ask.
Thank you.
A-36
-------
.DISTANCE
FROM RUNWAY
CENTERLINE
(1000 FT)
NOISE FOOT PRINT COMPARISON
100 EPNdB
w
2
0
2
LOCKHEED ELECTRA
-16 -14 -12 -10 -8 -6-4 -20 24 68 10 12 14 16 18 20 22
APPROACH
TAKEOFF
DISTANCE (1000 FT)
-------
CO
CO
r^/ Divisor! o? General Motots Corpoiution
DI S"f AN CE '
FROM RUNWAY
CENTERLINE
,(1000 FT) 2
0
NOISE FOOT PRINT COMPARISON
HOOEPNdB
LOCKHEED ELECTRA
-16 -14 -12 -10 -S -6 -4 -2 0 2 4 6 8 10 12 14 16 18 20
APPROACH TAKEOFF
!D I STANCE (1000 FT) ": BYPASS
RATIO
22
2
0
2
AMSTCOf\W£SC!AI. DERIVATIVE
-------
"v, r* r-*-rv'i?t" nr-ir"1:! rr',r?"^'"i-1>
.11 luLi/S- Jto L»iiJaL;I ^iis.iiijk*
D:v^.ii3ii of Gcnciil Motors Corpaialion
ENGINE DEVELOPMENT CYCLE
w
CO
TECHNOLOGY DEVELOPMENT
J.
DEMONSTRATION PROGRAM
MODEL DEVELOPMENT
-2 -1 0 il ;2 i3 i4
YEARS FROM TECHNOLOGY AVAILABILITY
PRODUCTION
-------
DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT
.WASHINGTON, D. C. 20410
ASSISTANT SECRETARY FOR .__,
COMMUNITY PLANNING AND MANAGEMENT ' ••! 9 9 TJ'J
Mr. John C. Schettino
Director, Aircraft/Airport Noise Study
Office of Noise Abatement and Control
Environmental Protection Agency
Washington, D. C. 2
-------
Department of Housing and Urban Development
Comments on
RECOMMENDATIONS ON THE EPA TASK FORCE ON AIRCRAFT/AIRPORT NOISE PROBLEMS
A. HUD's ROLE IN NOISE ABATEMENT
It has long been HUD's policy to encourage the creation and maintenance
of a quiet environment. To further this goal, HUD issued, on August h,
1971, a policy Circular on "Noise Abatement and Control: Departmental
Policy, Implementation Responsibilities and Standards." This policy
was promulgated after several years of development, in an effort to ful-
fill the Department's mandate to "provide a decent home and a suitable
living environment for every American family". With the issuance of this
policy, HUD stated its conviction that "noise is a major source of envi-
ronmental pollution which represents a threat to the serenity and quality
of life in population centers." The policy formalized and expanded
existing FHA noise regulations which had been in effect for many years,
and drew upon the work of several other agencies and groups and on a
long standing and developing body of knowledge in the area.
The policy establishes noise exposure policies and standards to be ob-
served in the approval or disapproval of all HUD projects; it supersedes
those portions of existing program regulations and guidance documents
which have less demanding noise, exposure requirements. Further, it is
HUD's general policy to foster the creation of controls and standards
for community noise abatement and control by general purpose agencies of
State and local governments. HUD also requires that noise exposures and
sources of noise be given adequate consideration as an integral part of
urban environments in connection with all HUD programs which provide
financial support to planning. The policy emphasizes the importance of
compatible land use planning in relation to airports, other general modes
of transportation, and other sources of high noise, and supports the use
of planning funds to explore ways of reducing environmental noise to
acceptable exposures by use of appropriate methods. Reconnaissance
studies, and, where justifiable, studies in depth for noise control and
abatement will be considered allowable costs.
Because HUD's noise standards are technically specific in nature, the
Department has published "Noise Assessment Guidelines", a manual to pro-
vide HUD's personnel and the general public with a practical methodology
for preliminary evaluation of noise levels at given project sites. An
important facet of the Department's noise control activities is a con-
tinuing program of sponsored research into various aspects of the cause
and effects of environmental noise. Typical of these is a series of
Metropolitan Aircraft Noise Abatement Policy Studies, funded jointly by
HUD and the Department of Transportation. This work was summarized and
A-41
-------
-2-
extended in the form of a guideline manual, to help localities plan com-
munity growth in the vicinity of airports. The manual discusses the costs,
"benefits and limitations of alternative methods of noise alleviation such
as compatible land use development, zoning, and noise attenuation measures
in building construction. Applicable to all type of airports, it will be
used to develop procedures for dealing with a variety of local airport
noise situations. It also contains relevant information on Federal and
State programs to assist in achieving compatible airport-community de-
velopment. The manual entitled "Aircraft Noise Impact: Planning Guide-
lines for Local Agencies," is'now in printing by the Government Printing
Office and will be given wide distribution.
B. HUD's POSITION ON ISSUES RELATED TO THE WORK OF THE TASK FORCE
1. Cumulative Noise Exposure
We believe that there is an urgent need to standardize a measure of noise
exposure as a prerequisite to promulgating a national set of noise exposure
standards and implementing procedures. We, therefore, strongly support
the activities of Task Group 3. The lack of what might be called a
"perfect" index of measure is no excuse for inaction on the growing prob-
lems of noise abatement and control. Our major concern is that any pro-
posed aircraft noise assessment method be compatible with those now in use
by this Department in implementing the HUD noise policy, i.e., Composite
Noise Rating (CNR) or Noise Exposure Forecast (NEF).
We are in agreement with the long term goal of Ldn of 60 (NEF 25) recom-
mended in the Task Group repor^ though we feel that further clarification
is needed. Current HUD policy is to discourage residential development
beyond 30 NEF (though some discretion is applied in certain cases where
noise exposures lie between NEF 30 and 1*0). The NEF 30 value corresponds
roughly to an Ldn of 65. Thus, the current allowable noise exposure for
HUD assisted new residential construction is marginally higher than the
long term goal recommended by the Task Group. However, we fully hope
and anticipate that the EPA, with the cooperation of other Federal agen-
cies and industry groups, will be successful in reducing noise through
source and operational controls, so that noise reduction from these activ-
ities will bring current residential construction satisfying existing HUD
criteria well within the long term objective (Ldn of 60). It is important
to emphasize that since new construction represents the long term estab-
lishment of a given land use to a particular area, implementation of long
term goals requires immediate action of the type HUD has been actively
pursuing in the last two years.
A-42
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-3-
We assume that the immediate goal of Ldn (45 NEF) of 80 is to be imple-
mented through source and operations controls, building modifications,
and where necessary, condemnation and relocation, and is to be applied
to existing residential units. We fully support such a recommendation
providing adequate relocation resources are available at a price the dis-
placees can afford (pursuant to provisions of the Uniform Relocation Act).
We are concerned, however, that noise levels less than Ldn 80 may also
constitute risks to health resulting from sleep interference, unless
airports have stringent restrictions on night-time operations. The pro-
blem is exacerbated with windows open, as they must be in the summer
months in many areas when adequate alternative ventilation is not avail-
able.
We support recommendation concerning a standardized computer program for
calculating cumulative noise exposure. Further, there should be a stand-
ardized definition of data input requirements and a central data center
which can generate contours of cumulative noise exposure for use by Federal,
State and local agencies in making land use decisions.
2. Airport Noise Regulation
We would endorse the recommendations that airport operators exercise their
authority to regulate aircraft operations to reduce noise in residential
areas. The requirement that airport operators predict operations and noise
exposure to determine compatibility of airport operations with the adjacent
land uses and then take actions to achieve a larger measure of compatibility
through reduction in the noise effective size of the airport is an important
element in the total program to reduce airport-community conflicts. Deci-
sions on runway alignment, airport expansion and volume and type of aircraft
use are as essential to ameliorating and preventing noise conflicts as are
the control of noise at the source and the control and guidance of land use
development in the airport environs.
It is understood that the FAA has the authority for requiring airport cer-
tification under existing legislation. That agency should therefore be
encouraged to take the necessary action to meet the EPA compliance schedule.
3. Continuing Program for Noise Abatement
We would concur in the need for a continuing Federal Program to assist in
implementing a comprehensive national aircraft/airport noise abatement pro-
gram. We would be happy to participate in those aspects of the program which
are of interest and concern to the Department.
C. OTHER RELATED ISSUES
There are other problems that need to addressed to further goals of the air-
craft/airport noise abatement program; some of these are:
A-43
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-4-
1. National Airport System Planning
A National Airport System Plan appears to offer a key to the problem of
location and expansion of airports in the Nation, and a meaningful docu-
ment can lessen the potentially adverse impacts of such development.
The long range plan could identify the projected kinds and volume of oper-
ations at specific classes of airports so that there would not continue to
be the many surprises which appear to develop fairly regularly following
the creation of an airport or changes in operations at existing airports.
Communities in the airport environs would then have an explicit idea of
the kinds of airport development expected and could plan accordingly.
The National Airports System Plan should have a rational national focus
and not be only a compilation of airport projects conceived solely by
state and local authorities. •
2. Modification of Airport and Airway Development Act (AADA)
We believe that the AADA can be strengthened to insure a greater measure
of compatibility between airports and their surrounding areas, as follows:
a) Aircraft noise is not specifically addressed in the law.
In view of the growing concern with environmental quality
and the impact of the airport development program, noise
merits specific recognition. The law does not now support
the acquisition of land to be exposed to severe levels of
noise;consideration should therefore be given to modifying
the statute to allow the acquisition of such land, by ease-
ment or fee simple, as part of the airport development pro-
ject costs. Inclusion of such a provision to cover areas
of very severe noise exposure is both desirable and tfecjsssary
to any meaningful solution to. the noise problem. . , ;
b) The rules promulgated by the FAA for implementing the Planning
Grant Program under the AADA are not consistent with Section II
of the Act. Airport systems planning should be an integral
part of multi-modal transportation planning for the metropolitan
area, and should be handled by the appropriate public comprehensive
planning agency. Environmental considerations and airport loca-
tion should be a significant part of the systems planning process
rather than a token after-the-fact issue in airport master planning.
MCE
6/21/73
A-44
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LOCKHEED-CALIFORNIA COMPANY
A DIVISION OF LOCKHEED AIRCRAFT CORPORATION
BURBANK. CALIFORNIA 915O3
RECEIVED
April 25, 1973 MAy 3
Mr. W. C. Speriy
Chairman, Task Groups ^ & 5
Aircraft/Airport Noise Study Task Force
Office of Noise Abatement and Control
Washington, B.C. 20U60
Dear Bill:
As part of the Lockheed effort in support of the EPA Aircraft/Airport
Noise Task Force, we some time ago asked Rolls-Royce to provide their
evaluation of the potential for further engine noise reduction. I feel
that consideration of the Rolls-Royce input by EPA is appropriate both
because of the pre-eminence of Rolls-Royce in aircraft engine noise
technology and because Rolls-Royce engines power a growing proportion
of the U.S. air transport fleet.
The attached statement was prepared by Mike Smith, Manager of the
Rolls-Royce Noise Department, and approved for submission to EPA by
Mr. E. M. Eltis, Director of Engineering, RB.211 Programme. I hope
you will find it useful.
Sincerely,
H. Drell
Flight Sciences Division
Commercial Engineering
HD:JRT:jg
Attach.
A-45
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16 April 1973
CONSIDERATIONS RELEVANT TO QUIETENING OF AIRCRAFT NOISE
IN THE IMMEDIATE FUTURE
The noise environment around airports is governed almost entirely by aircraft
powered by engines designed about a decade ago. With less than 5% of world
fleets currently comprising the newer more quiet Trijets, the L-1011 and
DC.10, this situation is likely to prevail until at least.1978, when the
FAA propose that all types comply with FAR Part 36 Standards. Even then
the improved standard of the high bypass engines over modified earlier counter-
parts will ensure that newer types cannot be cited as the main offenders.
There would therefore appear to be little justification for demanding unduly
improved standard from new equipment, for the effect would not be reflected
in the overall environmental picture.
However, some improvement in noise standard for new types entering service
in the second half of this decade is desirable, to ensure that the problem
is largely solved during the 1980's. Having said this, two important problems
to be addressed are how much the improvement should be and when new regulations
should be enacted. The following paragraphs express our view and are offered
to the EPA for their consideration.
The RB.211 is a prime example of the new breed of quiet engines. Its main
features were designed in 1966, development commenced in 1967, and the first
production engines entered service in early 1972. Any radically new engine
can be expected to follow approximately the same cycle of events, and there-
fore it would be unrealistic to apply stringent new regulations before the
end of this decade, since the technology to meet such standards is not
developed today.
What is available today is the technology to make limited, but nevertheless,
worthwhile improvements. The improvements possible are limited by the new
problems' that have been revealed in the developments of the newer engines,
a prime example being the noise floor created by the core engine. This fact
has already been recognised by U.S. Government Agencies in the Research and
Development Contracts offered to Industry in the recent pas-c, and clearly
the answers will not appear without considerable research, involving in some
cases new test facilities.
We therefore see two clearly defined stages in improving the noise environ-
ment, viz:
a) limited improvements possible with todays technology, for
implementation en engines entering service in the second half
of this decade.
b) further improvements made possible by ongoing research, over
the next three to five years, for implementation on engines
entering service during the- -:arly to L'.id I'-cO's.
Let vis consider each category in turn.
A-46
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a) Improvements possible using todays technology
On an engine of the KB. 211 type there are two important flight conditions
to be considered in defining the improvement afforded by engineering action.
These are the high power case for lateral and Take-off noise, and part power
for Approach.
The KB. 211 noise source distribution has been defined as shown in Figure 1.
Without resorting to major changes to the rotating machinery improvements
are possible by virtue of better aerodynamic standards and improved liner
performance. The latter may result from improved design of the liner struc-
ture, or the introduction of extra surfaces in the main air-flow passages,
Already we are proposing modest improvements for developed versions of the
KB. 211, and estimate that such action will improve the standard by about
2 EPNL. Even these improvements are not, however, without penalty. The
weight change alone would cost the Tristar the equivalent of five passengers
(unless the aircraft weight can be increased by an equivalent amount).
On an aircraft already bettering Part 36 standards by 10 EPNL at full power
and U EPNL at approach it is difficult to see the extra cost being readily
borne by the operator.
Further improvements are possible, at an increased operating penalty.
The Company entered a partnership with the U.K. Government nine months
ago to produce a quiet engine demonstrator based on the KB. 211. This pro-
gramme is directed at improving the noise standard by 5 PNdB, but the modi-
fications are not in any. way designed for the production powerplant. Some
of the modifications could eventually be incorporated in a saleable power-
plant, but others like the full length bypass duct splitters, would involve
major redesign, performance penalties and mechanical complication. For
example the whole thrust reverser system would need replacing. To integrate
all the improvements in a powerplant would cost around 350 Ibs weight per
engine, and the c-ruise sfc penalty would probably be of the order of 1/2%.
Furthermore if significant modification were required to the inlet system,
for example by the introduction of a splitter ring, the full effect would
be a further increase of sfc of at least 1/2^ and 200 Ib in weight per engine.
Moreover' such devices would require careful consideration of the vibration
problems of the fan assembly and may necessitate changes to the fan design.
We would estimate that a 5 PNdB package would take not less than four years
to develop and apply to a production standard engine. Assuming a go-ahead
early in 19?U, quieted production engines could be available in the late 1970' s,
The overall result, taking installed performance into account, would probably
be a Trijet some 3 - ^ EPNL better than the standard of the TriStar today.
b) Further improvements in newly designed engines
Our research progrtursnes are indicating that basic improvements, other than
the extensive use of sound absorbing materials, will only come from more
extens ive redes i
-------
Even so the potential for such further basic improvement does not, at the
present time, appear to be more than about 3 PNdB, and it is our belief
that the contribution of the powerplant alone cannot be regarded as the
ultimate solution to the noise problem. It will be necessary for the
airframe design to be even more closely integrated with the powerplant
to ensure full benefit from shielding by wing and fuselage structures,
and such constraints may well dictate the design of future airplanes.
Another factor clearly affecting potential noise reduction is the noise
generated by the airframe itself, and unless this can be reduced it is
unprofitable to demand an improved standard from the engines alone.
CONCLUSIONS
We see two distinct stages relating to future noise legislation;
1. A reduction in Part 36 standards during the latter part of this
decade, probably of the order of *4- - 8 EPNL with the provision
that the measuring points are modified to remove the current
inequality between the landing and take-off measuring distance.
Such reduced levels could be demanded from all new aircraft,
including developed versions of existing- types. The relationship
between the two, three and four engined aircraft would however
need careful consideration.
2. A further reduction of the order of 5 EPNL during the early part
of the 1980's, to be applicable to completely new types only. The
practicality of"this reduction, of course, depends upon the level
to which airframe noise can be reduced.
Beyofld that point it is necessary to define both the technically feasible
noise floor and the noise level beyond which community exposure is not
longer a problem. Assuming that these two criteria are not coincident,
it will be necessary to carefully balance technical feasibility and
economic impact against any long term legislation proposals.
A-48
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RB.211-22C IN FLIGHT NOISE SOURCE DISTRIBUTION
APPROACH
TAKE-OFF
*.
CO
0!
TOTAL-
-41
PNdB
_0
-12
CO!
CO
oo
UJ
c_>
X
'LU
0 i -^TOTAL
-4
PNdB
-8
-12
o
IX
'UJ
CO
C£
ZD
-------
25 KNOB HILL ROAD, GLASTONBURY, CONNECTICUT 06033
203 - 633-2835
Rational Organization to Insure a^Sound-controUed ^Environment
June 30, 1973
iir. V;illlani Sperry
Chairman Task Group 4
Aircraft/Airport Uoise Study Task Force
U.S. iinvironnental Protection Agency
Suildlnr: 2, Crystal Mall
Arlington, Virginia 20460
Dear ."Ir. Sperry:
V.'e have participated in the meetings of Task Group *+, working
on" I.'oise Source Abatement Technology and Cost Analysis
Includinr. Retrofit *for the Environmental Protection Agency
Aircraft/Airport hoise Report Gtudy and subn.it the following
as the position of the National Organization to Insure a Sound-
Controlled Environment.
Aircraft^Poyxerplant :-ioise Abatenent
We find that aircraft powerplant noise abatement technology has
advanced rapidly since the introduction of the hif?h oy -pass turoo -
fan en-.ine which produces less noise in the jet wake and where
the internal noise can be abated by acoustic treatment of the
inlet and discharge ducts. While continued RSD is necessary
for the further noise abatement of powerplants to be used in
future desi-ns of aircraft it is important that the benefits
of the present state of the art be used to provide relief to
airport neighbors as soon as possible.
It should be noted that aircraft models arc expected to remain
in production for 10 years or more and that the airlines operate
these aircraft for 10 years or Tnore after delivery. This fact
together with the fact that a few noisy aircraft in the fleet
A-50
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Mr. V/illiam Sperry June 30 1073
Pa^e 2
••keeps-:.the noise exposure level high shows that the riolse in
areas in the airport environs nay reflect the noise abatement
technology of a period 20 years or more earlier. For this reason,
during periods of rapid technological development in noise
abatement, two means for shortening the period of excessive
noise must be utilized to the fullest. They are:
(a) Metro fits of noisy powerplants with quieter ones takinp;
advantage of improvements in powerplant performance where
possible.
(b) Updating the powerplant being used on the aircraft which
is in production as the state of the art advances or
changing to a quieter powerplant during the production
period.
An analysis of the aircraft in the airline fleet in the future
indicates that if a retrofit is made which extends the life of
aircraft into a period when the presently delivered aircraft
are being retired it should be as quiet or quieter than the
presently delivered aircraft otherwise it will stand out as a
noisy and therefore undesirable aircraft.
It is anticipated that airport operators will, in the future,
be required to permit only a specified noise exposure in the
environs of the airport. In that case the aircraft which can
provide the maximum service per unit of noise exposure will be
welcome and the noisy aircraft may be barred. For these reasons
We recommend that:
(a) Any retrofit which extends the life of an aircraft be
levels
designed to reduce the noise of the aircraft to/ as low as
A-51
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Mr. William Sperry June 30, 1973
Page 3
or lower than the noise levels of new aircraft in
production.
(b) Aircraft powerplants in production be updated every 3 to
5 years to incorporate advances in the state of the art
in aircraft noise abatement.
Noise^ Abatement Operating Procedures
While operating procedures is the subject of the Task Group 2
Study, technology is involved in providing equipment to facilitate
noise abatement operating procedures. There are two areas where
technology can contribute significantly to aircraft noise
abatement. They are:
1. Aircraft automatic control equipment to facilitate the
use of 2 segment, decelerating approaches where engine
thrust is kept to a minimum and flaps are used to bring
the aircraft to touchdown speed Just prior to touchdown.
This sives a minimum of both engine noise and flap tur-
bulence prior to reaching the airport boundary.
2. The improvement of aircraft performance in crossv/ind and
tallwind operation on preferential runways. It has been
found, for example, that an increase in the permissible
crosswind from 10 to 20 or 25 knots will in some cases
permit the use of a preferential runway 902 or more of
the time as compared with 20 or 305?. This may make it
possible to shrink a noise sensitive residential area
exposed to unacceptable noise to a small fraction of its
previous size.
A-52
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Mr. William Sperry June 30, 1973
Pap:e 4
; :J °j-j e_ Ap. ate Ren t By I rap roved Aircraft Performance
It is well known that two engine aircraft have steeper
climbout capability than three and four engine aircraft
because of their higher power loading. This steeper climb
and larger percentage thrust cutback which is possible with
high power loading aircraft rr.akes possible large reductions in
the areas enclosed within specified noise exposure contours
on takeoff.
In the competition to carry the most passengers £ per unit
of noise exnosure on takeoff under the airport noise certification
procedure,, airlines will want to. exploit all possible pro-
cedures for getting aircraft into the air with a minimum
contribution of noise exposure. This competition nay be the
incentive for new developments in the aircraft/airport
syster. for noise reduction.
Cost of Aircraft -loise Reduction
The cost of aircraft noise reduction becomes reasonable after
the size of the area of incompatible land use has been reduced
by the introduction of quiet aircraft and noise abatement
operating procedures. As discussed in detail in our position
paper presented to Task Group 1, we recommend that the cost
of aircraft noise reduction and the cost of land use change
A-53
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Mr. William Sperry June 30, 1973
Page 5
required as a result of excessive aircraft noise be
paid for by the users of the air transport system.
Sincerely yours,
John M. Tyler andfiloyd vY nintftfn, iX^citYve ^Directors"
A-54
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u
^t Qf Wf"li^n0V RirCrC> DIVISION OF UNITED AIRCRAFT CORPORATION
"
ft
May 15, 1973
Mr. William C. Sperry
Office of Noise Abatement and Control
Aircraft/Airport Task Force
Environments 1 Protection Agency
Washington, DC 20460
Dear Bill:
During the meetings of your Environmental Protection Agency Task Group 4,
you requested position papers from the members commenting on the various
possible source control options for reducing aircraft noise.
The attached comments from Pratt 5 Whitney Aircraft are divided into
two sections. The first section covers the various options for noise
retrofit of the narrow-body commercial transport fleet. We do not believe
that sufficient data is yet available to make a decision on the feasibility
of retrofit. Our comments are based on the technical information available.
The second section provides comments on the development of new quieter
engines, including a comparison of the JT9D and NASA Quiet Engine.
These comments along with the previously provided report, "Noise Reduction
Programs at Pratt ft Whitney Aircraft," comprise the information we wish
to provide to Task Group 4. We hope this information will be of assistance
to you.
Sincerely,
PRATT $ WHITNEY AIRCRAFT
W. E. Helfrich
Project Engineer - Noise Reduction
WEHrcaz
Enclosure
A-55
EAST HARTFORD, CONNECTICUT 06108
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:.Y;T <; V.;;ITM:Y \ii r MT
NO I SI Rl.TRORT OF Till; NARROW-BODY COMMERCIAL TRANSPORT FLEET
The Environmental Protection Agency Task Group 4 is considering the var-
ious possible options for retrofit of the current narrow-body commercial
transport fleet to reduce aircraft noise. Because the JT3D and JT8D
powered aircraft comprise a large part of the current U.S. fleet, and have
many more years of useful life, a decision on how to best provide noise
reduction for these airplanes involves a complex array of economic and
technical factors.
The FAA treated nacelle programs have not yet been completed and the NASA
refan programs are still in the design stage. Results of these programs
will provide comparative data on economics, performance and noise reduc-
tion. These results will determine whether a noise retrofit program is
feasible which meets the requirements of Public Law 90-411. The follow-
ing arc Pratt 5 Whitney Aircraft's comments based on the technical
information available.
General
Noise levels of the current narrow-body airplanes along with various
retrofit schemes are shown in Figures 1, 2 and 3 at approach, takeoff and
sideline conditions. Noise levels of the wide body aircraft are shown
for comparison. >
Summaries of the various retrofit schemes for a 727-200 and a 707-320B
are given in Boeing reports, references 2 and 3, showing the estimated trade-
offs between noise footprint area, airplane range and retrofit cost.
Nacelle Treatment
Treated nacelles which will meet FAR 36 noise levels have been developed
and certified by Boeing for the 727 and 737 and are being developed by
Douglas for the DC-9. As may be seen in Figures 1, 2 and 3, the
untreated JT8D powered aircraft are close to FAR 36 noise levels, and
consequently these treated nacelles will only provide small noise
reductions. A typical case for the 727 shown in the reference 2 Boeing
report indicates a modest retrofit cost and a small change in airplane
range, hut the noise footprint area for a 90 F.PNdB contour is only
reduced from 29.4 to 26.4 square miles. This comparison implies that
treated nacelles for JT8D powered aircraft will not provide meaningful
noise reduction to the airport communities in a retrofit program.
A-56
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Treated nnci'llcs :irc being developed for the 707 in a Rocing/FAA program.
Flight tests to demonstrate performance and noise levels arc currently
in progress. Predicted flyover noise levels would provide significant
noise reduction, as shown in Figures 1, 2 and 3. This would be equiva-
lent to a reduction in noise footprint area from 54 to 21 square miles.
The estimated retrofit cost is approximately 0.75 million dollars and
the estimated reduction in range is 2.7% as shown in reference 2.
Nacelle Treatment and Jet Suppressor
A Boeing/FAA program to develop an ejector-suppressor and treated nacelle
for the 727 was completed. As shown in reference 2, this configuration gave
a siginficant reduction in the 90 EPNdB noise footprint area from 29.4
to 6.6 square miles but the range penalties were not considered reason-
able for airline operation.
Boeing developed a plug nozzle suppressor for the 707, but the final
configuration did not give any significant noise reduction.
Based on the adverse results of these extensive programs, it does not
appear that the nacelle treatment and jet suppressor concept is currently
a satisfactory candidate for retrofit.
Refan Engines and Nacelle Treatment
A detailed description of the JT8D and JT3D refan engines was given in
reference 1.
The JT8D refan engine is expected to provide a 13% increase in static
takeoff thrust, a 5% increase in max cruise thrust and a 3% reduction in
cruise fuel consumption compared to the present JT8D engine. Primary jet
velocity is reduced by 16%, giving a 9 dB reduction in jet noise. Pre-
dicted noise levels for JT8D refan engines with treated nacelles in 727,
737 and DC-9 airplanes are shown in Figures 1, 2 and 3 for approach,
takeoff and sideline. These are NASA predicted noise levels, based on
input from the aircraft companies, and are well below FAR 36 levels. As
shown in reference 2, the 90 EPNdB noise footprint area for a 727-200
would be reduced from 29.4 to 3.9 square miles with refan engines, which
would place the noise footprint almost within the boundary of many air-
ports. This would provide significant noise reduction to airport
communities.
The JT8D refan engine development program is in progress and a demonstra-
tion ground test is scheduled in early 1974.
A-57
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The JT3D rcfnn engine is estimated to provide a 17% increase in static
.takeoff thrust, a 7% increase in max cruise thrust and a 7% decrease in
cruise fuel consumption compared to the present JT3D engine. Primary
jet velocity is decreased hy 14% resulting in a 7 dB reduction in jet
noise. NASA predicted noise levels for JT3D refan engines with treated
nacelles in the 707 are shown in Figures 1, 2 and 3. Where the FAA
treated nacelles for the 707 are predicted at FAR 36 noise levels for
approach and takeoff, the refan predictions are 6-7 EPNdB below FAR 36
at approach and takeoff, and sideline is 12 below FAR 36. The refan
engines would reduce the 90 EPNdB footprint area from the baseline of 54
to 8 square miles and would provide a small improvement in maximum
range as shown in reference 3.
The JT3D refan engine development has been terminated by NASA due to lack
of funds. This refan program could still be completed in a reasonable
time if it were reinstated in the near future, since the engine redesign
has already been completed.
Re-engine
Retrofit of the JT3D and JT8D powered commercial transport fleets with new
quiet engines is not feasible. There are no high bypass ratio replace-
ment engines available in the 20,000 Ib. thrust class, and engines of
this type will not be available during the next few years which is the
critical period for retrofit. Even if new engines were available, the
retrofit cost of new engines and new treated nacelles would be consider-
ably higher than the other retrofit options.
Fleet Replacement
There are no suitable aircraft available to replace the JT3D and JT8D
powered fleet. The current large wide-body aircraft with high bypass
ratio engines would not be efficient replacements for the many short
range and long range airline routes where smaller passenger capacity is
required. It is anticipated that a new 100-200 passenger aircraft with
new technology engines may be introduced in the late 1970's which will
gradually replace the current 707, DC-8 and 727 aircraft during the
following decade.
A-58
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PRATT 4 WHITNEY AIRCRAFT
DEVELOPMENT OF NEW QUIETER ENGINES
Pratt & Whitney Aircraft has been conducting noise reduction research and
development programs for jet engines since the beginning of the jet era.
Programs at P&WA in this field currently include basic noise research,
development of noise reduction hardware for current engines, and develop-
ment of new quieter engines. The current P&WA noise research programs
along with retrofit programs for current engines were covered in
reference 1. Some comments on the development of new quieter engines are
included here.
JT9D Engine Noise Reduction Features
The JT9D high bypass ratio turbofan engine which powers the Ihl and DC10-UO
wide-bodied transports was designed in 1965, well before Federal aircraft
noise standards were established. Because public concern over airplane
noise was recognized at that time, noise suppression was included among
the design objectives for the JT9D engine. Significant reductions in jet
noise were achieved because the high bypass cycle chosen for the JT9D
had lower jet velocities than earlier engines. Discrete tone noise
from the single stage fan of the JT9D was minimized by reduction in fan
tip speed, the omission of inlet guide vanes, providing ample spacing
between the fan rotor blades and exit guide vanes, and the selection of
the optimum number of fan blades and exit vanes. Acoustical treatment
was incorporated in the fan exhaust cases. The low noise design features
of the JT9D were selected based on prior P&WA fan noise research work.
In addition to the low noise features of the engine, acoustical treat-
ment is incorporated in the nacelles of both the ?U7 and the DC10-UO to
provide aircraft noise levels below the requirements of FAR Part 36.
Comparison of the JT9D and NASA Quiet Engine
The NASA Quiet Engine Program has utilized the core from a current high
bypass ratio engine as a vehicle to ground test the effects of fan tip
speed on noise. One of the demonstrator engines, known as "Quiet Engine
A", incorporated similar noise reduction features to the JT9D high bypass
ratio engine and went one step further by lowering the tip speed of the
fan. Whereas the fan RPM of the JT9D and the other high bypass ratio
production engines was selected to ensure subsonic tip speed at approach
thrust and hence the absence of combination tone noise from the inlet,
the tip speed of the Quiet Engine A fan was selected to be subsonic at
takeoff as well as approach. Because of the lower fan speed, the Quiet
Engine A demonstrator has fan noise about 5> PNdB quieter than an engine
such as the JT9D when both are installed in a nacelle that does not
incorporate acoustical treatment. Comparisons between the takeoff noise
level of Quiet Engine A and the JT9D scaled to the same size are shown
in the following table at ground test conditions:'
A-59
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PRATT * WHITNEY AIRCRAFT
(De-Rated)
Quiet Scaled Scaled
Engine "A" JT9D JT9D
Fan Pressure Ratio l.U l.U -1.50
200 Ft. Sideline
Peak PNdB 121 121.5 125
Fan Tip Speed,
Ft/Sec. 10UO 1225 1370
Two columns are shown for the JT9Dj one when the fan is operated derated
at the same pressure ratio as the Quiet Engine A, and one for operation
at the rated JT9D takeoff condition that reflects the higher design
pressure ratio of the JT9D. As shown by the table, the "derated" scaled
JT9D produces similar noise to the Quiet Engine A but the scaled engine
is about 1; PNdB louder because of the higher tip speed and fan pressure
ratio.
Noise levels of the scaled JT9D and the Quiet Engine A at approach thrust
conditions are compared below:
Quiet Engine A Scaled JT9D
Fan Pressure Ratio 1.15 1.15
Fan Tip Speed, Ft/Sec. 695 850
200 Fcot Sideline, Peak PNdB 107.5 112.5
At this part power condition, the lower fan tip speed of Quiet Engine A
provides a noise level about 5 PNdB lower than the scaled JT9D with an
untreated configuration.
P&WA/FAA Fan Research Program
The effects of fan tip speed on noise generation were also measured in
an FAA sponsored research program at P&WA. High, medium and low tip
speed fans were tested in a large scale outdoor fan noise rig. These
results also showed that the lower fan tip speeds could reduce aft arc
fan noise by about 5 PNdB. Noise levels from the low tip speed fan were
very close to those measured on NASA Quiet Engine A, when scaled to the
same size, as shown below:
A-60
-------
Takeoff
Quiet
Engine A
1.4
1040
121
Scaled
FAA
Fan
1.4
910
118.5
Approach
Quiet
Engine A
1.15
695
107.5
Scaled
FM
Fan
1.15
585
106.5
Fan Pressure Ratio
Fan Tip Speed, Ft/Sec.
200 Ft. Sideline, Peak
PNdB
Future Engine Technology
Both the NASA Quiet Engine Program and the Pf,WA/FAA Fan Research Program
demonstrated that source noise reductions could be achieved by lower
speed fans. However, this technology cannot be arbitrarily applied to
all new engine designs. The low speed fan gives a heavier, larger and
more expensive engine design with present technology because of the
larger low turbine required. This leads to a larger, less efficient
aircraft for the same mission. Conversely, a high speed fan gives a
lighter, less expensive engine and a.more efficient aircraft. The amount
of acoustic treatment required and the associated performance losses are
significant in determining the optimum engine cycle. An airplane/engine
system trade study is essential to determine the best economics for a
given set of requirements.
F.ach airplane/engine installation presents unique problems and specific
design requirements. The type of engine installation has a significant
effect on the aircraft noise level. Choice of the optimum engine design
for a particular installation requires a thorough study of all approaches
to obtaining a given noise objective. As noise research programs provide
new techniques for reducing engine noise generation, these will be
included in the engine cycle trade studies.
Reference 1: "Noise Reduction Programs at Pratt F, Whitney Aircraft",
Presented to the F.PA Aircraft/Airport Noise Study Task
Force, Task Group 4, February 23, 1973 by W. F.. Helfrich.
Reference 2: Boeing Report D6-6019f), "Noise Reduction Research and
Development 1972 Progress", March 1973.
Reference 3: Boeing Report D6-40982, "JT.WJTSn Refan Preliminary
Economic Study", April 1973.
A-61
-------
APPROACH NOISE LEVELS AT 1 N.MI.
i
en
to
120
115
110
NOISE LEVEL
EPNdB 105
100
95
90
• NO ACOUSTIC TREATMENT
O ACOUSTIC TREATMEAT
D REFAN ENGINES WITH ACOUSTIC
TREATMENT (NASA PREDICTION]
DC-9-30
737-200
• 707-320B
•I DC-8-50/61
- EXP NACELLE
I
JT8D-D
REFAN
°\ DC-10-10
L-1011
FAA NACELLE
PREDICTION
j_L
, , . ,
50 100 200 300 500 1000
MAX TAKEOFF GROSS WEIGHT - 1000 IBS
Pratt &
fiircraft
-9
731503
f .M'FO AiRCBAFT CORPORATION
FIGURE 1
-------
TAKEOFF NOISE LEVELS AT 3.5 N.MI.
O
CO
120
115
110
NOISE LEVEL 105
EPNdB
100
95
90
85
• NO ACOUSTIC TREATMENT
O ACOUSTIC TREATMENT '"
DREFAN ENGINES WITH
ACOUSTIC TREATMENT
(NASA PREDICTION]
NASA NACELLE
FAA NACELLE PREDICTION
727-200
DC-9-30
737-200
DC-8-50/61
» 707-320B
FAR-36 J
EXP
L NACELLE
O
747-200 J
JT3D
REFAN
I
I
D
DC-10-40
O
°DC-10-10
O
L-1011
JT8D
REFAN
i
I i Mill
50 100D 200 300 500 1000
MAX TAKEOFF GROSS WEIGHT ~ 1000 IBS
J6572-10
731503
Pratt &
Whitney
fiircraft
U
DMSlON OF UNlTtO AIRCRAFT CORPORATION
fi.
FIGURE 2
-------
SIDELINE NOISE LEVELS
a>
120
115
110
NOISE LEVEL
EPNdB 105
100
95
90
1500 FT FOR 2 AND 3 ENGINES
2100 FT FOR 4 ENGINES
• NO ACOUSTIC TREATMENT
O ACOUSTIC TREATMEAT
-DREFAN ENGINES WITH ACOUSTIC
TREATMENT (NASA PREDICTION]
707-320B
DC-8-50/61 f
FAR-36^ ^^^ NASA
"TnC.g.30 NACELLE ? FAA NACELLE
737-200 .T . 727-200 j PREDICT'°N -
747-200
M o
DD
JT8D
REFAN
JT3D 0
REFAND A ODC-10-40
L-1011
50
100
200 300 500
1000
Pratt &
Whitney
fiircraft
U
A IRC I
n.
MAX TAKEOFF GROSS WEIGHT - looo IBS
J6572-11
731503
3F uNfTCD AIRCRAFT CORPORATION
FIGURE 3
-------
Hi rC Tel it DIVISION OF UNITED AIRCRAFT CORPORATION
STRATFORD, CONNECTICUT O66O2 H
PHONE (2O3) 378-6361
July 20, 1973
SEL-1+095
Mr. William Sperry
Environmental Protection Agency
Crystal Mall, Building #2
1921 Jefferson Davis Highway
Arlington, Virginia 20h60
Dear Mr. Sperry:
During the last meetings of the Environmental Protection Agency Task Groups
on June 21 and 22, 1973, it was indicated that written positions from concerned
groups would-be considered and incorporated into the task group reports. The fol-
lowing remarks summarize the position of Sikorsky Aircraft on VTOL noise certifi-
cation. It is requested that these remarks be incorporated into the Task Group k
and 5 Reports.
In establishing the categories into which to place the various classes of
aircraft for noise certification purposes, it is strongly recommended that VTOL be
considered separately from STOL and RTOL. Placement of VTOL in a separate category
would free it from the operational limitations necessary to accommodate the flight
profiles of the other two classes if grouped in a combined category. Significant
reductions in noise footprint by flight trajectory control are available and should
be allowed to be developed in keeping with the intent of the Noise Control Act of
1972, to make aircraft inherently quieter and to have them flown as quietly as
possible.
The issuance of a noise rule for the VTOL category of aircraft is prema-
ture at this time because of the following reasons:
a) There "is insufficient data available on VTOLs in the unit most likely
to bd used in the rule to properly assess the state of the art.
Measurement programs must be carried out to rectify this lack of in-
formation.
b) Relevant research is due to be completed by NASA within a year on
VTOL noise to establish the state of the art on the applicability
of noise reduction technology to current helicopter designs.
i ii \\ ^ I-.AKS ..i
|fU)--'J , I <\*JS)
l-f)£i>*lt)£i)
1 IKSISin II K.I I I
A-65
-------
Page 2 of
SEL-U095
c) Operational procedures have not yet been adequately explored to assure
that the noise certification concept will take full advantage of the
low noise capabilities of the helicopter.
d) Current rating schemes do not appear to rate the annoyance of "blade
slap" noise accurately. "Blade slap" is the impulsive type of noise
that can be produced by some helicopter rotor systems under certain
operating conditions.
No penalty should be levied against helicopters as a class for the occur-
rence of blade slap, as it occurs only on certain types of helicopters under a
limited number of operating conditions.
An initial noise rule should allow all current generation helicopters to
become certificated. De-escalation should not be considered until sufficient in-
formation has been generated to allow an accurate assessment of its economic im-
pact and requirements for technological advances which may result.
Caution should be observed in attempting to relate the existing hover PNL
data for helicopters to EPNL. The large variation in noise levels between the
hover and the takeoff, landing, and cruise conditions coupled with the wide avail-
able operational range for these vehicles makes the conversion highly variable.
Economic considerations dictate flight paths below 3000 feet altitude for
VTOLs in typical operations. Enroute noise controls which may force the cruise
altitude to be significantly higher can have a significant impact on the operating
economics of this type of aircraft, and therefore should not be considered until
the consequences have been evaluated. A more viable solution to the regulation of
enroute noise by certification appears to be the use of a measure of cumulative
noise exposure impact, such as the Noise Exposure Forecast footprints, to dictate
flight paths and operational procedures. This approach allows control of the en-
vironmental impact on areas of the community located between ports of operation in
a manner which fully accounts for the environmental protection requirements of the
community while not imposing unnecessary economic penalties on the helicopter
operator.
Ambient noise should be considered when evaluating the impact of noise on
the community. In V-port areas where higher than average background noise levels
are likely to exist, the masking effect of these ambients should be factored into
the allowable noise from aircraft.
We hope the preceeding comments have identified in a constructive manner,
some of the potential pitfalls associated with VTOL noise regulation. It is our
feeling that a workable VTOL noise certification rule can be developed in a rea-
sonable period of time and that the rule can fully satisfy the environmental re-
quirements intended by the Congress while stimulating the growth of this important
facet of air transport. We hope to work further with you in this endeavor.
Yours truly,
SIKORSKY AIRCRAFT
. / V V*« ^^
fonald G. Schlegel
Supervisor - Acoustics
A-66
-------
APPENDIX B
TASK GROUP PARTICIPANTS
-------
Chairman and Staff
William C. Sperry
Peter P. Back
Damon C. Gray
Harvey J. Nozick
Environmental Protection Agency
Consultant
Consultant
Consultant
Members
Lou Achitoff
Don Ahrens
Betsy Amin-Arsala
Larry P. Bedore
Robert S. Bennin
Vaughan L. Blumenthal
Bernard D. Brown
Edward A. Carroll
Jim Conroy
William G. Cornell
Charles R. Cox
Allen W. Dallas
Joseph T. Davis
Harry Drell
Richard Dyer
Earl B. Fish
John D. Fredrickson
Roger Flynn
William J. Galloway
John S. Gibson
Alan G. Gray
William E. Helfrich
Lloyd Hint:on
James C. Johnson
Robert J. King
H. Ray Lahr
A. L. McPike
Charles P. Miller
Robert H. Morse
Noel Peart
William H. Roudebush
Robert W. Schroeder
Paul A. Shahady
R. S. Stahr
M. C.. Steele
Jack Suddreth
Port Authority of New York and
New Jersey
Cessna Aircraft Company
George Washington University
National Business Aviation Association
The City of New York
Boeing Commercial Airplane Company
British Aircraft Corporation
Trans World Airlines
Environmental Action, Inc.
General Electric Company
Bell Helicopter Company
Air Transport Association
Delta Air Lines
Lockheed Aircraft Corporation
National Association of State Aviation
Officials
Douglas Aircraft Company
Boeing Commercial Airplane Company
Air Transport Association
Bolt, Beranek and Newman
Lockheed-Georgia Company
Rolls Royce Limited
Pratt and Whitney Aircraft
National Organization to Insure a
Sound Environment
Environmental Protection Agency
Sikorsky Aircraft Company
Air Line Pilots Association
Douglas Aircraft Company
Aircraft Owners and Pilots Association
Pratt and Whitney Aircraft
Boeing Commercial Airplane Company
National Aeronautics and Space
Administration
Lewis Research Center, NASA
U. S. Air Force
Eastern Airlines
Airesearch
National Aeronautics and Space
Administration
B-l
-------
Members (con't)
Gary Thompson
James R. Thompson
John M. Tyler
George Westphal
Observers
Leslie Carothers
James Conroy
Russell Dawson
Diane L. Donley
Charles R. Foster
John Hellegers
Harvey H. Hubbard
Hugh Kaufman
Arthur Kohler
James J. Kramer
John B. Large
Robert B. Meyersburg
Carl Modig
Cole Morrow
Harold R.. Mull
James Mullins
Shellie Ostroff
Harvey Safeer
Alice Suter
R. N. Tedrick
Brian S. Tennant
Margaret Tifft
Ernest Weiss
Frank Wilson
Simone Yaniv
Correspondents
Jake Applewhite
George Bender
Robert J. Bresnahan
K. M. Eldred
Gordon Getline
Robert E. Ginther
James Hammond
A. E. P. Jennings
Raelyn Janssen
Robert J. Kingston
Stephan E. Lawton
Ken Linnerqth
Bert J. Lockwood
Geoffry C. Lowe
Beech Aircraft Corporation
Lockheed-California Company
National Organization to Insure a
Sound Environment
Grumman Corporation
Environmental Protection Agency
Environmental Action, Inc.
Noise Control Report
Council on Environmental Quality
Department of Transportation
Environmental Defense Fund
Langley Research Center, NASA
Environmental Protection Agency
Professional Air Traffic Controllers
National Aeronautics and Space
Administration
Institute of Sound and Vibration (England)
Consultant to Task Group 2
Informatics, Inc.
Federal Aviation Administration
Bell and Associates, Inc.
Federated Department Stores
Informatics, Inc.
Department of Transportation
Environmental Protection Agency
Airesearch
Boeing Company
Environmental Protection Agency
George Washington University
Informatics, Inc.
Environmental Protection Agency
Congressional Staff, California 17th
District
Boston Logan International Airport
Orange County Airport
Bolt, Beranek and Newman
Convair Aerospace
Senate Committee on Commerce
The Boston Globe
Aeronautical Research Council (England)
Environmental Defense Fund
Department of Environment (Canada)
House Committee on Interstate Commerce
Fairfax County, Va.
Los Angeles International Airport
British Embassy Counseller (Civil
Aviation)
B-2
-------
Correspondents (con't)
John 0. Powers
Henry L. Martin
James F. Miller
Barrett J. Riordan
Richard Ross
R. W. Rummel
Louis F. Skooi
Richard P. Skully
Norman J. Snow
Mills M. Spangberg
Willis E. Sullivan
Cedric Sun
Curtis L. Walker
James F. Woodall
Robert W. Young
Jack K. Zimmerman
Federal Aviation Administration
Society of Automotive Engineers
Department of Housing and Urban
Development
Council on Environmental Quality
Gates Learjet Corporation
Trans World Airlines, Inc.
Rockwell International Corporation
Federal Aviation Administration
Rohr Corporation
Garrett Corporation
Garrett Corporation
Aircraft Porous Media, inc.
General Motors
Federal Aviation Administration
U. S. Navy
Hydrospace-Challenger, Inc.
MIS. GOVERNMENT PRINTING OFFICE: 1973 546-310/83 1-3
B-3
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