A STUDY OF EXHAUST EMISSIONS FROM
RECIPROCATING AIRCRAFT POWER PLANTS
Prtpartd for
AIR POLLUTION CONTROL OFFICE
ENVIRONMENTAL PROTECTION AGENCY
SCOTT RESEARCH LABORATORIES, INC.
P 0. BOX D-ll
PLUMSTEAOVILLE, PENNSYLVANIA 18949
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A Study Of Exhaust Emissions From
Reciprocating Aircraft Power Plants
APCO (Formerly NAPCA) Project CPA 22-69-129
Scott Project Number 1136
Prepared for
Air Pollution Control Office
Division of Motor Vehicle Research & Development
Environmental Protection Agency
5 Research Drive
Ann Arbor, Michigan 48103
December 28, 1970
SCOTT RESEARCH LABORATORIES, INC.
P. 0. Box D-ll
Plumsteadvi'lle, Pennsylvania 18949
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TABLE OF CONTENTS
Page No.
Summary
1.0 Introduction 1-1
2.0 Background 2-1
3.0 Description of Test Aircraft 3-1
4.0 Test Equipment and Procedures 4-1
4.1 Aircraft Analytical Instrument System 4-2
4.2 Installation of Aircraft Analytical Instrument System 4-3
4.3 Aircraft Testing Procedures 4-10
4.4 Laboratory Analysis 4-12
4.5 Data Reduction and Calculations 4-13
5.0 Results of Aircraft Emission Tests 5-1
5.1 Takeoff-Cruise-Landing(TCL) Cycle 5-1
5.2 Emission Test Results 5-3
5.3 Emission Rates 5-3
6.0 Discussion of Data Collected 6-1
6.1 Effect of Operational Mode on Exhaust Emissions 6-1
6.2 The Effect of Aircraft Parameters on Exhaust Emissions 6-3
6.3 Comparison of Emissions from Light Aircraft & Automobiles 6-6
6.4 Afterburning 6-8
6.5 Control Techniques for Aircraft Emissions 6-11
6.6 Conclusions 6-12
6.7 Recommendations for Future Studies 6-13
(Continued)
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TABLE OF CONTENTS (Continued)
Page NO.
7.0 References 7-1
Appendix of Data A-l
Concentration and Temperature Data A-2
Emissions as Ib/lb Fuel A-ll
Emissions as Ib/min A-19
Mode and Cycle Emissions A-29
Afterburning Analysis A-38
SCOTT RESEARCH LABORATORIES. INC
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SUMMARY
Under contract with the Air Pollution Control Office (formerly
National Air Pollution Control Administration), Scott Research Laboratories
has documented the exhaust emissions of light, piston engine aircraft and
investigated the phenomena of natural afterburning of the exhaust gases on
contact with the ambient air. The approach used in this study was to
measure the exhaust emissions of representative aircraft as they were flown
in a normal manner. At the same time, the extent of afterburning was
measured by sampling the exhaust plume downstream of the exhaust stack and
comparing the plume composition, corrected for dilution, to the composition
of the stack gases.
The exhaust emissions from nine light aircraft were determined
using a 9-mode takeoff-cruise-landing (TCL) cycle developed for this
study. Exhaust component concentrations and fuel consumption rates
were measured for each mode during ten test flights per aircraft. The
pollutant concentrations were converted to emission rates per pound of
fuel, per minute, per mode, per TCL cycle, and per landing-takeoff (LTO)
cycle. A summary of light aircraft emissions is given below.
Summary of Emissions from Nine Light Aircraft
Rate Parameter
Pounds per Pound of Fuel
Pounds per Minute
Pounds per TCL cycle
Pounds per LTO cycle
CO
0.847
0.614
21.0
14.1
CO?
1.74
1.27
43.3
25.5
Total HC
(as hexane)
0.0210
0.0152
0.520
0.431
NOX
(as NO?)
0.0102
0.0074
0.254
0.128
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The rich mixtures employed during most operations resulted
in incomplete combustion as demonstrated by the high ratio of carbon
monoxide to carbon dioxide recorded. During lean cruise operation
carbon monoxide and hydrocarbons were substantially lower and nitrogen
oxides were much higher than at the normal rich mixture operation.
The difference in exhaust composition from one rich mode to another
was small.
The fuel injected engines tested emitted much higher concen-
trations of hydrocarbons than the normally aspirated engines. Exhaust
composition differences due to engine age, size and airframe design
were minor.
No afterburning of exhaust carbon monoxide and hydrocarbons
was found for any of the test aircraft at any mode. Apparently the
exhaust temperatures at the stack exit were too low for burning to
occur. Means for enhancing afterburning are discussed. The application
of automobile exhaust reactors to light aircraft is considered, and
design problems which must be solved are noted.
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1-1
1.0 INTRODUCTION
This report describes the work performed by Scott Research
Laboratories, Inc. on the Air Pollution Control Office's project,
"A Study Of Exhaust Emissions From Reciprocating Aircraft Power
Plants" (Contract No. CPA-22-69-129). This project was sponsored by the
Division of Motor Vehicle Research and Development of the Air Pollution
Control Office.
1.1 PROJECT OBJECTIVES
The general objective of the contract was to study the exhaust
emissions of light utility, piston engine aircraft. The specific
objectives of the study were:
1. Document the emissions of carbon monoxide, hydrocarbons
and nitrogen oxides from light aircraft under typical
use conditions.
2. Determine the extent of natural afterburning in the
emitted exhaust and consider means of increasing the
extent of afterburning under typical use conditions.
3. Reach conclusions regarding the potential usefulness of
exhaust system reactors in general, and the need for
alternative methods for reducing carbon monoxide and
organic gases emitted by light aircraft.
The general approach used in reaching these objectives consisted
of monitoring the exhaust constituents of representative aircraft as they
were flown in a normal manner. This approach was used because simulation
of normal flight in a test cell was considered extremely difficult.
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1-2
1.2 OUTLINE OF REPORT
This report has been organized into six sections following
the introduction.
Section 2 supplies the background to this study.
Section 3 describes the aircraft tested during this study and
the reasons for their selection.
Section 4 describes the equipment and ifethodology used in
conducting this study.
Section 5 presents the results of the study.
Section 6 discusses the results and presents the conclusions
and recommendations.
The report concludes with references in Section 7 and an
appendix of data collected during test operations.
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2-1
2.0 BACKGROUND
Atmospheric contaminants emitted by aircraft constitute a small
but significant contribution to air pollution in the form of carbon monoxide,
nitrogen oxides, particulates and various organic compounds. These are
basically the same pollutants as those emitted by highway vehicles. In
1965 a study by the Los Angeles County Air Pollution Control District found
that non-military aircraft were responsible for between one. and two per-
cent of all organic gases, carbon monoxide, and oxides of nitrogen., and
approximately ten percent of all aerosols emitted in Los Angeles County. The
nationwide figures indicate that civil aircraft were responsible for about
one percent of all organic gases and carbon monoxide emitted in the
United States. This percentage will increase, however, as controls are
tightened on other pollution sources and the aircraft population increases.
The development of high speed aircraft with greater fuel consumption rates
will also increase this percentage.
A great deal of attention has been given to the emissions of
large turbojet engines. This is due to their optically dense plume,
characteristic odor and their concentration around major air terminals.
The turbojet aircraft are generally large, multi-engined commercial
aircraft. Several programs are underway to determine the amount and type
of emissions from turbojets and the best way to reduce the quantities
emitted.
1. Page 1 of Ref. 1
2. Table 43, page 283, Ref. 2
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2-2
The general aviation category of aircraft, however, consists
primarily of light, piston engine aircraft. They are large in number and
relatively dispersed across the country. The emissions of this type of
aircraft have not been well documented, particularly the emissions under
true flight conditions. These aircraft engines are very similar to
automobile engines in their manner of operation. The basic element is
the combustion chamber in which fuel and air mixtures are burned and from
which energy is extracted through a piston and crank mechanism that drives
a propeller. Nearly all aircraft piston engines have two or more cylinders
and are generally classified according to their cylinder arrangement. The
arrangement in general use is the opposed configuration. Some radial
engines are still in use in older large transport aircraft.
All of the emission control techniques applicable to automobile
engines are applicable, in principle, to aircraft piston engines. However,
the techniques vary widely in their practicability. Some reduction in
emissions from piston engined aircraft was believed to occur as a result
of natural afterburning of hot exhaust gases as they enter the atmosphere.
Natural afterburning would reduce the amount of carbon monoxide, organic
gases and perhaps carbonaceous particulates emitted. Little documentation
of the existence and effect of this afterburning can be found. The
enhancement of afterburning is potentially a simple, effective means
of reducing emissions from aircraft piston engines.
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3-1
3.0 DESCRIPTION OF TEST AIRCRAFT
Aircraft tested under this contract were selected to represent
typical engines, exhaust system geometries and airframes found in the
present light aircraft population. From talks with consultants, aircraft
dealers, pilots and engine manufacturers, it was determined that the
engines in the present population were almost exclusively of horizontal,
opposed cylinder configuration, with four or six cylinders. It was also
determined that most of the engines had a single exhaust stack, and the
most popular airframe was a single-engine monoplane with fixed tricycle
landing gear.
The characteristics of the test aircraft are summarized in
Table 3-1. All the engines in these aircraft had a horizontal, opposed
cylinder configuration. These aircraft were selected so that they could
be grouped in various ways to show the effect of certain variables on
exhaust emissions and afterburning:
1. Engine Operating Time - The effect of total engine operating
time was studied by testing a group of three Cessna 172's with
four cyclinder engines and a group of two Cessna 182's with
six cylinder engines.
2. Airframe Design - The effect of airframe design was
investigated by comparison of a Piper PA-23, a low wing,
twin-engined aircraft with retractable landing gear,
with a Cessna 172, a high wing, monoplane with a fixed
tricycle landing gear. Both aircraft were powered by
similar engines.
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AIRCRAFT
Test
No. Manufacturer Model
1 Cessna Skyhawk
172K
2 Cessna Skyhawk
172D
3 Cessna Skyhawk
1721
4 Cessna Skyhawk
172K
5 Beechcraft Bonanza
36
6 Cessna Skylane
182H
7 Cessna Skylane
182H
8 Piper Apache
PA-23
9 Cessna Centurion
T210F
Reg.
No.
N78658
N236OU
N8410L
N7048G
N1697A
N1976X
N92687
N1314P
N6739R
ENGINE INFORMATION
Manufacturer
Lycoming
Continental
Ly coming
Lycoming
Continental
Continental
Continental
Lycoming
Continental
Engine
No. of Operation
Model Cylinders Time
0-320-E2D 4 140
Hrs.
0-300-D 6 295
Hrs.
0-320-E2D 4 672
Hrs.
0-320-E2D 4 105
Hrs.
IO-520-B 6 334
Hrs.
0-470-R 6 1053
Hrs.
0-470-R 6 53
Hrs.
0-320-A 4 423
Hrs.
TS-520-C 6 900
Hrs.
HP
150
145
150
150
285
230
230
150
285
P rope Her
Tvpe
Fixed
Pitch
Fixed
Pitch
Fixed
Pitch
Fixed
Pitch
Variable
Pitch
Variable
Pitch
Variable
Pitch
Variable
Pitch
Variable
Pitch
Fuel -Air
System
Normal
Aspiration
Normal
Aspiration
Normal
Aspiration
Normal
Aspiration
Fuel Injected
Normal
Aspiration
Normal
Aspiration
Normal
Aspiration
Turbo-chgd.
& Fuel Inj.
Exhaust
System
Single
Stack
Dual
Stack
Single
Stack
Single
Stack
Dual
Stack
Single
Stack
Single
Stack
Single
Stack
Single
Stack
OJ
ro
Table 3-1. Characteristics of Test Aircraft
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3-3
3. Engine Design Variables - Common engine design variations
were represented by the Beechcraft Bonanza 36 with fuel
injection, the turbocharged Cessna 210 with fuel injection,
and the Cessna 182 with natural carburetion. A super-
charged aircraft was not tested because they are relatively
rare. Supercharging has been replaced almost entirely by
turbocharging in the newer aircraft.
4. Exhaust System Geometry - Exhaust geometries represented
included the six cylinder Cessna 172 with a dual exhaust,
the Piper PA-23 with a venturi-ejector exhaust and the
Cessna 172 and 182 with the more common single exhaust stack.
The fuel used by all the aircraft except P5 and #9 was 80
octane. The fuel injected aircraft used 100 octane fuel. The specifications
for both these fuels are presented in Table 3-2.
The aircraft tested were obtained from three local aircraft
dealers and air taxi operators. The aircraft available from these
sources were well maintained and inspected every 100 operating hours.
The aircraft selected for this program represented 68.5% of the
eligible* aircraft in the national population based upon FAA categories
presented in Reference 5. The only major class not represented was the
small (one to three place) aircraft because of limited room for our
instrumentation. Table 3-3 presents the FAA categories, the number of
aircraft in each category, and the aircraft tested in each category.
* Aircraft that are both registered and carry a valid airworthiness
certificate.
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3-4
Table 3-2. Specifications for Aviation Gasolines
(ASTM D910-70)
Knock value, min, octane
number, lean rating
Knock value, min, octane
number, rich rating
Color
Dye content:
Permi ssible blue dye,
max, mg per gal
Permissible yellow dye,
max, mg per gal
Permi ssible red aye,
max, mg per gal
Tetraethy 1 lead, max, ml
per gal
Net heat of combustion,
min, Btu per Ib
Grade
80-87
80
87
Red
0-5
none
8.65
0.5
18 720
i
Grade
100-130
100
Isooctane plus
1 .28 ml of
tetraethyl lead
per gal Ion
Green
<».7
7-0
none
3-0
18 720
Requirements for All Grades
Distillation temperature, deg F
10 per cent evaporated, max
50 per cent evaporated, max
90 per cent evaporated, min
90 per cent evaporated, max
Final boiling point, max, deg F
Sum of 10 and 50 per cent evaporated temperatures,
min, deg F
Distillation recovery, min, per cent
Distillation residue, max, per cent
Distillation loss, max, per cent
Acidity of distillation residue
Vapor pressure, max, Ib
Potential gum (5 hr aging gum), max, mg per 100 ml
Visible lead precipitate, max, mg per 100 ml
Sulfur, max, per cent
Freezing point, max, deg F (deg C)
Water tolerance
Permissible antloxidants, max, Ib per 1000 bbl
0*2 gal)
158
221
212
257
338
307
97
1.5
1.5
Shall not be acid
7.0
6
3
0.05
- 72 (-58)
Volume change not to
exceed +_ 2 ml
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3-5
Table 3-3. United States light aircraft
population as categorized by the FAA.
FAA Category
(by total rated
engine takeoff power) Eligible Aircraft* Aircraft Tested
Single Engine
100 hp and less 28,262
101-200 hp 47,018 Cessna 172
201-350 hp 31,231 Cessna 182, 210 &
Beechcraft 36
351-500 hp 1,328
501-700 hp 559
over 700 hp 235
2 - Engine
500 hp and less 5,533 Piper Apache
501-800 hp 8,220
Total 122,386
* Aircraft that are both registered and carry a valid airworthiness certificate.
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4-1
4.0 TEST EQUIPMENT AND PROCEDURES
In order to accomplish the objective of the study, it was
necessary to monitor the concentration of carbon monoxide, hydro-
carbons and nitrogen oxides in the exhaust stack and the concentrations
of carbon monoxide and hydrocarbons in the exhaust plume after any
afterburning had occurred. Ideally, all monitoring should be done
by an analytical instrument system installed in the aircraft. Since
this was not practical because of weight, volume and power constraints,
an optimal combination of a limited analytical system in the aircraft
for continuous analysis of the stack samples and laboratory analysis
of the dilute exhaust plume sample was used. Table 4-1 summarizes
the analytical techniques used in this study.
Table 4-1
Analytical Techniques For Aircraft Exhaust
Method Used for Method Used for
Compound (s) Stack Samples Plume Samples
Carbon Monoxide Continuous Infrared Gas Chromatography of
Analyzer in aircraft bag sample in labora-
tory
Carbon Dioxide Continuous Infrared Gas Chromatography of
Analyzer in aircraft bag sample in labora-
tory
Total Hydrocarbons Continuous Flame Bag sample by Flame
lonization Detector lonization Detector
in aircraft in laboratory
Nitrogen Oxides Continuous Electro-
chemical Analyzer in
aircraft
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4-2
4.1 AIRCRAFT ANALYTICAL INSTRUMENT SYSTEM
The primary considerations in the design of an aircraft
analytical instrument system are accuracy, power consumption, weight and
volume. Most of the aircraft tested under this contract were light,
four place aircraft with minimum baggage space. Since the flight crew
consisted of the pilot and an engineer to operate the instrument system,
the space available for equipment was limited to the remaining seating
and baggage area and had to weigh no more than two people (340 Ibs) plus
the baggage allowance. The equipment also had to remain operable in an
airborne environment with its attendant shock and vibration field, and
temperature and altitude variation. The aircraft tested generally had
little electrical power available beyond that needed for aircraft
operation. For this reason and to avoid fluctuating voltage due to
engine speed and aircraft electrical load variations, the instrumentation
was powered by an independent auxiliary power supply.
The instruments chosen were two Mine Safety Appliance Corp.
LIRA Model 300 infrared analyzers for 0-10% carbon monoxide and 0-15%
carbon dioxide, a Beckman Model 109A flame ionization detector and a
Whittaker Model NX110 nitrogen oxides analyzer. The responses of these
instruments as well as that of the thermocouples mounted on the exhaust
probes, were recorded continuously on battery powered Esterline Angus
Model T-171B strip chart recorders. The instruments were powered by a
heavy duty storage battery using a 250 VA inverter to convert the
12 volts DC to 115 volts AC at 60 Hertz. A diaphram pump mated to a
12 volt DC motor was used to drive the sample through the analyzers.
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4-3
The pump was powered by the aircraft electrical system since voltage variations
would not seriously affect its operation. When the engine was not running,
such as before start up and after shut down, the pump was powered by the
auxiliary power supply.
Figure 4-1 shows a schematic of the flow and electrical systems of
the airborne analytical instrument package. Inputs to the system were
selected by valves V-l and V-2. The possible inputs were: 1. stack probe,
2. plume probe, 3. zero gas, 4. hi-span gas and 5. low-span gas. The exhaust
sample was taken at a rate of five liters per minute and passed through a
water trap, a particulate filter and a cold trap in an ice bath. The flow
rate was monitored by flowmeters FM-1, FM-2, and FM-3 and controlled by
valves FL-1 and FL-2. The pressure at the inlets of the infrared analyzers
was measured and logged throughout the test. After passing through the
infrared analyzers and flow control equipment, the sample passed through
the nitrogen oxides monitor and the hydrocarbon analvzer. Valve V-3 then
directed the sample to a vent or to the connection where Tedlar bags were
filled for subsequent laboratory analysis.
4.2 INSTALLATION OF AIRCRAFT ANALYTICAL INSTRUMENT SYSTEM
Prior to installation of the equipment, all seats but the pilot's
were removed. The equipment was grouped into modules in order to facili-
tate handling. The five recorders, NOX analyzer, thermocouple reference
cell and thermocouple selector switch were mounted in a rack made of
aluminum angle. The selector valves, water trap, particulate filter and
pump switch were mounted on a small flow control panel. This panel was
usually attached to the forward end of the recorder rack within easy reach
of the operator. The rack and flow control panel are shown in Figure 4-2.
SCOTT RESEARCH LABORATORIES, INC
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i
§
NOTES:
I. ELECTRICAL WIRING 4 INSTRUMENTS
) STRIP CHART RECORDERS ESTERLINE ANGUb
MODEL T-17IB (BATTERY POWERED)
CD INVERTER
r
i f
1
f
M
AIRCRAFT
CVLJAI |Cf
PIPE
SWCK r«^| STACK
Xi— - — THtRMO- . .
hi COUPLE ; ;
PROBE -i
THERMO- IL JJ _ . 1 U L ' '
DILUIF_^^- — T2
rWJUt , i
7FBn r 1*1 i — t '
co r &j.~ r1 ... ^ ! ' A
co,j £& 1 auNi1 ?!
Hr / e*s i _r
CALIBRATION
BAGS
r r-^_-^.— ... ^! [-"r'-t-----!^
~ r-> — = r; t:rr.: i i j 250 VA
J ' r.o— - ^ JREFERENCE | ' ~^-
CELL -
. . — — 1 i —
- - U-FJ-^ !
i _.j ;«vj jr
STORAGE BATTERYl,
TO AIRCRAFT BUS^^j OFF J pR^JX..^
» fAUGEtT^
- ,
- PARTICULATE | 1 — i ',
iv-i FILTER _c-; Fu , -. )F
r ^ ^ n (ft — co^'—i
r 1 1 v"V — *•
WATER LM 5L,^S/M,« ^TT
TRAP J.L.^
1 roi n TRAP ' ''' '" '_A.
t^ (-ULL> 1RAK i co« 'tj
IL ' '
V-P f 1 nU) t Pi CTTDITAI
SCHEMATIC FOR AIRCRAFT
EXHAUST SAMPLING SYSTEM
' ^ POWER JUNCTION
1 BOX
LJ!Qy_6OxJ I
-,-.--,-,'
. _ - _ _i . !
, i
' ""*
A ' .^ 1 * Ljf ir/1^
-*» NO, | I -B*- W
^..ii.1 >"^'
', ! r-J ! '
LjfhFM-jLii6^^'"0^! 1 ^^Nf
^J ZM£S IO
-------
30
B
m
n
oo
O
pa
s
o
Figure 4-2. Recorder Rack, NOx Monitor and
Flow Control Panel Installed in a Cessna 210.
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4-6
The two MSA infrared analyzers and the Beckman 109A FID were bolted
together and shock mounted ae a unit on an aluminum pallet as shown in Figure
4-3. This assembly also held the nitrogen-hydrogen fuel and compressed air
cylinders for the FID as well as the two flow control valves (F , F in
Figure 4-1) and two flowmeters (FM., FM ) . The pump and motor were likewise
shock mounted on an aluminum pallet. The operator's seat, a storage battery
holder and the inverter were mounted on a plywood floor panel. The floor
panel was then placed in the rear seat/baggage area and bolted to the seat
rails and seat belt attachment points. The recorder rack was then attached
to the plywood floor panel. The operator occupied the right rear seat area
and the recorder rack occupied the left rear seat area. The inverter and
storage battery occupied the baggage area and are shown in Figure 4-4.
The shock mounted analyzer package was attached to the right front
seat rails and seat belt anchor points. The pump module was fastened down
in whatever space remained - either to a seat rail or to the plywood floor
panel. Interconnecting tubing and wiring completed the cabin installation.
Exhaust gases were collected by a probe that was custom-made for
each installation. It contained two gas sampling points, one well within
the exhaust stack to sample the stack gases and a second usually about four
inches below and four inches downstream of the exhaust stack exit to sample
the plume gases. The probe used on aircraft #9 is shown in Figure 4-5.
Thermocouples were located near each sampling point to monitor the gas
temperature at the two probe inlets. The exhaust sample was brought into
the cabin through the existing inspection hatch located on the aircraft belly
using Teflon and stainless steel tubing. The length of tubing from the
sampling points to the analyzers was approximately ten feet.
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SCOTT RESEARCH LABORATORIES, INC
4-7
Figure 4-3. Infrared Analyzers and Flame lonization
Unit Mounted on Aluminum Pallet in a Cessna 210.
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oo
Figure 4-4. Inverter and Storage Battery
in Baggage Area of a Cessna 210.
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4-9
Figure 4-5. Sampling Probe Installed
on the Exhaust Stack of a Cessna 210 (two views)
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4-10
When the installation of the exhaust analysis equipment was
complete as shown in Figure 4-6, the FAA was notified and a request for
aircraft recertification was made. The aircraft was then inspected by
an FAA representative and recertified in the Experimental category. In
this category an airplane may be flown only by the project crew and
only within a specified low population density area.
After completing the testing on the aircraft, the equipment
was removed and the aircraft returned to the standard configuration. At
that time application was made to the FAA for certification of the air-
craft into Standard category. The aircraft was then inspected and certified
by the FAA, and returned to the owner.
4.3 AIRCRAFT TESTING PROCEDURES
The test program was performed at Central Bucks Airport,
Doylestown, Pennsylvania. Approximately ten test flights were
conducted for each aircraft. A typical test flight lasted about a
half hour from engine start to engine shutdown. During each mode of the
takeoff-cruise-landing (TCL) cycle, the on-board instruments continuously
monitored the stack gases. During part of each steady-state mode, Tedlar
bag samples and nitrogen oxide readings were taken of the exhaust plume.
The bag samples were taken to Scott's Plumsteadville laboratory for
analysis at the end of the flight. The steady-state modes were taxi,
ascent, cruise and descent. Modes such as takeoff and landing were non-
steady-state because the engine conditions changed rapidly due to loading
variations as well as adjustments by the pilot. Calibrations were per-
formed using on-board calibration bags three times during each flight, one a
at the end of the initial taxi, another during the cruise mode and the last
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X
rr
y
-r
c
X
--
Figure 4-6. Complete Instrument System
Installed in a Beechcraft Bonanza 3G.
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4-12
after shutdown. Randomly selected bag samples of the stack gases were
taken for laboratory analysis as a cross-check on the aircraft analytical
system. Samples of the ambient air were also taken during the flight and
brought to the laboratory for analysis with the other bag samples.
Fuel flow data were obtained by two methods. For aircraft with
a gravity fuel feed, a calibrated rotometer was inserted in the fuel line.
The readings were logged as the aircraft was flown through the various
operating modes. If the aircraft had a fuel pump, a calibrated turbine
meter was installed in the fuel line and its readings logged. The
stainless steel turbine meter had a flow range of 3.5 to 45 USGPH. The
turbine meter could only be used on aircraft with fuel pumps because
the pressure drop across the meter restricted the gasoline flow of
gravity fed aircraft.
4.4 LABORATORY ANALYSIS
The Tedlar bag samples of the exhaust plume returned to the
Plumsteadville Laboratory were analyzed for carbon monoxide, carbon
dioxide and total hydrocarbons. The concentrations of the carbon
oxides were determined by gas chromatography. The hydrocarbon concen-
tration was measured using a Beckman Model 109A flame ionization
detector operated under laboratory conditions. The stack samples were
analyzed in a similar manner. The ambient air samples were analyzed only
for carbon dioxide and hydrocarbons since normal carbon monoxide levels
are extremely low.
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4-13
4.5 DATA REDUCTION AND CALCULATIONS
The continuously recorded strip charts indicating temperature,
carbon monoxide, carbon dioxide, hydrocarbons and nitrogen oxides were
reduced by a manual procedure. This procedure consisted of marking off
the various modes of the flight utilizing the hack marks recorded by the
operator, and taking an average reading for each mode. These raw values
were corrected for altitude and converted to concentrations via cali-
bration curves made for the in-flight instrument calibrations. The
resultant concentrations were averaged over the flight to arrive at an
average pollutant concentration per mode per plane. Table 4-2 summarizes
the calculations performed on the data.
The average stack concentrations were then reduced to a molar
carbon basis and emission rates in pounds per pound of fuel and pounds
per minute for each pollutant calculated. This calculation is shown in
Table 4-2. Also illustrated in Table 4-2 are calculation procedures to
determine the amount of afterburning. The plume analyses for CO, C02
and THC were adjusted for background levels and then for dilution, and
compared with the appropriate stack concentrations. Afterburning would
result in an increase in carbon dioxide levels with corresponding
decreases in carbon monoxide and hydrocarbon levels.
SCOTT RESEARCH LABORATORIES, INC
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Table 4-2. Calculation Procedures
Used in the Reduction of the Raw Data.
ALTITUDE CORRECTION OF AIRBORNE INSTRUMENT READINGS:
Sea Level Bar. Pressure (atm.)
Bar. Pressure at altitude (atm.)
x Instrument reading at altitude = corrected reading
MASS EMISSION CALCULATIONS FOR POLLUTANT A:
ni_ _ ... . Wt % C in Fuel 1 (Vol % A in exhaust) x Mn
Ib Of A/lb Fuel = r— X — x - rr^; —: A
100 12 Vol % C in exhaust
where:
Wt % C in fuel = Weight percent carbon in fuel
Vol % C in exhaust = Volume percent of carbon containing compounds in exhaust
(Vol % CO2 + Vol % CO + Vol % THC as methane)
Vol % A in exhaust = Volume percent of A in exhaust
M = Molecular weight of A
A
Also:
Ib of A/min = (Ibs of A/lb Fuel) x (Ib Fuel/min)
CORRECTION OF PLUME SAMPLES FOR DILUTION:
Dilution Factor =
(Vol%CO2+Vol%CO+Vol%THC(as methane)) in stack
(Vol%CO2+Vol%CO+Vol%THC(as methane)) in plume - lVol%CO2+Vol%THC(as methane)) in air
Corrected Plume Value for A = Dilution Factor X (VOL%A in plume - Vol%A in air)
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5-1
5.0 RESULTS OF AIRCRAFT EMISSIONS TESTS
5.1 TAKEOFF-CRUISE-LANDING (TCL) CYCLE
In order to compile meaningful emissions data, it was first
necessary to establish an operating cycle for light aircraft. The
takeoff-cruise-landing (TCL) cycle described in Table 5-1 was
developed based on discussion with pilots and several test flights.
The cycle was representative of light aircraft operation at Central
Bucks Airport. However, since it may not be representative of
operations at other airports, additional cycle definition may be
needed.
The time in each mode shown in Table 5-1 is approximate and
may vary from aircraft to aircraft. Each mode has its own character-
istic power and mixture setting. The power setting is a combination
of a throttle and propeller pitch setting, or in the case of an
aircraft with a fixed pitch propeller, a throttle setting alone. The
mixture setting determines the engine air-fuel ratio.
All modes are reasonably steady-state except for run-up,
cruise pattern and final approach. These three modes are not steady
because of changing engine loads and pilot adjustments. The rich
cruise mode is used during relatively short trips. For longer trips
the air-fuel mixture is leaned to reduce fuel consumption once cruise
altitude had been reached.
The cruise altitude during tests was usually 3,000 feet MSL.
Since higher performance aircraft, such as those with fuel injection and
turbocharging, generally cruise at higher altitudes, aircraft Mos. 5,
7, 8 and 9 were tested at a cruise altitude of 5,000 feet.
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5-2
Table 5-1. Takeoff-Cruise-Landing Cycle
Used in Study of Emissions from Ldght Aircraft.
Mode
Taxi
Run-up
Ascent
Cruise, Rich
Cruise, Lean
Descent
Cruise Pattern
Final Approach
Final Taxi
Description
Startup of engine and
taxi to end of runway
Checkout procedure at end
of runway, includes a run-
up of the engine
Takeoff and ascend to
cruise altitude
Rich cruise at cruise
altitude
Lean mixture cruise at
cruise altitude
Descend to landing pattern
altitude
Hold in landing pattern
Descend and land
Taxi back to hangar
Approximate
Time in Mode
(minutes)
4.5
1.5
6.5
2.5
7.5
2
2
1.7
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5-3
5.2 EMISSION TEST RESULTS
The concentrations of carbon monoxide, carbon dioxide, hydro-
carbons and nitrogen oxides found in the exhaust of the nine test aircraft
are summarized in Table 5-3 along with stack gas temperatures. Data are
presented for the minimum, maximum and average for each of the nine modes
in the TCL cycle. Detailed data for each aircraft are given in the Appendix.
The reported emission values are subject to random error due to
differences in atmospheric conditions and pilot settings, and to random
error inherent in the overall instrument system. There is also a small
systematic error introduced by the instrument system. The systematic error
was minimized by careful calibration of the system. The magnitude of the
random error is indicated by the standard deviations of the data for
individual flights. The deviations were a function of the compound beinq
measured, because of differences in the instruments used and the levels
being measured, and the mode of operation, since certain modes were more
reproducible than others. The indicated precision of the emission data is
shown in Table 5-2.
Table 5-2. Precision of Emission Data
Precision*, %
Parameter Steady-State Modes Non Steady-State Modes
Carbon Dioxide 8 8
Carbon Monoxide 12 12
Hydrocarbons 11 30
Nitrogen Oxides 30 50
* One sigma limits (1S% as defined in ASTM Recommended Practice F.177) .
SCOTT RESEARCH LABORATORIES. INC
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RESEARCH LABORATOR
m
0
Table 5-3
Mode
Taxi - Initial
Idle (Run up)
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Min.
5.20
6.41
6.86
5.43
0.47
5.72
5.38
4.30
3.62
C0(%)
Max.
11.69
10.35
9.91
10.19
4.80
10.98
10.89
8.39
10.00
Avg.
8.42
8.13
8.08
7.82
2.66
8.99
7.86
6.64
7.50
Min.
6.78
6.60
8.48
7.93
11.35
5.08
7.20
4.70
7.14
Summary of Exhaust
for
C02(%)
Max.
11.82
10.66
13.34
12.15
14.75
11.44
11.08
10.57
11.15
Composition Data
Nine Light Aircraft
Total HC(ppm-r)
Avg.
9.18
9.43
10.77
10.13
13.06
8.06
9.45
7.79
8.78
Min.
3270
2150
990
987
207
906
1140
2300
4080
Max.
15180
13080
3090
2730
1770
29000
5160
35000
27700
Avg.
7950
5820
2140
1850
966
6660
2950
16300
10500
NOx(ppm)
Min.
71
86
138
80
674
162
125
79
77
Max.
280
1220
600
612
4750
703
458
326
808
Stack Temp. (°F)
Avg.
128
355
334
213
2200
291
254
157
237
Min.
113
188
215
208
221
221
228
199
170
Max.
907
1150
1500
1450
1550
1380
1290
1010
889
Avrj .
6TS
849
1220
1190
1289
970
1090
759
642
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5-5
5.3 EMISSION RATES
The exhaust composition data were utilized to compute emission
rates on a basis of pounds of pollutant emitted per pound of fuel con-
sumed. An average fuel composition of 85 weight % carbon and 15 weight %
hydrogen was assumed. The computed emission rate data were converted to
pounds of pollutant emitted per minute using the measured fuel consumption
rates.
Summaries of emission rates on a per pound of fuel basis and a
per minute basis are presented in Tables 5-4 and 5-5, respectively. The
minimum, maximum and average emission rates for each operating mode are
given. Detailed data for each aircraft are included in the Appendix.
The air-fuel ratios shown in Table 5-4 and the Appendix were
estimated from the ratios of carbon monoxide to carbon dioxide measured
in the the exhaust. The estimates were based on composition data for
an aircraft engine given in Figure 10-6, Page 317 of Reference 4.
The total emissions per TCL cycle were calculated using the
time per mode shown in Table 5-1. The emissions for a Landing-Takeoff
(LTO) cycle were also calculated by omitting the cruise modes. Total
emission data for each pollutant are presented in Table 5-6 for each
mode and test cycle. Data for each test aircraft are given in the
Appendix.
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8
en
30
O
00
o
§
30
m
_ Mode
t
Taxi - Initial
Idle (Run-up)
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Table 5-4. Summary of Exhaust Emission Rates
for Nine Light Aircraft, Ib/lb fuel
Air-Fuel
Ratio*
(Ib/lb)
11.4
11.6
11.9
11.8
14.0
11.0
11.7
11.6
11.6
Emissions (Ib/lb Fuel)
Carbon Monoxide
Min.
.629
.746
.677
.740
.0792
.662
.778
.561
.475
Max.
1.170
1.167
.953
1.073
.560
1.186
1.175
.993
1.098
Avg.
.910
.896
.849
.859
.326
1.011
.917
.825
.853
Carbon Dioxide
Min.
1.07
1.21
1.59
1.40
2.22
0.90
1.22
1.18
1.23
Max.
2.08
1.90
2.04
1.95
3.01
2.08
1.89
1.96
2.30
Avg.
1.58
1.63
1.77
1.75
2.60
1.43
1.64
1.52
1.61
Hydrocarbons (as Hexane)
Min . Max . Avg .
.00175
.0123
.00521
.00518
.00179
.00536
.00645
.0148
.0247
.0819
.0680
.0053
.0163
.0110
.168
.0245
.189
.147
.0426
.0322
.0115
.0104
.00615
.0384
.0182
.1036
.0590
Nitroqen Oxides (as NO->)
Min.
.00122
.00233
.00226
.00136
.0135
.00288
.00214
.00137
.00140
Max.
.00565
.0235
.0127
.0137
.0977
.0130
.00855
.00699
.0195
Avg.
.00235
.00660
.00607 ^
.00422
.0463
.00535
.00477
.00343
.00502
* Estimated
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COTT RESEARCH LABORATORIES.
O
Table 5-5.
Summary of Exhaust Emission Rates
for Nine Light Aircraft, Ib/minute
Emissions (Ib/min)
Carbon Monoxide
Mode
Taxi - Initial
Idle (Run-up)
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
• Taxi - Final
Min.
.126
.351
.724
.621
.0568
.279
.306
.131
.0893
Max.
.407
.733
1.747
1.685
.665
1.109
1.256
.407
.396
Avg.
.223
.483
1.044
.943
.291
.536
.694
. 188
.196
Carbon Dioxide
Min.
.218
.571
1.73
1.31
1.81
.236
.742
.246
.231
Max.
.727
1.388
3.09
2.94
3.87
1.468
1.486
.550
.652
Avg.
.387
.885
2.13
1.85
2.22
.806
1.1C
.325
.363
Hydrocarbons (as
Min.
.00343
.00691
.00590
.00606
.00128
.00378
.00253
.00286
.00478
Max.
.0374
.0440
.0251
.0231
.0150
.0439
.0259
.0881
.0606
Hexane)
Avg.
.0116
.0184
.0144
.0115
.00555
.0147
.0146
.0240
.0161
Nitrogen Oxides
Min.
.000335
.000666
.00232
.00127
.0205
.000752
.00102
.000344
.000288
Max.
.00167
.00996
.0139
.0115
.0912
.00439
.00734
.00131
.00376
Avg.
.000597
.00329
.00718
.00417
.0376
.00234
.00413
.000647
.00103
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5-8
Table 5-6. Summary of Exhaust Emissions from Nine
Liqht Aircraft during Typical Operating Cycles
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
1.00
.725
6.27
6.13
.764
4.02
1.39
.394 '
.334
21.0
14.1
Mode
Carbon
Dioxide
1.74
1.33
12.81
12.00
5.80
6.05
2.32
.678
.617
43.3
25.5
Emissions (Ib.)
Hydrocarbons
(as Hexane)
.0521
.0276
.0862
.0747
.0150
.110
.0820
.0452
.0274
.520
.431
Nitrogen Oxides
(as NO?)
.00269
.00493
.0442
.0271
.0988
.0651
.00827
.00144
.00174
.254
.128
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
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6-1
6.0 DISCUSSION OF DATA COLLECTED
The composition of the exhaust from a light, piston engine
aircraft is a complex function of the various fixed aircraft parameters,
such as engine type and airframe design, and the operating mode of the
aircraft. The aircraft selected for testing and the modes defined in
the takeoff-cruise-landing (TCL) cycle allow evaluation of the effects
of many of these variables on the exhaust composition and the emission
rates.
6.1 EFFECT OF OPERATIONAL MODE ON EXHAUST EMISSIONS
Light aircraft are generally operated with a rich mixture
setting during all operations except long cruise modes in which case
the mixture may be leaned to reduce fuel consumption. Rich mixtures
are employed to protect the engine through cooler operation and to
provide for greater safety through more stable engine operation with
less chance of stalling than with stoichiometric mixtures. In addition,
the pilot does not have to adjust the mixture control during the
critical operations of takeoff and landing.
The exhaust composition resulting from the rich mixture
setting was relatively high in carbon monoxide as shown in Table 5-3.
The differences in carbon monoxide among the various rich modes were
small. The hydrocarbons varied to a greater extent with the lowest
concentrations found at the high power settings used for ascent and
cruise, and the higher concentrations found at low power modes such
as descent, final approach and taxi. The highest hydrocarbon con-
centrations occurred during final approach, a mode in which the engine
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6-2
absorbed energy through the propeller while idling as the aircraft lost
altitude. Nitrogen oxides concentrations showed little change from
one rich mixture mode to another.
When the mixture was leaned during the cruise mode, a sub-
stantial reduction in carbon monoxide occurred along with a moderate
reduction in hydrocarbons, a moderate increase in carbon dioxide and
a very large increase in nitrogen oxides. The emission rate of nitrogen
oxides at lean cruise exceeded the sum of the emission rates at the
other eight modes.
As the aircraft's altitude increases, the decrease in ambient
air pressure might be expected to produce a richer air-fuel mixture
and thus less complete combustion. However, the comparison data shown
in Table 6-1 indicate that cruise altitude had little effect on exhaust
emissions expressed as pounds per pound of fuel. On the other hand,
it was noted that fuel consumption increased with altitude thereby
producing greater emissions per unit time.
Table 6-1. Effect of Cruise Altitude on Exhaust Emissions
Aircraft #3
Cruise @ 1,200'MSL
Cruise @ 3,000'MSL
Aircraft #1
Cruise @ 3,000'MSL
Cruise @ 4,500'MSL
Ib
CO
1.16
1.17
1.02
1.11
pollutant/lb fuel
CO?
1.24
1.23
1.44
1.36
THC
0.0258
0.0231
0.0280
0.0328
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6-3
During warm, humid weather ice can form in the induction system
as an aircraft descends from cool air aloft into the humid air below or
as it passes through clouds. To prevent ice from forming, the intake
air to the carburetor is heated in a heat exchanger using exhaust gas as
the source of heat. Heating the intake air reduces the air-fuel ratio
and thus produces higher emissions. This is illustrated in Table 6-2
where both carbon monoxide and hydrocarbons were about 30% higher when
the carburetor intake was heated than when it was not. However, since
carburetor heat is generally used only for short periods of time, the
increase in total emissions is small.
Table 6-2. Effect of Carburetor Heat on Exhaust Composition
Air-fuel
Ratio CO CC>2 THC
Aircraft #8 (Ib/lb) (%) (%) (ppm-C)
Descent with
Carburetor Heat 10.6 10.6 8.0 3300
Descent without
Carburetor Heat 11.5 8.3 10.3 2500
6.2 THE EFFECT OF AIRCRAFT PARAMETERS ON EXHAUST EMISSIONS
The aircraft tested in this program were selected to allow an
assessment of the effect of design differences on exhaust emissions.
Of particular interest was the effect of engine operating time, engine
size, engine induction system and airframe design on the composition of
the exhaust. To quantify the comparisons made in this section, the
exhaust emissions as pounds of pollutant per pound of fuel were averaged
over the most reproducible rich modes of operation, specifically the
ascent, rich cruise, descent and final taxi modes. These comparisons
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6-4
are limited to exhaust composition and do not take into account
differences in fuel consumption rates.
6.2.1 THE EFFECT OF ENGINE OPERATING TIME
The effect of engine operating time, that is the total number
of hours the engine has been operated since its manufacture or last major
overhaul, is indicated by examining the emissions data for three similar
four cylinder and two similar six cylinder craft. The data shown in
Table 6-4 indicates that the effect of engine age is small. The
differences in pollutant levels are probably due to engine settings rather
than engine use.
6.2.2 THE EFFECT OF ENGINE SIZE
The Cessna 172 and 182 have similar airframes, but the 182 is
heavier and has a larger engine. The data presented in Table 6-4
indicates combustion in the larger engines is more efficient. The two
Cessna 182's emitted an average of 15 percent less carbon monoxide and
49 percent less hydrocarbons per pound of fuel than the three 172's.
Table 6-4. Effect of Engine Use
and Size on Exhaust
Emissions
Average Emissions Durinq Steady-State Modes
(Ib/lb Fuel)
Aircraft
#3
»1
*4
»6
*7
Cessna
Cessna
Cessna
Cessna
Cessna
172
172
172
182
182
Engine Power .
(HP)
150
150
150
235
235
Number of
Cylinders
4
4
4
6
6
Engine Use
(hrs)
672
140
105
1053
53
CO CO,
0
0,
1,
0.
0.
.820 1.79
,928 1.62
,011 1.46
766 1.88
789 1.87
THC
(as Hexajie)
0.0227
0.0184
0.0304
0.0128
0.0104
NOX
(as NO?)
0.00604
0.
0.
0.
,00822
00265
00207
.
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6-5
6.2.3 THE EFFECT OF ENGINE INDUCTION SYSTEM
A comparison of emission data for six cylinder engines with
fuel injection and normal aspiration is made in Table 6-5. The fuel
injected engines in the Beechcraft 36 and Cessna 210 emitted 23 percent
more carbon monoxide and 307 percent more hydrocarbons per pound of
fuel than the Cessna 182's with normal aspiration. There was little
difference between the emissions from the turbocharged Cessna 210 and
the Beechcraft 36 without turbocharging.
Table 6-5. Effect of Engine
Induction System on exhaust Exi.aiona
Average Emissions During Steady-State Modes
(Ib/lb Fuel)
Aircraft
»6 Cessna 182
• 7 Cessna 182
• 5 Bonanza 36
»9 Cessna 210
Induction System
Normal Aspiration
Normal Aspiration
Fuel Injection
Fuel Injection,
Turbocharged
Engine Power
(HP)
230
230
285
28)
CO COj
0.776 1.88
0.789 1.87
0.994 1.43
0.955 1.49
(as
0
0
0
0
THC
Hexane)
.0128
.0104
.0462
.0482
NOX
(as NOi)
0.00207
-
0.00232
0.00380
6.2.4 THE EFFECT OF AIRFRAME DRSIGN
Two distinctly different airframes with similar engines were
included in the test program. Both the Cessna 172 and Piper ^A-23
utilized 4 cylinder, 150 HP engines. The Cessna 172 was a high wing
monoplane with fixed tricycle landing gear, while the Piper PA-23
was a low wing twin-engine aircraft with retractable landing gear.
The Piper also had' an ejector type exhaust. The ejector
exhaust is a venturi-shaped duct placed around the exhaust stack with
the stack ending at the venturi throat. The rear end of the duct is
open to the atmosphere and the front end is open to the engine com-
partment. The high speed flow from the engine exhaust stack draws
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6-6
ambient air over the engine thereby cooling it with little or no
additional drag. The air also passes over the exhaust stacks and
cools the exhaust gases. This is evident by the temperatures of
approximately 200°F found at the stack sampling point.
The data presented in Table 6-6 show that the emissions
from the Piper were slightly lower in carbon monoxide and hydrocarbons
than any of the three Cessna 172's. However, it is not possible to
draw firm conclusions based on one aircraft.
Table 6-6. Effect of Airframe
Design on Exhaust
Emissions
Average Emissions During Steady-State Modes
(Ib/lb Fuel)
Aircraft
»3 Cessna 172
»1 Cessna 172
«4 Cessna 172
US Piper Apache
Airframe Design
High wing mono-
plane with fixed
landing gear.
U>w wing twin engine
Engine Use
(hrs)
672
140
105
423
CO CO?
0.820 1.78
0.928 1.62
1.011 1.46
0.736 1.93
THC
(as Hexane)
0.0227
0.0184
0.0304
0.0163
NOX
(as NO?)
0.00604
0.00822
0.00265
-
landing gear and
exhaust ejector.
6.3 COMPARISON OF EMISSIONS FROM LIGHT AIRCRAFT AND AUTOMOBILES
The engines and fuels used in light aircraft are similar to
those employed in automobiles so that a comparison of emissions from
these two sources may be made. The emission rates for light aircraft
obtained in this study are compared to present and projected rates for
automobile exhaust in Table 6-7 on a basis of pounds of pollutant per
pound of fuel.
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6-7
Table 6-7. Comparison of Light
Aircraft and Automobile Emissions
Ib pollutant/lh fuel consumed
Present Uncontrolled
Light Aircraft*
Uncontrolled
Automobiles**
Automobiles Meeting
1972 Federal Stds.**
Automobiles Meeting
Proposed HEW 1975
Federal Standards**
Carbon
Monoxide
0.847
0.525
0.176
0.050
Hydrocarbons
as Hexane
0.0210
0.066
0.015
0.002
Nitrogen Oxides
as
Nitrogen Dioxide
0.0102
0.018
No Standard
0.0041
* Average value for aircraft operated over TCL cycle described in Table 5-1,
** Reference 6 - Average values for automobiles operated over new Federal
urban driving cycle assuming 12 miles per gallon of gasoline.
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Carbon monoxide emissions from light aircraft were approximat tvly
60 percent higher than uncontrolled automobiles and nearly five times as
high as allowable emissions for 1972 automobiles. Hydrocarbon emissions
from current aircraft were only slightly higher than 1972 automobile
standards. However, ground operations of aircraft produced hydrocarbons
at approximately twice the rate of the TCL cvcle. Nitrogen oxides
emissions from aircraft, expeciallv on the ground, were not much hiqher
than proposed 1975 standards. However, continued attention must be paid
to nitrogen oxides since control techniques for carbon monoxide and
hydrocarbons could increase aircraft nitrogen oxides emissions.
6.4 AFTERBURNING
Afterburning can take place when very hot exhaust gases con-
taining high concentrations of carbon monoxide and hydrocarbons come
in contact with air. This combustion could eliminate much of the carbon
monoxide, hydrocarbons, hydrogen and carbonaceous particles present in the
exhaust. Natural afterburning at the end of the aircraft exhaust stack
would provide a convenient means of pollution control. It would be
expected that afterburning would occur most readily at the high exhaust
temperatures and rich mixtures present during the ascent and rich cruise
modes.
Samples of the exhaust plume were taken downstream of the
exhaust stack during the initial taxi/ ascent, rich cruise and descent
modes. The plume composition was corrected for dilution by carbon
balance after correcting for ambient air concentrations of carbon dioxide
and hydrocarbons. The corrected plume concentrations are compared to
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6-9
the corresponding stack values in Table A-37 in the Appendix. A frequency
distribution of the net change in carbon dioxide concentration is shown
in Figure 6-1. The figure shows a near normal distribution of data
points. The difference between corrected plume and stack data was ten
percent or less for ninety percent of the test points. This range covers
the expected level of random error. A study of those points showing a
carbon dioxide increase of fifteen percent or more indicates that they
are widely distributed over aircraft and operating modes and thus the
result of random data error and not afterburning.
The changes in hydrocarbons given in Table A-37 exhibit greater
dispersion than the changes in carbon dioxide and carbon monoxide. This
is due to greater fluctuation of hydrocarbons during steady-state modes
and less precision in the plume measurements. However, there is no
evidence of any consistent reduction in hydrocarbon emissions for any
aircraft or operating mode.
The fact that no afterburning was found in this study is
plausible when the exhaust gas temperatures are examined. The highest
temperatures occurred during ascent and cruise where values as high as
1500°F were recorded at the stack sampling point. Cooling undoubtedly
occurred between the sampling point and the end of the stack. Thus,
the temperature at the point where air needed for afterburning first
came in contact with the exhaust was too low for burning to take place.
One means of enhancing afterburning would be to minimize the
distance from the engine manifold to the exhaust vent. This exhaust
configuration was used on many radial piston engine aircraft for which
visible afterburning was reported at the exhaust vents. Afterburning
might also be enhanced by insulation of the exhaust system.
SCOTT RESEARCH LABORATORIES, INC
-------
s
o
X
o
38
Figure 6-1. Distribution of % change
in CO? concentration from stack to
plume from afterburning analysis
60-
o
I
« • • * *
IvXv!
>.
u
c
0)
a
o1
0)
40-
•*««** ***«*«
>*«•>**• ******
****** *••*•*
* • * » • • »**«**
• * * * * « ******
Xv.v. •.•.•/.•.•.
l 20-
vv«
•*•*** »*»**f|
*» » * » «
,
* * * * *•*•
* • •!* ***.
* * * * *
******
•*••«•
.v.v.v-
Xv*Xv vXvX
; ^gx
'.' ».«•»«..
15orless -10 -5 0 *5 +10 +15ormorc
% Change in CO« concentration
-------
6-11
6.5 CONTROL TECHNIQUES FOR AIRCRAFT EMISSIONS
In addition to natural afterburning, techniques which have been
applied to automobile exhaust are potentially applicable to aircraft exhaust.
However, greater constraints are placed on the design of an aircraft
control system as compared to one suitable for automobiles. Aircraft
safety must not be impaired in any manner. This means that engine performance
cannot be reduced, any heat generated must be safely dissipated, and
additional weight and power requirements must be minimal. On the other
hand, high temperatures must be maintained and substantial amounts of
air added to achieve combustion of exhaust products.
While leaning of the engine mixture was shown to result in
substantial reductions in carbon monoxide and hydrocarbons at the cruise
mode, this cannot be done safely with the present engine design at the
high performance modes such as ascent. The mixture could possibly be
leaned during ground operations, but a large increase in nitrogen oxides
emissions would be anticipated.
Exhaust reactors can be applied in principle to aircraft
emissions. The volume of air required for complete combustion of the
carbon monoxide, hydrocarbons and hydrogen in the exhaust would be as
great as 50 percent of the total exhaust volume at rich modes. A pump
capable of supplying this large volume of air would be heavy and require
additional power thus limiting its practicability. It would appear that
the air would best be supplied by the ram air pressure generated by the
aircraft motion. The incoming air would have to be heated, preferably
in a heat exchanger with heat supplied by the reactor effluent, in
order to maintain combustion in a thermal reactor. This may prove
SCOTT RESEARCH LABORATORIES, INC
-------
6-12
difficult at ground level modes where exhaust temperatures are relatively
low. A catalytic reactor could be used to obtain combustion at lower
temperatures, but with added catalyst bed weight and cost. The lead
present in the exhaust would limit catalyst life but this could be over-
come by the use of unleaded fuel.
In summary, the technology which has been developed for
controlling automobile exhaust emissions will be valuable in developing
control techniques for aircraft emissions. However, a number of con-
straints unique to aircraft will make it necessary to carry out additional
design efforts to adapt the techniques and hardware utilized for auto-
mobiles for satisfactory performance in aircraft. In the meantime,
proper engine maintenance and setting of the air-fuel mixture to the
minimum richness required for safe operation would be beneficial in
minimizing aircraft exhaust emissions.
6.6 CONCLUSIONS
As a result of this study of nine light aircraft, the following
conclusions can be drawn:
1. The light piston engine aircraft tested emitted exhaust
containing levels of carbon monoxide higher than
uncontrolled automobiles and substantially higher than
standards set for 1972 vehicles in terms of pounds of
pollutant per pound of fuel. Hydrocarbon emissions
from the test aircraft were in the range emitted by
current controlled automobiles. Aircraft nitrogen
oxide emissions were low except during lean mixture
operation.
SCOTT RESEARCH LABORATORIES. INC
-------
6-13
2. Carbon monoxide and hydrocarbon emissions can be
substantially reduced by leaning the aircraft air-
fuel mixture, but this is not done because it
increases the possibility of engine stalling.
3. Fuel injected engines of current design emitted much
higher concentrations of hydrocarbons than normally
aspirated engines. The effect of other aircraft
parameters such as use time, engine size, and
airframe design, on exhaust composition was small.
4. No natural afterburning of carbon monoxide
or hydrocarbons occurred in the exhaust from
the light aircraft tested during any operating
mode.
5. Analytical instrumentation packages are avail-
able to monitor exhaust emissions of light
aircraft during actual flight operation.
6.7 RECOMMENDATIONS FOR FUTURE STUDIES
Future investigations related to light aircraft emissions
should be concentrated in two areas: the contribution of light air-
craft emissions to pollution levels in the vicinity of airports and
the feasibility of various control techniques for reducing exhaust
emissions.
Work on aircraft contributions to pollution levels rhould
obtain information on typical operations at a number of airports and
thus improve upon the TCL cycle developed in the current study. Special
SCOTT RESEARCH LABORATORIES. INC
-------
emphasis should be placed on operations at or near ground level with
attention also focused on the dispersion of pollutants in the atmosphere
surrounding the airports.
The evaluation of control techniques should investigate the
potential schemes discussed in the previous section. It "hould include
enhancement of natural afterburning via increased temperatures at the
stack vent. Both thermal and catalytic reactors should be tested.
Because of the importance of temperature in control device performance,
and because actual inflight heat transfer is difficult to simulate in
a test cell, the evaluations would best be accomplished in actual
flight tests.
SCOTT RESEARCH LABORATORIES. INC
-------
7-1
7.0 REFERENCES
1. "Nature and Control of Aircraft Engine Exhaust Emissions"
Report of the Secretary of Health, Education & Welfare to the
United States Congress; December, 1968.
2. "Nature and Control of Aircraft Engine Exhaust Emissions"
Report prepared by Northern Research and Engineering Corporation
for the National Air Pollution Control Administration under
Contract No. PH22-68-27.
3. "Standard Specifications for Aviation Gasolines" ASTM Standards
(D910-70), Part 17, November, 1970.
4. "Internal Combustion Engines Analysis and Practice" Second
Edition by Edward F. Obert.
5. "Aviation Statistics (Interum Report}", Office of Management
Systems, Information and Statistics Division, FAA/DOT,
September, 1970.
6. "Congressional Record-Senate", September 21, 1970, pg. S16113.
SCOTT RESEARCH LABORATORIES, INC
-------
A-l
Appendix of Data
SCOTT RESEARCH LABORATORIES, INC
-------
Table A-l
Composition of Light Aircraft Exhaust
if!
O
90
m
30
O
X
r-
i
30
i
2
m
O
MODE: Taxi - initial
1.
2.
2.
3.
4.
5.
6.
7.
a.
9.
Plane
Cessna 172K
(Right) - Cessna 172D
(Left) - Cessna 172D
Cessna 1721
Cessna 172K.
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
CO
8.68
10.85
10.45
5.20
11.69
8.46
6.97
7.92
7.39
8.88
002
7.79
7.03
7.02
10.92
6.78
9.60
11.82
10.82
8.51
9.50
THC
(ppm-C)
4650
9450
4050
3780
14670
15180
3630
3270
3525
16020
NOX
(ppm)
74
109
88
157
107
99
71
90
280
171
Stack
Temp. (°F)
630
643
653
631
774
747
907
753
113
512
KJ
-------
Table A-2
Composition of Light Aircraft Exhaust
i
30
m
in
r*i
33
n
r-
00
c
1
30
o
MODE
1.
2.
2.
3.
4.
5.
6.
7.
a.
9.
: Run-up
Plane
Cessna 172K
(Right) - Cessna 172D
(Left) - Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
CO
-
10.35
9.69
6.41
8.53
8.63
8.09
7.23
7.78
8.33
C02
-
6.81
6.40
10.39
8.71
9.72
10.66
10.45
8.89
10.01
THC
(ppm-C)
-
5670
4410
3540
8460
13080
3810
2150
3300
7080
NOX
(ppm)
360
120
292
320
140
86
260
1220
280
Stack
Temp. (OF)
-
849
892
855
1030
916
1150 >
i
GO
967
188
815
-------
Table A-3
Composition of Light Aircraft Exhaust
m
C/l
8
30
m
m
•a
n
t-
00
o
30
H
0
30
-
0
MODE: Ascent
Plane
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
Cessna
(Right)
172K
- Cessna 172D
(Left) - Cessna 172D
Cessna
Cessna
Bonanza
Cessna
Cessna
1721
172K
36
182H
182N
Piper Apache
Cessna
210
CO
6.
8.
7.
9.
8.
8.
7.
6.
6.
9.
88
34
76
41
64
64
39
86
96
91
C02
8
8
8
10
9
10
12
12
13
11
.48
.15
.85
.83
.64
.10
.45
.43
.34
.14
THC
(ppm-C)
1550
3180
2350
2610
1640
2840
1740
990
2050
2770
NOX
(ppm)
600
4R5
678
483
217
201
138
202
-
247
St.-ick
Temp. (°F)
1 ~\'/D
I )1"
IV.n
Win
140',
ran
I'iOO
MOO
'/.I*.
M>
-------
Table A-4
Composition of Light Aircraft Exhaust
SI MODE: P.ich
Cruise - 3,000'
CO
C02
2 Plane . (%) (%)
30
pn
t/i
m
30
n
LABOR,
*-
O
30
?
P
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
Cessna
(Right)
(Left)
Cessna
Cessna
Bonanza
Cessna
Cessna
172K
- Cessna 172D
- Cessna 172D
1721
172K
36*
182H
182N*
Piper Apache *
Cessna
210*
5.
7.
8.
7.
7.
10.
7.
8.
7.
8.
43
31
36
45
30
19
35
75
28
83
9.
3.
7.
10.
9.
8.
11.
10.
12.
10.
14
46
39
49
99
48
80
6
15
61
THC
(ppn-C)
1250
2580
2520
1970
1320
2730
1370
987
2060
2370
NO
(ppm)
612
330
387
164
85
85
80
112
-
208
Stack
Temp. (°F)
1260
1290
1290
1220
1350
1240
1450 >
i
1430
208
1260
* Cruise at .5,000', all others at 3,000'
-------
Tahle A-5
Composition of Light Aircraft Exhaust
am
M MODE: Lean Cruise - 3,000'
-> Plane
73
m
m
33
n
X
CD
O
30
H
0
30
J"
Z
0
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
Cessna
(Right)
(Left)
Cessna
Cessna
172K
- Cessna 172D
- Cessna 172D
1721
172K
Bonanza 36 *
Cessna
Cessna
182H
182N *
Piper Apache *
Cessna
210*
CO
0.
—
2.
2.
3.
4.
3.
1.
3.
2.
47
64
24
09
80
02
61
20
91
CC-2
11.
—
.* 11.
13.
13.
12.
14.
14.
13.
13.
35
41
2G
40
12
75
29
64
36
THC
(ppm-C)
207
~
1520
879
795
1770
789
435
696
1580
NOX
(ppm)
2050
~
1880
2030
1910
1360
2900
4750
-
674
Stack
Temp. (OF)
1410
1440
1310
1470
1340
1550
1530
221
1310
* Cruise at 5,000', all others at 3,000'
-------
Table A-6
Composition of Light Aircraft Exhaust
m
mm MODE: Descent
f.
n
50
m
m
50
n
X
r-
00
0
50
25
o
50
m
n
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
Plane
Cessna 172K
(Right) - Cessna 172D
(Left) - Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
CO
(%)
9.32
9.50
9.92
9.28
10.98
10.41
8.08
5.72
6.83
10.57
C02
6.32
5.07
5.09
7.42
6-77
7.25
10.48
11.44
9-76
7.99
THC
(ppm-C)
4630
30400
27700
6180
7170
4410
1900
906
1970
3720
NOX
(ppm)
180
945
460
385
162
162
186
-
-
256
Stack
Temp. (°F)
743
1100
1130
803
894
1150
1330 >
-j
1380
221
1090
-------
Table A-7
Composition of Light Aircraft Exhaust
mm
1
so
m
in
m
n
r-
DO
O
SO
H
O
50
5
o
MODE: Pattern
Plane
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
Cessna
(Right)
(Left)
Cessna
Cessna
Bonanza
Cessna
Cessna
172K
- Cessna 172D
- Cessna 172D
1721
172K
36
182II
182N
Piper Apache
Cessna
210
CO
-
8.
8.
7.
6.
9.
8.
7.
6.
10.
07
78
55
88
63
20
04
73
89
C02
-
9.
7.
9.
8.
8.
10.
10.
9.
7.
30
84
64
50
78
66
89
70
20
THC
(ppm-C)
1410
4650
5670
3030
3780
3390
2460
1140
2160
3990
NOX
(PPM)
-
500
415
255
324
150
125
—
-
212
Stack
Temp. (°F)
-
1290
1270
1070
1170
1190
1260 >
i
03
1290
228
1040
-------
Table A-8
Composition of Light Aircraft Exhaust
m
1H MODE: Final Approach
8
30
[/>
30
n
LABORATOR]
f
2
p
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
Plane
Cessna 172K
(Right) - Cessna 172D
(Left) - Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
CO
6.54
-
5.09
4.30
6.26
8.26
5.38
7.87
7.70
8.39
C02
7.31
-
4.70
9.47
7.20
7.11
10.57
9.13
7.97
6.62
THC
(ppm-C)
14900
-
14500
15100
27600
35000
9570
9450
2300
18500
NOX
(ppm)
120
-
185
326
182
79
86
-
-
121
Stack
Temp. (°F)
558
-
729
740
809
1010
995 >
i
995
199
800
-------
Table A-9
Composition of Light Aircraft Exhaust
1 SCOTT RESEARCH U
00
0
30
s
30
0
MODS
1.
2.
2.
3.
4.
5.
6.
7.
8.
9.
: Taxi - Final
Plane
Cessna 172K
(Right) - Cessna 172D
(Left) - Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
CO
7.66
9.88
9.78
3.62
10.00
8.07
6.74
8.18
4.88
8.50
C02
8.31
7.16
7.12
11.15
7.18
8.49
10.8
9.70
8.31
7.94
THC
(ppm-C)
4080
10500
7350
4500
11700
24100
4350
4620
4290
27700
NOX
(ppm)
140
280
145
288
126
83
77
808
158
Stack
Temp. (°F)
551
599
623
594
690
768
889 >
840 °
170
667
-------
Table »-10
Light Aircraft Exhaust Emissions
r RESEARCH LABORATORIES. INC
MODE: Taxi - Initial
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Air-Fuel
Ratio
Clb/lb)
11.0
10.3
12.8
10.0
11.5
12.3
11.9
11.6
11.4
Carbon
Monoxide
1.022
1.150
1.166
0.629
1.170
0.862
0.726
0.829
0.907
0-887
Emissions
Carbon
Dioxide
1.44
1.17
1.23
2.08
1.07
1.54
1.94
1.78
1.64
1.49
(Ib/lb Fuel)
Hydroc arbons
(as Hexane)
.0280
.0513
.0231
.0233
.0751
.0792
.0194
.0175
.0222
.0819
Nitrogen
Oxides (as NO2)
.00143
.00190
.00200 >
.00312 ^
.00176
.00166
.00122
.00155
.00565
.00281
-------
Table A-ll
Light Aircraft Exhaust Emissions
30
t*l
tfl
m
= MODE: Run-up
CO
O
30
2 Number
8 *
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Air-Fuel
Ratio
Clb/lb)
-
10.3
12.3
11.3
11.5
11.9
12.0
11.5
11.7
Carbon
Monoxide
-
1.165
1.169
0.746
0.941
0.876
0.844
0.806
0.913
0.872
Emissions
Carbon
Dioxide
-
1.20
1.21
1.90
1.51
1.55
1.75
1.83
1.64
1.65
(Ib/lb Fuel)
Hydrocarbons
(as Hexane)
-
.0327
.0272
.0211
.0478
.0680
.0203
.0123
.0198
.0380
Nitrogen
Oxides (as NC-2)
-
.00666
.00238
.00558
.00580
.00233
.00147
.00476
.0235
.00482
-------
Table A-12
Light Aircraft Exhaust Emissions
r RESEARCH LABORATORIES. 1!
P
MODE: Ascent
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Air-Fuel
Ratio
Clb/lb)
11.7
11.4
11.6
11.5
11.6
12.3
12.5
12.6
11.5
Carbon
Monoxide
.885
.986
.919
.916
.935
.906
.737
.706
.677
.927
Emissions
Carbon
Dioxide
1.71
1.52
1.65
1.66
1.64
1.66
1.95
2.01
2.04
1.64
(Ib/lb Fuel)
Hydrocarbons
(as Hexane)
.0102
.0230
.0143
.0130
.00909
.0153
.00886
.00521
.0102
.0133
Nitrogen
Oxides (as NOj
.0127
.00942
.0132 *
.00772 ^
.00386
.00346
.00226
.00342
-
.00380
-------
SCOTT RESEARCH
LABORATORIES,
P
.1. «-*j_* _i- ^ n JL j
Light Aircraft Exhaust Emissions
MODE: Rich Cruise
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36 *
Cessna 182H
Cessna 182N *
Piper Apache *
Cessna 210 *
Air-Fuel
Ratio
Clb/lb)
12.3
11.3
12.0
11.9
10.8
12.2
11.5
12.3
11.7
Carbon
Monoxide
.737
.910
1.042
.820
.836
1.073
.760
.898
.740
.895
Emissions
Carbon
Dioxide
1.95
1.66
1.45
1.81
1.80
1.40
1.92
1.71
1.94
1.69
(Ib/lb Fuel)
Hydrocarbons
(as Hexane)
.00862
.0164
.0161
.0111
.00772
.0147
.00726
.00518
.0107
.0123
Nitrogen
Oxides (as NO2)
.0137
.00675
.00793
.00296
.00160
.00147
.00136
.00189
-
.00346
* Cruise at 5,000', all others at 3,000'.
-------
Table A-14
SCOTT RESEARCH
LABORATORIES, INC
Light Aircraft Exhaust Emissions
MODE: Lean Cruise
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36 *
Cessna 182H
Cessna 182N *
Piper Apache *
Cessna 210 *
Air-Fuel
Ratio
Clb/lb)
15.1
13.9
14.3
13.8
13.1
14.0
14.8
13.8
13.9
Carbon
Monoxide
.0792
-.371
.286
.372
.560
.338
.202
.378
..353
Emissions
Carbon
Dioxide
3.01
2.52
2.67
2.54
2..22
2.59
2.81
2.53
2.55
(Ib/lb Fuel)
Hydrocarbons
(as Hexane)
.00179
.0110
.00575
.00490
.0106
.00451
..00279
.00420
.00985
Nitrogen
Oxides (as NO^
.0566
.0434 :
1
.0426
.0377
.0261
.0533
.0977
-
.0135
Cruise at 5.000', all •: ;:h^r at 3,000'.
-------
§
30
m
t*i
30
n
3C
r~
i
30
VTORIES. INC
MODE: Descent
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Table A-15
Light Aircraft Exhaust Emissions
Air-Fuel
Ratio
db/lb)
10.4
9.8
10.7
10.2
10.4
11.8
12.7
12.0
10.6
Carbon
Monoxide
1.155
1,076
1.113
1.069
1.186
1.147
.860
.662
.812
1.114
Emissions (Ib/lb Fuel)
Carbon
Dioxide
1.23
.90
.90
1.34
1.15
1.26
1.75
2.08
1.82
1.32
Hydroc arbo ns
(as Hexanel
.0294
.176
.159
.0364
.0397
.0249
.0104
.00536
.0120
.0200
Nitrogen
Oxides(as
.00366
.0176
.00848
.00729
.00288
.00293
.00325
CTi
.00443
-------
3
RESEARCH L
00
O
o
30
m
~
o
MODE: Pattern
Number
1
2 (Right)
2 (Left)
2
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Table A-16
Light Aircraft Exhaust Emissions
Air-Fuel
Ratio
llb/lb)
11. 3
11.8
11.7
11.0
11.8
12.2
12.0
10.3
Carbon
Monoxide
.903
1.019
.861
.871
1.025
.856
.778
.807
1.175
Emissions (Ib/lb Fuel)
Carbon
Dioxide
1.64
1.43
1.73
1.69
1.47
1.75
1.89
1.83
1.22
Hydrocarbons
(as Hexane)
.0266
.0337
.0177
.0245
.0185
.0132
.00645
.0133
.0220
Nitrogen
Oxides(as NO2
.00919
.00791
.00478
.00674
.00262
.00214
.00376
-------
1
RESEARCH LAB
o
90
>
o
X
tn
J«
P
raoie A-I /
Light Aircraft Exhaust Emissions
HODS: Final Approach
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Air-Fuel
Ratio
Ub/lb)
11.5
11.1
12.8
11.6
10.9
12.7
11.6
11.3
10.8
Carbon
Monoxide
.851
-
.904
.561
.770
.874
.635
.875
.966
.993
Emissions
Carbon
Dioxide
1.49
-
1.31
1.94
1.39
1.18
1.96
1.60
1.57
1.23
(Ib/lb Fuel)
Hydrocarbons
(as Hexanel
.0992
-
.131
:101
.174
.189
.0578
.0538
.0148
.112
Nitrogen
Oxides (as NO2)
.00256
-
.00540 >
i
00
.00699
.00368
.00137
.00167
-
-
.00235
-------
i
RESEARCH I
CD
)RATOH1ES, 1
O
MODE: Taxi - Final
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Table A-18
Light Aircraft Exhaust Emissions
Air-Fuel
Ratio
Ub/lb)
11.4
10.5
13.4
10.5
11.4
12.2
11.6
12.4
11.1
Carbon
Monoxide
.933
.1.090
1.106
.475
1.087
.349
.748
.890
.715
.883
Emissions (Ib/lb Fuel)
Carbon
Dioxide
1.59
1.24
1.27
2.30
1.23
1.40
1.88
1.66
1.91
1.30
Hydrocarbons
(as Hexane)
.0254
.0591
.0426
.0302
.0651
.130
.0247
.0257
.0322
.147
Nitrogen
Oxides (as NO2)
.00280
.00507
.00270
.00620
.00225
.00143
.00140
.0195
.00270
-------
Table A-19
Light Aircraft Exhaust Emissions
• RESEARCH LABO
33
O
33
2
O
MODE: Taxi
- Initial
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
(Ib/min)
.204*
.204*
.204*
.204
.472
.177
.216
.296
.243
Emissions (Ib/min)
Carbon
Monoxide
.208
.236
.128
.239
.407
.126
.179
.268
.216
Carbon
Dioxide
.294
.245
.424
.218
.727
.343
.384
.485
.362
Hydrocarbons
(as Hexanel
.00571
.00759
.00475
.0153
.0374
.00343
.00378
.00657
.0199
Nitrogen
Oxides (as NO2)
.000292
.000398
i
.000636 o
.000359
.000784
.000216
.000335
.00167
.000683
* Fuel Flow estimated from measurements on Aircraft #4..
-------
Table A-20
Exhaust Emission Rates
for Light Aircraft
-5
a
ITj
£ MODE: Run-up
n
§ Aircraft
> Number
1 1
p 2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
Clb/minl
-
.470*
.470*
.470
.647
.455**
.562**
.424**
.841**
Emissions (Ib/min)
Carbon
Monoxide
-
.548
.351
.442
.567
.382
.453
.387
.733
Carbon
Dioxide
-
.571
.893
.710
1.003
.793
1.028
.697
1.388
Hydrocarbons
Cas Hexanel
_
.0141
.00992
.0225
.0440
.00920
.00691
.00840
.0320
Nitrogen
Oxides (as NO?.)
.00212
.00262
.00273
.00151
.000666
.00268
.00996
.00405
* Fuel Flow estimated from measurements on Aircraft #4.
** Fuel Flow estimated from measurements on other aircraft
-------
Table A-21
Exhaust Emission Rates
for Light Aircraft
RESEARCH LABORATORIES, II
P
MODE: Ascent
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
1
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
Clb/minl
1.093*
1.093*
1.093*
1.093
1.479
1.028
1.133
1.069
1.885
Emissions (Ib/min)
Carbon
Monoxide
.967
1.041
1.001
1.022
1.340
.758
.800
..724
1.747
Carbon
Dioxide
1.87
1.73
1.81
1.79
2.46
2.00
2.28
2.18
3.09
Hydrocarbons
(as Hexane);
.0111
.0204
.0142
..00994
.0226
.00911
.00590
.0109
.0251
Nitrogen
Oxides (as NO?)
.0139
.0124
.00844
i
.00422 K
.00512
.00232
.00387
.00716
* Fuel Flow estimated from measurements on Aircraft #4.
-------
Table A-22
Exhaust Emission Rates
for Light Aircraft
T RESEARCH LABORATORIES,
P
MODE: Rich Cruise
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
Clb/minI
0.842*
0.842*
0.842*
0.842
1.57
.933
1.17
.648
1.74
Carbon
Monoxide
.621
.822
.690
.704
1.685
.709
1.051
.648
1.557
Emissions
Carbon
Dioxide
1.64
1.31
1.52
1.52
2.20
1.79
2.00
1.70
2.94
(Ib/min)
Hydrocarbons
(as Hexanel
.00726
.0137
.00935
.00650
.0231
.00677
.00606
.00936
.0214
Nitrogen
Oxides (as NO?)
.0115
.00618
.00249
.00135
.00231
.00127
.00221
-
.00602
I
K)
* Fuel Flow estimated from measurements on Aircraft #4.
-------
Table A-23
X
o
a
m
t/)
en
^ MODE: Lean Cruise
X
r-
o
o
5 Aircraft
o Number
rn
_ 1
p
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Exhaust Emission Rates
for Liqht Aircraft
Fuel Flow
Rate
Clb/minl
.717*
.717*
.717*
.717
1.187
.826
.933
.758
1.52
Emissions (Ib/min)
Carbon
Monoxide
.0568
.266
.205
.267
.665
.279
.188
.287
.537
Carbon
Dioxide
2.16
1.81
1.91
1.82
2.64
2.14
2.62
1.92
3.87
Hydrocarbons
(as Hexanel
.00128
.00789
.00412
.00351
.0126
.00373
.00260
.00318
.0150
Nitrogen
Oxides (as NO?)
.0406
.0311
.0305
.0270
.0310
.0440
.0912
-
.0205
NJ
.fc.
*Fuel Flow estimated from measurements on Aircraft #4.
-------
Table A-24
Exhaust Emission Rates
for Light Aircraft
r RESEARCH UBORATORIES,
O
MODE: Descent
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
Clb/m±nL
.261*
.261*
.261*
.261
.967
.648
.706
.505
.991
Emissions (Ib/min)
Carbon
Monoxide
.302
.286
.279
.310
1.109
.557
.467
.410
1.104
Carbon
Dioxide
.322
.236
.351
.300
1.218
1.134
1.468
.919
1.308
Hydrocarbons
(as Hexanel
.00769
.0439
.00953
.0104
.0241
.00674
.00378
.00606
.0198
Nitrogen
Oxides (as NO?.)
.000957
.00341
.00191
.000752
.00283
.00211
-
-
.00439
* Fuel Flow"estimated from measurements on Aircraft #4.
-------
Table A-25
Exhaust Emission Rates
RESEARCH LABORATORIES. INC
MODE: Pattern
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
( Ib/min 1.
-
.859 *
.859*
.859
.889
.476**
.393
.446**
1.069
Emissions (Ib/min)
Carbon
Monoxide
-
.825
..740
.748
.911
.407
.306
.360
1.256
Carbon
Dioxide
-
1.319
1.486
1.452
1.307
.833
.742
.816
1.304
Hydrocarbons
(as Hexanel
-
.0259
.0152
.0210
.0164
.00628
.00253
..00593
.0235
Nitrogen
Oxides (as NO?)
-
.00734
i
.00411 £
.00579
.00233
.00102
-
-
.00420
* Fuel Flow estimated from measurements on Aircraft #4.
** Fuel Flow estimated from measurements on other aircraft.
-------
Table A-26
Exhaust Emission Rates
for Light Aircraft
T RESEARCH U
03
o
ya
1
to
P
%
MODE: Final Approach
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Aircraft
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
Clb/minl
.188*
.188*
.188*
.188
.466**
.206**
.216
.193**
.240**
Carbon
Monoxide
.160
.170
.150
.144
.407
.131
.189
.186
.238
Emissions
Carbon
Dioxide
.280
.246
.364
.261
.550
.404
.346
.303
.295
(Ib/min)
Hydrocarbons
(as Hexanel
.0186
.0246
.0190
.0326
.0881
.0119
.00333
.00286
.0269
Nitrogen
Oxides (as NO?)
.000481
.00102
.00131
.000690
.000638
.000344
-
-
.000564
* Fuel Flow estimated from measurements on Aircraft #4.
** Fuel Flow estimated from measurements on other aircraft.
-------
Table A-27
Exhaust Emission Rates
RESEARCH LABORATORIES, INC
MODE: Taxi - Final
Aircraft
Number
1
2 (Right)
2 (Left)
3
4
5
6
7
8
9
Type
Cessna 172K
Cessna 172D
}
Cessna 172D
Cessna 1721
Cessna 172K
Bonanza 36
Cessna 182H
Cessna 182N
Piper Apache
Cessna 210
Fuel Flow
Rate
(Ib/min)
.188*
.188*
.188*
.188**
.466
.206**
.216
.193**
.240**
Emissions (Ib/min)
Carbon
Monoxide
.175
.206
.0893
.204
.396
.154
.192
.138
.212
Carbon
Dioxide
.299
.236
.423
.231
.652
.387
..359
.369
.312
Hydrocarbons
(as Hexanel
.00478
.00956
.00568
.0122
.0606
.00509
.00555
..00621
.0353
Nitrogen
Oxides (as NO?)
.000526
.00073O
>
.00117 a
.000423
.000666
.000288
-
.00376
.000648
* Fuel Flow estimated from measurements on Aircraft #4.
** Fuel Flow estimated from measurements on other aircraft.
-------
A-29
Table A-28- Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 1 - Cessna 172K
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
0.936
-
5.80
4.04
0.142
2.27
-
0.320
0.298
-
-
Carbon
Dioxide
1.323
-
11.22
10.66
5.40
2.42
-
0.560
0.508
-
_
Hydrocarbons
(as Hexane)
0.0257
-
0.0666
0.0472
0.00320
0.0577
-
0.0372
0.00813
-
-
Nitrogen Oxides
(as NO?)
0.00131
-
0.0834
0.0748
0.102
0.00718
-
0.000962
0.000894
-
-
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC
-------
A-30
Table A-29. Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 2 - Cessna 172D
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.
1.
6
6.
2.
7.
2
2
1.
34.
25.
5
5
5
5
5
7
2
2
Carbon
Monoxide
1.
0.
6.
5.
0.
2.
1.
0.
0.
18.
12.
062
822
25
34
665
15
65
340
350
63
62
Carbon
Dioxide
1.
0.
10.
8.
4.
1.
2.
0.
0.
30.
17.
103
857
38
52
53
77
64
492
401
69
64
Hydrocarbons
(as Hexane)
0
0
0
0
0
0
0
0
0
.0341
.0212
.122
.0891
.0197
.329
.0518
.0492
.0163
.732
.624
Nitrogen Oxides
(as NO?)
0
0
0
0
0
0
0
0
0
.00179
.00318
.0744
.0402
.0778
.0256
.0147
.00204
.00124
.2410
.1230
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC
-------
A-31
Table A-30• Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 3 - Cessna 1721
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
0.576
0.527
6.01
4.49
0.513
2.09
1.48
0.300
0.152
16.14
11.14
Carbon
Dioxide
1.91
1.34
10.86
9.88
4.78
2.63
2.97
0.728
0.719
35.82
21.16
Hydrocarbons
(as Hexane)
0.0214
0.0149
0.0852
0.0608
0.0103
0.0715
0.0304
0.0380
0.00966
.2207
.1496
Nitrogen Oxides
(as NO?)
0.00286
0.00393
0.0506
0.0162
0.0763
0.0143
0.00822
0.00262
0.00199
.1770
.0845
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC
-------
A-32
Table A-31. Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 4 - Cessna 172K
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
1.076
0.663
6.13
4.58
0.668
2.33
1.50
0.288
0.347
17.56
12.33
Carbon
Dioxide
0.981
1.065
10.74
9.88
4.55
2.25
2.90
0.522
0.393
33.28
18.85
Hydrocarbons
(as Hexane)
0.0689
0.0338
0.0596
0.0423
0.00878
0.0780
0.0420
0.0652
0.0207
.4193
.3682
Nitrogen Oxides
(as NO?)
0.00162
0.00410
0.0253
0.00878
0.0675
0.00564
0.0116
0.00138
0.000719
.1266
.0504
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC.
-------
A-33
Table A-32. Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 5 - Bonanza 36
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
1.83
0.851
8.04
10.95
1.66
8.32
1.82
0.814
0.673
26.92
14.31
Carbon
Dioxide
3.27
1.51
14.8
14.3
6.60
9.14
2.61
1.10
1.11
54.4
33.5
Hydrocarbons
(aa Hexane)
0.168
0.0660
0.136
0.150
0.0315
0.181
0.0328
0.176
0.103
1.044
.863
Nitrogen Oxides
(as NO?)
0.00353
0.00227
0.0307
0.0150
0.0775
0.212
0.00466
0.00128
0.00113
.348
.256
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC
-------
A-34
Table A-33. Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 6 - Cessna 182H
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
CMin.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
0.567
0.573
4.55
4.61
0.698
4.18
0.814
0.262
0.262
16.52
11.21
Carbon
Dioxide
1.54
1.19
12.0
11.6
5.35
8.51
1.67
0.808
0.658
43.3
26.4
Hydrocarbons
(as Hexane)
0.0154
0.0138
0.0547
0.0440
0.00933
0.0506
0.0126
0.0238.
0.00865
.2329
.1796
Nitrogen Oxides
(as NO?)
0.000972
0.000999
0.0139
0.00826
0.110
0.158
0.00204
0.000688
0.000490
.295
.177
* Cycle as defined in Section 5.1.
'* Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC
-------
A-35
Table A-34. Exhaust Emissiona During
Normal Operating Cycles for
Aircraft Mumber 7 - Cesina 182N
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Min.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
0.806
0.680
4.80
6.83
0.0470
3.50
0.612
0.378
0.326
18.40
11.10
Carbon
Dioxide
1.73
1.54
13.7
13.0
6.55
11.0
1.48
0.692
Q.61Q
50.3
30.8
Hydrocarbons
(as Hexane)
0.0170
0.0104
0.0354
0.0394
0.00650
0.0284
0.00506
0.00666
0.. 00.944
0.1583
0.1124
Nitrogen Oxides
(as NO?)
0.00151
0.00402
0.0232
0.0144
0.228
-
-
-
^
•
_
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES, INC
-------
A-36
Table A-35. Exhaust Emissions During
Normal Operating Cycles for
Aircraft Number 8 - Piper Apache
(1 Engine)
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Win.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
1.21
0.581
4.34
4.21
0.718
3.08
0.720
0.372
0.235
15.47
10.54
Carbon
Dioxide
2.18
1.046
13.1
11.1
4.80
6.89
1.63
0.606
0.627
42.0
26.1
Hydrocarbons
(as Hexane)
0.0296
0.0126
0.0654
0.0608
0.00795
0.0455
0.0117
0.00572
0.0106
.2499
.181
Nitrogen Oxides
(as NO?)
0.00752
0.0149
-
-
•
-
-
-
0.00639
-
-
* Cycle as defined in Section 5.1.
** Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES. INC
-------
A-37
Table A-36. Exhaust Emisaione During
Normal Operating Cycles for
Aircraft Number 9 - Cessna 210
Mode Emissions (Ib.)
Mode
Taxi - Initial
Run-up
Ascent
Rich Cruise
Lean Cruise
Descent
Pattern
Final Approach
Taxi - Final
Total-TCL Cycle*
Total-LTO Cycle**
Mode Time
(Win.)
4.5
1.5
6
6.5
2.5
7.5
2
2
1.7
34.2
25.2
Carbon
Monoxide
0.972
1.10
10.48
10.12
1.34
6.28
2.51
0.476
0.360
35.64
24.18
Carbon
Dioxide
1.63
2.08
18.5
19.1
9.68
9.81
2.61
0.590
0.530
64.5
35.8
Hydrocarbons
(as Hexane)
0.0895
0.0480
0.151
0.139
0.0375
0.149
0.470
0.00538
0.0600
1.149
.973
Nitrogen Oxides
(as NO?)
0.00307
0.00608
0.0430
0.0391
0.0513
0.0329
0.00840
0.00113
0.00110
.1861
.0957
* Cycle as defined in Section 5.1.
•* Landing-Takeoff Cycle - as TCL cycle without cruise modes.
SCOTT RESEARCH LABORATORIES. INC
-------
Table A-37 . Comparison of Stack and Corrected
o
30
m
I"
O
Aircraft
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Flight
1
2
3
3
4
4
6
6
6
4
A
4
5
5
5
7
7
8
9
9
10
10
10
11
12-
Mode
Ascent
Cruise
Cruise
Descent
Ascent
Descent
Ascent
Cruise
Descent
Taxi
Ascent
Cruise
Taxi
Ascent
Cruise
Ascent
Cruise
Ascent
Ascent
Cruise
Ascent
Cruise
Descent
Ascent
Cruise
Plume Analysis to Detect Afterburning
CO
(%)
6.85
A. 84
6.50
5.43
7.30
6.40
6.96
5.75
6.90
10.40
8.32
6.52
11.70
11.72
8.38
8.00
7.00
7.AO
8.00
8.AO
7.62
8.20
9.04
8.00
7.34
Stack
C02
(%)
9.60
8.70
8.65
3.20
9.68
2.60
8.41
8.12
2.88
6.80
7.86
8.16
7.15
11.70
10.90
8.00
8.50
9.70
9.10
7.47
8.70
7.25
5.25
7.90
8.72
Corrected Plume
HC
(PPMCI
450
380
480
555
A25
1070
6AO
SAO
2960
2640
1305
920
6200
1280
9A5
1210
780
820
730
825
775
800
12400
810
790
CO
(%)
6.5A
5.05
6.58
5.30
7.67
5.9A
5.63
2.55
5.75
8.01
8.68
6.53
12.16
10.92
7.98
7.61
7.23
7.37
7.5A
8.23
7.67
7.52
9.67
7.91
7.97
C02
(%1
9.89
8.AA
8.58
3.24
9.27
3.07
9.76
11.33
4.16
9.25
7.48
8.15
6.92
12.38
11.24
8.20
8.14
9.57
9.39
7.48
8.49
7.76
5.04
7.81
7.92
HC
(PPMC).
528
808
286
1294
671
876
366
347
1601
2000
1365
831
3784
2419
1378
3027
1989
2318
2333
2310
2211
2442
8179
2528
2372
Dilution
Factor
11.33
48.58
17.20
7.33
18.33
13.15
55.22
40.18
15.01
27.92
37.25
33.75
18.31
58.10
44.98
32.68
4.82
55.67
53.46
48.50
40. A6
43.11
86.42
39.12
29.05
% Change in Cone.
CO
-4.48
4.38
1.37
-2.22
5.18
-7.08
-19.07
-55.62
-16.63
-22.97
A.A2
.23
A.00
-6.80
-4.66
-4.81
3.39
-.38
-5.63
-1.95
.74
-8.24
6.97.
-1.11
8.67
i
OJ
-------
Table A-37 Continued
o
m
•x
n
O
33
O
Aircraft
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
4
5
5
Flight
1
1
1
4
4
4
5
5
6
6
7
8
8
11
11
11
2
2
4
4
4
5
5
5
6
6
6
6
7
7
7
8
1
1
Mode
Ascent
Cruise
Descent
Ascent
Cruise
Descent
Ascent
Cruise
Ascent
Cruise
Descent
Ascent
Cruise
Taxi
Cruise
Descent
Taxi
Cruise
Ascent
Cruise
Descent
Taxi
Ascent
Descent
Taxi
Ascent
Cruise
Descent
Ascent
Cruise
Descent
Cruise
Taxi
Ascent
CO
(%)
9.28
8.02
7.80
9.38
7.72
8.17
9.87
7.90
8.68
6.93
10.37
9.50
7.92
6.39
7.45
11.24
11.17
6.18
8.50
7.41
10.84
10.60
8.78
11.39
12.74
8.77
7.61
10.70
9.05
7.76
13.02
6.88
8.78
8.33
Stack
C02
(%)
9.73
9.65
8.42
9.40
9.60
7.80
11.97
11.38
11.17
10.59
6.82
11.10
10.59
10.44
11.80
7.00
6.51
10.39
10.08
10.32
6.91
7.91
10.00
6.83
7.25
11.00
10.52
7.68
9.98
10.65
6.52
9.51
8.74
11.04
Corrected Plume
HC
(PPMC1
980
740
1103
870
660
1590
905
640
840
630
2360
890
680
1055
650
2170
4650
595
640
415
2000
2040
580
3800
5700
560
500
1330
52"0
420
2800
420
27000
2391
CO
(%)
9.70
7.96
7.39
10.08
7.34
8.70
10.29
7.92
9.37
7.25
10.50
9.99
7.93
6.02
7.64
10.96
10.26
6.32
9.12
7.81
10.78
10.98
9.54
10.86
12.84
9.52
7.96
10.46
8.73
7.13
11.97
7.42
10.36
8.91
C02
9.11
9.54
8.64
8.53
9.83
7.09
11.33
11.13
10.26
10.01
6.43
10.38
10.37
10.60
11.42
6.98
7.02
10.17
9.34
9.77
6.84
7.07
9.13
7.43
6.61
10.20
10.07
7.78
10.15
11.16
6.84
8.88
8.59
10.40
HC
CPPMC1
2866
2341
2891
2521
2120
3314
3021
2829
3002
3109
4797
3086
2690
3044
2435
5122
8590
1279
1791
1761
3108
6509
1609
3013
10960
907
1488
2629
1884
1541
10018
1244
12599
2911
Dilution
Factor
48.05
42.07
38.22
19.44
22.64
23.56
57.39
66.36
58.13
62.64
18.19
60.95
63.10
41.66
64.70
23.75
64.62
36.94
35.37
28.57
20.50
59 . 76
38.64
20.27
73.10
36.82
31.24
22.16
38.73
33.78
23.87
26.13
22.82
42.41
% Change in Cone.
CO
4.55
-.62
-5.21
7.48
-4.87
6.49
4.26
.29
7.96
4.67
1.34
5.16
.23
-5.85
2.66
-2.48
-8.12
2.35
7.34
5.49
-.46
3.62
8.66
-4.64
.81
8.62
4.60
-2.19
-3.43
-B.05
-8.02
7.87
18.06
7.03
CO?
-6.37
-1.13
2.61
-9.25
2.39
-9.10
-5.34
-2.19
-8.14
-5.A7
-5.71
-6.48
-2.07
1.53
-3.22
-.28
7.83
-2.11
-7.34
-5.32
-1.01
-10.61
-8.70
8.78
-8.82
-7.27
-4. 27
1.30
1.70
4.78
• 4.90
-6.62
-1.71
-5.79
HC
192.47
216.38
162.14
189.80
221.27
108.45
233.84
342.13
257.38
393.57
103.28
246.84
295.71
218.43
274.71
136.05
84.73
115.09
179.92
324.37
55.43
219.11
177.42
-20.68
92.28
62.02
197.68
97.70
262.34
267.10
257.80
196.41
-53.33
21.76
I
LO
-------
Table £-37 Ccniinued
Aircraft
••
m
m
0
o
^
rn
m
33
n
P.
33
O
33
1
33
."
2
O
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
6
6
6
6
6
6
6
6
6
6
6
6
Flight
2
2
2
3
3
3
4
4
5
5
5
6
6
6
7
7
7
a
8
8
3
9
9
10
10
10
10
1
1
1
2
2
2
2
3
3
3
4
4
Mode
Taxi
Cruise
Descent
Ascent
Cruise
Descent
Taxi
Descent
Ascent
Cruise
Descent
Taxi
Ascent
Descent
Taxi
Ascent
Cruise
Taxi
Ascent
Cruise
Descent
Ascent
Cruise
Taxi
Ascent
Cruise
Descent
Taxi
Ascent
Cruise
Taxi
Ascent
Cruise
Descent
Taxi
Ascent
Descent
Taxi
Ascent
CO
(%)
8.88
9.30
8.99
8.46
9.68
8.92
8.86
12.40
8.80
11.09 .
10.34
8.30
8.88
10.70
9.00
8.94
10.59
8.01
8.40
9.82
9.82
R.50
9.80
8.14
8.54
9.52
10.48
6.91
7.78
7.68
6.70
7.55
7.78
8.52
5.79
7.73
7.40
7.71
7.81
Stack
CO2
(%)
9.09
9.32
8.35
9.75
8.72
11.21
9.81
6.21
9.71
7.49
7.18
8.45
10.19
6.92
10.10
10.24
8.73
10.48
10.53
9.37
6.85
9.87
8.62
9.99
10.25
8.91
6.51
10.47
10.89
11.20
11.11
11.02
10.87
10.39
11.99
11.64
10.12
11.72
12.61
Corrected Plume
HC
(PPMCJ
12771
2220
2739
2400
2520
2709
12600
5709
3960
3330
3960
21300
2370
3435
18540
3534
3000
9900
2790
2775
5100
2340
2580
15600
2400
2490
6000
4074
2154
1404
4050
1695
1440
2520
2190
1752
2142
4200
1980
CO
(%)
9.53
9.50
8.49
7.71
9.02
9.74
9.14
11.64
8.83
11.26
10.32
7.68
8.12
10.91
9.97
9.29
11.00
8.89
8.48
10. 01
10.31
8.63
9.50
9.01
8.59
9.58
10.87
7.06
7.23
7.48
6.57
7.40
7.70
8.18
6.14
8.18
7.26
7.96
8.47
C02
8.58
8.98
8.78
10.43
9.27
10.22
9.62
6.10
9.79
7.10
7.17
9.36
10.76
6.41
9.51
9.91
8.13
9.58
10.41
9.03
6.52
9.68
8.71
9.51
10.18
8.66
6.35
10.42
11.48
11.37
11.38
11.17
10.92
10.77
11.61
11.17
10.29
11.52
11.98
HC
(PPMC).
11309
3505
3354
2477
3569
4270
11610
14314
2769
5407
4133
18319
4102
6404
14658
3200
4777
9977
3072
4177
3344
2876
4532
11522
2578
4234
3629
2995
1611
1619
2527
1571
1604
2035
2445
1858
1755
3580
1642
Dilution
Factor
21.75
60.82
71.92
17.48
65.33
78.16
41.03
48.58
16.32
51.18
58.51
43.41
37.41
73.92
25.23
17.23
54.51
28.11
45.42
68.38
50.94
15.33
56.12
25.05
15.28
60.64
50.66
17.22
17.02
20.32
14 . 37
15.93
17.90
24.93
16.75
15.40
23.52
19.15
17.92
% Change in Cone.
CO
7.36
2.21
-5.51
-8.78
-6.79
9.27
3.24
-6.12
.39
1.58
-.12
-7.46
-8.47
1.97
10.82
4.01
3.93
11.07
1.01
1.99
5.06
1.55
-2.98
10.79
.58
.71
3.74
2.26
-6.99
-2.58
-1.81
-1.93
-.96
-3.96.
6.06
5.91
-1.79
3.32
8.48
CO?
-5.f>]
-3.64
s . ] £
7.48
ft . 30
-8.83
-1.93
-1.77
.82
-5.20
-.13
10.7f,
5.59
-7.36
-5.84
-3.22
-6.87
-8.58
-1.13
-3.62
-4.81
-1.92
1.04
-4.80
-.68
-2.80
-2.45
-.47
3.41
1.51
2.43
1.36
.45
3.65
-3.16
-4.03
1.67
-1.70
-4.y9
HC
-11.44
57.91
22.47
3.21
41.65
57.65
-7.84
150.74
-30.06
62.38
4.37
-13.99
73.09
86.46
-20.93
-9.44
59.25
.78
10.12
50.53
-34.42
22.94
77.59
-26.13
7.42
72.05
-39.50
-26.47
-25.17
15.31
-37.59
-7.25
11.44
-19.20
11.65
6.06
-18.05
-14.75
-17.04
-------
Table A-37 Continued
Aircraft
9
9
^^H
C/i
8
3
30
m
C/J
pi
x
0
a:
03
O
•sa
-i
O
2
P
2
0
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
7
7
7
7
7
7
7
7
7
7
7
7
Flight
4
4
5
5
5
5
6
6
6
7
7
7
8
8
8
8
9
9
9
10
10
1
3
3
3
3
4
4
4
5
6
6
6~
Mode
Cruise
Descent
Taxi
Ascent
Cruise
Descent
Taxi
Ascent
Cruise
Ascent
Cruise
Descent
Taxi
Ascent
Cruise
Descent
Ascent
Cruise
Descent
Cruise
Descent
Cruise
Taxi
Ascent
Cruise
Descent
Taxi
Ascent
Cruise
Ascent
Taxi
Descent
Ascent
CO
(%)
8.07
8.52
7.10
7.80
7.55
7.87
7.08
6.51
7. 04
7.11
7.14
8.37
6.99
6.99
6.70
7.80
7.19
6.02
6.64
7.88
8.70
8.60
6.30
5.90
10.60
5.10
6.20
5.80
7.10
8.50
12.90
8.20
6.80
Stack
CO2
(%)
11.86
10.65
11.44
12.11
11.50
10.25
11.21
13.08
11.74
13.15
12.02
10.33
11.06
12.26
11.57
9.84
13.85
13.00
11.52
13.23
11.28
10.70
10.80
11.60
10.50
11.60
9.90
10.10
10.10
13.50
11.30
12.50
10.70
Corrected Plume
HC
CPPMC1
1428
1920
3660
1833
1404
2079
4110
1686
1251
1545
1260
1692
4260
1710
1284
1806
1695
1206
1866
1500
1971
1140
2370
570
720
570
2580
900
900
1110
2820
990
2160
CO
(%)
8.30
8.53
7.13
7.89
7.37
7.86
7.36
7.84
6.82
7.33
6.94
8.23
7.54
7.36
6.85
7.82
8.19
6.26
6.86
8.04
8.66
8.90
6.86
6.00
8.99
5.17
6.06
5.14
7.04
9.69
10.48
9.41
6.46
CO2
(%}
11.62
10.64
11.47
12.04
11.74
10.27
11.06
11.75
11.94
12.92
12.20
10.46
10.62
11.90
11.41
9.83
12.84
12.75
11.31
13.06
11. 33
10.37
10.27
11.47
12.06
11.50
10.12
10.77
10.15
12.27
13.69
11.29
11.23
HC
(PPMCL
1485
1863
2979
1539
1437
1892
2748
1613
1331
1540
1344
1701
3071
1518
1280
1619
1653
1256
1612
1488
1740
1296
2024
742
1132 .
744
1725
700
930
1314
2957
907
1808
Dilution
Factor
16.56
31.77
18.70
21.19
25.38
23.76
23.30
17.05
16.11
18.86
20.17
24.09
20.61
16.75
17.87
22.60
18.86
24.80
25.33
19.41
29.68
14.96
18.58
12.05
5.84
12.08
17.62
11.17
5.52
14.49
25.95
12.32
26.33
% Change in Cone.
1.
-2,
CO
.87
.16
.52
.20
.32
-.09
3.97
20.45
-3.06
3.14
-2.70
-1.67
7.92
5.42
2.26
.26
14.02
4.04
3.43
2.12
-.34
3.54
8.95
1.84
-15.16
1.53
-2.18
-11.31
-.82
14.11
-18.69
14.80
-4.86
.46
>
-9.68
4.95
-------
Table A-37 Continued
Aircraft
Si
m
•H
o
30
m
>
50
n
X
r-
CD
O
33
d
33
m
J«
P
7
7
7
7
7
/
7
7
7
7
7
7
8
8
8
8
8
8
8
8
8
8
8
8
9
9
9
9
9
9
9
9
9
9
9
9
Flight
7
7
7
8
8
8
9
9
9
10
10
10
1
2
2
2
2
3
3
4
4
4
5
5
3
3
4
4
4
9
9
9
10
10
10
10
Mode
Taxi
Cruise
Descent
Taxi
Cruise
Descent
Taxi
Ascent
Descent
Taxi
Cruise
Descent
Taxi
Taxi
Ascent
Cruise
Descent
Taxi
Ascent
Taxi
Ascent
Cruise
Cruise
Descent
Ascent
Cruise
Taxi
Ascent
Cruise
Taxi
Ascent
Cruise
Taxi
Ascent
Cruise
Descent
CO
7.30
6.50
6.20
9.30
9.40
5.00
8.10
9.50
5.80
8.10
9.80
5.70
8.25
6.60
6.25
6.20
6.60
9.60
6.50
6.65
6.95
8.10
6.30
7.35
10.70
8.95
8.25
9.15
8.00
7.70
10.75
9.60
7.80
9.35
8.10
8.65
Stack
C02
10.50
11.70
10.60
11.20
10.80
13.10
11.30
10.80
12.00
11.40
13.60
14.00
7.10
9.35
13.80
12.30
10.80
7.35
13.40
9.90
14.40
12.80
11.60
9.05
10.50
10.00
9.22
11.20
9.70
10.10
11.00
9.80
8.65
11.10
10.30
8.20
Corrected Plume
HC
(PPMC1
3000
780
840
6600
1320
720
4500
1350
900
3180
1320
1020
3900
3330
2460
1785
1710
3825
1545
3270
2160
2280
2025
2205
1680
900
16800
2790
2235
14100
2160
2580
16350
3240
2295
3930
CO
(%)
7.52
6.63
6.17
10.41
9.38
5.45
9.15
7.43
4.86
8.64
11.16
6.10
6.91
6.59
6.79
4.69
5.72
7.76
5.54
7.55
5.42
5.97
5.40
7.07
10.64
8.19
8.98
8.37
7.65
8.10
11.29
9.44
7.60
9.43
7.91
7.95
CO2
(%)
10.37
11.41
10.56
10.43
10.83
12.54
10.40
12.73
12.95
10.88
12.21
13.63
8.56
9.46
13.37
13.87
11.60
9.23
14.36
9.03
15.84
15.00
12.57
9.34
10.47
10.67
9.51
12.04
10.08
9.44
10.38
9.98
8.88
11.08
10.50
8.89
HC
(PPMCI
1982
2243
1473
3062
1112
1692
2878
2701
697
2865
1543
688
2594
2190
1265
1010
2334
3316
1380
2854
3002
1496
1180
1972
2435
1621
6434
2088
1864
16636
2863
2239
15976
2543
2054
3983
Dilution
Factor
18.37
10.07
13.82
26.41
5.71
13.91
24.83
15.46
15.97
18.49
7.77
19.88
20.76
21.70
18.70
18.49
19.03
19.28
18.74
17.00
15.42
13.05
11.97
11.76
4.38
16.77
14.33
4.67
15.98
61.40
4.09
16.51
25.12
3.95
13.91
72.91
% Change in Cone .
CO
3. '?
2.10
-.40
11.99
-.17
9.07
13.03
-21.74
-16.11
6.71
13.89
7.05
-16.17
-.04
8.65
-24.22
-13.19
-19.13
-14.64
13.65
-21.96
-26.27
-14.21
-3.67
-.53
-8.40
8.96
-8.42
-4.34
5.26
5.07
-1.61
-2.50
.90
-2.25
-8.03
CO?
-:.^3
-2.47
-.37
-6.87
.34
-4.27
-7.96
17.87
7.91
-4.56
-10.22
-2.64
20.56
1.17
-3.11
12.76
7.40
25.57
7.16
-8.7K
10.06
17.18
8.36
3.20
-.22
6.79
3.22
7.51
3.96
-6.52
-5.59
1.92
2.68
-.13
2.00
8.41
HC
-33.90
187.64
75.45
-53.60
-15.74
135.11
-36.02
100.11
-22.52
-9.89
16.93
-32.45
-33.47
-34.22
-48.56
-43.38
36.50
-13.30
-10.66
-12.69
38.98
-34.35
-41.69
-10.52
47.94
80.16
-61.70
-25.14
-16.59
17.98
32.55
-13.18
-2.28
-21.50
-10.48
1.37
------- |