Airplane Greenhouse Gas Standards
Technical Support Document (TSD)
United States
Environmental Protection
^1	Agency

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Airplane Greenhouse Gas Standards
Technical Support Document (TSD)
Assessment and Standards Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
£%	United States
Environmental Protection
^1	Agency
EPA-420-R-20-028
December 2020

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TABLE OF CONTENTS
Chapter 1: Industry Characterization	2
1.1	Introduction	2
1.2	Market Basics	5
1.3	Product Categories	6
1.4	Product Manufacturers	9
Chapter 2: Technology and Cost	14
2.1	Overview	15
2.2	Technology Principles	17
2.3	Technologies	33
2.4	Technology Application	39
2.5	Estimated Costs	42
2.6	Airplane Fuel Savings	53
2.7	Fuel Prices	56
2.8	Summary of Benefits and Costs	56
Chapter 3: Test Procedures	72
3.1	CAEP Test Procedure Requirements-Overview	72
3.2	Test Procedures for Airplane GHG Emissions Based on the Consumption of Fuel.... 72
3.3	Determination of the Fuel Efficiency Metric Value	73
3.4	Application of Rules for New Version of an Existing GHG-Certificated Airplane	75
3.5	Changes for non-GHG Certificated Airplane Types	78
Chapter 4: Airplane Performance Model and Analysis	82
4.1	Purpose and Scope	82
4.2	Methodology of the EPA Emissions Inventory and Stringency Analysis	82
4.3	Fleet Evolution Model and Data Sources	84
4.4	Full Flight Simulation with PIANO and Unit Flight Matrix	90
4.5	Inventory Modeling and Stringency Analysis	91
Chapter 5: Impacts on Emissions and Fuel Burn	96
5.1	Executive Summary	96
5.2	Introduction	96
5.3	Fleet Evolution Results and Baseline Emissions	97
5.4	Stringency Analysis of U.S. and Global CO2 Emission Impacts	107
5.5	Sensitivity Case Studies	109
Chapter 6: Analysis of Alternatives	122
6.1	Overview	122
6.2	GHG Emission Reductions and Costs of Two Alternative Scenarios	133
6.3	Sensitivity Case Studies	146
6.4	Summary	148
Chapter 7: Regulatory Flexibility Analysis	160
7.1	Requirements of the Regulatory Flexibility Act	160
7.2	Need for the Rulemaking and Rulemaking Objectives	160
7.3	Definition and Description of Small Entities	161
7.4	Summary of Small Entities to Which the Rulemaking Will Apply	161
7.5	Related Federal Rules	161
7.6	Projected Effects of the Rulemaking on Small Entities	161

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List of Acronyms
AC
Aircraft
AIR
Aerospace Information Report
ANPR
Advanced Notice of Proposed Rulemaking
APU
Auxiliary Power Unit
ASK
Available Seat Kilometers
ASTM
American Society for Testing and Materials
ATK
Available Ton Kilometers
AVL
Asset Value Loss
BAU
Business As Usual
BGA
Business and General Aviation Airplane
BPR
Bypass Ratio
CAA
Clean Air Act
CAEP
Committee on Aviation Environmental Protection
CAT
Airplane Category
CBI
Confidential Business Information
CFR
Code of Federal Regulations
CI
Continuous Improvement
CMS
Continuous Modification Status
ch4
Methane
C02
Carbon Dioxide
co2db
C02 Certification Database
COD
Common Operations Database
DICE
Dynamic Integrated Climate and Economy model
DOC
Direct Operating Cost
DOT
Department of Transportation
ECS
Environmental Control System
EIA
Energy Information Administration
EIS
Entry Into Service
EP
Extended Production
EPA
Environmental Protection Agency
FAA
Federal Aviation Administration
FUND
Climate Framework for Uncertainty, Negotiation, and Distribution model
G&R
Growth and Replacement
GDP
Gross Domestic Product
GHG
Greenhouse Gas
HLFC
Hybrid Laminar Flow Control
1AM
Integrated Assessment Model
ICAO
International Civil Aviation Organization
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ICF
ICF International, Inc.
InP
In-production
IWG
Interagency Working Group
M
Millions
MTOM
Maximum Takeoff Mass
MTOW
Maximum Takeoff Weight
NG
Next Generation
NHTSA
National Highway Traffic Safety Administration
NLF
Natural Laminar Flow
NRC
Non-recurring Cost
NT
New Type Designs
n2o
Nitrous Oxide
OD
Origin-Destination
OMB
Office of Management and Budget
PAGE
Policy Analysis of the Greenhouse Gas Effect model
PIANO
Project Interactive Analysis and Optimization
PIP
Performance Improvement Package
R&D
Research and Development
RC
Retirement Curve
RFA
Regulatory Flexibility Act
RGF
Reference Geometric Factor
RIA
Regulatory Impact Analysis
RPM
Revenue Passenger Miles
RTM
Revenue Ton Miles
SAE
Society of Automotive Engineers
SAR
Specific Air Range
SBA
Small Business Administration
SBFA
Small Business Flexibility Analysis
SBREFA
Small Business Regulatory Enforcement Fairness Act
SC
Survival Curve
SOs
Stringency Options
TAF
Terminal Area Forecast
TC
Type Certificate
TRL
Technology Readiness Level
TSD
Technical Support Document
TSFC
Thrust Specific Fuel Consumption
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Executive Summary
The Environmental Protection Agency (EPA) is adopting greenhouse gas (GHG) emission
standards and other requirements applicable to greenhouse gas emissions from certain classes of
engines used by certain civil subsonic jet airplanes (those with a maximum takeoff mass greater
than 5,700 kilograms), as well as larger subsonic propeller-driven airplanes (those powered by
turboprop engines with a maximum takeoff mass greater than 8,618 kilograms). These standards
are equivalent to the Airplane CO2 Emission Standards adopted by the International Civil
Aviation Organization (ICAO) in 2017 and will apply to both new type designs (new type design
airplanes) and in-production airplanes, consistent with U.S. efforts to secure the highest
practicable degree of uniformity in aviation regulations and standards. The standards will also
meet the EPA's obligation under section 231 of the Clean Air Act (CAA) to adopt GHG
standards as a result of the 2016 positive endangerment and contribution findings for six well-
mixed GHGs emitted by certain classes of airplane engines.
We project no reductions in fuel consumption and GHG emissions associated with the
standards. This is because all the potentially affected airplanes currently in production either
meet the stringency levels of the standards or will be out of production when the standards will
take effect, according to our projected technology responses.
This Technical Support Document (TSD) is generally organized to provide overall
background information, methodologies, and data inputs, followed by results of the various
technical and economic analyses. A summary of each chapter of the TSD follows.
Chapter 1: Industry Characterization. In order to assess the impacts of the GHG standards
upon the affected industries, and especially on any small entities, it is important to understand
the nature of the industries potentially impacted by the regulations. Further, it is helpful to put
the contribution of the potentially impacted industry in context regarding its contribution to the
overall mobile source GHG inventories. This chapter provides a general overview of the
airplane and airplane engine industries, including some basic information on the companies
involved in them. It also provides brief overviews of current and projected future air traffic, as
well as the relative contribution of this market to overall mobile source GHG emissions.
Chapter 2: Technology and Cost. This chapter presents details of the airplane and airplane
engine technologies and technology packages for reducing airplane GHG emissions and fuel
burn. The methodologies used for projecting technology usage and resultant improvements in
GHG/fuel burn are presented for both the near/mid-term and the long term. Specific airplane and
engine technologies and their associated fuel burn improvements are then discussed, followed by
the projected costs of these technologies. This information provides the basis for the emissions
and cost projections.
Chapter 3: Test Procedures. This chapter describes the relevant test procedures, including
methodologies for determining GHG emissions based on fuel consumption and the determination
of the fuel efficiency metric value, which are used to determine compliance with the regulations.
Finally, a description of when changes to an existing airplane design will trigger the need for a
new certification is presented.
Chapter 4: Airplane Performance Model and Analysis. This chapter describes
methodologies, assumptions and data sources used to develop the airplane GHG emissions and
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fuel burn inventories for the standards and two alternative stringency scenarios that were
evaluated. A description of the airplane fleet and how we project it to evolve is first presented,
followed by a description of how this fleet evolution is projected to translate into airplane
activity. Finally, the methodology is presented for determining individual airplane flight GHG
emissions, fuel consumption, and how that data is used in conjunction with airplane activity
projections to develop overall emissions inventory projections.
Chapter 5: Results of Performance Model Analysis. This chapter describes the results of the
analysis using the methodology described in Chapter 4 to determine the impacts of the standards.
Included are analyses of the baseline emissions, the impact of the standards, and some sensitivity
studies looking specifically at the impacts of some key assumptions.
Chapter 6: Analysis of Alternatives. This chapter provides EPA's analysis of two
alternatives to the standards. The emissions reductions and costs associated with scenarios of
accelerated timing and accelerated timing in conjunction with more stringent regulatory levels
are presented.
Chapter 7: Regulatory Flexibility Analysis. This chapter describes the EPA's analysis of the
small business impacts of the regulations.
For reasons discussed throughout this TSD, the EPA does not project any emissions
reductions associated with the GHG regulations.
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Industry Characterization
Table of Contents
Chapter 1: Industry Characterization	2
1.1	Introduction	2
1.1.1	Overview	2
1.1.2	Air Traffic	2
1.1.3	Greenhouse Gas Emissions from Aircraft	4
1.2	Market Basics	5
1.3	Product Categories	6
1.3.1	Airplanes	6
1.3.1.1	Commercial - Large Jet	7
1.3.1.2	Commercial - Regional Airplane	8
1.3.1.3	Business and General Aviation	8
1.3.2	Airplane Engines	8
1.4	Product Manufacturers	9
Table of Figures
Figure 1-1 Projection of Domestic Passenger Traffic	3
Figure 1-2 Projections of International Passenger Traffic	4
Figure 1-3 Contribution to GHG Emissions from U.S. Transportation in 2017	5
Table of Tables
Table 1-1 - Airplane Manufacturers	9
Table 1-2 - Airplane Engine Manufacturers	10
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Industry Characterization
Chapter 1: Industry Characterization
1.1 Introduction
1.1.1	Overview
In order to assess the impacts of the regulations upon the affected industries, it is important to
understand the nature of the industries potentially affected by the regulations. In general, this
includes the manufacturers of subsonic civil jet airplanes with a maximum takeoff mass
(MTOM) greater than 5,700 kilograms (kg), the manufacturers of subsonic propeller-driven
airplanes (those powered by turboprop engines) with MTOM greater than 8,618 kg, and the
manufacturers of engines for these categories of airplanes. A brief description of the airplane
and engine development process is presented in section 1.2. A general description of these
product categories is contained in section 1.3. An overview of the potentially affected airplane
and engine manufacturers is contained in section 1.4.
1.1.2	Air Traffic
General information on air traffic in the U.S. was obtained via the Federal Aviation
Administration's (FAA) Aerospace Forecast; Fiscal years 2019-2039.1 This quick overview
looks at U.S. air traffic in four general categories - domestic commercial passenger
enplanements, international commercial passenger enplanements, cargo traffic (in revenue ton
miles) and operation hours for business/general aviation.
Figure 1-1 shows that domestic enplanements totaled over 780 million in 2018. The FAA
projects that domestic revenue passenger miles (RPM) will increase between 2019 and 2039 at
an average annual rate of 1.9 percent.1 In contrast, RPMs for international flights are projected to
grow at an annual rate of 3.0 percent during this same period, as illustrated in Figure 1-2.
1 This projection was developed before the COVID-19 pandemic. While the projected level of aircraft operations is
affected by the COVID-19 pandemic, aviation is a growth industry that is expected to recuperate over time.
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Industry Characterization

1,200

1,000
(/)

c

o

—
800


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Industry Characterization
Total Passengers To/From the U.S.
American and Foreign Flag Carriers
600
500
0
| 400
L
0
c
1	200
s
100
0
2018 2019 2023 2027 2031 2035 2039
Calendar Year
¦ Atlantic* ¦L.America ¦ Pacific ¦ Canada Transborder
Source: US Customs & Border Protection data processed and released by Department of Commerce; data also
received from Transport Canada
* Per past practice, the Mid-East region and Africa are included in the Atlantic category.
Figure 1-2 Projections of International Passenger Traffic3
In the business/general aviation sector, fixed wing turbine powered airplanes were projected
to operate approximately 8 million hours in 2019. Operating hours in this sector are projected to
grow at an annual rate of 2.4 percent through 2039.
U.S. carriers flew 42.8 billion revenue ton miles (RTM) in 2018. Of this, 15.8 billion RTMs
were domestic cargo, while 27.0 billion RTMs were international cargo. Of this, approximately
80 percent of cargo is carried by all-cargo carriers, with the remainder carried by passenger
carriers. Through 2039, domestic RTM growth is projected at a rate of 1.6 percent annually,
with international RTM growth projected at 4.0 percent annually. Overall RTM growth
(domestic and international combined) is projected at a rate of 3.3 percent annually.
1.1.3 Greenhouse Gas Emissions from Aircraft
The importance of this rulemaking is highlighted by the fact that GHGs from aviation made
up over 12 percent of total transportation-related GHG emissions in 2017, as shown in Figure
1-3. Although the aircraft portion of this chart contains three aviation sectors that are not
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Industry Characterization
covered by this rule (e.g., military, helicopters, and airplanes operating on aviation gasoline),
these three sectors comprised well under one percent of total transportation related GHG
emissions in 2017.
Source: U.S. EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2017, Tables 3-
104 and A-121, published 2019
54.0%
1 Cars, Light-Duty Trucks and
Motorcycles
¦ Medium- and Heavy-Duty
Trucks and Buses
Aircraft
Ships and Boats
i Rail
1 Pipeline
Figure 1-3 Contribution to GHG Emissions from U.S. Transportation in 2017
1.2 Market Basics
The development of a new airplane from the ground up (i.e., a "clean sheet" design) is a very
lengthy and expensive project. As such, completely new airplane designs (known as new type
designs) are not introduced very often. The introduction of the Boeing 787, and Airbus A3 50
and A220 (formerly the Bombardier CSeries) in the last 10 years has marked a relatively active
period in the introduction of new type designs in the commercial airplane market.
In contrast to the development of new type designs discussed above, a more common practice
is to develop generational updates to existing airplane designs (or redesigns of the airplane). For
example, the Boeing 737 was first introduced into commercial operation in 1968. Since that
time, it has seen three redesigns - the Classic series in the 1980s, the Next Generation (NG) in
the 1990s, and the recent MAX series, introduced in 2017. These generational updates can
include any number of improvements/modifications to the previous design, but frequently
include new engines, new or redesigned wings, and updated operating systems (or some
combination of these modifications). Such updates are not considered new type designs for
purposes of certification. Rather, they are considered to be redesigns of an existing design. As
such, they are not required to undergo a completely new certification process, but instead go
through an amendment certification process of the existing type certificate. Thus, the 737 MAX
is covered under an amended version of its original 50 year-old type certificate.
This distinction between new type designs and redesigned versions of existing in-production
types is an important one for the purposes of the regulations, which contain different
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Industry Characterization
applicability dates and regulatory limits for new type design and in-production airplanes. An in-
production airplane is one which received it initial type certificate (TC) prior to the applicability
date of the standards for new type designs. Even if an in-production airplane receives a major
redesign as described above, it would likely still be considered an in-production airplane for the
purposes of the standards applicability.
Engines used on airplanes subject to the standards are generally designed specifically for the
airplane type on which they will be used, with precise thrust ratings tailored specifically to an
airplane's requirements. The range and payload capacity (as indicated by MTOM) are primary
drivers of the engine specifications. Also, it is common for there to be multiple variants of a
given airplane type, with different ranges and/or stretched or shortened fuselages. Each of these
variants similarly require a variant of the original engine type, with a slightly different required
thrust rating. It is common for an airplane manufacturer to offer engines from two (or in some
cases, three) different manufacturers on a given airplane type. However, it is also common in the
case of some smaller commercial airplanes and especially business jets for a manufacturer to
only offer a single engine option.
1.3 Product Categories
This section contains a high-level overview of the types of airplanes and engines that are
potentially affected by the regulations. ICF performed a detailed industry characterization of
these industries for the EPA.4 This section, and the following section 1.4, contain a brief
summary of that report. As described in Section II of that report, ICF draws on a number of
sources to develop their industry forecasts, including working directly with the airplane and
equipment production industries, attending industry conferences and keeping up with the latest
industry news, published articles and papers. ICF synthesizes all of these sources into their own
market forecasts, which they then benchmark against global market forecasts done by Boeing
and Airbus to assure that their forecasts fall within a reasonable range.
1.3.1 Airplanes
Airplanes potentially affected by the regulations can be broadly divided into three main
groups - large commercial jets, regional commercial jets, and business and general aviation
airplanes. Although there is some overlap among these categories, notably the blurring of the
line between the small end of the large commercial jet range and regional commercial jets, these
categories serve as a useful way to subdivide the world of potentially affected airplanes for
purposes of the cost and emissions analyses contained in later chapters of this document.
In general, the aviation marketplace is an international one. Manufacturers produce and sell
their airplanes for use around the world. The global prevalence of international flights (i.e.,
those that originate in one country and terminate in another) means that airplanes (especially
those in the large commercial jet category) are generally designed to operate in the international
air transport market. For example, the U.S. flight data which served as the basis for the analyses
presented later in this document show that in 2015 almost nine percent of commercial flights
originating in the U.S. were to destinations outside of the U.S. Even smaller airplanes with
ranges not suitable for international flights are often sold to countries other than a manufacturer's
home country.
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Industry Characterization
Finally, while this summary focuses on passenger-carrying airplanes, it is noted that a small
number of dedicated freight airplanes are also produced which are subject to the regulations.
These tend to be modifications of existing passenger airplane designs rather than airplanes
designed exclusively for freight applications.
1.3.1.1 Commercial - Large Jet
The large commercial jet category consists of a broad range of turbofan-powered airplane
types, from single-aisle airplanes seating over 100 people to very large twin-aisle airplanes that
can seat well over 500 passengers. The smallest of these are not generally used for transoceanic
international flights. Collectively, there were 1,443 large commercial jets manufactured world-
wide in 2016, with a total value of $102B. The large commercial jet category can be further
divided into four subcategories: small single aisle, small twin aisle, large twin-aisle and large
quads.
The small single aisle category consists of airplanes with a single passenger aisle and
designed to carry roughly 100-200 passengers at up to six abreast. These airplanes tend to have a
range of 60,000 kg to 97,000 kg in MTOM. Examples include the Boeing 737 series and the
Airbus A320. As previously mentioned, the line between large commercial jets and regional jets
is becoming less clear with the coming introduction of the Airbus A220 (formerly Bombardier
CSeries) and the Embraer E2 series. In terms of 2016 production, 72 percent of large
commercial jets were small single aisle. However, they only accounted for 45 percent of the
total production value.
Small twin-aisle airplanes are wide enough to feature two passenger aisles and can typically
carry 230-300 passengers at up to eight abreast. They tend to range from 186,000 kg to 308,000
kg in MTOM. Main examples of small twin-aisle airplanes are the Boeing 787 and the Airbus
A330. This subcategory accounted for 10 percent of the 2016 production and 17 percent of the
production value.
Large twin-aisle airplanes also feature two passenger aisles but with wider fuselages that can
accommodate up to 400 passengers at up to eight abreast and with MTOM from 233,000 kg to
around 350,000 kg. An example of a large twin-aisle is the Boeing 777, although the large
variants of the Airbus A330 and A350 (small twin-aisles) blur the distinction between small and
large twin-aisles. This subcategory accounted for 15 percent of the 2016 production and 30
percent of the production value.
The last subcategory of large commercial jets is the large quad. These airplanes are also twin-
aisle, but they are large enough to require four engines (as opposed to the three previously
discussed subcategories which are typically powered by two engines). These airplanes can carry
as many as 575 passengers in ten-abreast configuration. Examples include the Boeing 747 and
the Airbus A3 80. This subcategory accounted for 3 percent of the 2016 production and
accounted for 8 percent of the production value. However, demand for large quad airplanes is
declining dramatically for multiple reasons. First, the increasing efficiencies, range and
passenger (and payload) capacity of the large twin-aisle airplanes has made them attractive as
replacements for large quads. Second, the development of Extended-range Twin-engine
Operational Performance Standards (ETOPS) has allowed twin-engine airplanes to safely service
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Industry Characterization
routes previously only serviced by airplanes with more than two engines. Finally, the overall
growth in the commercial passenger aviation market has resulted in making more city pairs
profitable using direct flights with smaller airplanes, thus reducing the demand for large quads to
service the "hub and spoke" model of passenger air traffic. Although the future of the large quad
market has been the subject of much debate in the aviation world, ICF's 2018 analysis projected
that production of large quad airplanes is likely to end altogether by the mid-2020s. As
discussed further in Chapter 5 and Chapter 6, since the ICF analysis was completed, Airbus has
announced plans to end production of the A3 80 in 2021.
Total sales of large commercial jets are projected to climb to almost 1,800 units in 2021 but
drop back to around 1,600 units in 2026. More significantly, it is expected that the large quad
subcategory will shrink dramatically in this time frame.
1.3.1.2	Commercial - Regional Airplane
The regional commercial airplane category can be divided into two subcategories: the
regional jet and the regional turboprop. Regional jets are turbofan-powered jets which typically
carry 50-100 passengers with an MTOM in the range of 19,000 kg to 60,700 kg. Examples
include the Embraer EJet and the Bombardier CRJ. Regional turboprops are also powered by
turbine engines, but the engines' power is instead used to drive a propeller. Regional turboprops
tend to be smaller than their jet counterparts, with an MTOM range of 18,600 kg to 30,000 kg
and a capacity of around 40 to 80 passengers. Examples include the ATR 42/72 and the
Bombardier Q400. While turboprops tend to be more fuel-efficient than their turbofan
counterparts, they are also slower and have higher levels of cabin noise which somewhat serves
to offset the appeal of that better fuel efficiency.
There were 267 regional commercial airplanes produced in 2016, with a total value of $6.3B.
Regional jets accounted for 57 percent of the production volume and 69 percent of the
production value. Production of regional airplanes is projected to remain relatively steady
through 2026.
1.3.1.3	Business and General Aviation
The business jet and general aviation market includes a wide range of small, turbofan-
powered airplanes designed for business and personal use. These airplanes range from 6,200 kg
to 48,000 kg MTOM, with capacities of 6 to 19 passengers. There were 567 business and
general aviation airplanes produced in 2016, with a market value of $16.8B. Production of this
category of airplanes is expected to steadily grow to well over 800 units in 2026. The main
manufacturers in this market include Embraer, Dassault, Gulfstream, Cessna and Bombardier.
1.3.2 Airplane Engines
There are two main types of engines potentially affected by the regulations - turbofans and
turboprops. While both are turbine engines, they differ in their mode of propulsion. A turbofan
engine utilizes the mechanical energy of the turbine to power a ducted fan which provides the
majority of the propulsion. However, the air that flows through the turbine itself and exits as
combustion exhaust also provides a portion of a turbofan's propulsion. In contrast, a turboprop
utilizes the turbines mechanical energy to power an open propeller, which provides the entirety
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Industry Characterization
of turboprop's propulsion. In terms of utilization on airplanes covered by the regulations,
turbofans are used across the entire spectrum of airplanes, from the smallest business jets to the
largest commercial airplanes. In contrast, turboprops tend to be limited in use to commercial
regional airplanes.
There were 5,069 commercial engines produced in 2016 for airplane classes subject to the
regulations. Large commercial jet engines accounted for 64 percent, while regional jet engines
accounted for 12 percent and business/general aviation engines accounted for the remaining 24
percent. In terms of production value, large commercial airplane engines accounted for 89
percent of the $38B total, with regional airplane at four percent and business/general aviation
accounting for the remaining seven percent.
Commercial engine production is driven by airplane production and is expected to grow to
5,817 units in 2026. Most of this growth is expected to be in the business/general aviation
sector.
1.4 Product Manufacturers
This section contains a brief overview of the manufacturers of products that covered by this
rule. Some of this information (i.e., each manufacturer's number of employees) was used in the
screening analysis for the Small Business Flexibility Analysis (SBFA) which evaluates the
potential impacts of the rule on small entities. That analysis is discussed in Chapter 7.
Table 1-1 - Airplane Manufacturers
Manufacturer
Categories3
Main Products
Employee Countb
Airbus
Comm
A220, A320, A330, A350, A380
136,574
ATR
B/GA
ATR 42, ATR72
1,300°
Boeing
Comm
737, 747, 767, 777, 787
147,683
Bombardier
Comm, B/GA
CRJ, Q400
61,900
Cessna
B/GA
Citation
36,000
CO MAC
Comm
ARJ
Unavailable
Dassault
B/GA
Falcon
11,942
Embraer
Comm, B/GA
Legacy, Phenom, ERJ, E2
19,357
Gulfstream
B/GA
G150, G280, G450, G550, G650
13,313




Irkut
Comm
MS-21
10,000
Mitsubishi
Comm
MRJ
68,247
Pilatus
B/GA
PC-24
1,905
Sukhoi
Comm
Superjet
10,000
Comm = commercial, B/GA = business and general aviation
In some cases, the employee count is that of the parent company
ATR is jointly owned by Airbus and Leonardo. Thus, the parent companies have significantly more than the
1,500 employee cutoff used to determine whether a company is a small entity. See Chapter 7.
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Industry Characterization
Table 1-2 - Airplane Engine Manufacturers
Manufacturer
Categories3
Main Products'5
Employee Count
CFM International
Comm
CFM56, LEAP
NAC
Engine Alliance
Comm
GP7200
NAd
GE
Comm, B/GA
GEnx, GE9x, CF6, CF34, Passport

Honeywell
B/GA
HTF7000, TFE731
40,000
International Aero
Comm
V2500
NAe
Pratt & Whitney
Comm
PW4000, GTF
35, 104
Pratt & Whitney Canada
B/GA
PW100, PW500, PW800
9,200
PowerJet
Comm
SAM 146
NAf
Rolls-Royce
Comm, B/GA
Trent series, BR700, AE3007
49,900
Safran
B/GA
Silvercrest
15,700
Williams International
B/GA
FJ44
<1,000
a. Comm = commercial, B/GA = business and general aviation
This is not an exhaustive list, and only includes products that are potentially affected by the regulations. It
also includes some products which are still under development but nearing commercial introduction.
CFM International is a joint venture between GE and Safran.
Engine Alliance is a joint venture between GE and Pratt & Whitney.
International Aero is a joint venture between Pratt & Whitney, Japanese Aero Engine Corporation and MTU
Aero Engines.
PowerJet is a joint venture between Safran and NPO Saturn.
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REFERENCES
Industry Characterization
1	FAA, 2020: FAA Aerospace Forecast; Fiscal Years 2019-2039, U.S. Federal Aviation Administration, TC18-
0004. Accessed March 18, 2020 at https://www.faa.gov/data researcli/aviation/aerospace :forecasts/media/FY20.1.9~
39 FAA Aerospace Forecast.pdf (last accessed March 20. 2020).
2	See Reference #1
3	See Reference #1
4	ICF, 2018: Aircraft CO2 Cost and Technology Refresh and Industry Characterization, Final Report, EPA Contract
Number EP-C-16-020, September 30, 2018.
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Technology and Cost
Table of Contents
Chapter 2: Technology and Cost	14
2.1	Overview	15
2.2	Technology Principles	17
2.2.1	Short- and Mid-Term Methodology	17
2.2.2	Long-Term Methodology	26
2.2.2.1	Fuel Burn Reduction Prospect Index	26
2.2.2.2	Market Driver Index	27
2.2.2.3	Metric Value Improvement Acceleration Index	28
2.2.2.4	Example for Long-Term Metric Value Forecast	29
2.2.2.5	Long-Term Replacement Airplane Analysis (2030-2040)	 31
2.3	Technologies	33
2.3.1	Airframe Technologies	35
2.3.1.1	Advanced Wingtip Devices	35
2.3.1.2	Adaptive Trailing Edge	35
2.3.1.3	Aft Body Redesign	36
2.3.1.4	Hybrid Laminar Flow Control - Empennage	36
2.3.1.5	Riblet Coatings	37
2.3.1.6	ECS Aerodynamics and On-Demand ECS Scheduling	38
2.3.2	Engine Technologies	38
2.4	Technology Application	39
2.4.1	Technology Responses	40
2.4.2	One Percent Additional Design Margin for Technology Response	42
2.5	Estimated Costs	42
2.5.1	Non-Recurring Costs	42
2.5.1.1	Non-Recurring Costs Component Proportions	43
2.5.1.2	Non-Recurring Cost Scaling Factors	44
2.5.2	Comparing the EPA NRC to ICAO/CAEP NRC for International Airplane CO2
Emission Standards	47
2.5.3	Certification Costs	51
2.5.4	Recurring Costs	52
2.5.5	Reporting Costs	53
2.6	Airplane Fuel Savings	53
2.7	Fuel Prices	56
2.8	Summary of Benefits and Costs	56
Appendix A. - Airframe Technologies	57
Appendix B. - Engine Technologies	63
Appendix C. - Example Supply Curves by Airplane Category	64
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Table of Figures
Figure 2-1.- Expected Value Technology Impact	18
Figure 2-2 Graphical Form of Metric Value Index Scoring	29
Figure 2-3. Example Supply Curve	41
Figure 2-4. Single Aisle Category Non-Recurring Cost Component Proportions	44
Figure 2-5. Example Non-Recurring Cost Scaling by Airplane Category - Large Incremental Update	46
Figure 2-6. CAEP NRC Surface's Coefficient D (left) and f (AMV) (right) Formulation	49
Figure 2-7. CAEP Cumulative CO2 (Megatonnes) Reductions from the Effective Date to 2040 	54
Figure 2-8. CAEP Change in Cumulative Costs for 2028 Effective Date-	55
Figure 2-9 Example Supply Curve for Small BGA	64
Figure 2-10 Example Supply Curve for Large BGA	65
Figure 2-11 Example Supply Curve for Turboprop	65
Figure 2-12 Example Supply Curve for Regional Jet	66
Figure 2-13 Example Supply Curve for Single Aisle	66
Figure 2-14 Example Supply Curve for Small Twin Aisle	67
Figure 2-15 Example Supply Curve for Large Twin Aisle	67
Figure 2-16 Example Supply Curve for Large Quad	68
Table of Tables
Table 2-1 - Airplane Metric Value (MV) Forecast/Reduction (PIANO Data)	22
Table 2-2 Metric Value Index Scoring	28
Table 2-3 Single Aisle Example for Fuel Burn Reduction Prospect Index	30
Table 2-4 Other Airplane Category Examples of Fuel Burn Reduction Prospect Index	31
Table 2-5 Single Aisle Example for Metric Value Improvement Acceleration Index	31
Table 2-6 Long-Term Potential Replacement Airplanes	32
Table 2-7 Airframe and Systems Technologies	34
Table 2-8 Engine Technologies	34
Table 2-9. Representative Engine Performance Improvement Packages	39
Table 2-10 - Non-Recurring Cost Component Scaling Factor Sources	45
Table 2-11 - Non-Recurring Cost Component Scaling Factors	45
Table 2-12 Comparison Results of EPA NRC to CAEP NRC Surface ($ Billions) - Part 1	50
Table 2-13 Comparison Results of EPA NRC to CAEP NRC Surface ($ Billions) - Part 2	51
Table 2-14 Fuel Burn and Costs Impacts for Advanced Wingtip Devices	58
Table 2-15 Fuel Burn and Costs Impacts for Adaptive Trailing Edge	59
Table 2-16 Fuel Burn and Costs Impacts for Aft Body Redesign	60
Table 2-17 Fuel Burn and Costs Impacts for Hybrid Laminar Flow Control - Empennage	60
Table 2-18 Fuel Burn and Costs Impacts for Riblet Coatings	61
Table 2-19 Fuel Burn and Costs Impacts for ECS Aerodynamics and On-Demand ECS Scheduling	62
Table 2-20 Fuel Burn and Costs Impacts for Engine Technologies	63
Table of Equations
Equation 2-1 Metric Value Reduction	19
Equation 2-2: Calculation of Metric Value Reduction - Advanced Wingtip Devices for A330 in 2018	20
Equation 2-3: Calculation of Metric Value Reduction - Adaptive Trailing Edge for A330 in 2018	20
Equation 2-4 Function of CAEP's NRC Surface	48
Equation 2-5 Equation to Calculate AMV	49
Equation 2-6 Equation to Calculate Normalized MV Improvement	49
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Chapter 2: Technology and Cost
As described in section VII of the preamble, the EPA and FAA participated in ICAO/CAEP's
analysis that informed the adoption of the international airplane CO2 standards (ICAO Airplane
CO2 Emission Standards). A summary of that analysis was published in the report of
ICAO/CAEP's tenth meeting,5 which occurred in February 2016. This summary is useful in
giving an overview of the analytical results used by CAEP in deciding on the final standards.
However, due to the commercial sensitivity of much of the underlying data used in this ICAO
analysis, the ICAO-published report (which is publicly available) provides only limited
supporting data for the ICAO analysis. This EPA TSD compares the ICAO analysis to the EPA
analysis.
For the purposes of the final GHG standards, the EPA presents an evaluation based on
publicly available and independent data. In support of this work, the EPA had an analysis
conducted of the technological feasibility and costs of the international Airplane CO2 Emission
Standards through a contractor (ICF) study.6'7 The results developed by the contractor include
estimates of technology responses and non-recurring costs for the domestic GHG standards,
which are equivalent to the international Airplane CO2 Emission Standards. Technologies and
costs needed for airplane types to meet the final GHG standards were analyzed and compared to
the improvements that are anticipated to occur in the absence of standards (business as usual
improvements).
The ICF study is an update to work performed in support of the 2015 U.S. EPA Aircraft
Greenhouse Gas Emissions Advance Notice of Proposed Rulemaking (henceforth the "2015
ANPR").8 At that time, the EPA contracted with ICF to develop estimates of technology
improvements and responses needed to modify in-production airplanes to comply with the
international Airplane CO2 Emission Standards. ICF conducted a detailed literature search,
performed a number of interviews with industry leaders, and did its own modeling to estimate
the cost of making modifications to in-production airplanes.9 Subsequently, for this rulemaking,
the EPA contracted with ICF to update its analysis (herein referred to as the "2018 ICF updated
analysis"), which is located in the docket for this rulemaking. 10'u It had been three years since
the initial 2015 ICF analysis was completed, and with the fast pace of advancing aviation
technology the status of CO2 technology improvements has changed in this short time frame.111
The 2018 ICF updated analysis was peer-reviewed by multiple independent subject matter
II	The data sources for the 2018 ICF updated analysis are detailed in section II. 1.2 of this ICF analysis (or this ICF
report), including a description of ICF's broad and thorough aviation market interview program on technology
performance, modeling approach and methodology, commercial feasibility, and costs. ICF conducted over 40
interviews with an expansive cross-section of key aviation individuals in the industry - airframe, engine, and
systems manufacturers, and airlines ~ and in university/research organizations. In addition, ICF leveraged
knowledge they had gained through past and ongoing project work on in-depth cost and performance models for
aviation.
III	The ICAO test procedures for the international airplane C02 standards measure fuel efficiency (or fuel burn).
Only two of the six well-mixed GHGs—CO2 and N20 are emitted from airplanes. The test procedures for fuel
efficiency scale with the limiting of both CO2 and N20 emissions, as they both can be indexed on a per-unit-of-
fuel-burn basis. Therefore, both CO2 and N20 emissions can be controlled as airplane fuel burn is limited. Since
limiting fuel burn is the only means by which airplanes control their GHG emissions, the fuel burn (or fuel
efficiency) reasonably serves as a surrogate for controlling both CO2 and N20.
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experts, including experts from academia and other government agencies, as well as an
independent technical expert.11
2.1 Overview
As described in the preamble, ICAO/CAEP traditionally sets standards that are technology-
following standards, rather than technology-forcing standards. This means that the international
standards reflect a level of emissions performance that is already achieved by some portion of
current in-production airplanes. For the international Airplane CO2 Emission Standards,
ICAO/CAEP determined in 2012 that all technology responses for its analysis would have to be
based on technology that would be in common use by the time the standards were to be decided
upon in 2016 or shortly thereafter (ICAO/CAEP's analysis was completed in 2015 for the
February 2016 ICAO/CAEP meeting). This generation of technology or technical feasibility was
defined within CAEP as "... any technology expected to be demonstrated to be safe and
airworthy and proven Technology Readiness Level (TRL) 8 by 2016 or shortly thereafter""7
(approximately 2017) — and "expected to be available for application in the short term over a
sufficient range of newly certificated aircraft" (approximately 2020).12 This means that the
analysis that informed the international standards considered the emissions performance of in-
production and on-order or in-developmentv airplanes, including types that would first enter into
service by about 2020.
In assessing the airplane GHG standards, the 2018 ICF updated analysis, which was
completed a few years after the ICAO analysis, uses a different approach for technology
responses. ICF based these responses on technology available at TRL8 by 2017 and assumed
continuous improvement of fuel efficiency metric values for in-production and in-development
(or on-order) airplanes from 2010 to 2040 based on the incorporation of these technologies onto
these airplanes over this same timeframe/1 Also, ICF considered the end of production of
airplanes based on the expected business as usual status of airplanes (with the continuous
improvement assumptions). The ICF approach differed from ICAO/CAEP's analysis for years
2015 to 2020 and diverged even more for years 2021 and after. We believe this approach
provides a more up to date assessment compared to ICAO/CAEP's analysis/11 Since ICF used
the final effective dates in their analysis of the airplane GHG standards (for new type design
airplanes 2020, or 2023 for airplanes with less than 19 seats, and for in-production airplanes
2028), ICF was able to differentiate between airplane GHG technology improvements that would
1V TRL is a measure of Technology Readiness Level. CAEP has defined TRL8 as the "actual system completed and
'flight qualified' through test and demonstration." TRL is a scale from 1 to 9, TRL1 is the conceptual principle,
and TRL9 is the "actual system 'flight proven' on operational flight." The TRL scale was originally developed by
NASA. ICF International, CO 2 Analysis of C02-Reducing Technologies for Airplanes, Final Report, EPA
Contract Number EP-C-12-011, see page 40, March 17, 2015.
v Airplanes that are currently in-development but were anticipated to be in production by about 2020.
V1 ICF used the terminology, "C02 metric values," in their updated analysis, consistent with ICAO, when referring to
fuel efficiency metric values.
vu ICAO/CAEP did not consider continuous improvement of metric value (from 2010 to 2040) for in-production and
project (or on-order) airplanes based on incorporating 2016/2017 TRL8 technologies (or 2017 technologies).
Instead, ICAO/CAEP considered transition pairs, where project airplanes (or on-order airplanes) would replace
their paired in-production airplanes, and these transitions typically represented a step-change in technology and
MV improvement.
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occur in the absence of the final standards compared to technology improvements/responses that
will be needed to comply with the final standards.
To further substantiate the projection of continuous improvement, historically, airplane fuel
efficiency has continually improved on an annual basis (for the in-service fleet of airplanes and
new jet airplanes). For example, GE stated the following on the annual fuel efficiency
improvement of the in-service airplane fleet: "[o]ver the past 30 years, installing more
technologically advanced and fuel-efficient GE Aviation and CFM International engine models
has equated to the fleet in airline service reducing its fuel burn every year on average by 1 to
1.5%."13 The 2020 fact sheet issued by the Air Transport Action Group (ATAG), whose
members include Airbus, Boeing, the International Air Transport Association (IATA), Airports
Council International, (ACI), ATR, CFM International, and Civil Air Navigation Services
Organisation (CANSO), stated that airlines have continued to improve their global fuel
efficiency between 2009 and 2019 at an average annual rate of 2 percent.14 Moreover, the
ATAG fact sheet indicated that the cumulative fuel efficiency improvement of the in-service
fleet was 21 percent between 2009 and 2019, 38 percent between 2000 and 2019, and 54 percent
between 1990 and 2019. Also, the 2020 IAE tracking report indicated that the energy intensity
of commercial passenger aviation has decreased 2.8 percent per year on average since 2000
(improvements have slackened over time).15 The 2020 Annual Energy Outlook indicates that the
energy use per seat miles available of travel from aircraft is projected to continue to decrease
annually for the long term, about 1 percent per annum from 2019 to 2050, because of the
economically driven adoption of energy-efficient technology and practices.16
For new jet airplanes, ICAO's 2019 CAEP/11 Independent Experts (IE)17 Review projected
that annual reduction rates in fuel burn as follows: single aisle airplanes from 2017 to 2027 is 1.3
percent and from 2017 to 2037 is 1.2 percent — twin aisle airplanes from 2017 to 2027 is 1
percent and 2017 to 2037 is 1.3 percent. This annual improvement rate represented the
independent experts view of challenging, but achievable technology goals for new airplanes.
Also, the 2019 ICAO Environmental Report18 stated that under an optimistic-trends scenario the
long-term fuel efficiency improvement per year would be 1.37 percent, and it includes the
combined improvements associated with both technology and operations. The individual
contributions from technology and operations improvements are .98 percent and .39 percent,
respectively. The ICAO Environmental Report stated that the .98 percent technology
improvement (fuel efficiency improvement for new jet airplanes) is slightly lower than the 1.3
percent annual improvement cited in the 2019 CAEP/11 IE Review for single aisle airplanes. In
addition, the 2020 ICCT white paper19 for new commercial jet airplanes indicated that from 1960
to 2019, annual fuel burn reductions averaged 1.1 percent (1.1 percent on the ICAO metric value
or system, which matches the finalized metric value or system, and 1.3 percent on the block fuel
intensity metric). Also, ICCT stated that a comprehensive technology assessment found that the
rate of fuel burn improvement for new airplanes could be accelerated up to 2.2 percent per
annum through 2034 by the adoption of cost-effective technologies.
ICF projected incremental fuel efficiency improvements or business as usual improvements
for newly produced airplanes at 0.25 to 0.5 percent annually (out to 2040), depending on the
airplanes size category. This is based on the smoothed continuous improvement forecast. ICF's
research revealed that performance improvement packages (PIPs) or technology improvements
for individual airplanes occur in step functions and not in continuous improvements per year.
However, a reasonable projection of inserting these technologies over the forecast period yielded
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an annualized 0.25 to 0.5 percent improvement in fuel burn. Ultimately, based on the historical
performance improvement described earlier by industry and the other sources, as well as the
basket-of-2017-vintage TRL8 technologies available for insertion going forward, this continuous
improvement depiction (or business as usual improvement methodology) was reasonable.
2.2 Technology Principles
2.2.1 Short- and Mid-Term Methodology
ICF analyzed the feasible technological improvements to new in-production airplanes and the
potential GHG emission reductions they could generate. For this analysis, ICF created a
methodological framework to assess the potential impact of technology introduction on airplane
GHG emissions for the years 2015-2029 (short- and mid-term timeframe). Baseline emission
rates over the ICAO/CAEP test procedure/cycle, as described in Chapter 3 of the TSD and
section III of the preamble, were generated using PIANO data (PIANO is a physics-based
airplane performance model).vm These emission rates are in units of kilograms of fuel burned
per kilometer and are referred to as metric values.
ICF's framework included six steps to estimate annual metric value improvements for
technologies that are being or will be applied to in-production airplanes. First, ICF identified the
technologies that could reduce GHG emissions of new in-production airplanes. Second, ICF
evaluated each technology for the potential GHG reduction and the mechanisms by which this
reduction is achieved. Third and fourth, the technologies were passed through technical success
probability and commercial success probability screenings, respectively. These first four steps
were analyzed by airplane category. Fifth, individual airplane differences were assessed within
each airplane category to generate GHG emission reduction projections by technology at the
airplane family level (e.g., 737 family). Finally, ICF extended the GHG emission reduction
projections by technology to the airplane variant level or airplane model level (e.g., 737-700,
737-800, etc.).
ICF refers to their methodological framework for projection of the metric value improvement
or reduction as the expected value methodology. The expected value methodology is a
projection of the annual fuel efficiency metric value improvement1* from 2015-2029 for all the
technologies to be applied to each airplane, or business as usual improvement in the absence of a
standard. Figure 2-1 is a flow chart of the expected value methodology (or expected value
vm To generate metric values, the 2015 ICF analysis and 2018 ICF updated analysis used PIANO (Project Interactive
Analysis and Optimization) data so that their analyses results can be shared publicly. Metric values developed
utilizing PIANO data are similar to ICAO metric values. PIANO is the Aircraft Design and Analysis Software by
Dr. Dimitri Simos, Lissys Limited, UK, 1990-present; Available at www.piano.aero (last accessed March 17,
2020). PIANO is a commercially available aircraft design and performance software suite used across the
industry and academia.
1X Also referred to as the constant annual improvement in fuel efficiency metric value.
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technology impact methodologyx).xl xl1"20 21 The elements in the flow chart are described in more
detail later in this chapter.
Key Steps	Output
Identify the technologies that can reduce
C02 emissions if installed on new In-
Production airplanes
Technology List
Identifythe magnitudeand meansby which
these technologies reduce C02 emissions
by airplane category
Unconstrained
Technology Impact
Matrix
Assess the probability of technical success
by technology and airplanecategory
Technical Success
Screened Matrix
Assessthe probability of commercial
success by t e ch n o I ogy a n d a i rpl a n e category
COj Emissions
Reduction Forecast
(by airplane category)
Drive the forecasted C02 reductions down to
the airplane family level within airplane category
COz Emissions
Reduction Forecast
(by airplane family)
Exte n d t h e f o re ca st C02 re d u ct i o n s d o w n to
airplane variantlevel based on airplane
family level improvements
CO, Emissions
Reduction Forecast
(by airplane variant)
Figure 2-1.- Expected Value Technology Impact
As a modification to the 2015 ICF analysis, the 2018 ICF updated analysis extended the
metric value improvements at the airplane family level to the more specific airplane variant
level. Thus, to estimate whether each airplane variant (e.g., 737-700, 737-800, etc.) complied
with the final GHG standard, ICF projected airplane family metric value reductions to a baseline
(or base year) metric value of each airplane variant. Equation 2-1 below shows this approach.
x The use of the term, "expected value technology impact methodology," versus "expected value methodology" in
the title of Figure 2-1 is to highlight the following: for the short- and mid-term analysis we evaluated each
technology and the level or amount of fuel burn and metric value impact (or improvement) the technology
contributes to each airplane variant.
X1 ICF based technology responses on technology that was TRL8 in 2017 ~ considering continuous improvements of
in-production and project (or on-order) airplane metric values from the incorporation of these technologies in the
2015 to 2029 timeframe (for the short- and mid-term timeframe). Also, in this same time frame, ICF estimated
the expected production status of in-production airplanes based on business as usual improvements (or the
continuous improvement assumptions). The approach differing compared to ICAO/CAEP's analysis for years
2015 to 2020 and diverging even more for years 2021 and after ~ due to ICF including the continuous
improvement assumptions).
xu Through interviews, prior project work, and extensive literature research ICF identified the sources of airplane
fuel burn improvement. Subsequently, by going through the major systems within an airplane (aerostructures,
engines, airframe systems, interior, avionics), ICF then determined the range of magnitude of MV improvements,
its applicability to each airplane size category, and other drivers as listed in the diagram (such as probability of
technical feasibility, commercial feasibility, etc.).
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ICF used this approach to estimate metric values for 125 airplane models, and this approach
allows for a comparison of the estimated metric value for each airplane model to the level of the
final GHG standards at the time the standards will go into effect. Table 2-1 below provides the
results of the analysis of metric value reduction (i.e., fuel efficiency improvement) by airplane
variant for the years 2015, 2018, 2020, 2023, and 2028 (the 2015-2029 timeframe) using the
short- and mid-term methodology, and 2030 and 2040 (the 2030-2040 timeframe) using the long-
term methodology, which is described later in section 2.2.2
Equation 2-1 Metric Value Reduction
Metric value reduction
= Technology applicability percentage
*	commercial feasibility factor * probability of technical success
*	Average metric value benefit of technology by airplane type
where:
Technology applicability percentagexm = percentage representing the metric value benefit a
technology provides for an airplane family (some technologies only realize partial benefits on
certain particular airplane families);
Commercial feasibility factor = factor representing the probability of commercial success a
technology provides for an airplane family;
Probability of technical success = factor representing the probability of technical success a
technology provides for an airplane family; and,
Average metric value benefit of technology by airplane type = absolute metric value
reduction of a technology by airplane size category.X1V
xm For technology applicability percentage, we accounted for partial applicability of an MV reducing technology for
an airplane model. Typically, in-development airplanes will have lower baseline metric values (improved or
better performing metric values) compared to legacy airplanes, since they have more advanced technologies
implemented within the initial launch of the airplane. Consequently, there will be fewer incremental
improvements available from future technologies for in-development airplanes. Due to the addition of a number
of new in-development airplanes into the analysis, ICF modified the technology applicability matrix from
analyzing each technology in a binary manner (i.e. technology can only be fully applicable or fully un-
applicable), to a continuous manner so that partial impacts of technologies could be applied to new airplane
models (i.e. percentage magnitude of a fuel burn impact will each technology provide).
X1V The initial average metric value benefit assessment is conducted at the airplane size category level. Then, we use
this airplane size category level assessment for each technology and apply the technology applicability percentage
for each in-production airplane variant, which extends the magnitude of metric value benefit from the size
category level to the variant level.
As an example, the winglet is assessed to have a 3.5% metric value benefit for widebodies (airplane size category
level). We then take this assessment and multiply for the MS-21 airplane, which we assess will only reap 50% of
the benefit (variant level) [3.5%*50%], Another example is the 777X airplane, which we assess will reap none of
the benefit (variant level) [3.5%*0%]; because winglets are not applicable to 777X wing design.
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Example calculation #1 of metric value reduction ~ advanced wingtip devices for A330
in year 2018:
Technology applicability percentage of advanced wingtip devices (A330): 100%
Commercial feasibility factor (advanced wingtip devices in 2018): 10%
Probability of technical success (advanced wingtip devices in 2018): 100%
Average metric value benefit of technology by airplane type (large twin aisle): 3.5%
Equation 2-2: Calculation of Metric Value Reduction - Advanced Wingtip Devices for A330 in 2018
= technology applicability percentage of advanced wingtip devices (i4330)
*	commercial feasibility factor (advanced wingtip devices in 2018)
*	probability of technical success (advanced wingtip devices in 2018)
*	average metric value benefit of technology by airplane type (large twin aisle)
= (100% * 10% * 100%) * 3.5% = 0.35%
This means that 0.35% of MV benefit in A330 in 2018 is attributable to advanced wingtip
devices. To obtain the total MV reduction in a particular year, we perform this calculation for all
applicable technology and then sum up the results of MV benefit for each technology.
Example calculation #2 of metric value reduction - adaptive trailing edge for A330 in
year 2028:
Technology applicability percentage of adaptive trailing edge (A330): 100%
Commercial feasibility factor (adaptive trailing edge in 2028): 15%
Probability of technical success (adaptive trailing edge in 2028): 100%
Average metric value benefit of technology by airplane type (large twin aisle): 2.0%
Equation 2-3: Calculation of Metric Value Reduction - Adaptive Trailing Edge for A330 in 2018
= technology applicability percentage of adaptive trailing edge (i4330)
*	commercial feasibility factor (adaptive trailing edge in 2028)
*	probability of technical success (adaptive trailing edge in 2028)
*	average metric value benefit of technology by airplane type (large twin aisle)
= (100% * 15% * 100%) * 2.0% = 0.3%
This means that 0.3% of MV benefit in A330 in 2028 is attributable to adaptive trailing edge.
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In addition, ICF projected which airplane models will end their production prior to the
effective date of the final GHG standards. These estimates of production status, at the time the
standards will go into effect, further informed the projected response of airplane models to the
final standards.
As described earlier in section 2.2.1, the short- and mid-term methodology (2015-2029) is
appropriate for the EPA GHG standards because it is from assumptions based on the actual
effective dates of the GHG standards. A description of the airplane and engine technologies,
which are the primary basis for these assumptions for the short- and mid-term methodology, is
provided later in section 2.3.
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Table 2-1 - Airplane Metric Value (MV) Forecast/Reduction (PIANO Data)
Airplane Model
Manufacturer
Market Category
Airplane Type
2015
2018
2020
2023
2028
2030
2040




MV
MV
MV
MV
MV
MV
MV
A380-842
AIRBUS
Air Transport
Large Quad
2.9007
2.8582
2.8220
2.7665
2.6838
2.6495
2.5156
A380-861
AIRBUS
Air Transport
Large Quad
2.9007
2.8582
2.8220
2.7665
2.6838
2.6495
2.5156
B747-8
BOEING
Air Transport
Large Quad
2.5462
2.5096
2.4783
2.4303
2.3608
2.3317
2.2177
B747-8F
BOEING
Air Transport
Large Quad
2.6503
2.6122
2.5796
2.5296
2.4573
2.4270
2.3084
A330-203
AIRBUS
Air Transport
Large Twin Aisle
1.6506
1.6264
1.6058
1.5742
1.5272
1.5068
1.4132
A330-223
AIRBUS
Air Transport
Large Twin Aisle
1.6506
1.6264
1.6058
1.5742
1.5272
1.5068
1.4132
A330-243
AIRBUS
Air Transport
Large Twin Aisle
1.6506
1.6264
1.6058
1.5742
______
1.5068
1.4132
A330-2F
AIRBUS
Air Transport
Large Twin Aisle
1.6258
1.6020
1.5817
1.5506
1.5042
1.4841
1.3920
A330-2F
AIRBUS
Air Transport
Large Twin Aisle
1.6258
1.6020
1.5817
1.5506
1.5042
1.4841
1.3920
A330-303
AIRBUS
Air Transport
Large Twin Aisle
1.6169
1.5932
1.5730
1.5421
1.4960
1.4760
1.3844
A330-323
AIRBUS
Air Transport
Large Twin Aisle
1.6169
1.5932
1.5730
1.5421
1.4960
1.4760
1.3844
A330-343
AIRBUS
Air Transport
Large Twin Aisle
1.6169
1.5932
1.5730
1.5421
1.4960
1.4760
1.3844
B777-200ER
BOEING
Air Transport
Large Twin Aisle
1.9493
1.9257
1.9046
1.8723
1.8265
1.8060
1.7105
B777-200LR
BOEING
Air Transport
Large Twin Aisle
2.1836
2.1572
2.1336
2.0974
2.0460
2.0231
1.9161
B777-300ER
BOEING
Air Transport
Large Twin Aisle
2.1439
2.1179
2.0948
2.0592
2.0088
1.9863
1.8812
B777-2LRF
BOEING
Air Transport
Large Twin Aisle
2.1846
2.1582
2.1346
2.0983
2.0470
2.0241
1.9170
A350-800
AIRBUS
Air Transport
Large Twin Aisle
1.5110
1.4897
1.4714
1.4434
1.4029
1.3851
1.3028
A350-900
AIRBUS
Air Transport
Large Twin Aisle
1.6060
1.5833
1.5639
1.5342
1.4911
1.4722
1.3847
A350-1000
AIRBUS
Air Transport
Large Twin Aisle
1.7640
1.7391
1.7178
1.6851
1.6378
1.6171
1.5209
A330-800-NEO
AIRBUS
Air Transport
Large Twin Aisle
1.4700
1.4700
1.4585
1.4406
1.4156
1.4061
1.3632
A330-900-NEO
AIRBUS
Air Transport
Large Twin Aisle
1.4410
1.4410
1.4297
1.4121
1.3877
1.3783
1.3363
B777-9X
BOEING
Air Transport
Large Twin Aisle
1.7830
1.7830
1.7741
1.7483
1.7125
1.6987
1.6340
B777-8X
BOEING
Air Transport
Large Twin Aisle
1.8210
1.8210
1.8119
1.7855
1.7490
1.7349
1.6688
B767-3ER
BOEING
Air Transport
Small Twin Aisle
1.5695
1.5484
1.5309
1.5039
1.4639
1.4456
1.3588
B767-3ER
BOEING
Air Transport
Small Twin Aisle
1.5695
1.5484
1.5309
1.5039
1.4639
1.4456
1.3588
B767-3ERF
BOEING
Air Transport
Small Twin Aisle
1.5854
1.5641
1.5463
1.5191
1.4787
1.4602
1.3725
B787-8
BOEING
Air Transport
Small Twin Aisle
1.4102
1.3933
1.3795
1.3581
1.3269
1.3123
1.2408
B787-8
BOEING
Air Transport
Small Twin Aisle
1.4102
1.3933
1.3795
1.3581
1.3269
1.3123
1.2408
B787-9
BOEING
Air Transport
Small Twin Aisle
1.5105
1.4924
1.4776
1.4547
1.4213
1.4057
1.3291
B787-9
BOEING
Air Transport
Small Twin Aisle
1.5105
1.4924
1.4776
1.4547
1.4213
1.4057
1.3291
-------
Airplane Model
Manufacturer
Market Category
Airplane Type
B787-10
BOEING
Air Transport
Small Twin Aisle
B787-10
BOEING
Air Transport
Small Twin Aisle
A318-122
AIRBUS
Air Transport
Single Aisle
A318-112/CJ
AIRBUS
Air Transport
Single Aisle
A319-115
AIRBUS
Air Transport
Single Aisle
A319-133
AIRBUS
Air Transport
Single Aisle
A319-115/CJ
AIRBUS
Air Transport
Single Aisle
A319-133/CJ
AIRBUS
Air Transport
Single Aisle
A320-233
AIRBUS
Air Transport
Single Aisle
A320-214
AIRBUS
Air Transport
Single Aisle
A321-211
AIRBUS
Air Transport
Single Aisle
A321-231
AIRBUS
Air Transport
Single Aisle
B737-700
BOEING
Air Transport
Single Aisle
B737-700W
BOEING
Air Transport
Single Aisle
B737-700IGW (BBJ)
BOEING
Air Transport
Single Aisle
B737-800
BOEING
Air Transport
Single Aisle
B737-800W
BOEING
Air Transport
Single Aisle
B737-900ER
BOEING
Air Transport
Single Aisle
B737-900ERW
BOEING
Air Transport
Single Aisle
A319-NEO
AIRBUS
Air Transport
Single Aisle
A319-NEO
AIRBUS
Air Transport
Single Aisle
A320-NEO
AIRBUS
Air Transport
Single Aisle
A320-NEO
AIRBUS
Air Transport
Single Aisle
A321-NEO
AIRBUS
Air Transport
Single Aisle
A321-NEO
AIRBUS
Air Transport
Single Aisle
B737-7
BOEING
Air Transport
Single Aisle
B737-8 (BBJ)
BOEING
Air Transport
Single Aisle
B737-8
BOEING
Air Transport
Single Aisle
B737-9
BOEING
Air Transport
Single Aisle
CSIOO
BOMBARDIER
Air Transport
Single Aisle
2015
2018
2020
2023
2028
2030
2040
MV
MV
MV
MV
MV
MV
MV
1.4747
1.4571
1.4426
1.4203
1.3876
1.3724
1.2976
1.4747
1.4571
1.4426
1.4203
1.3876
1.3724
1.2976
0.8412
0.8307
0.8224
0.8098
0.7899
0.7804
0.7369
0.8412
0.8307
0.8224
0.8098
0.7899
0.7804
0.7369
0.8750
0.8640
0.8554
0.8423
0.8216
0.8117
0.7664
0.8750
0.8640
0.8554
0.8423
0.8216
0.8117
0.7664
0.8968T
0.8856
0.8768
0.8633
0.8421
0.8319
0.7856
0.8968
0.8856
0.8768
0.8633
0.8421
0.8319
0.7856
0.8670
0.8562
0.8477
0.8347
0.8141
0.8043
0.7595
0.8670
0.8562
0.8477
0.8347
0.8141
0.8043
0.7595
0.9990
0.9865
0.9767
0.9617
0.9380
0.9267
0.8751
0.9990
0.9865
0.9767
0.9617
0.9380
0.9267
0.8751
0.8762
0.8656
0.8573
0.8446
0.8245
0.8148
0.7701
0.8365
0.8264
0.8185
0.8063
0.7872
0.7779
0.7353
0.9110
0.9000
0.8913
0.8781
0.8572
0.8471
0.8007
0.9308
0.9196
0.9107
0.8972
0.8759
0.8656
0.8181
0.8911
0.8804
0.8719
0.8589
0.8385
0.8287
0.7832
0.9586
0.9470
0.9379
0.9240
0.9020
0.8914
0.8425
0.9586
0.9470
0.9379
0.9240
0.9020
0.8914
0.8425
0.7262
0.7169
0.7096
0.6983
0.6808
0.6724
0.6339
0.7262
0.7169
0.7096
0.6983
0.6808
0.6724
0.6339
0.7272
0.7179
0.7105
0.6992
0.6817
0.6733
0.6348
0.7272
0.7179
0.7105
0.6992
0.6817
0.6733
0.6348
0.8557
0.8448
0.8361
0.8228
0.8022
0.7923
0.7469
0.8557
0.8448
0.8361
0.8228
0.8022
0.7923
0.7469
0.7290
0.7266
0.7209
0.7121
0.6987
0.6931
0.6688
0.7817
0.7792
0.7730
0.7635
0.7492
0.7432
0.7171
0.7817
0.7792
0.7730
0.7635
0.7492
0.7432
0.7171
0.8247
0.8220
0.8155
0.8055
0.7904
0.7841
0.7566
0.6550
0.6501
0.6439
0.6346
0.6201
0.6132
0.5816
-------
Airplane Model
Manufacturer
Market Category
Airplane Type
2015
2018
2020
2023
2028
2030
2040
CS300
BOMBARDIER
Air Transport
Single Aisle
0.7120
0.7066
1 0.7000
0.6898
0.6741
0.6665
0.6322
MS-21-300
IRKUT
Air Transport
Single Aisle
0.7380
0.7380
0.7380
0.7271
0.7103
0.7028
0.6688
MS-21-300
IRKUT
Air Transport
Single Aisle
0.7380
0.7380
0.7380
0.7271
0.7103
0.7028
0.6688
MS-21-200
IRKUT
Air Transport
Single Aisle
0.6870
0.6870
0.6870
0.6769
0.6612
0.6542
0.6226
MS-21-200
IRKUT
Air Transport
Single Aisle
0.6870
0.6870
| 0.6870
| 0.6769
0.6612
0.6542
0.6226
C919ER
CO MAC
Air Transport
Single Aisle
0.7120
0.7120
0.7082
0.6969
0.6795
0.6711
0.6331
CRJ700
BOMBARDIER
Air Transport
Regional Jet
0.6144
0.6055
0.5991
0.5894
0.5735
0.5664
0.5339
CRJ900
BOMBARDIER
Air Transport
Regional Jet
0.6451
0.6357
0.6290
0.6189
0.6021
0.5947
0.5606
CRJ1000
BOMBARDIER
Air Transport
Regional Jet
0.6738
0.6640
, 0.6570
, 0.6464
0.6290
0.6212
0.5855
ERJ135-LR
EMBRAER
Air Transport
Regional Jet
0.4182
0.4121
j 0.4078
j 0.4012
0.3903
0.3855
0.3634
ERJ145
EMBRAER
Air Transport
Regional Jet
0.4201
0.4141
0.4097
0.4031
0.3922
0.3873
0.3651
ERJ175
EMBRAER
Air Transport
Regional Jet
0.6877
0.6777
0.6706
0.6597
0.6419
0.6340
0.5976
ERJ190
EMBRAER
Air Transport
Regional Jet
0.7769
0.7656
0.7575
0.7453
0.7252
0.7162
0.6751
ERJ195
EMBRAER
Air Transport
Regional Jet
0.7699
0.7588
0.7508
0.7386
0.7187
0.7098
0.6690
RRJ-95
SUKHOI
Air Transport
Regional Jet
0.6699
0.6602
0.6532
0.6427
0.6254
0.6177
0.5823
RRJ-95LR
SUKHOI
Air Transport
Regional Jet
0.7154
0.7051
0.6977
0.6864
0.6679
0.6597
0.6219
MRJ-70
MITSUBISHI
Air Transport
Regional Jet
0.5340
0.5340
0.5340
0.5257
0.5121
0.5060
0.4782
MRJ-90
MITSUBISHI
Air Transport
Regional Jet
0.5540
0.5540
0.5540
0.5454
0.5313
0.5250
0.4961
ERJ-175 E2
EMBRAER
Air Transport
Regional Jet
0.5920
0.5892
| 0.5831
| 0.5739
0.5588
0.5521
0.5213
ERJ-190 E2
EMBRAER
Air Transport
Regional Jet
0.6040
0.6011
1 0.5949
1 0.5856
0.5702
0.5633
0.5318
ERJ-195 E2
EMBRAER
Air Transport
Regional Jet
0.6150
0.6121
0.6058
0.5962
0.5806
0.5736
0.5415
ATR42-5
ATR
Air Transport
Turboprop
0.3353
0.3311
0.3280
0.3234
0.3157
0.3125
0.3009
ATR72-2
ATR
Air Transport
Turboprop
0.3779
0.3732
0.3697
0.3645
0.3559
0.3522
0.3392
Q400
BOMBARDIER
Air Transport
Turboprop
0.4960
0.4898
| 0.4852
j 0.4783
0.4670
0.4623
0.4451
CL-605
BOMBARDIER
BGA
Large BGA
0.4990
0.4928
0.4878
0.4804
0.4685
0.4633
0.4411
CL-850
BOMBARDIER
BGA
Large BGA
0.4911
0.4849
1 0.4801
1 0.4727
0.4610
0.4559
0.4341
G-5000
BOMBARDIER
BGA
Large BGA
0.6428
0.6348
0.6285
0.6188
0.6035
0.5969
0.5683
G-6000
BOMBARDIER
BGA
Large BGA
0.6924
0.6838
0.6770
0.6666
0.6501
0.6429
0.6121
-------
Airplane Model	Manufacturer Market Category Airplane Type
FAL900LX
DASSAULT-AVIATION
BGA
Large BGA
FAL7X
DASSAULT-AVIATION
BGA
Large BGA
ERJLEG
EMBRAER
BGA
Large BGA
GVI
GULFSTREAM
BGA
Large BGA
GULF5
GULFSTREAM
BGA
Large BGA
GULF4
GULFSTREAM
BGA
Large BGA
Global 7000
BOMBARDIER
BGA
Large BGA
Global 8000
BOMBARDIER
BGA
Large BGA
Learjet 40XR
BOMBARDIER
BGA
Small BGA
Learjet 45XR
BOMBARDIER
BGA
Small BGA
Learjet 60XR
BOMBARDIER
BGA
Small BGA
CL-300
BOMBARDIER
BGA
Small BGA
CNA525B
CESSNA
BGA
Small BGA
CNA525C
CESSNA
BGA
Small BGA
CNA560-XLS
CESSNA
BGA
Small BGA
CNA680
CESSNA
BGA
Small BGA
CNA750
CESSNA
BGA
Small BGA
FAL2000LX
DASSAULT-AVIATION
BGA
Small BGA
EMB505
EMBRAER
BGA
Small BGA
G280
GULFSTREAM
BGA
Small BGA
GULF150
GULFSTREAM
BGA
Small BGA
Learjet 70
BOMBARDIER
BGA
Small BGA
Learjet 75
BOMBARDIER
BGA
Small BGA
CNA680-S
CESSNA
BGA
Small BGA
CNA750-X
CESSNA
BGA
Small BGA
PC-24
: PILATUS
BGA
j Small BGA
2015
2018
2020
2023
2028
2030
2040







0.4712
0.4653
0.4607
0.4536
0.4424
0.4375
0.4166
0.4911
0.4849
0.4801
0.4727
0.4610
0.4559
0.4341
0.4990
0.4928
0.4878
0.4804
0.4685
0.4633
0.4411
0.5734
0.5663
0.5607
0.5521
0.5385
0.5326
0.5072
0.5853
0.5780
0.5722
0.5635
0.5495
0.5434
0.5174
0.6419
0.6339
0.6275
0.6179
0.6026
0.5959
0.5674
0.5880
0.5880
0.5823
0.5736
0.5597
0.5538
0.5280
0.5960
0.5960
0.5930
0.5842
0.5702
0.5641
0.5380
0.3344
0.3305
0.3276
0.3234
0.3165
0.3136
0.3037
0.2947
0.2912
0.2887
0.2850
0.2790
0.2764
0.2676
0.3444
0.3403
0.3374
0.3330
0.3259
0.3229
0.3127
0.3831
0.3785
0.3753
0.3704
0.3626
0.3592
0.3478
0.2421
0.2393
0.2372
0.2341
0.2292
0.2271
0.2199
0.2421
0.2393
0.2372
0.2341
0.2292
0.2271
0.2199
0.3265
0.3226
0.3199
0.3157
0.3090
0.3062
0.2965
0.3865
0.3820
0.3788
0.3739
0.3660
0.3627
0.3513
0.4084
0.4036
0.4002
0.3951
0.3868
0.3833
0.3713
0.3870
0.3824
0.3792
0.3742
0.3663
0.3630
0.3514
0.2749
0.2716
0.2693
0.2658
0.2602
0.2578
0.2496
0.4426
0.4374
0.4337
0.4280
0.4190
0.4152
0.4021
0.3850
0.3805
0.3772
0.3723
0.3644
0.3611
0.3496
0.3457
0.3416
0.3387
0.3344
0.3274
0.3244
0.3142
0.3457
0.3416
0.3387
0.3344
0.3274
0.3244
0.3142
0.3865
0.3820
0.3788
0.3739
0.3660
0.3627
0.3513
0.3716
0.3672
0.3641
0.3594
0.3519
0.3487
0.3378
0.2930
0.2918
0.2894
0.2857
: 0.2798
0.2773
0.2687
-------
Technology and Cost
2.2.2 Long-Term Methodology
To project metric value improvements for the long-term, years 2030-2040, ICF generated a
different methodology compared to the short- and mid-term methodology. The short- and mid-
term methodology is based on forecasting metric value improvements due to the implementation
of specific existing technologies. ICF projects that in about the 2030 timeframe a new round of
technology implementation will begin.22 For this reason, ICF developed a different method for
predicting metric value improvements for the long term. For 2030 or later, ICF used a
parametric approach to project annual metric value improvements.23 This approach included
three steps. First, for each airplane type, technical factors were identified that drive fuel burn
and metric value improvements in the long-term (i.e., propulsive efficiency, friction drag
reduction), and the fuel burn reduction prospect index, which is described below in section
2.2.2.1, was estimated on a scale of 1 to 5 for each technical factor. Second, a long-term market
prospect index was generated on a scale of 1 to 5 based on estimates of the amount of potential
research and development (R&D) put into various technologies for each airplane type. Third, the
long-term market prospect index for each airplane type was combined with its respective fuel
burn reduction prospect index to generate an overall index score for their metric value
improvements. A low overall index score indicates that the airplane type will have a decelerated
annual metric value reduction, and a high overall index score indicates an accelerated annual
metric value improvement (relative to an extrapolated short- and mid-term annual metric value
improvement).xv
As discussed earlier in section 2.1, ICAO/CAEP's analysis did not include a long-term
technology assessment for 2030-2040, but instead focused on technology that would have been
in operation by 2016/2017 (and considered the emissions performance of in-production and on-
order or in-developmentxvl airplanes, including types that would first enter into service by about
2020). ICF's long-term approach is appropriate for the EPA GHG standards because it derives
reasonable assumptions based on the best available information for this timeframe.
2.2.2.1 Fuel Burn Reduction Prospect Index
The fuel burn reduction prospect index is a projected ranking of the feasibility and readiness
of technologies (for reducing fuel burn) to be implemented for 2030 and later. For the fuel burn
reduction prospect index, the technology factors that mainly contribute to fuel burn were
identified.24 These factors included the following engine and airframe technologies as described
below: (Engine) sealing, propulsive efficiency, thermal efficiency, reduced cooling, and reduced
power extraction and (Airframe) induced drag reduction and friction drag reduction. A number
of these technology factors are described in more detail later in section 2.3. Also, the 2018 ICF
updated analysis provides further details on the technology factors.
Sealing: Imperfect air sealing in the engine leads to leaking that diminishes the engine
efficiency (especially in the engine compressor) that ultimately increases the fuel burn.
xv Accelerated metric value improvement rate means that the metric value is improving at an accelerated rate (i.e.,
faster than the historical rate). Decelerated metric value improvement rate means that the metric value is
improving at a decelerated rate (i.e., slower than the historical rate).
XV1 Airplanes that are currently in-development but were anticipated to be in production by about 2020.
Page: 26
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Technology and Cost
Propulsive efficiency: This is the part of the kinetic energy added to the air that contributes to
thrust. (Not to be confused with the overall propulsive efficiency, which is the product of the
propulsive efficiency and the thermal efficiency). Increasing bypass ratio is the primary approach
to increase propulsive efficiency and thus reduce fuel burn.
Thermal efficiency: This is the efficiency with which the chemical energy of the fuel is
converted into mechanical power. The primary approach to increase the thermal efficiency is by
increasing the turbine entry temperature.
Reduced cooling: To cool the hotter parts of the engine, bleed air is taken from the engine
compressor stage. This leads to a loss that on its own that increases the fuel burn but contributes
to improving the thermal efficiency by making it possible to raise the turbine entry temperature.
Reduced power extraction: Bleed air is commonly used for other airplane systems (anti-icing,
cabin pressurization, pneumatic actuators, etc.). In addition to power extraction through bleeding
air, shaft power may be extracted through electric generators to power airplane systems. The less
the power extraction, the less the fuel burn.
Induced drag reduction: This type of drag is induced by the generation of lift. For a given lift,
this can be decreased by optimizing the distribution of pressures on the wing through
aerodynamic shaping, increasing wingspan, and adding wing tip devices. The lower the induced
drag, the lower the fuel burn.
Friction drag reduction: This type of drag is due to mechanical friction of the air with the
airplane surface. This can be decreased by reducing the exposed area, improving surface
finishing, and through aerodynamic shaping. The lower the friction drag, the lower the fuel burn.
Profile drag reduction: This type of drag is due to flow separation that causes a turbulent wake
where energy is dissipated. Profile drag can be decreased by aerodynamic shaping.
The technology factors were each scored on three dimensions that were considered to drive
the overall fuel burn reduction effectiveness in the latter end of the forecast years. These three
scoring dimensions include the following criteria:
Effectiveness of technology in improving fuel burn;
Likelihood of technology implementation; and
Level of research effort needed.
The scoring dimensions of the effectiveness of technology in improving fuel burn and level of
research effort needed were considered the primary drivers in the technical factors because of
past experience. These two factors are the most important since the effectiveness of a
technology in decreasing fuel burn (or decreasing the metric value) would most incentivize
manufacturers to pursue research, while the level of research effort directs how economically
feasible a technology is. Thus, heavier weightings were allocated to these two factors (40
percent weighting on each of these factors) compared to likelihood of implementation (20
percent weighting on this factor). The scoring of each of the technical factors on the three
dimensions was averaged to develop an overall fuel burn reduction prospect index.
2.2.2.2 Market Driver Index
Page: 27
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Technology and Cost
Market driver indices for each airplane type25 were developed based on where the market is
projected to shift towards in the latter end of the forecast years. The extent of research and
development that manufacturers will carry out was also weighted towards this shift. Engine
manufacturers were projected to make more efficient engines that would enable more point-to-
point travel, subsequently decreasing the need for large quad airplanes and creating more market
demand and more focus on improvements for single aisle and small twin-aisle airplanes. Recent
technology developments have been focused on re-engine improvements, and thus, it was
anticipated that there would be ample possibilities for an airframe redesign in the next round of
technological improvement due in the early 2030s. In addition, it was projected that the number
of business jets, turboprops, and regional jet airplanes would grow slightly slower compared to
the recent past (or the growth in the number of these airplanes would be relatively stagnant in the
outbound years). We expect the highest long-term growth in number of airplanes to occur in the
single aisle and small twin aisle airplane categories (the highest near- and mid-term growth is
also anticipated in these two airplane categories).26
2.2.2.3 Metric Value Improvement Acceleration Index
The fuel burn reduction prospect index was combined with the market driver index via
weighted average for each airplane type to calculate the overall metric value improvement
acceleration index.27 A scoring of 1 was a 60 percent improvement rate relative to extrapolated
short/mid-term annual metric value improvement, a scoring of 3 was a continued extrapolated
short/mid-term annual metric value improvement, and a scoring of 5 was a 140 percent
improvement rate relative to extrapolated short/mid-term annual metric value improvement.
Table 2-2 below shows the improvement rates for this assessed index scoring. (A little more
weighting was put on the technological factors (or fuel burn reduction prospect index) with a 65
percent scoring weight, compared to market factors (market driver index) with a 35 percent
scoring weight, because of past experience. The weighting is reasonable since while fuel burn
prospects are the most important factor for manufacturers, the manner in which the overall
market is evolving (e.g., more single aisle airplanes) would affect the way manufacturers
apportion their research efforts.) Finally, the short/mid-term metric value improvement impact
estimates described earlier were extended to the end of the long-term forecast timeframe (2040)
and overall metric value improvement acceleration index scoring developed by each airplane
type was applied to those estimates.
Table 2-2 Metric Value Index Scoring
MV Acceleration
Index Scoring
Improvement rate (relative to extrapolated
short/mid-term annual MV improvement)
1
60%
2
80%
3
100%
4
120%
5
140%
Figure 2-2 provides the graphical form of the improvement rates for this assessed index
scoring, which is in Table 2-2 above. It was extrapolated to cover all scores between 1 and 5.
The scoring follows the linear regression of y = 0.2x + 0.4 (where x is the scoring, and y is the
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resulting improvement rate). Figure 2-2 can be utilized to interpret intermediate scores (that are
in between 1 and 5) to obtain how much faster or slower the metric value improvement is based
on the technical factor scoring of the fuel burn reduction prospect index. 100 percent (or a score
of 3) indicates that the pace of metric value improvement will continue at 100 percent of the
estimated current rate of reduction (i.e., rate higher than 100% means larger of reduction and rate
lower than 100% means vice versa). Furthermore, a score of 3 means that the continuous annual
metric value improvement rate for the short- and mid-term methodology remains the same for
the long-term methodology or timeframe. A score of 2 means that the continuous annual metric
value improvement rate decelerates (or decreases) for the long-term methodology, and a score of
4 means that the rate accelerates (or increases).
Scoring
Figure 2-2 Graphical Form of Metric Value Index Scoring
2.2.2.4 Example for Long-Term Metric Value Forecast
An example of an overall fuel burn reduction prospect index for a single aisle airplane type is
provided below in Table 2-3.28 Also, examples of fuel burn reduction prospect indexes for the
other airplane categories are shown below in Table 2-4.
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Table 2-3 Single Aisle Example for Fuel Burn Reduction Prospect Index
Single Aisle
Technical Factors:
Effectiveness in
reducing fuel burn
(1-5) [40%]
Likelihood of
implementation in
new technology
(1-5) [20%]
Level of Research
Effort Required
(l-5)xvii [40%]
Fuel Burn
Reduction Prospect
Index
Weight
N/A
N/A
N/A
N/A
Sealing
1
2
4
2.4
Propulsive
3
3
2
2.6
efficiency




Thermal efficiency
3
3
2
2.6
Noise reduction
1
2
3
2
Reduced cooling
3
3
3
3
Reduced power
3
3
3
3
extraction




Reduced thermal
3
3
3
3
management




Induced drag
5
4
1
3.2
reduction




Friction drag
5
4
1
3.2
reduction




Overall Fuel Burn 2.8
Reduction Prospect
Index:
For single aisle, it was projected that there will be a new clean sheet design that will have
substantial aerodynamics improvement, which will reduce drag, and it will have the latest engine
technologies. Thus, there is plenty of potential for the scoring dimensions of fuel burn
effectiveness and likelihood of implementation (favorable scoring in these dimensions).
However, due to the efforts required, there will be risks related to attaining the improvement.
This reasoning led to an overall fuel burn reduction prospect indexxvm that is a little decelerated
from a technical perspective.
xvn For Level of Research Effort, 5 is the least amount of effort needed (more favorable) and 1 is the most amount of
effort needed (less favorable).
xvm As described earlier, the fuel burn reduction prospect index is a projected ranking of the feasibility and readiness
of technologies (for reducing fuel burn) to be implemented for 2030 and later. There are three main steps to
determine the fuel burn reduction prospect index. First, the technology factors that mainly contribute to fuel burn
were identified. These factors included the following engine and airframe technologies as described below:
(Engine) sealing, propulsive efficiency, thermal efficiency, reduced cooling, and reduced power extraction and
(Airframe) induced drag reduction and friction drag reduction. Second, each of the technology factors were
scored on the following three scoring dimensions that will drive the overall fuel burn reduction effectiveness in
the outbound forecast years: effectiveness of technology in reducing fuel burn, likelihood of technology
implementation, and level of research effort required. Third, the scoring of each of the technical factors on the
three dimensions were averaged to derive an overall fuel burn reduction prospect index.
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Table 2-4 Other Airplane Category Examples of Fuel Burn Reduction Prospect Index
Technical Factors:
Large
Quad
Large Twin
Aisle
Small Twin
Aisle
Single
Aisle
Regional
Jet
Turboprop
Large
BGA
Small
BGA
Weight
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Sealing
2.8
2.8
2.8
2.4
2.4
2.2
2.2
1.8
Propulsive efficiency
2.6
2.6
2.6
2.6
2.6
1.6
1.6
1.6
Thermal efficiency
2.6
2.6
2.6
2.6
2.6
1.6
1.6
1.6
Reduced cooling
3.4
3
3
3
3
2.4
2.4
2.4
Reduced power
extraction
3.4
3
3
3
3
2.4
2.4
2
Reduced thermal
management
3.4
3
3
3
3
2.4
2.4
2.4
Induced drag
reduction
3.2
3.2
3.2
3.2
3.6
3
3
3
Friction drag
reduction
3.2
3.2
3.2
3.2
3.6
3
3
3
Profile drag
reduction
2.4
2.4
2.4
2
2
1.8
1.8
1.4
Fuel Burn Reduction
Prospect Index
3
2.9
2.9
2.8
2.9
2.3
2.3
2.1
However, we recognized that the single aisle market is expected to be thriving in the long-
term based on more point-to-point travel from more fuel-efficient engines, as described earlier.
Thus, it is projected that the market driver index for single aisle is quite favorable with a scoring
of 5, since manufacturers are anticipated to concentrate their research efforts on this market.
Combining the fuel burn reduction prospect index and the market driver index, the resulting
metric value improvement acceleration index is 3.56 as provided in Table 2-5 below.
Table 2-5 Single Aisle Example for Metric Value Improvement Acceleration Index
Fuel Burn Reduction Prospect
Index [65%]
Market Driver Index
[35%]
Metric Value Improvement Acceleration
Index
2.78
5
3.56
This 3.56 score shows that the single aisle metric value improvement will be accelerated
faster compared to an extrapolated short/mid-term metric value improvement rate. With the
linear regression that a 1 score represents 60 percent annual metric value decelerated
improvement rate and a 5 score represents a 140 percent annual metric value accelerated
improvement rate, a score of 3.56 represents that single aisle will annually accelerate at a rate of
111 percent. This annual metric value accelerated improvement rate was integrated into the
extrapolated short/mid-term metric value forecast for the appropriate airplane models.
2.2.2.5 Long-Term Replacement Airplane Analysis (2030-2040)
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In addition to the long-term metric value forecast, the potential long-term replacement
airplanesxlx were analyzed according to the following factors: historical airplane design
transitions, metric value improvement step-down (metric value improvements of 10-20 percent)
per airplane generation, and timing of airplane design transition.xx-29 Based on these factors, the
potential long-term airplane replacements that current/new generation airplanes will transition
into were developed for the latter end of the forecast years. The potential airplane replacements
were identified as provided below in Table 2-6.XX1
Table 2-6 Long-Term Potential Replacement Airplanes
Market
Category
Airplane
Type
2030-2040 Replacement
Estimated
EISa
MV Improvement
Estimate
Uncertainty
Band (+/-)
Air Transport
Large Quad
No direct replacement.
N/A
N/A
N/A
Air Transport
Large Twin
Aisle
777X
beyond
2040
N/A
N/A
Air Transport
Small Twin
Aisle
Re-wing or re-engine small twin
aisle
late 2030
~15%
3%
Air Transport
Single Aisle
Clean sheet airplane
early 2030
~20%
4%
Air Transport
Regional Jet
Re-wing regional jet
early 2030
~10%
2%
Air Transport
Turboprop
Re-wing or re-engine turboprop
airplane
early 2030
-10%
2%
Air Transport
Freighter
A330neo or 777X freighter
late 2020
N/A
N/A
BGAb
Large BGA
Re-wing or re-engine large
business jet
early 2030
-10%
2%
BGA
Small BGA
Re-wing or re-engine small
business jet
early 2030
-10%
2%
a. Entry into service (EIS)
BGA means business and general aviation airplane.
The detailed results of the long-term replacement and reference airplane assessment is in the
Technology Response Database that accompanies the 2018 ICF updated analysis, which is
located in the docket for this rulemaking.xxu In the Technology Response Database, the long-
term replacement airplanes for all in-production and in-development airplane models (models
covered by the MTOM thresholds of the final standard) were evaluated, and metric values for
XLX The term, "replacement airplane," in the long-term methodology means airplane that are projected to replace in-
production airplane and current in-development (or on order airplane) that are expected to go out of production in
the 2030-2040 timeframe. For some airplane categories, ICF identified specific airplane to replace airplane (e.g.,
777X for Large Twin Aisle category), and for most categories ICF identified a generic airplane (e.g.. Clean sheet
airplane for Single Aisle category and re-wing or re-engine small twin aisle for Small Twin Aisle category).
xx Every 15 to 25 years after entry into service, airplane models normally incur major redesigns that are motivated
by aerodynamics or engine efficiency improvements that substantially reduce fuel burn. These major re-designs
normally generate significant reductions in fuel burn and MV - 10 percent to 20 percent compared to the previous
generation they replace, depending on the type of redesign. There are three types of major airplane redesigns:
redesigned engines (re-engine), redesigned wings (re-wing), or clean sheet development.
XX1 This table shows historical examples of major re-design improvements that have been achieved by airplane
manufacturers. Clean sheet re-designs have historically produced about 20+ percent, re-wing have historically
yielded about 15 to 20 percent, while re-engine have historically accomplished about 10 to 15 percent.
xxn ICF, 2018, Airplane CO2 Cost and Technology Refresh and Industry Characterization, EPA Contract Number
EP-C-16-020, September 30, 2018. Technology Response Database that accompanies this report provides these
detailed results of the long-term replacement and reference airplane assessment.
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these long-term replacement airplanes were projected based on the available metric values of
reference airplanes,™111 which were grouped by airplane type and manufacturer.
Also, uncertainty bands in determining the metric value improvement estimates were
provided for the long-term replacement and reference airplane assessment. These uncertainty
bands differ by the magnitude of design improvement expected by airplane type. The more
challenging the design improvement, the higher the uncertainty band. For example, designing a
clean sheet airplane will result in a greater potential metric value improvement, but there are
more risks related to attaining the design improvement; therefore, a higher uncertainty band was
estimated. In contrast, a re-engine design improvement has less risk related to achieving the
improvement, and thus, a lower uncertainty band was estimated.
Table 2-1 above provides the results of the analysis of metric value reduction by airplane
variant for the years 2030 and 2040 (the 2030-2040 timeframe) using the long-term methodology
and years 2015, 2018, 2020, 2023, and 2028 (the 2015-2029 timeframe) using the short- and
mid-term methodology, which is described earlier in section 2.2.1.
2.3 Technologies
ICF identified and analyzed about seventy different airframe and engine technologies for fuel
burn reductions, as shown in Table 2-7 and Table 2-8. These technologies are mainly for the
short- and mid-term methodology, years 2015-2029, since the effective dates for the final
standards will be within this time frame: 2020 (or 2023 for airplanes with less than 19 seats) for
new type design airplanes and 2028 for in-production airplanes. Further details on these
technologies are presented in the appendix of the 2018 ICF updated analysis. Although weight-
reducing technologies affect fuel burn in-use, they do not affect the metric value for the final
GHG standards.XX1V Thus, ICF's assessment of weight-reducing technologies was not included in
this rule, which excluded about one-third of the technologies evaluated by ICF for fuel burn
reductions. Therefore, based on the methodology described earlier in section 2.2.1, ICF utilized
a subset of the about fifty aerodynamic and engine technologies to account for the improvements
to the metric value for the final standards (for in-production and in-development airplanesxxv).
The 2018 ICF updated analysis considered a number of technologies incorporated on
airplanes that had entered service since the initial 2015 analysis. Thus, there are actual service
histories to consider now, especially for natural and hybrid laminar flow. Also, the recent
completion of some major design changes (i.e., re-engine, re-wing) were assessed.
"" Reference airplane means an existing in-production airplane or in-development airplane that is expected to go
out of production in 2030-2040 timeframe (and which will have a replacement airplane take its place in the fleet
in the long-term).
XX1V The metric value does not directly reward weight reduction technologies because such technologies are also used
to allow for increases in payload, equipage, and fuel load (this is the case for incorporating weight reduction
technologies to in-production airplanes, but it may not be the case for new type design airplanes). Thus,
reductions in empty weight can be canceled out or diminished by increases in payload, fuel, or both; and, this
varies by operation. Empty weight refers to operating empty weight. It is the basic weight of an airplane
including the crew, all fluids necessary for operation such as engine oil, engine coolant, water, unusable fuel and
all operator items and equipment required for flight but excluding usable fuel and the payload.
xxv Airplanes that are currently in-development but will be in production by the applicability dates. These could be
new type design or redesigned airplanes.
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Table 2-7 Airframe and Systems Technologies
Airframe Technologies
Aerodynamic
Structural
Systems
• Adaptive Trailing Edge
• Advanced Metals
• Lightweight Lightening Strike
• Advanced Wingtip Devices
• Increased Composite
Protection
• Variable Camber Trailing Edge
Application
• More Electric Systems
• Re-Wing (non-retrofittable)
• Advanced Composites (non-
• On demand Environmental
• Riblet Coatings
retrofittable)
Control Systems
• Laminar Flow Control
• Re-Wing (non-retrofittable)
• Fuel cell Auxiliary Power Unit
• Natural and Hybrid
• Advanced Configurations (non-
(APU)
• Nacelle, Empennage, and Wing
retrofittable)
• Light interior
• Advanced Configurations (non-
• Titanium Landing Gear
• Fly By Wire
retrofittable)
• Lightweight Paint / Surface
• Carbon brakes
• Gap Reductions
Treatment
• Zonal Drying
• Aft Body Redesign
•
• Control Surface
• Light Profile

•
Table 2-8 Engine Technologies

Engine Technologies

Materials
Architecture
Systems
• Titanium Aluminide (TiAl)
• Ultra High By Pass(UHBP)
• Bleedless engines
turbine airfoils
engine (above 10 Bypass Ratio
• Electric engine start
• TiAl compressor airfoils
(BPR))
• High Pressure Compressor
• Ceramic-matrix composites
• UHBP (above 20 BPR)
(HPC) mod. Clearance control
(CMC) turbine shrouds/ Outer
• Open rotor
• Turbine mod. Clearance
Air Seal (OAS)
• Variable cycle
control
• CMC High Pressure Turbine
• Intercooled compressors
• Clearance control w/ feedback
(HPT) blades/ vanes
• Integrated propulsion system
• High Pressure (HP)/LP power
• CMC Low Pressure (LP) blades/
• Lightweight component fab
extraction sharing
vanes
techniques
• High eff. Oil/air cooler
• Organic Matrix Composite
• Reduced hub-tip ratio fan
• Recuperative exhaust
(OMC) fan blades
• Fan drive gear

• OMC case
• Next gen load sharing

• CMC exhaust nozzle
architecture

• Ceramic bearings


• Turbine coatings


• OMCstator


• OMC comp. cases


Aerodynamics
Sealing
Coating / Cooling
• Next gen engine airfoil designs
• Compressor blisks
• Compressor airfoil coating
• Optimized fan root fairing
• Turbine blisks
• Turbine air cooling air cooling
• Scalloped fan exhaust

• Next gen. turbine airfoil
• Low Pressure Ratio (PR) fan

cooling design
• Low drag inlet/nacelle


Airframe technologies: The airframe technologies that accounted for the improvements to the
metric values from airplanes included aerodynamic technologies that reduce drag. Drag-
reducing technologies included advanced wingtip devices, adaptive trailing edge, aft body
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redesign, laminar flow control (hybrid laminar flow control - empennage), riblet coatings, and
environmental control system (ECS) aerodynamics and on-demand ECS scheduling. For the
2018 ICF updated analysis, the technical feasibility projection was increased for riblet coatings
due to recent progress on this technology, and the commercial feasibility was mainly decreased
for hybrid laminar flow control (empennage) due to the decrease in fuel prices.
Engine technologies: Engine manufacturers target improvements to address thrust specific
fuel consumption (TSFC), propulsion system weight reduction, maintenance cost reduction,
performance improvement, or system reliability. Though there are a range of improvement
drivers that can be embodied (including the use of better materials and optimization in engine
architecture), the gas turbine engine technologies that accounted for incremental reductions to
the metric values are mainly driven by improvement in airfoil aerodynamics and sealing
technologies. Airfoil aerodynamics technologies included next generation engine airfoil designs,
and sealing technologies included compressor and turbine blisksXXV1.30 For the 2018 ICF updated
analysis, the fuel burn reduction impact and commercial feasibility were increased for engine
technologies due to recent progress in the technologies listed above. This reflects the
observation that engine manufacturers are constantly improving these technologies, and it seems
to be a high priority for industry to incorporate such engine technology improvements.
Details on the airframe and engine technologies listed above for metric value improvement
are described below in sections 2.3.1 and 2.3.2 and the appendix for Chapter 2. Further details of
these technologies are also provided in the 2018 ICF updated analysis (particularly section VII
Appendices, Appendix 6, Technology Profiles).
2.3.1 Airframe Technologies
2.3.1.1	Advanced Wingtip Devices
Advanced wingtip devices are successful at increasing the lift-to-drag ratio of an airplane,
which improves its performance (including takeoff and climb performance) and reduces fuel
burn. The annual rate of fuel burn improvement is projected to be 3.5 percent for all the airplane
categories. These advanced wingtip devices include winglets (single or split) or span extensions.
Enlarging the span or the vertical extent of the wing reduces the lift-induced drag by spreading
the vorticity, decreasing the adverse impact that this vorticity has on the remainder of the wing.
There are tradeoffs between extending the wing horizontally compared to installing a winglet.
Aerodynamically, a wing horizontal extension is more effective in decreasing the induced drag
compared to an equivalent increase in the vertical extent of the wing. The equivalent horizontal
extension can be made smaller for the same induced drag reduction, and this further reduces the
viscous drag penalty. However, the horizontal extension induces larger bending moments on the
wing and thus results in a heavier wing, which makes it more challenging to integrate on a wing
that has already been designed.
2.3.1.2	Adaptive Trailing Edge
XXV1 Blisks means disks and individual blades are manufactured in one piece - blades are not inserted into disk later -
which removes the need for blade roots and disk slots.
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The objective of the adaptive trailing edge is to tailor the wing to minimize the drag at
different flight conditions. Instead of using hinged surfaces to modify the shape of the wing,
morphing the wing (or morphing the trailing edge of the wing) changes the shape of the structure
continuously by using piezoelectric materials or by internal mechanisms. (A morphing wing can
change its geometric shape during flight to optimize performance.). The outcome is a smooth
variation in the shape of the wing with no gaps that would otherwise add to the overall drag.
There are two possibilities to implementing the morphing trailing edge: (a) local morphing on
the trailing edge or conventional moving surfaces to augment or replace the conventional
adaptive trailing edge technology or (b) replace all control surfaces with morphing. The latter
possibility would have the advantage of eliminating the drag from gaps, and it enables a finer
control of the spanwise distribution of the trailing edge camber. The annual rate of fuel burn
improvement of this technology is projected to range from 0.5 to 2 percent for the various
airplane categories. However, the small business and general aviation category is projected to
have no fuel burn improvement from this technology (due to technical or economic reasons).
2.3.1.3	Aft Body Redesign
There are possibilities for aerodynamic improvements on the aft body of numerous
contemporary airplanes. The majority of aerodynamic analysis and design effort targets the
wings; however, opportunities for drag reduction on non-lifting parts such as the fuselage have
also become an emphasis of airplane manufacturers. For example, this technology is on the
Boeing 737 MAX.xxvii
For in-production airplanes, it is not practical for airplane manufacturers to conduct a major
redesign of the aft body, but it is possible to make modifications on the existing shape. The area
where the horizontal and vertical tails join the fuselage is especially important for interference
drag, and it is an effective area for redesign. The annual rate of fuel burn improvement of this
technology is projected to range from 1 to 1.3 percent for the various airplane categories.
2.3.1.4	Hybrid Laminar Flow Control - Empennagexxvul
Skin-friction drag is one of the main sources of drag on an airplane, and it typically accounts
for over 50 percent of the total drag at cruise operations. This drag is due to the friction caused
by the boundary layer.XX1X Boundary layers can be either laminar or turbulent, and the former
produce less friction and therefore less drag. Laminar boundary layers are also thinner,
contributing to a reduction in pressure drag as well. Because of the combination of high speed
and scale of commercial transport airplanes, the boundary layers on these airplanes are almost
entirely turbulent. It is especially challenging to attain a laminar boundary layer in this flow
xxvii "Tilc [aj( cone wiii be extended and the section above the elevator thickened to improve steadiness of air flow.
This eliminates the need for vortex generators on the tail. These improvements will result in less drag, giving the
airplane better performance." April 11, 2012. Available at fattp://www.b737.org.uk/737max.htm (last accessed
March 17, 2020)
xxv in j]le empennage, commonly called the tail assembly, is the rear section of the airplane. Its primary purpose is to
provide stability to the airplane. It includes the horizontal stabilizer and the vertical stabilizer or fin. Available at
fat tp: //www. p i to tfrie nd. co m/t ra i ni n g/ffl i gfaf	f rai ni n g/fxd	w i n g/e mp. htm (last accessed March 17, 2020).
xxk j]le boundary layer is a thin layer of air flowing over the surface of an airplane wing or airfoil (as well as other
surfaces of the airplane). Available at http://www.Dilotfriend.com/training/flight training/aero/boundarv.htm
(last accessed March 20, 2020).
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regime through passive means, particularly in lifting surfaces that are swept. Even though they
begin as laminar at the leading edges, they will quickly transition to turbulent unless the right
technology is utilized.
Natural laminar flow (NLF) depends exclusively on the careful design of the aerodynamic
shape to delay the transition of the boundary layer from laminar to turbulent as much as possible.
The higher the speed and the longer the dimensions, the more difficult it is to attain.
Furthermore, wing sweep has an adverse effect. Therefore, NLF is currently not feasible on
wings of commercial transports flying at high subsonic speeds.
Yet, recent progress has made it possible to attain NLF for a substantial portion of engine
nacelles, as is the case in the Boeing 787. NLF necessitates particularly tight manufacturing
tolerances and focus on the paint material and thickness. The Boeing 777X will also have
nacelles with NLF.
The boundary layer will ultimately transition from laminar to turbulent when the streamwise
distance is long enough. To increase the extent of laminar flow beyond what is possible through
passive means of NLF, or to ensure laminar flow with an adverse shape or flight condition, it is
possible to use hybrid laminar flow control (HLFC).
HLFC uses suction to delay the transition from laminar to turbulent and, therefore, generate
areas with a laminar boundary layer. This technology was tested for the 787-9 vertical tail.
Typically, the suction is generated by mechanical means and requires a source of power. The
patent filed by Boeing seems to show a system that does not necessitate mechanical power: it
sucks the boundary layer in through tiny holes in the skin to a plenum, or hollow chamber, inside
the leading edge vertical tail that is then connected to an area of lower pressure elsewhere. This
technology decreases the complexity of the system and eliminates the power requirement,
making it commercially more viable. The annual rate of fuel burn improvement of this
technology is projected to range from 0.3 to 2.5 percent for the various airplane categories.
However, as indicated earlier since the initial 2015 ICF analysis, the commercial feasibility of
this technology has reduced — primarily due to the decreased price of jet fuel. Also, based on
Boeing's continued review of this technology for drag reduction for the 787, we found that
because of the current wing shape and several other factors, the technology is not producing as
effective a balance of cost and performance as initially expected.
2.3.1.5 Riblet Coatings
Riblets are a pattern of tiny ridges that are aligned in the direction of the flow. This
technology decreases the turbulence at the surface in the direction perpendicular to the flow,
decreasing the skin friction drag. Although this is a well understood approach of decreasing skin
friction drag, the issues of this technology are the manufacturing cost, the durability in service,
and maintenance. With the rising value of decreasing drag, there is a chance that this technology
will be deployed early in the next decade. The annual rate of fuel burn improvement of this
technology is projected to range from 0.5 to 1.5 percent for the various airplane categories. For
the updates to the technologies in the 2018 ICF updated analysis compared to the initial 2015
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ICF analysis, Airbus and Lufthansa are already experimenting with shark skin coatings,xxx and
British Airways has conducted a test trial with riblet coatings on the transatlantic route-dedicated
Airbus A318. Thus, as described earlier, for the updates to riblet coatings in the 2018 ICF
updated analysis compared to the initial 2015 ICF analysis, the technical feasibility projection
was increased for this technology due to this recent progress on this technology.
2.3.1.6 ECS Aerodynamics and On-Demand ECS Scheduling
The airplane's environmental control system (ECS) provides air supply, thermal control, and
cabin pressurization for the crew and passengers. In addition, avionics cooling, smoke detection
and fire suppression are normally considered part of an airplane's environmental control system.
The Boeing 787 and Airbus A350 both have aerodynamic and power-saving improvements to
the ECS system. The inlet and outlet ducts to the system's compressor have been optimized to
decrease the pressure drag. Also, on-demand ECS scheduling now enables engines to power the
system only when necessary as opposed to powering it for an entire flight. The annual rate of
fuel burn improvement of this technology is projected to be 0.6 percent for all the airplane
categories.
2.3.2 Engine Technologies
Airplane gas turbine engine manufacturers are continually incorporating technologies into
engines to address TSFC, performance improvement, or system reliability. Engine technologies
include a range of improvements, such as materials (e.g., ceramic matrix composite parts),
architecture (e.g., optimizing thermal efficiency versus propulsive efficiency), airfoil
aerodynamics, sealing (e.g., blade tip clearances), and cooling (i.e., blade cooling to enable
higher operating temperatures). Usually, it is airfoil aerodynamics and sealing technologies that
are applied to engines in new in-production airplanes to improve fuel burn, and it is projected
that the annual rate of fuel burn improvement of these technologies will be 0.2 percent for all
airplane categories (except a 0.1 percent annual rate for turboprops). An airplane gas turbine
engine is a highly integrated set of systems that typically limit the number of modifications that
can be made to a new engine after entry into service.
Furthermore, engine manufacturers regularly produce performance improvement packages
(PIPs) that improve fuel burn, reduce maintenance cost, and/or improve performance —
representative PIPs are shown in Table 2-9. below. A minimum of 0.5 to 1 percent fuel burn
improvement (total) is needed to justify the development and certification costs of PIPs. With
the numerous new engine developments that occurred recently or are ongoing, technologies
developed for new engines (such as LEAP-X and Trent XWB) are being migrated back to prior
versions of existing engines (e.g., technology developed for the Trent 1000 and 700EP was
incorporated into a PIP for the Trent 900). While PIPs will vary from engine to engine,
technologies developed in recent engine programs (e.g., GEnx, Trent 1000/XWB, geared
turbofan (GTF), LEAP-X, etc.) will be incorporated into existing engines.
xxx Shark skin riblet coatings have a structure like the skin texture of sharks. Available at
https://www.tr3velandleisure.com/airlines~airports/sharkskin~squid~helping~build~planes (last accessed March 17,
2020).
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Technology and Cost
Table 2-9. Representative Engine Performance Improvement Packages
Trent 900
V2500
CFM56-5B / -7B
Trent 900
Introduction of elliptical leading-
edge modifications throughout
the entire compression system
Improved high- and
intermediate pressure
(HP/IP) compressor
blades and vanes
Improved fan and outlet
guide vanes
Tweaks to the air management
system
New software for electronic engine
control (EEC)
New variable stator vane (VSV)
and bleed valve schedules
High Pressure Compressor (HPC)
•	Improved airfoil technology
•	Improved airfoil surface
finish
•	Controlled leading edge
profile
•	Latest design standards
Re-staggered first row of low
pressure turbine (LPT) vanes
New materials / coatings,
advanced sealing, and airfoil
cooling in the high pressure turbine
(HPT)
HPC kit - improved blade
aerodynamics
HPT blade kit - low shock airfoil
with improved cooling
LPT nozzle kit - improved cooling
Lower NOx combustor
2.4 Technology Application
Based on the short- and mid-term methodology and the resulting expected metric value
improvements described above for airplanes (or business as usual improvements to airplane
metric values in the absence of a standard), the EPA does not project the final GHG standards
will cause manufacturers to make technical improvements to their airplanes that will not have
occurred in the absence of the standards. The EPA projects the manufacturers will meet the
standards independent of the EPA standards for the following reasons (as was described in
section VILA of the preamble):
Manufacturers have already developed or are developing improved technology in response to
the ICAO standards that match the final GHG standards;
ICAO decided on the international Airplane C02 Emission Standards, which are equivalent to
the final GHG standards, based 011 proven technology by 2016/2017 that was expected to be
available over a sufficient range of in-production and on-order airplanes by approximately 2020.
Thus, most or nearly all in-production and on-order airplanes already meet the levels of the final
standards;
It is likely that those few in-production airplane models that do not meet the levels of the final
GHG standards are at the end of their production life and are expected to go out of production in
the near term; and
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Technology and Cost
These few in-production airplane models anticipated to go out of production are being
replaced or are expected to be replaced by in-development airplane models (airplane models that
have recently entered service or will in the next few years) in the near term — and these in-
development models have much improved metric values (which are expected to meet the final
standards) compared to the in-production airplane model they are replacing.
Therefore, a technology response will likely not be necessary for airplane models to meet the
final standards. This result confirms that the international Airplane CO2 Emission Standards are
technology-following standards, and that the EPA's GHG standards as they will apply to in-
production and in-development airplane models will also be technology following.
For the same reasons, a technology response is not necessary for new type design airplanes to
meet the final GHG standards. The EPA is currently not aware of a specific model of a new type
design airplane that is expected to enter service after 2020 (no announcements have been made
by airplane manufacturers). Additionally, any new type design airplanes introduced in the future
will have an economic incentive to improve their fuel burn or metric value at the level of or less
than the final standard.XXX1
2.4.1 Technology Responses
As described above, the final standards will likely not require a technology response.
However, it is informative to describe the different steps in our technology response
methodology for the short- and mid-term (for years 2015-2029) in addition to the discussions
above on short- and mid-term methods and technologies. First, we determined the difference in
metric value of an airplane model compared to the stringency levels of stringency scenarios.
Note, Chapter 6 of this TSD describes the three stringency scenarios we analyzed for this rule,
and these three scenarios comprise the final standards and two alternatives. Using PIANO
metric valuesXXX11 and the metric value reduction forecast, we compared the projected metric
values for each airplane model to the stringency levels of the scenarios in the year of their
effective dates — to estimate the difference between the expected performance of the airplane
model to stringency scenarios. Second, we sorted out from the analysis those airplane models
that will end production before an effective date of a stringency scenario. Third, airplane models
that met the levels of the stringency scenarios were sorted out next, and thus, the remaining
airplane models were those models that did not meet at least one of the stringency scenarios.
Chapter 6 of the TSD discusses the airplane models that do not meet the stringency scenarios and
the impacts associated with these scenarios.
ICF developed supply curves that provide the projected metric value improvement of a given
technology against its estimated non-recurring costs (NRC).31 NRC is described in detail later in
section 2.5. The outcome of the supply curves is a ranking of the incremental technologies by
airplane family, from most cost effective to least cost effective. For determining a technical
response, it was assumed that a manufacturer will invest in and apply the most cost-effective
technologies to start and subsequently continue to the next most cost-effective technology — to
attain the incremental metric value improvements anticipated by the metric value reduction
xxx! Tilcrc will be new type design airplanes in the future, and we expect these airplanes to meet the final standards.
This projected outcome would be the baseline status of airplanes, or it would be the business as usual status of
airplanes without this rule,
xxxn as indicated earlier, baseline metric values were generated using PIANO data.
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Technology and Cost
forecast. When the new technology is implemented, there is expected to be a step change in the
metric value reduction - where metric value reductions are achieved all at once (instead of
gradually).
For an example, see Figure 2-3 below (MV improvement percentage versus NRC ($million)),
which presents business as usual improvements for the Supeijet 100 airplane. From the base
year to an example effective date of standards (2025), the metric value reduction forecast
estimates a given reduction — 6.25 percent. Yet, to attain that amount of reduction, the
manufacturer will need to incorporate Advanced Wingtip Devices and Engine Technologies onto
the airplane, for a total of 7.7 percent in metric value reductions. Although the smoothed
forecasted reduction shown in the supply curve is 6.25 percent at the example effective date, the
actual reductions are greater since the metric value improvement from the technology is fully
realized when the technology is incorporated onto the airplane. Representative metric value
improvements and their associated non-recurring costs by airplane category are shown in Table
2-10 and Table 2-11 below. Also, the NRC and fuel burn reduction for each technology
described earlier in section 2.3 are provided in the technology profiles in the Appendix of this
chapter. Also, see the Appendix for examples of supply curves by the different airplane
categories.
Example: Superjet 100 Incremental Improvement Technoloqy Supply Curve
$1,600 -[				Traill.,^.
Concrd Surface- Opfmal Control
Lskva for horizontal stab trim
Nacuril Lam nar Rm Control -
MkHH
Gap RtdiKtiws - Sire, SpoifcKi,
etc.
Aerodynarric APtl Fairing /Aft
body rrdasgn
Other Systems Im provemena
ECS Aero and On Dem and ECS
Scheduling
Otfier Aarodyramc Improvements
R*duei#* Pr&fiie oftht L«ehti
Enpne Technologies
W ngTip Dtvfc«f -
— —	Retrofit
^ MV SuddCurve Line
0%	2%	4%	6%	8%	10%	12%	14%
Metric Value Improvement
Accelerated technology insertion analysis methodology:
Q For a given future year, a manufacturer's technology insertion is assumed to have progressed up the supply curve
Q Implementation of those technologies may yield a greater MV reduction than the smoothed MV forecast implies
^ Remaining more expensive technologies are the ones eligible for accelerated investment
Figure 2-3. Example Supply Curve
The approach below was used to develop a projected business as usual metric value
improvement in the form of a smoothed forecast for each airplane type that needs a technology
response (to comply with a stringency scenario):
$1,400
Gap to scenario (%)
2025 impnovemert Level
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Technology and Cost
1.	For a given future year, a manufacturer's technology insertion was assumed to have
moved up the supply curve (i.e., technologies with the largest improvement and most
economical cost are implemented first). Thus, these most economical technologies
will have already been applied by the stringency year and will not be available for
future investment.
2.	The smoothed forecasted incremental metric value improvement is overlaid by the
stringency year on an airplane model's distinct supply-curve. From this overlay, the
most economical technologies were identified that already have been applied by the
stringency year.
3.	The remaining technologies not yet applied are available for accelerated investment
when a technology response is necessary. For each in-scope airplane model, these
technology responses were assessed using PIANO data.
2.4.2 One Percent Additional Design Margin for Technology Response
In the event where a technology response was modeled, we assumed that a manufacturer will
need to provide an additional 1 percent design margin beyond the level needed to achieve the
standard. This design margin ensures the technology response attains the level of the standard,
where in reality fuel burn reductions for a given technology response can be variable.
2.5 Estimated Costs
This section provides the elements of the cost analysis for technology improvements,
including non-recurring costs (NRC), certification costs, and recurring costs. As described,
above, the EPA does not anticipate new technology responses due to the GHG standards, and,
consequently, we do not expect any costs (technology costs) from the GHG standards. However,
it is informative to describe the characteristics of these different cost elements. While
recognizing that the GHG rule does not have NRC, certification costs, or recurring costs, it is
informative to describe the elements of these costs (particularly to provide context for the NRC
of an alternative described later in Chapter 6).
2.5.1 Non-Recurring Costs
Non-recurring cost (NRC) consists of the cost of engineering and integration, testing (flight
and ground testing) and tooling, capital equipment, and infrastructure (capital). Engineering and
integration costs include the engineering and research and development (R&D) needed to
progress a technology from its current technology readiness status to a status where it can be
incorporated into a production airframe,XXX1U as well as costs for airframe and technology
integration. Testing costs include the fixed costs for test instrumentation, infrastructure, and
project management and variable costsxxxlv associated with the amount of required flight and
ground testing. Capital costs include the following: (a) tooling necessary to change the
production line to support the fuel burn improvement, (b) modifications to plant, property, and
equipment, and (c) other items such as information technology and supply chain systems.
xxxm §ee description of technology readiness levels (TRLs) earlier in section 2.1.
XXX1V Variable costs are flight and ground testing costs that scale with the amount of time used for testing. For
example, fuel costs and crew/test engineer salaries scale with the time for flight and ground testing.
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Technology and Cost
As described earlier for the technology improvements and responses, ICF conducted a
detailed literature search, conducted a number of interviews with industry leaders, and did its
own modeling to estimate the NRC of making modifications to in-production airplanes. The
EPA used the information gathered by ICF for assessing the cost of individual technologies,
which were used to build up NRC for incremental improvements (a bottom-up approach). These
improvements are for 0 to 10 percent improvements in the airplane fuel efficiency metric value,
and this magnitude of improvements is typical for in-production airplanes (the focus of our
analysis). In the initial 2015 ICF analysis, ICF developed NRC estimates for technology
improvements to in-production airplanes, and in the 2018 ICF updated analysis these estimates
have been brought up to date. The technologies available to make improvements to airplanes are
described earlier in section 2.3.
The methodology for the development of the NRC for in-production airplanes consisted of
five steps. First, technologies were categorized either as minor PIPs with 0 to 2 percent (or less
than 2 percent) fuel burn improvements or as larger incremental updates with 2 to 10 percent
improvements. Minor PIPs were aerodynamic cleanups (e.g., redesigned fairings) and other fuel
burn improvements where frequently compliance is attained by analysis and without dedicated
flight test airplanes.xxxv Large incremental updates were aerodynamic or structural
improvements (e.g., winglets) that reduce fuel burn, where compliance includes flight test
programs - typically with production airplanes. Second, the components of non-recurring costs
were identified (e.g., engineering and integration costs), as described earlier. Third, baseline
non-recurring cost component proportions were developed by incremental technology category
for single-aisle airplanes. Fourth, the baseline NRC components for a single-aisle airplane were
scaled to the other airplane size categories. Fifth, we compiled technology supply curves by
airplane model. Appendices A and B of this Chapter 2 and the 2018 ICF updated analysis
provide a more detailed description of this NRC methodology for technology improvements and
results.32
2.5.1.1 Non-Recurring Costs Component Proportions
For single aisle airplane technologies, the proportions of the various NRC components differ
whether it is an airframe or engine technology.33 Also, for airframe technologies, this proportion
varies whether the technology is a minor PIP or a large incremental update. Figure 2-4 below
shows the NRC component proportions for the category of single aisle airplanes. Generally, for
engine improvements, flight and ground testing is a substantial portion of the NRC. However,
for minor airframe PIPs, the NRC is mainly engineering costs. Since minor airframe PIPs
typically do not necessitate dedicated flight testing, NRC is focused on the engineering design
and analysis required to analytically show compliance for PIPs. Large incremental updates for
airframes necessitate a flight test program, and thus, a substantial fraction of the NRC is from
this testing.
" Compliance for minor PIPs would typically include only minor ground, wind tunnel, and flight tests (with the
analysis).
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Technology and Cost
Engrg
35%
Engrg
. 55%
Engrg
, 85%
Airframe
Large
Airframe
Minor PIP
Engine
Engrg = Engineering and Integration PIP = performance improvement package
Figure 2-4. Single Aisle Category Non-Recurring Cost Component Proportions
2.5.1.2 Non-Recurring Cost Scaling Factors
Non-recurring cost components for metric value improvement scale differently with airplane
size — or maximum takeoff mass; therefore, different scaling factors were used. Engineering and
integration costs and capital costs are not strongly correlated with airplane size, and thus,
airplane realized sale price was used to scale this component. Flight and ground testing scales
with airplane operating costs; therefore, block hourxxxvl average operating costs were used to
scale with this component. Table 2-10 below shows estimates of these scaling sources.
Engineering and capital scale by 15 percent of the differential in average realized sale price,
with the single aisle airplane category as the baseline.xxxv" Testing scales with 100 percent of the
operating cost differential, using the single aisle airplane category as the baseline. This results in
factors that scale the cost components for the baseline of the single aisle airplane category to the
other airplane categories, as shown in Table 2-11.34 Using these scaling factors, NRC was
estimated for technologies for each of the airplane categories. (The basic premise is that we
believe that the larger the airplane, the more expensive the engineering and integration cost is.
Anchoring single aisle airplane as the base index for engineering and integration, as an example,
we then extrapolate the small twin aisle engineering and integration cost index by airplane
realized price. See example calculation below.)
XXXV1 Block hour means the time from when the airplane door closes at departure until the airplane door opens upon
arrival (for a given flight).
xxxvn j0 derive the 15 percent scaling factor for engineering and integration costs, we conducted interviews with
market experts to confirm the appropriate factors for engineering and integration ~ and that engineering and
integration cost does not scale linearly with airplane value (or realized sale price).
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Technology and Cost
Table 2-10 - Non-Recurring Cost Component Scaling Factor Sources
Aircraft
Category
Average Realized
Sale Price
Avg Operating Cost
($/Btock Hour)
Small BGA
$10M
$1,340
Large BGA
S40M
$2,688
Turboprop
$25M
$2,016
Regional Jet
S30M
$2,688
Single Aisle
S45M
$4,538
Small Twin
Aisle
S130M
$8,143
Large Twin
Aisle
S165M
$10,500
Very Large
Aircraft
$195M
$14,449
Table 2-11 - Non-Recurring Cost Component Scaling Factors
Aircraft
Category
Engineering &
Integration Cost
Flight & Ground Test
Tooling, Capital
Equipment!, &
Infrastructure
Small BGA
0.88
0.30
0.88
Large BGA
0.98
0.59
0.98
Turboprop
0.93
0.44
0.93
Regional Jet
0.95
0.59
0.95
Single Aisle
1
1,00
1
Small Twin
Aisle
1,28
1.79
1.28
Large TWin
Aisle
1.40
2.31
1.40
Very Largo
Aircraft
1.50
3.18
1.50
Below is an example calculation of the engineering and integration cost.
We assumed a representative realized price of:
•	Single aisle: $45M
•	Small twin aisle: $130M
•	Large twin aisle: $165M
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Technology and Cost
We then scale the engineering and integration cost by 15 percent of the differentialxxxvm in
average realized prices.
•	Small twin aisle: 1+15%($130M-$45M)/$45M= 1.28
•	Large twin aisle: 1+15%($165M-$45M)/$45M=1.40
For all large incremental updates (2 to 10 percent improvements), it was assumed that there is
a minimum $5 million (M) fixed cost, and this fixed cost was used for all incremental upgrades
(which meant the same amount of minimum fixed cost regardless of technology or airplane
category). This minimum fixed cost is for a manufacturer's overhead of basic program
management that comes with any degree of improvement
For an example of the use of the NRC scaling factors by airplane category, see Figure 2-5
below that represents winglets — which are a large incremental update. For the single aisle
airplane baseline, the total NRC is comprised of the following components: 3 percent baseline
fixed, 52 percent engineering and integration, 40 percent testing, and 5 percent capital. For this
example, an NRC of $173 million was used for the category of single aisle airplanes. With this
baseline, the cost component breakdown provided earlier in Table 2-10 separated the total NRC
into the different components.35
$M NRC
¦Tooling, Capital
Equip. &
Infrastructure
¦ Flight & Ground
Test
B Engineering &
Integration
¦ Minimum Fixed
Cost
Turboprop Regional Jet Single Aisle Small Twin Large Twin Very Large
Aisle	Aisle Aircraft
Figure 2-5. Example Non-Recurring Cost Scaling by Airplane Category - Large Incremental Update
xxxvm j]le approach of scaling the engineering and integration from the single aisle category to the other airplane
categories using the 15% differential in average realized prices was developed by ICF, based on their data
sources. As described earlier in this chapter, the data sources for the 2018 ICF updated analysis are detailed in
section II. 1.2 of this ICF analysis (or this ICF report). These data sources include ICF's broad and thorough
market interview program (with key individuals in the aviation industry and university/research organizations),
research, and knowledge gained through past work on in-depth aviation cost models.
$400
$350
$300
$250
$200
$150
$100
$50
SO
$375
$305
$257
$173
$128
$140
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Technology and Cost
2.5.2 Comparing the EPA NRC to ICAO/CAEP NRC for International Airplane CO2
Emission Standards
As described earlier, ICAO's CAEP conducted an analysis of the international Airplane CO2
Emission Standards, which were agreed to at CAEP in February 2016, and this analysis included
an assessment of the NRC. For purposes of showing all the available data on NRC for the
standard, we are providing a comparison of the NRC costs in our analysis to the NRC costs in
the CAEP analysis. Note that CAEP published a report of their meeting in February 2016, and
Appendix C of this meeting report is a summary of the methods and results - for costs and
emission reductions — from the CAEP analysis.36 Some of the information used in the CAEP
analysis is not available in this report and thus to the public, due to commercial sensitivities.
Any information from the CAEP analysis that is not in the report of the February 2016 CAEP
meeting cannot be shared outside of CAEP, and thus, it will not be provided in this EPA TSD.
As described in the 2015 ANPR, CAEP developed an approach for estimating NRC that was a
function of an airplane's MTOM and the required metric value improvement (percent metric
value improvement for a technology response), which CAEP termed the Continuous
Modification Status (CMS) approach. Based on past practice, industry provided estimates for
developing clean sheet designs and redesigns, only including high level information that has
been made available to the public. As a result, this was a top-down estimate which included all
airplane development costs (type certification, noise, in-flight entertainment, etc.), not just those
costs for CO2 improvements.
Since the initial dataset provided by industry only included major changes (or major
improvements), the EPA supplemented this dataset with an estimate of CCh-only improvements,
which was a bottom-up estimate. These changes are much smaller, on the order of a few percent,
and could be applied to in-production airplanes. As described earlier, we contracted with ICF to
develop an estimate of the cost to modify in production airplanes to comply with CO2 standards
(the initial 2015 ICF analysis).37 The results from this 2015 ICF peer-reviewed study (for small
changes) were then combined with inputs from the industry and the other CAEP participants (for
large changes) to develop the CO2 technology response and cost estimation. For the cost
estimation, the CAEP combined the two different methodologies to develop the final cost
surface.XXX1X Due to this combination of these methods for CAEP's CMS approach, CAEP
indicated that the accuracy of the costs generated by the NRC methodology is representative and
considered fit for purpose.
As described above, CAEP's top-down approach in NRC for large changes would be seen in
redesigns or new type designs. For redesigns that result in new series of an established model,
these types of changes may include redesigned wings, new engine options, longer fuselages,
improved aerodynamics, or reduced weight. When making significant design changes to an
airplane, many other changes and updates get wrapped into the process that do not affect the CO2
emissions of the airplane, and redesigns may not have been spurred solely by changes to fuel
efficiency (CO2 reductions). This confluence of changes led CAEP to agree that it was
reasonable to use the full development cost for a new type design or redesign for significant
design changes. Total costs for past projects were used to estimate non-recurring cost for the
xxxix jjlc (W0 datasets were merged together, and a single cost surface was then generated to calculate the cost to
modify any airplane based on the MTOM, and percent metric value change needed.
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Technology and Cost
CAEP analysis. This type of airplane improvement/development program has historically
ranged approximately from $1 to $15 billion depending on the size of the airplane and scope of
the improvements desired.
As discussed above, CAEP's bottom-up approach was used to model smaller incremental
metric value changes to airplane design. CAEP agreed that the above top-down approach is not
the best approach for minor changes or incremental improvements, because the significant
design efforts include many changes that are not be required for smaller CO2 reductions. The
EPA used the information gathered by ICF in their 2015 report to provide input to CAEP on the
cost for individual technologies, and the ICF's information was used to build up CAEP's non-
recurring costs for these incremental improvements (a bottom-up approach). The technologies
available to make incremental improvements to airplanes are wide ranging and airplane specific.
Some examples of technologies are described earlier in section 2.3. As an example, in the initial
2015 analysis, ICF estimated that depending on the additive nature of specific technologies and
the magnitude improvement required, the cost to incrementally improve the Boeing 767 could
range from approximately $230 million to $1.3 billion US dollars (3.5 percent to 11 percent
metric value improvement).38
CAEP's CMS approach was based on the functional form of the NRC surface as provided in
Equation 2-4 below.39 NRC is measured in billions of US Dollars with a 2010 reference year.xl
The NRC surface has been calibrated to generate NRC estimates across a broad range of airplane
sizes or MTOMs (MTOM is the same as MTOW) and metric value improvements. The method
consists of a single cost surface that is a function of metric value improvement and airplane
MTOM.
Equation 2-4 Function of CAEP's NRC Surface
Reference	Reference	Aircraft
Airframe NRC	Engine NRC	Si* Sctiing
Where coefficients andfunctions; A, B, C, D andf(AMV) are defined as follows:
NRC Surface Coefficients
ABC
0.188902 3.247077 -0.142274
All coefficients are regressed based on metric value improvement data, except for D, which
along with f(AMV) is represented as a sigmoid function, as shown in Figure 2-6 below. Since
boundaries of metric value improvements differ with MTOM (or MTOW), the cost surface is
driven by a normalized metric value improvement. The normalized metric value improvement is
generated by:xh
xl CAEP's NRC is measured in billions of US Dollars with a 2010 reference year.
xh The Metric Value Improvement Upper and Lower Bounds were airplane specific terms developed by CAEP.
These terms were not discussed, nor were data provided on them, in the publicly available Appendix C of the
February 2016 CAEP meeting report, and thus, they are not described further in this EPA TSD.
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Technology and Cost
Equation 2-5 Equation to Calculate AMV
AMV = |MV Improvement\ — MV Improvement Lower Bound
Equation 2-6 Equation to Calculate Normalized MV Improvement
Normalized MV Improvement = x
AMV
MV Improvement Upper Bound - MV Improvement Lower Bound
0.75
0.7
0.65
0.6
a
0.55
0.5
0.45
0.4
D = 0,5453 +
0,697 - 0,5453
1 _j_ e (-2 5 (*-0.3))
0.2
0.4	0.6
x (Normalized AMV)
0.8
0.16
0.14
0.12
0.1
>
S 0.08
0.04 :	Q15
>	1 + e(-2six-,m
0.2	0.4	0.6	0.8	1
x (Normalized AMV)
Figure 2-6. CAEP NRC Surface's Coefficient D (left) and f (AMV) (right) Formulation
Table 2-12 and Table 2-13 below show a comparison of today's NRC results from the EPA
analysis (based on 2018 ICF updated analysis) to the results of the ICAO/CAEP's NRC Surface
(for the CAEP 10 meeting in 2016): NRC ($B) for percent metric value improvement. Table
2-12 and Table 2-13 provide NRC for representative airplanes in each airplane category, ranging
from a percent metric value improvement of 3.5 percent to greater than or equal to 10 percent.
Note that ICAO/CAEP's NRC are a function of MTOM, and nearly all the representative
airplanes and associated airplane categories have different MTOMs, which shows how the
ICAO/CAEP NRC changes with MTOM. The results from the ICAO/CAEP NRC surface are on
average about 170 percent greater compared to EPA's analysis. Table 2-12 indicates that the
results from the CAEP NRC surface are on average about 90 percent greater for small BGA
through single aisle airplane categories, and Table 2-13 shows that the CAEP NRC are on
average 245 percent greater for small twin aisle through large quad categories.
These results are expected for two reasons. First, CAEP's technology responses were based
on technology available in 2016-2017 (or frozen technology 2016-2017) — compared to the
EPA's responses that considered technology available by 2017 and assumed continuous
improvement until 2040 based on the incorporation of these technologies onto airplanes. Also,
ICF considered the end of production of airplanes based on the expected business as usual status
of airplanes. Thus, ICF was able to use the actual effective dates of the final standards in their
analysis. Second, the CAEP NRC surface is a combination of the two different methodologies
discussed above, top-down and bottom-up approaches, and today's EPA NRC results were only
based on the bottom-up approach. Including the top-down approach in the CAEP NRC surface
likely adds to the overestimation of the CAEP NRC estimate because it includes all airplane
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Technology and Cost
development costs (type certification, noise, in-flight entertainment, etc.), and not just those costs
for CO2 improvements.
Table 2-12 Comparison Results of EPA NRC to CAEP NRC Surface ($ Billions) - Part 1
ICF
COit
ICAO
CNA
52S1
!£»
FA1
20001X
ICF
Celt
JOMJ
CL-iiS
ICAO
Global
aoao
ICF
Cast
ICAO
ATI
42-5
ICAO
AN
140
ICF
Cost
ICAO
CM
7«J
ICAO
ERJ
195 E2
ICF
COft
ICAO
A319-
131
ICAO
BUTT
of if-
700
ICF
Cost
ICAO
MI«U
NEO
ICAO
~ 717
0/it~
7MAX
0.10
0 08
0,13
0.10
0,14
0,18
0,10
0.13
0,14
0,10
0,16
0.20
0,20
0,22
0 77
0.20
0,23
0,23
0.20
0,23
0,45
0.30
0.48
0,70
0,20
0.44
0,48
0,30
0,59
0.82
0,40
0,92
0,90
0.40
0,95
0.95

0,23
0.45

0,43
0.71

0.45
0,49

0.61
0.84

0,9*
0.92

0,37
0.97
0.20
0.24
0.45
0.30
0.49
0,72
0,30
0.45
0,49
0,30
0,61
0.15
0,40
0,35
0.93

0.98
0.58

0.25
0.49

0,53
0.78

0.48
0,53

0,66
0.32

1,04
1.02

1,07
1.07

0,25
0,50

0.53
0,78

S.4E
0,53

0.66
0.93
0,50
1,04
1,02
0.50
1,07
1.07

0,28
0,50

0,54
0.80

0.49
0.54

0,67
0.34

1.0S
1.04

1,10
1,10
0,30
0,2§
0,51
0.40
034
0.80
0.30
0.50
0,5#

0.68
0.95

1,07
1.05

1,10
1.10
0.30
0,28
0.5#

0.58
O.S6

0.53
0.58

0.72
1.02

1.15
1,13

1.19
1,13

0,28
0.55

0.59
0.87

0.54
0,53

0,73
1.M

1.17
1.14

1,20
1.20

0,30
0,57

0.61
0,91

0.56
0,61
0,40
0.76
1.07

1,21
1.19

1,25
1,25

0,31
0,60

0,64
0.95
A *50
0.59
0,64

0.80
1.13

1,27
:

1,31
1,31

0.32
0.61

:
0,56

0.59
? ::

0,3©
1.14

1,28
1.25

1,32
1,32
0,50
0 =11
0.62

0.66
0,38

0,61
0,§§
0,50
0.82
1.16

1.31
1.28

1,35
1,35

0,33
0.63

0.67
0.99

0.62
0,67

0.83
1.18
0,80
1,33
1.30
0.80
1,37
1.37

0,34
0,65

0,63
1.01
0,60
0.63
0,63

0,85
1.20

1,35
1.32

1,33
1,39
0.60
0,35
0.67

0.71
1,04

0.66
0,71

0.87
1.23

1.33
1.36

1,44
1,44
0.80
0,31
0,68
0.60
0,72
1,06
0.70
0.67
0.72
0.60
0,89
_ :.=
1,00
1.41
1.38
1.00
1,46
1,46
Page: 50
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Technology and Cost
Table 2-13 Comparison Results of EPA NRC to CAEP NRC Surface ($ Billions) - Part 2
ire ifAA
Cost 3ER
Mi* 1,20
ICF ICAO
Cost B787-8
ic*o
B787-
li
ICf
CWSt
ic*e icao
AJ30- B777-
¦Jftt w|ri|
ICAO
ICf A330-
Cost 800-
NEO
ICAO
B777-
«K
ICF
Cost
ICAO ICAO
A380-8 B747 8
0.20
0.70
0.42
1 QQ
1.3o
2.03
2.05
2.Z7
2.28
2.33
2.35
2.54
158
2.68
2.82
2.85
2.91
2.95
3.00
3.10
0.45
i n
£,UL
2.17
2.20
2.43
2.45
2.50
1 CI
£«i3i£.
2.73
2.77
2.88
3.03
3.06
3.13
3.17
3.23
3.33
0.30
1.00
1,00
0.43
2.03
2.09
2.11
2.34
2.35
2,40
2.42
2.62
2,6©
2.76
2.91
2.93
3.00
3.04
3.10
3,13
0.48
2.30
2.37
2.40
2.65
2.67
2,73
2,75
*3 Q.Q
3.03
3.15
3.31
3.34
3,42
3,46
3,53
3,64
0.50 0.44
2.06
1.20 2.11
2.14
2.36
2.38
2.43
2.44
2.65
2.59
2.50
2.94
1 60 2.97
3.04
3.07
3 1 3
.13
3.23
0,54
2.64
2.71
2.75
3.05
3.06
3.14
3.15
3.43
3,48
3.62
3,81
3.85
3.93
3.91
4.06
4,19
1.00
1.10
0.30 0.67
2,80
2,88
1	Q1
3.27
3.29
O.JI/
3.40
3.74
1.20 3.81
2	QQ
*J 8
4.24
4.29
4.41
4.48
4.58
4.76
0,58
-1 77
2.44
2.47
2.75
2.77
2,84
2,88
3.15
3.20
3.35
3.56
3.50
3,71
3.76
4.00
2.5.3 Certification Costs
After the EPA issues the rulemaking for the GHG standards, the FAA will issue a rulemaking
to enforce compliance to these standards, and any potential certification costs for the GHG
standards will be attributed to the FAA rulemaking. However, it is informative to discuss
certification costs.
As described earlier, manufacturers have already developed or are developing technologies to
respond to ICAO standards that are equivalent to the final standards, and they will comply with
the ICAO standards in the absence of U.S. regulations. Also, this rulemaking will potentially
provide for a cost savings to U.S. manufacturers since it will enable them to domestically certify
their airplanes via the subsequent FAA rulemaking instead of having to certify with foreign
certification authorities (which will occur without this EPA rulemaking). If the final GHG
standards, which match the ICAO standards, are not adopted in the U.S., the U.S. civil airplane
manufacturers will have to certify to the ICAO standards at higher costs because they will have
to move their entire certification program(s) to a non-U.S. certification authority.xlu Thus, there
xln In addition, European authorities charge fees to airplane manufacturers for the certification of their airplanes, but
FAA does not charge fees for certification.
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Technology and Cost
are no new certification costs for the final standards.xlm However, it is informative to describe
the elements of the certification cost, which include obtaining an airplane, preparing an airplane,
performing the flight tests, and processing the data to generate a certification test report.
Earlier in section 2.5.1, the testing component of the NRC is described as including fixed
costs for test instrumentation, infrastructure, and project management, and this component of the
NRC includes different costs (and expected to be greater costs) compared to the testing costs
related to only certification discussed in this section. The testing included in certification costs is
only for certifying an airplane to the GHG standards, and for an existing in-production airplane
that is non-GHG certificated this means that the manufacturers will need to conduct some
amount of re-testing and pre- and post-test work to show compliance with the GHG standards.
In contrast, the testing component of the NRC includes the full amount of testing to incorporate a
technology improvement into an airplane and is not limited to testing only for purposes of
certification to GHG standards.
The ICAO certification test procedures to demonstrate compliance with the international
Airplane CO2 Emission Standards — incorporated by reference in this rulemaking — were based
on the existing practices of airplane manufacturers to measure airplane fuel burn and cruise
performance.40 Therefore, manufacturers already have airplane test data (or data from high-
speed cruise performance modelling, which they can use to demonstrate compliance with the
international Airplane CO2 Emission Standards). In the absence of the standards, the relevant
CO2 or fuel burn data will be gathered during the typical or usual airplane testing that the
manufacturer regularly conducts for non-GHG standard purposes (e.g., for the overall
development of the airplane and to demonstrate its airworthiness). In addition, such data for new
type design airplanes, where data has not been collected yet, will be gathered in the absence of a
standard. The baseline status for manufacturers is that they likely will have already done the
work needed to certify their airplanes in the absence of the final standards. These details further
support the rationale above for there being no certification costs for the final standards.
CAEP assessed the certification costs for the international Airplane CO2 Emission Standards.
The results of CAEP's assessment of certification costs were not described in the summary of the
CAEP analysis,41 and thus, we are unable to share these CAEP results in this EPA TSD.
Nonetheless, the EPA believes there are no certification costs that should be attributed to this
rule, for the reasons described earlier in this section. Also, the EPA is not making any attempt to
quantify the costs associated with certification by the FAA.
2.5.4 Recurring Costs
There will be no recurring costs for the final standards; however, it is informative to describe
the components of recurring costs. The components of recurring costs for incorporating
technologies that improve fuel burn will include additional maintenance, material, labor, and
tooling costs. The EPA analysis shows that airplane fuel efficiency improvements typically
result in net cost savings through the reduction in the amount of fuel burned. This makes
economic sense because if technologies add significant recurring costs to an airplane, operators
(e.g., airlines) will likely reject these technologies.42
xlm Due the unprecedented nature of the final airplane emission standards providing cost savings to manufacturers in
this manner, we are unable to quantify the amount of these costs savings.
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Technology and Cost
CAEP's analysis for the international Airplane CO2 Emission Standards included an
assessment of the recurring costs.43 CAEP's recurring costs were described as recurring direct
operating costs (DOC) and included the following elements: (a) capital costs (including finance
and depreciation), (b) other-DOC (including crew, maintenance landing and route costs) and (c)
fuel costs. The results of the CAEP analysis showed the fuel savings from the standards will far
outweigh any of the other elements of the recurring costs. Thus, in total the recurring costs
ended up being a cost savings.
2.5.5 Reporting Costs
The costs of generating a certification test report should not be attributed to this rule. The
FAA is expected to promulgate a rule to enforce compliance to these standards subsequent to the
EPA final rule of these standards, and any potential costs of the certification will be attributed to
this FAA rule.
2.6 Airplane Fuel Savings
As described earlier, manufacturers have already developed or are developing technologies to
respond to ICAO standards which are equivalent to the standards adopted today. Additionally,
they will need to find a way to certify to the ICAO standards even in the absence of U.S.
regulations. As a result, all airplane models (in-production and in-development airplane models)
are expected to be in compliance with the final standards by the time they will become effective.
Therefore, there will be no fuel savings from this rulemaking. Chapter 6 of this TSD discusses
the fuel savings from an alternative scenario (Scenario 3) we analyzed, which is different from
the final standards (Scenario 1) that match the international standards. (The other alternative
scenario (Scenario 2) does not have fuel savings).
CAEP's analysis for the international Airplane CO2 Emission Standards included an
assessment of the fuel savings.xllv First, CAEP provided results for the cumulative CO2
reductions for different effective dates for the 10 stringency options (SOs) assessed. Chapter 6
provides a description of the 10 CAEP stringency options.xlv The international Airplane CO2
Emission Standards that were ultimately adopted by CAEP for in-production airplanes were
stringency option 7 (S07) for in-production airplanes (for airplanes with MTOMs greater than
xllv ICAO, 2016: Tenth Meeting Committee on Aviation Environmental Protection Report, Doc 10069, CAEP/10,
432 pp, AN/192, Available at: http://www.icao.int/publicatlons/Pages/cataiogne.aspx „(last accessed July 11,
2018). The ICAO CAEP/10 report is found on page 27 of the English Edition 2018 catalog and is copyright
protected; Order No. 10069. The summary of technological feasibility and cost information is located in
Appendix C (starting on page 5C-1) of this report. Figure 9 of Appendix C shows the cumulative CO2 reductions
for stringency options, and Figure 12 provides the change in cumulative costs (including fuel savings or negative
fuel costs) for the stringency options.
xlv As described in the 2015 ANPR and later in Chapter 6 (section 6.1.1), for the international Airplane CO2
Emission Standards, CAEP analyzed 10 different SOs for standards of both in-production and new type design
airplanes, comparing airplanes with a similar level of technology on the same stringency level. These stringency
options were generically referred to numerically from "1" as the least stringent to "10" as the most stringent. The
2015 ANPR described the range of stringency options under consideration at ICAO/CAEP as falling into three
categories as follows: (1) CO2 stringency options that could impact only the oldest, least efficient airplanes in-
production around the world, (2) middle range CO2 stringency options that could impact many airplanes currently
in-production and comprising much of the current operational fleet, and (3) CO2 stringency options that could
impact airplanes that have either just entered production or are in final design phase but will be in-production by
the time the international Airplane CO2 Emission Standards become effective.
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Technology and Cost
60 tonnes) with an effective date of 2028. Because ICAO analyzed the stringency options
relative to a 2016/2017 fixed technology baseline (without continuous improvement and without
considering the expected end of production of airplanes), the ICAO analysis reports CO2
reductions and technology costs for the international standard. ICAO's projected CO2 reductions
from S07 with a 2028 effective date are shown in Figure 2-7 below, and the results indicate
about 350 Megatonnes (Mt) of CO2 reductions (labeled as 2028-Case-l and in negative
Megatonnes by CAEP in Figure 2-7). These reductions are for S07 applying to all covered
airplanes, even though the international standards that were adopted for airplanes less than or
equal to 60 tonnes MTOM are less stringent, S03. Thus, according to CAEP's approach in their
analysis, the CO2 reductions would be less than 350 Mt.
Cumulative C02 (Megatonnes) Relative to the Basdiue
SOI S02 SOS SOI S05 S06 S07 SOS 509 SO10
-200
-too
-600
-S00
-1000
-1200
12020-Case-l
~ 2023-Case-l
12025-Case-l
'v 2028-Case-l
2020-Case-4c
> 2023-Case-4c
Figure 2-7. CAEP Cumulative CO2 (Megatonnes) Reductions from the Effective Date to 2040xlvi
xlvl ICAO, 2016: Tenth Meeting Committee on Aviation Environmental Protection Report, Doc 10069, CAEP/10,
432 pp, AN/192, Available at: http://www.icao.int/publications/Pages/catalosue .aspx _(last accessed July 11,
2018). The ICAO CAEP/10 report is found on page 27 of the English Edition 2018 catalog and is copyright
protected; Order No. 10069. The summary of technological feasibility and cost information is located in
Appendix C (starting on page 5C-1) of this report. On page 5C-13, the cases analyzed by CAEP are defined.
Case 1 is also named the new type design and in-production airplane applicability case - full technology
response/out of production case. Case 1 is the analysis of the ten SOs at the agreed implementation dates (2020
and 2023; and, subsequently additional sensitivity analyses were conducted for 2025 and 2028), using all
technology responses defined by CAEP, and with airplanes assumed to go out of production at the
implementation dates if they cannot be made compliant to a stringency option level. Case 4 is also named the
new type design-only applicability case - alternative response/production case: Case 4 is the analysis of the ten
SOs at the agreed implementation dates for new type design-only applicability using responses informed by
Page: 54
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Technology and Cost
Also, CAEP characterized these fuel savings as negative fuel costs, as shown in Figure 2-8
below. (Note, the 10 stringency options CAEP analyzed are discussed later in Chapter 6 of this
TSD.) The results of Figure 2-8 show that the international standards (S07) for in-production
airplanes provided about $125 billion in fuel savings (labeled as 2028-Case-l and in negative
2010$ billions by CAEP in Figure 2-8).xlvu As described earlier, S03 would apply to airplanes
less than or equal to 60 tonnes MTOM, and thus, according to CAEP's approach in their
analysis, the fuel savings would be less than $25 billion (in 2010$).
C ha Dge in Cumulative Costs (20105 Billions)
S20C
: 023-C a se-l All Markets
S10C
SOI
so:
sos
sos
-3100
NRC
-S3CC
AVL
Total Cost (DOC-AVL-NRC)
-S40C
Figure 2-8. CAEP Change in Cumulative Costs for 2028 Effective Datexlviii xlix
For Figure 2-8, the yellow bars represent fuel costs, and since these fuel costs are negative, they are fuel savings.
AVL means owner /operator asset value loss. Other-DOC includes crew, maintenance landing and route costs.
market considerations, since manufacturers would not have a legal requirement to bring in-production types to
levels under a new type design-only standard. Case 4 is a range of response scenarios from a voluntary response
similar to Case 1 to an absence of any response by growth and replacement airplanes. Case 4c is a sub-case of
Case 4, and it is the analysis of the top 33 percent most likely airplane families to respond to a SO (for each of the
ten SOs). Also, the non-compliant families do not respond in Case 4c, but they remain in production.
xlvu CAEP used $3 per gallon of jet fuel in their analysis.
xlvm The cumulative costs include Total Recurring Direct Operating Costs (DOC), Manufacturer Non-Recurring
Costs (NRC) for Technology Response (TR) and Owner /Operator Asset Value Loss (AVL) from the
Implementation Year to 2040. Fuel Costs (or fuel savings) are shown in the yellow colored bars.
xllx ICAO/CAEP did not provide cost and cost-effectiveness results for its stringency option 10, and thus, this option
was not analyzed by ICAO/CAEP in the manner the other nine stringency options were analyzed.
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Technology and Cost
The primary difference in the results between the EPA and ICAO analyses is due to the
2016/2017 fixed technology baseline (without continuous improvement and without considering
the expected end of production of airplanes) in the CAEP analysis. For a further description of
the rationale on the fuel savings difference in the EPA analysis results and CAEP results, see the
earlier discussion on costs in this chapter. In addition, refer to Chapter 5 that further discusses
the differences between the EPA and CAEP methods and assumptions for modeling emission
reductions and fuel savings.1
2.7	Fuel Prices
The jet fuel price is not central to the EPA analysis, nor will it provide substantially different
results. The EPA analysis is based on demonstrated technology by 2017, and the projected
business-as-usual incorporation of this technology on airplanes out to 2040 (continuous annual
improvement). Also, we estimated the end of production of airplanes based on the expected
business as usual status of airplanes. For lower jet fuel prices, older in-production airplanes will
likely be flown longer, and fleet renewal will slow.44 However, as described later in Chapter 5,
we have a sensitivity analysis case that shows the results of extending production for some
airplanes. Also, in Chapter 5, we discuss a sensitivity analysis case without continuous metric
value improvement that shows the effect of less technology application in the fleet. For higher
jet fuel prices, there is typically an increase in new airplane (or redesign) launches as well as
incremental upgrades. However, there were recently numerous redesigns to airplanes, as well as
incremental upgrades, and we believe the prospects for such improvements will be low in the
next 10 to 15 years. In any event, these recent improvements and the case of higher fuel prices
will only ensure the final standards will have even less effect (due to market forces).
2.8	Summary of Benefits and Costs
ICAO intentionally established its standards, which match the final standards, at a level which
is technology following to adhere to its definition of technical feasibility that is meant to
consider the emissions performance of in-production and in-development airplanes, including
types that would first enter into service by about 2020. Independent of the ICAO standards
nearly all airplanes produced by U.S. manufacturers will meet the ICAO in-production standards
in 2028 due to business-as-usual market forces on continually improving fuel efficiency. The
cumulative fuel efficiency improvement of the global airplane fleet was 54 percent between 1990
and 2019, and over 21 percent from 2009 to 2019, which was an average annual rate of 2
percent.45 Business-as-usual improvements are expected to continue in the future. The
manufacturers anticipation of future ICAO standards will be another factor for them to consider
in continually improving the fuel efficiency of their airplanes. Thus, all airplanes either meet the
stringency levels, are expected to go out of production by the effective dates, or will seek
exemptions from the GHG standard. Therefore, there will be no costs and no additional benefits
from complying with these final standards - beyond the benefits from maintaining consistency or
harmonizing with the international standards and preventing backsliding by ensuring that all new
type design and in-production airplanes are at least as fuel efficient as today's airplanes.
1 For example, the EPA assumes the Airbus A380 will stop production before 2030, but CAEP assumes it will be in
production until 2040.
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Technology and Cost
Appendix A. - Airframe Technologies
During the evaluation of MV benefit for each technology, ICF determined a range of
possibilities of the MV benefit improvement for each technology, because the same technology
provides different levels of MV benefit depending on each airplane size category. Subsequently,
ICF determined where within the boundary the MV improvement is for each airplane size
category. For airplane categories where the technology would not yield much benefit, it was
categorized as (-), and ICF determined the benefit to be at lowest boundary of the MV benefit
improvement range. On the other hand, where the technology would be most beneficial for the
airplane size category, it was categorized as (+), and it was determined the benefit to be at the
highest boundary of the MV benefit improvement range. Finally, airplane size categories in
between were categorized as (=), for which the average of the minimum value and the maximum
value of the MV improvement range was used.
For example, variable camber trailing edge is predicted to produce between 0.5 - 3.0% of MV
improvement. For turboprops and regional jets, we do not expect this technology to provide
significant benefit; therefore, they were categorized as (-), which means 0.5% MV improvement.
For small twin aisle, large twin aisle, and large quad, this technology provides significant benefit
due to their sizes; therefore, they were categorized as (+), which means a 3.0% MV
improvement. Finally, for single aisle airplane it only provides moderate benefit; therefore, it
was categorized as (=), which means the average of a 0.5% MV improvement and a 3.0% MV
improvement, and this results in a 1.75% MV improvement.
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Technology and Cost
Table 2-14 Fuel Burn and Costs Impacts for Advanced Wingtip Devices46 47

Sources
Small BGA
Large BGA
_§ Q
-e s
£ Q
Regional
Jet
Single
Aisle
Small Twin
Large Twin
Large
Quad
Fuel
Burn
•	Blended winglets achieve 3-5% fuel burn
improvements over non-winglet aircraft
•	New winglet technologies, such as split wingtips
and Aviation Partners Boeing "Scimitar" winglets can
yield 1-3% improvement compared to current
generation winglet technologies
•	Winglets on 737MAX will offer 1-1.5% fuel burn
improvement compared to 737NG blended winglets,
depending on results of investigations into natural
laminar flow
=
=
=
=
=
=
=
=
3.5%
3.5%
3.5%
3.5%
3.5%
3.5%
3.5%
3.5%

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
5%
10%
14%
20%
30%
38%
Technical
Feasibility
100%
100%
100%
100%
100%
100%


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
•	Used publicly available pricing and interview input
to determine price of current technology winglets
•	Assumed next-generation winglets will have 10%
increased price
•	NRC estimated based on interview input and
some scaling relative to aircraft size
•	Advanced wingtip device NRC was used as a data
point to scale other technology NRCs
$98
$124
$111
$121
$150
$222
$264
$325
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Technology and Cost
Table 2-15 Fuel Burn and Costs Impacts for Adaptive Trailing Edge

Sources
Small BGA
Large BGA
Turbo-prop
Regional Jet
Single Aisle
Small Twin
Large Twin
Large Quad
Fuel
Burn
•	A full variable camber trailing edge would allow
reduced structural weight due to load alleviation, as
well as reduced control sizing and more efficient
cruise configurations
•	Scaled benefit from adaptive trailing edge given
aircraft manufacturer input and ICF analysis
•	Fuel burn reduction mechanism: induced drag
reduction
X
+
-
-
=
+
+
+
0.0%
2.0%
0.5%
0.5%
1.3%
2.0%
2.0%
2.0%

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
0%
0%
4%
10%
15%
17%
Technical
Feasibility
0%
0%
50%
100%
100%
100%


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
•	Relative scaling "check" to reflect value of
increased fuel savings
•	NRC estimates scaled relatively from known data
points on program NRC scale
$148
$188
$168
$184
$228
$338
$401
$493
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Technology and Cost
Table 2-16 Fuel Burn and Costs Impacts for Aft Body Redesign

Sources
Small BGA
Large BGA
Turbo-prop
Regional
Jet
Single Aisle
Small Twin
Large Twin
Large Quad
Fuel
Burn
• Fuel burn reduction mechanism: induced drag
reduction
-
=
=
=
=
=
=
=
1.0%
1.3%
1.3%
1.3%
1.3%
1.3%
1.3%
1.3%

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
9%
20%
28%
40%
60%
68%
Technical
Feasibility
90%
100%
100%
100%
100%
100%


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
•	Significant design and production change for
an aircraft program
•	Cost increase data scaled relatively to other
known modification and checked through
interview feedback
•	NRC estimates scaled relatively from known
data points on program NRC scale
•	Significant NRC related to design and changing
production process
$184
$233
$209
$228
$282
$419
$496
$611
Table 2-17 Fuel Burn and Costs Impacts for Hybrid Laminar Flow Control - Empennage

Sources
Small
BGA
Large
BGA
Turbo-
nrnn
Regional
ipt
Single
Aisle
Small
Twin
Large
Twin
Large
Quad
Fuel
Burn
•	Fuel burn reduction mechanism: skin friction
drag reduction
•	Possible issues with practicality (HLFC requires
small ports in aircraft skin that may become
frequently clogged in practice)
-
-
-
-
=
+
+
+
0.3%
0.3%
0.3%
0.3%
1.4%
2.5%
2.5%
2.5%

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
0%
3%
6%
10%
15%
17%
Technical
Feasibility
0%
80%
100%
100%
100%
100%


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
• NRC estimates scaled relatively from known
data points on program NRC scale
$254
$324
$289
$316
$391
$580
$688
$847
Page: 60
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Technology and Cost
Table 2-18 Fuel Burn and Costs Impacts for Riblet Coatings

Sources
Small
BGA
Large
BGA
Turbo-
nrnn
Regional
ipt
Single
Aklp
Small
Twin
Large
Twin
Large
Quad
Fuel
Burn
•	Not currently in production, but concept
validated
•	Potential issues with increased maintenance
and cleaning costs, and practicality in field
•	Sources for information included publicly
available documents, secondary research, and
confirmation from airframe manufacturer
interview sources (Gubisch)
•	Fuel burn reduction mechanism: skin friction
drag reduction
-
-
-
-
=
+
+
+
0.5%
0.5%
0.5%
0.5%
1.0%
1.5%
1.5%
1.5%

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
0%
5%
13%
25%
35%
51%
Technical
Feasibility
0%
50%
80%
100%
100%
100%


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
•	Riblet coatings would primarily affect
manufacturing costs, after initial design NRC is
performed to validate concept
•	Estimates from interviews/ICF team consensus
•	Unknown impact on maintenance costs
•	NRC estimates scaled relatively from known
data points on program NRC scale according to ICF
team judgment
$148
$188
$168
$184
$228
$338
$401
$493
Page: 61
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Technology and Cost
Table 2-19 Fuel Burn and Costs Impacts for ECS Aerodynamics and On-Demand ECS Scheduling

Sources
Small
BGA
Large
BGA
Turbo-
prop
Regional
Jet
Single
Aisle
Small
Twin
Large
Twin
Large
Quad
Fuel
Burn
• Fuel burn reduction mechanism is drag
reduction (Thomson)
=
=
=
=
=
=
=
=
0.6%
0.6%
0.6%
0.6%
0.6%
0.6%
0.6%
0.6%

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
8%
20%
28%
40%
60%
68%
Technical
Feasibility
100%
100%
100%
100%
100%
100%


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
•	Assumed that refining ECS system would result
in minor charges equal to 0.25% of realized
aircraft sale price
•	Changes are mainly from amortized NRC and
additional control electronics
•	NRC estimates scaled relatively from known
data points on program NRC scale *NRC is
aerodynamics and software design engineering
$40
$46
$43
$45
$50
$68
$77
$87
Page: 62
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Technology and Cost
Appendix B. - Engine Technologies
Table 2-20 Fuel Burn and Costs Impacts for Engine Technologies"'48'49

Sources
Small
BGA
Large
BGA
Turbo-
prop
Regional
Jet
Single
Aisle
Small
Twin
Large
Twin
Large
Quad
Fuel
Burn
•	Main reduction mechanisms are Airfoil
Aerodynamics and Sealing
•	Engine manufacturers typically do not charge
a premium for engine technology improvements
•	Modeled as a fixed percentage per year,
instead of using commercial or technical
probability built up from individual technologies
=
=
-
=
=
=
=
=
0.2%
/yr
0.2%
/yr
0.1%
/yr
0.2%
/yr
0.2%
/yr
0.2%
/yr
0.2%
/yr
0.2%
/yr

2015
2018
2020
2023
2028
2030
Commercial
Feasibility
N/A
N/A
N/A
N/A
N/A
N/A
Technical
Feasibility
N/A
N/A
N/A
N/A
N/A
N/A


Estimated Total NRC ($M) by Aircraft Category
Cost
Impact
•	Engine manufacturers typically do not charge
a premium for engine technology improvements
•	$100M of NRC for every 1% improvement (on
single aisle-sized engines) for TRL 6+
$118
$200
$115
$181
$270
$503
$681
$720
11TRL6 means system/subsystem or true dimensional test equipment validated in a relevant enviromnent.
ICF International, C02 Analysis of C02-Reducing Technologies for Aircraft. Final Report, EPA Contract Number
EP-C-12-011, see page 40, March 17, 2015.
Page: 63
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Technology and Cost
Appendix C. - Example Supply Curves by Airplane Category
Metric value improvement percentage versus estimated non-recurring costs ($million):
51,600
$1,400
$1,200
$1,000
Composites - C urrent State
Increased Apple at ion
1 1 Hybrid Lamnar Flow Control -
Empennage
1 1 Gap Reductions - Slats Spoilers,
etc.
Rblet Coatings
1 1 Other Aerodynamic
Improvements
Aerodynamic APU Fairing / Aft
body redesign
Other Systems Improvements
ECS Aero and On Demand ECS
Scheduling
1 ¦! Reducing Profile of the Lights
1 1 Engine Technologies
Advanced Wingtip Devtes-
Retrofit
MV Supply Curve Line
6%	8%
Metric Value Improvement
Figure 2-9 Example Supply Curve for Small BGA
Page: 64
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Technology and Cost
$1,S00
$1,600
$1,400
$1,200
$1,000
Rblet Coatings
i i Control Surface- Optimal Control
Laws for horizontafl stab tr im
] Other Aerodynamic
Improvements
] Other Systems Improvements
i i Aerodynamic APU Fairing / Aft
body redesign
Adaptive Trailing Edge
Variable Camber Traling Edge -
Morphing
ECS Aero and On Demand ECS
Scheduling
Reducing Profiie of the Lights
] Engine Technologies
dv arced Wingtip Devtes-
Stroffc
MV Supply Curve Line
8% 10% 12% 14% 16%
Metric Value Improvement
Figure 2-10 Example Supply Curve for Large BGA
$1,600
$1,400
$1,200
$1,000
$800
$600
$400
$200
I AdaptiveTraiing Edge
$o ^

I I Control Surface- Optimal Control
Laws for horizontal stab trim
J-
	,r l i=i
i i Natural Laminar FlowControl-
Nacele
3 Gap Reductions- Slats Spoilers,
etc.
~ Other Aerodynamic
improvements
I Other Systems improvements
^ E
3 Aerodynamic APU Fairing / Aft
body redesign
l ECS Aero and On Demand ECS
Scheduling
I Reducing Profiie of the Lights
~ Engine Technologies
I Advanced Wingtip Devtes-
Retrofit
-A— MV Supply Curve Line
2%
4%
6%	8%
Metric Value Improvement
10%
12%
Figure 2-11 Example Supply Curve for Turboprop
Page: 65
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Technology and Cost
$1,600
$1,400
$1,200
$1,000
AdaptiveTraiing Edge
i i Control Surface- Optimal Control
Laws for horizontafl stab trim
i i Natural Laminar Flow Control -
Nacelle
Gap Reductions- Slats Spoilers,
etc.
i i Aerodynamic APU Fairing / Aft
body redesign
Other Systems Improvements
ECSAeroandOn Demand ECS
Scheduling
Other Aerodynamic
Improvements
Reducing Profile of the Lights
] Engine Technologies
Advanced Wingtip Devtes-
Retroft
A— MV Supply Curve Line
Metric Value Improvement
Figure 2-12 Example Supply Curve for Regional Jet
$2,500
$2,000
$1,500
$1,000
$500
rjt
$0
-----

I I Gap Reductions - Siat$ Spoilers,
etc.
i i Other Aerodynamic
Improvements
i i Other Systems Improvements
i i R Id let Coatings
i i Aerodynamic APU Fairing / Aft
body redesign
I AdaptiveTraiing Edge
i Variable Camber Trailing Edge-
Morphing
I ECSAeroandOn Demand ECS
Scheduling
I Reducing Profile of the Lights
] Engine Technologies
I Advanced Wingtip Devizes -
Retrofit
- MV Su ppty C urve Line
2%
4%
6%
8% 10% 12% 14%
Metric Value Improvement
Figure 2-13 Example Supply Curve for Single Aisle
Page: 66
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$4,000
$3,500
$3,000
$2,500
$2,000
$1,500
$1,000
$500
Technology and Cost
$o


~T
¦ Adapts eTraiSng Edge
i i Composites - Current State
	 Increased Application
i I Gap Reductions - Slats Spoilers,
etc.
/ "
i i Hybrid Laminar Flow Control-
Nacelle
i I Other Aerodynamic
Improvements
Other Systems improvements
] Hybrid Laminar Flow Control -
Empennage
I R b let Coat rigs
I Variable Camber Tra3ing Edge -
Morphing
i i Engine Technologies
I Advanced Wingtip Dev tes-
Rdtrof't
MV Supply Curve Line
2% 4% 6% 8% 10% 12% 14% 16% 18%
Metric Value Improvement
Figure 2-14 Example Supply Curve for Small Twin Aisle
$4,500
$4,000
$3,500
$3,000
$2,500
$2,000
$1,500
$1,000
Gap Reductbns- Slats Spoilers,
etc.
i i Hybrid Laminar Flow Control -
Nacele
i i Other Aerodynamic
Improvements
i i Other Systems improvements
i I Hybrid Lam bar Flow Control -
Empennage
RbletCoatbgs
Adaptive'Trailing Edge
Variable Camber Traiing Edge -
Morphing
Reducing Profile of the Lights
I I Engine Technologies
Advanced Wingtip Devizes-
Retroft
MV Supply Curve Line
2% 4% 6% 8% 10% 12% 14% 16% 18% 20%
Metric Value Improvement
Figure 2-15 Example Supply Curve for Large Twin Aisle
Page: 67
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Technology and Cost
$6,000
$5,000
$4,000
$3,000
$2,000
$1,000

f
I i Aerodynamic APU Fairing / Aft
body redesign
I I Other Aerodynamic
Improvements
I I Other Systems Improvements
i i Hybrid Laminar FIct/y Control -
Empennage
I I Rtolet Coatings
AdaptiveTraiing Edge
I Variable Camber Traiing Edge -
Morphing
I ECS Aero and On Demand ECS
Scheduling
Reducing Profile of the Lights
i i Engine Technologies
2% 4% 6% 8% 10% 12% 14% 16% 18% 20%
Metric Value Improvement
Figure 2-16 Example Supply Curve for Large Quad
I Adv an ced Wingtip Dev t es -
Retrofit
MV Supply Curve Line
Page: 68
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REFERENCES
Technology and Cost
5ICAO, 2016: Tenth Meeting Committee on Aviation Environmental Protection Report, Doc 10069, CAEP/10, 432
pp, AN/192, Available at: http://www.icao.int/publications/Pages/catalogiie.aspx „(last accessed March 17, 2020,).
The ICAO CAEP/10 report is found on page 27 of the English Edition 2020 catalog and is copyright protected;
Order No. 10069. The summary of technological feasibility and cost information is located in Appendix C (starting
on page 5C-1) of this report.
6	ICF, 2018: Aircraft CO2 Cost and Technology Refresh and Industry Characterization, Final Report, EPA Contract
Number EP-C-16-020, September 30, 2018.
7	ICF International, 2015: COiAnalysis of CC>2-Reducing Technologies for Aircraft, Final Report, EPA Contract
Number EP-C-12-011, March 17, 2015.
8	U.S. EPA, 2015: Proposed Finding that Greenhouse Gas Emissions from Aircraft Cause or Contribute to Air
Pollution that May Reasonably Be Anticipated to Endanger Public Health and Welfare and Advance Notice of
Proposed Rulemaking, 80 FR 37758 (July 1, 2015).
9	See Reference #7.
10	See Reference #6.
11	RTI International and EnDyna, Aircraft CO2 Cost and Technology Refresh and Aerospace Industry
Characterization: Peer Review, June 2018, 112 pp.
12	See Reference #5.
13	GE, 2020: Comment to Notice of Proposed Rulemaking ("NPRM") for "Control of Air Pollution from Airplanes
and Airplane Engines: GHG Emission Standards and Test Procedures, " 85 FR 51,556 (August 20, 2020), Letter
from Gary Mercer and Greg Conlon, October 19, 2020.
14	AT AG, 2020: Tracking Aviation Efficiency, How is the aviation sector performing in its drive to improve fuel
efficiency, in line with its short-term goal? Fact Sheet #3, January 2020. Available at
https://aviationbenefits.org/downloads/fact-sheet-3-tracking.-aviation-efficiencv/.
15IAE, 2020, Aviation, Tracking report, June 2020, Available at https://www.iea.org/reports/aviation.
16	U.S. Energy Information Administration (EIA), 2020: Annual Energy Outlook 2020 with projections to 2050,
#AE02020, Available atwww.eia.gov/aeo (last accessed November 11, 2020).
17	ICAO, 2019: Independent Expert Integrated Technology Goals Assessment and Review for Engines and Aircraft,
Doc 10127. Montreal, 2019. 225 pp. Available at:
https://www.icao.int/publications/catalogue/cat_2020_sup01_en.pdf (last accessed November 10, 2020). It is
found on page 3 of the English Edition of the 2020 catalog's Supplement No. 1- December 2019/January 2020.
18	ICAO, 2019: Environmental Report 2019 -Aviation and Climate Change - Destination Green The Next Chapter,
2019, which is located at https://www.icao.int/environmental-protection/Pages/envrep2019.aspx (last accessed
November 10, 2020).
19ICCT, 2020, Fuel Burn of New Commercial Jet Aircraft: 1960 to 2019. September 20. Available at:
https://theicct.org/pnblications/fiiei-bnrn-new-com.m-aircrafl-1960-2019-sept2020 .
20	See Reference #6.
21	See Reference #7.
22	See Reference #6.
23	See Reference #6.
24	See Reference #6.
25	See Reference #6.
26	See Reference #6.
27	See Reference #6.
28	See Reference #6.
29	See Reference #6.
Page: 69
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Technology and Cost
30	MTU Aero Engines, Blisks (blade integrated disks), Available at fattp://power.mtu.de/engineering-and-
mannfacturing/aero-solutions/parts-manufacturing/rotating-components/blisks/ (last accessed March 20, 2020).
31	See Reference #6.
32	See Reference #6.
33	See Reference #6.
34	See Reference #6.
35	See Reference #6.
36	See Reference #5.
37	See Reference #7.
38	See Reference #5.
39	See Reference #5.
40	ICAO, 2016: Tenth Meeting Committee on Aviation Environmental Protection Report, Doc 10069, CAEP/10, 432
pp, AN/192, Available at: http://www.icao.int/pnblicafions/Pages/catalogiie.aspx _(last accessed March 20, 2020).
The ICAO CAEP/10 report is found on page 27 of the English Edition 2020 catalog and is copyright protected;
Order No. 10069. The summary of technological feasibility and cost information is located in Appendix C (starting
on page 5C-1) of this report.
41	See Reference #5.
42	See Reference #6.
43	See Reference #5.
44	See Reference #7.
45	AT AG, 2020: Tracking Aviation Efficiency, How is the aviation sector performing in its drive to improve fuel
efficiency, in line with its short-term goal? Fact Sheet #3, January 2020. Available at
https://aviationbenefits.org/downloads/fact-sheet-3-tracking-aviation-efficiencv/.
46	See Reference #6.
47	See Reference #7.
48	See Reference #6.
49	See Reference #7.
Page: 70
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Test Procedures
Table of Contents
Chapter 3: Test Procedures	72
3.1	CAEP Test Procedure Requirements-Overview	72
3.2	Test Procedures for Airplane GHG Emissions Based on the Consumption of Fuel.... 72
3.2.1	Flight Test Method	72
3.2.1.1	Preflight	72
3.2.1.2	Flight test- A16 §3.2.2	72
3.2.1.3	Test condition stability	73
3.2.1.4	Measurement of SAR	73
3.2.2	Data Validity	73
3.2.2.1 Reference Conditions & Corrections	73
3.2.3	Equivalent procedures	73
3.3	Determination of the Fuel Efficiency Metric Value	73
3.3.1	Airplane Fuel Efficiency Metric	73
3.3.2	Reference Geometric Factor	74
3.4	Application of Rules for New Version of an Existing GHG-Certificated Airplane	75
3.4.1 No Fuel Efficiency Change Threshold for GHG-Certificated Airplanes	76
3.5	Changes for non-GHG Certificated Airplane Types	78
Table of Figures
Figure3-1 - Crossectional View	75
Figure3-2 - Longitudinal View	75
Figure 3-3 - No Fuel Efficiency Change Thresholds for GHG Certificated Airplanes (ICAO Adopted No CO2
Emissions Change Thresholds)	77
Table of Equations
Equation 3-1 - International C02Emissions Metric for airplanes	73
Equation 3-2 - Equation to calculate Specific Air Range of the airplane	74
Page: 71
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Test Procedures
Chapter 3: Test Procedures
3.1	CAEP Test Procedure Requirements-Overview
Airplane CO2 emissions test procedures were developed at CAEP based on input from
manufacturers and regulators. In general, Specific Air Range (SAR) is measured on an engine
during flight at three test points. These SAR data represent the distance traveled per unit of fuel
burn and are used to determine the international CO2 metric value for the airplane type.
Manufacturers' flight test procedures for calculating fuel burn and cruise performance were used
as a starting point for development. This input was then standardized to create a consistent
procedure for regulatory purposes. Corrections have also been developed to improve data
consistency and interoperability of measurements. CAEP has also developed preliminary
guidance on equivalent procedures that could be used to meet the requirements. These test
procedures and metric are a measure of GHG emissions of airplanes.
3.2	Test Procedures for Airplane GHG Emissions Based on the Consumption of Fuel
All flight tests must be conducted in an approved manner to yield the fuel efficiency metric
value as described in Section 3.3 below. These procedures shall address the entire flight test and
data analysis process from pre-flight actions to post-flight data analysis.
The flight test procedure has been developed based on standard industry practices for
determining airplane fuel burn performance. This has been standardized into a regulatory
framework.
These test procedures and requirements are described in detail in ICAO Annex 16 Volume III
and in ICAO ETM Volume III.
3.2.1 Flight Test Method
3.2.1.1	Preflight
Annex 16 Vol. Ill §3.2.1 describes the pre-flight procedures that shall be approved by the
FAA prior to any certification testing. These requirements include conformity of the airplane to
the type design which is to be certificated, procedures to weigh the airplane before and after
flight testing, and specifying the fuel used must meet ASTM specification D4809-13 along with
when and how to test the fuel.
3.2.1.2	Flight test - A16 §3.2.2
Flight testing must be conducted in accordance with the requirements outlined in Annex 16
Vol. Ill Appendix 1 §3.2.2 and §3.2.3. The three test points, described in 3.3.1, must be
separated from each other by a minimum of 2 minutes or by a deviation outside of the stability
criteria for test points. It is recommended during the collection of SAR data that:
•	the airplane should be flown at constant pressure altitude and constant heading;
•	the engine thrust/power setting is stable for unaccelerated level flight;
•	the airplane is flown as close as practicable to the reference conditions to minimize
the magnitude of any corrections;
Page: 72
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Test Procedures
•	there are no changes in trim or engine power/thrust settings, engine stability and
handling bleeds, and electrical and mechanical power extraction (including bleed
flow). Any changes in the use of aeroplane systems that may affect the SAR
measurement should be avoided; and
•	movement of on-board personnel is kept to a minimum.
Flight testing should be conducted over a period of not less than 1 minute.
3.2.1.3	Test condition stability
For SAR measurement data to be valid, the flight test must remain within the tolerances
indicated in Annex 16 Vol. Ill Appendix 1 §3.2.3.
3.2.1.4	Measurement of SAR
The requirements for measurements and data sampling are described in Annex 16 Vol. Ill
Appendix 1 §4 and ETM Vol. Ill §3.1.
3.2.2	Data Validity
Data validity requirements are described in Annex 16 Vol. Ill Appendix 1 §6. The 90%
confidence interval of the data at the three reference masses shall not exceed 1.5% of the SAR
value without approval from the FAA. If clustered data are acquired independently for each of
the three gross mass reference points, the minimum sample size acceptable for each of the three
gross mass SAR values shall be six. Alternatively, SAR data may be collected over a range of
masses. In this case, the minimum sample size shall be 12, and the 90 per cent confidence
interval shall be calculated for the mean regression line through the data.
Further information on how to determine data validity is provided in ETM Vol. Ill §3.3.
3.2.2.1 Reference Conditions & Corrections
Where the flight test data does not match the reference conditions described in Annex 16 Vol.
Ill §2.5 corrections should be made as described in Annex 16 Vol. Ill Appendix 1 §5.2. Potential
corrections include energy, aeroelastics, altitude, apparent gravity, CG position, power extraction
and bleed, deterioration level, fuel spec, Mass Reynolds Number, and Temperature. ETM Vol.
Ill §3.2.2 describes these procedures in detail.
3.2.3	Equivalent procedures
Per Annex 16 Vol. Ill §1.10 equivalent procedures can be used to show compliance to the
ICAO Airplane CO2 Emission Standards with the prior approval of the FAA. ETM Vol. Ill §3.4
provides some initial guidance on procedures that could be used to show compliance with the
standard. These must still be approved by the FAA prior to their use.
3.3 Determination of the Fuel Efficiency Metric Value
3.3.1 Airplane Fuel Efficiency Metric
The metric (shown in Equation 3-1) for the GHG standards (equivalent to ICAO's airplane
CO2 emissions metric) uses fuel efficiency as a measure of GHG emissions from airplanes.
Equation 3-1 - International CO2 Emissions Metric for airplanes
Page: 73
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Test Procedures
(sir) /
C02 Emissions Metric =	(RGF)02*
When the international CO2 emissions metric is correlated against airplane mass it has a
positive slope. The international Airplane CO2 Emission Standards use MTOM of the airplane as
an already certificated reference point to compare airplanes. The CO2 Emissions Evaluation
Metric for an airplane is calculated from SAR and a reference geometric factor (RGF) (see
Section 3.3.2) using Specific Air Range. It is expressed in units of kilograms of fuel consumed
per kilometer.
Specific Air Range (SAR) is a measure of fuel efficiency widely used in the airplane industry.
It is a measure of distance traveled per fuel consumed and is calculated using Equation 3-2.
Equation 3-2 - Equation to calculate Specific Air Range of the airplane
TAS
SAR =
Wf
Where:
TAS is True air speed and Wf is airplane fuel flow
For the purposes of the international Airplane CO2 Emission Standards, the inverse of SAR is
used to calculate the airplane's metric value. 1/SAR values are calculated at each of the three
reference airplane mass test points (per Annex 16 Vol. Ill §2.3):
a)	high gross mass: 92 per cent maximum take-off mass (MTOM)
b)	mid gross mass: simple arithmetic average of high gross mass and low gross mass
c)	low gross mass: (0.45 x MTOM) + (0.63 x (MTOM0 924))
At each of these reference points, the airplane is operated at optimum speed and altitude.
The average of the three inverse SAR points will be used to calculate the airplane CO2 metric
value for an individual airplane. The EPA using this same procedure to calculate the fuel
efficiency metric value.
3.3.2 Reference Geometric Factor
The Reference Geometric Factor (RGF) is a non-dimensional measure of the fuselage size of
an airplane normalized by 1 square meter. It represents the usable space in the airplane through
the shadow area of the airplane's pressurized passenger compartment. This is defined by Annex
16 Vol. Ill App. 2. Figure3-1 and Figure3-2 show what is included in RGF.
Page: 74
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Test Procedures
Aeroplane with upper dedt
Aeroplane with single deck
Fuselage outer mould line {OM.)
Macimum vwlh of fuselage OM. for single and upper ded<
Actual fkxx yea
Figure3-1 - Crossectional View
Tapered outer skin width,
measured at the frame station
Permanent integrated fuel
tanks within cabin
Forward
boundary
Aft boundary
Forward
boundary with
non-crew seat
Forward
boundary
Figure3-2 - Longitudinal View
3.4 Application of Rules for New Version of an Existing GHG-Certificated Airplane
Under the international CO2 standards, a new version of an existing C02-certificated airplane
is one that incorporates modifications to the type design that increase the MTOM or increase its
CO2 Metric Value more than the No-CCh-Change Threshold (described in 3.4.1 below). ICAO's
standards provide that once an airplane is CO2 certificated, all subsequent changes to that
Page: 75
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Test Procedures
airplane must meet at least the CO2 emissions regulatory level (or CO2 emissions standard) of the
parent airplane. For example, if the parent airplane is certificated to the in-production CO2
emissions level, then all subsequent versions must also meet the in-production CO2 emissions
level. This also applies to voluntary certifications under ICAO's standards. If a manufacturer
seeks to certificate an in-production airplane type to the level applicable to a new type design,
then future versions of that airplane must also meet the same regulatory level. Once certificated,
subsequent versions of the airplane may not fall back to a less stringent regulatory CO2 level.
To comport with ICAO's approach, if the FAA finds that a new original type certificate is
required for any reason, the airplane will need to comply with the regulatory level applicable to a
new type design.
In this action, the EPA is establishing provisions for new versions of existing GHG-
certificated airplanes that are to the same as the ICAO requirements for the international
Airplane CO2 Emission Standards. These provisions will reduce the certification burden on
manufacturers by clearly defining when a new GHG metric value must be established for the
airplane.
3.4.1 No Fuel Efficiency Change Threshold for GHG-Certificated Airplanes
There are many types of modifications that could be introduced on an airplane design that
could cause slight changes in GHG emissions (e.g. changing the fairing on a light,1" adding or
changing an external antenna, changing the emergency exit door configuration, etc.). To reduce
burden on both certification authorities and manufacturers, a set of no CO2 emissions change
thresholds was developed for the ICAO Airplane CO2 Emission Standards as to when new metric
values will need to be certificated for changes. The EPA is adopting these same thresholds in its
GHG rules.
Under this rule, an airplane is considered a modified version of an existing GHG certificated
airplane, and therefore must recertify, if it incorporates a change in the type design that either (a)
increases its maximum take-off mass, or (b) increases its GHG emissions evaluation metric value
by more than the no-fuel efficiency change threshold percentages described below and in Figure
3-3mi:
lu A fairing is "a structure on the exterior of an aircraft or boat, for reducing drag."
https://www.dictionarv.com/browse/fairing
1111 Annex 16, Volume III, Part 1, Chapter 1. ICAO, 2017: Annex 16 Volume III - Environmental Protection -
Aeroplane CO2 Emissions, First Edition, 40 pp. Available at:
http://www.icao.int/pnblications/Pages/catalogiie.aspx (last accessed July 15, 2020). The ICAO Annex 16
Volume III is found on page 16 of English Edition 2020 catalog and is copyright protected; Order No. AN 16-3.
Also see: ICAO, 2020, Supplement No. 6 - July 2020, Annex 16 Environmental Protection - Volume III-
Aeroplane C02 Emissions, Amendment 1 (20/7/20). 22pp. Available at:
https://www.icao.int/publications/catalogue/cat_2020_sup06_en.pdf (last accessed October 27, 2020). The ICAO
Annex 16, Volume III, Amendment 1 is found on page 2 of Supplement No. 6; English Edition, Order No. AN16-
3/E/01.
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For airplanes with a MTOM greater than or equal to 5,700 kg, the threshold value
decreases linearly from 1.35 to 0.75 percent for an airplane with a MTOM of 60,000
kg.
For airplanes with a MTOM greater than or equal to 60,000 kg, the threshold value
decreases linearly from 0.75 to 0.70 percent for airplanes with a MTOM of 600,000
kg.
For airplanes with a MTOM greater than or equal to 600,000 kg, the threshold value is
0.70 percent.
I
o
X
o
c
¦v
C.9?*
0.6r
C,3:
No-Fuel Efficiency-Change Thresholds
No-fuel Efficiency Change
Threshold
(5.700 kg , i 55H}
i.SC.CCC kg , 0."Sf-c-l
(6CC.C00kg. Q7Cn)
,1C497E-C7>l4 1-412981-02
V = -9 25926E-1C;< 7 55556E-03
3CC, DC*C 400,000 SCC.0CC 6CC.X0
Maximum Take-Off Mass (kg)
700,000
Figure 3-3 - No Fuel Efficiency Change Thresholds for GHG Certificated Airplanes (ICAO Adopted No CO2
Emissions Change Thresholds)
The threshold is dependent on airplane size because the potential fuel efficiency changes to an
airplane are not constant across all airplanes. For example, a change to the fairing surrounding a
wing light, or the addition of an antenna to a small business jet, may have greater impacts on the
airplane's metric value than a similar change would on a large twin aisle airplane.
These GHG changes will be assessed on a before-change and after-change basis. If there is a
flight test as part of the certification, the metric value (MV) change will be assessed based on the
change in calculated metric value of flights with and without the change.
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Test Procedures
A modified version of an existing GHG certificated airplane will be subject to the same
regulatory level as the airplane from which it was modified. A manufacturer may also choose to
voluntarily comply with a later or more stringent standard.llv
Under this rule, when a change is made to an airplane type that does not exceed the no-change
threshold, the fuel efficiency metric value will not change. There will be no method to track
these changes to airplane types over time. If an airplane type has, for example, a 10 percent
compliance margin under the rule, then a small adverse change less than the threshold may not
require the re-evaluation of the airplane metric value. However, if the compliance margin for a
type design is less than the No Fuel Efficiency Change threshold and the proposed modification
results in a change to the metric value that is less than the no fuel efficiency change threshold,
then the airplane retains its original metric value, and the compliance margin to the regulatory
limit remains the same. The proposal stated that if the margin to the standard was less than the
No Fuel Efficiency Change Threshold that the plane would still be required to demonstrate
compliance with the standard. Some commenters pointed out that this language was different
than the description adopted by ICAO. To be consistent with ICAO, this language has been
corrected.
Under this rule, a manufacturer that introduces modifications that reduce GHG emissions can
request voluntary recertification from the FAA. There will be no required tracking or accounting
of GHG emissions reductions made to an airplane unless it is voluntarily re-certificated.
The EPA is adopting, as part of the GHG rules, the no-change thresholds for modifications to
airplanes discussed above, which are the same as the provisions in the international standard.
We believe that these thresholds will maintain the effectiveness of the rule while limiting the
burden on manufacturers to comply. The regulations reference specific test and other criteria
that were adopted internationally in the ICAO standards setting process.
3.5 Changes for non-GHG Certificated Airplane Types
After January 1, 2023, and until January 1, 2028, an applicant that submits a modification to
the type design of a non-GHG certificated airplane that increases the Metric Value of the
airplane type by greater than 1.5%lv will be required to demonstrate that newly produced
airplanes comply with the in-production standard. This earlier applicability date for in-
production airplane types, January 1, 2023, is the same as that adopted by ICAO and is similarly
designed to capture modifications to the type design of non-GHG certificated airplanes newly
manufactured (initial airworthiness certificate) prior to the January 1, 2028, production cut-off
llvETM Vol. Ill §2.2.3. ICAO, 2018: Environmental Technical Manual Volume III - Procedures for the CO2
Emissions Certification of Aeroplanes, First Edition, Doc 9501, 64 pp. Available at:
http://www.icao.int/pnblications/Pages/catalogne.aspx (last accessed July 15, 2020). The ICAO Environmental
Technical Manual Volume III is found on page 77 of the English Edition 2020 catalog and is copyright protected;
Order No. 9501-3. Also see: Doc 9501 - Environmental Technical Manual - Volume III - Procedures for the
CO2 Emissions Certification of Aeroplanes, 2nd edition, 2020.90pp. Available at
https://www.icao.int/publications/catalogue/cat_2020_sup06_en.pdf (last accessed October 28, 2020). The ICAO
Annex 16, Volume III, 2nd edition is found on page 3 of Supplement No. 6 - July 2020 , English Edition, Order
No. 9501 -3.
lv Note that IV.D. l.i, Changes for non-GHG certified Airplane Types, is different than the No GHG Change
Threshold described in IV.F. 1 below. IV.F. 1 applies only to airplanes that have previously been certificated to a
GHG rule. IV.D. l.i only applies only to airplane types that have not been certificated for GHG.
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date. The January 1, 2028 production cut-off date was introduced by ICAO as an anti-
backsliding measure that gives notice to manufacturers that non-compliant airplanes will not
receive airworthiness certification after this date.
An application for certification of a modified airplane type on or after January 1, 2023, will
trigger compliance with the in-production GHG emissions limit provided that the airplane's GHG
emissions metric value for the modified version to be produced thereafter increases by more than
1.5 percent from the prior version of the airplane type. As with changes to GHG certificated
airplane types, introduction of a modification that does not adversely affect the airplane fuel
efficiency Metric Value will not require demonstration of compliance with the in-production
GHG standards at the time of that change. Manufacturers may seek to certificate any airplane
type to this standard, even if the criteria do not require compliance.
As an example, if a manufacturer chooses to shorten the fuselage of a type certificated
airplane, such action will not automatically trigger the requirement to certify to the in-production
GHG rule. The fuselage shortening of a certificated type design would not be expected to
adversely affect the metric value, nor would it be expected to increase the certificated MTOM.
Manufacturers noted that ICAO included criteria that would require manufactures to recertify if
they made "significant" changes to their airplane. ICAO did not define a "significant change" to
a type design. The EPA did not include this requirement because "significant change" is not a
defined term in the certification process. However, it is expected that manufacturers will likely
volunteer to certify to the in-production rule when applying to the FAA for these types of
changes, in order to maximize efficiencies in overall airworthiness certification processes (i.e.,
avoid the need for iterative rounds of certification).This earlier effective date for in-production
airplane types is expected to help encourage some earlier compliance for new airplanes.
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REFERENCES
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Airplane Performance Model and Analysis
Table of Contents
Chapter 4: Airplane Performance Model and Analysis	82
4.1	Purpose and Scope	82
4.2	Methodology of the EPA Emissions Inventory and Stringency Analysis	82
4.3	Fleet Evolution Model and Data Sources	84
4.3.1	Mapping Base Year Operation to the Growth Forecast Database	84
4.3.2	Retirement Rate	86
4.3.3	Calculating Future Year Growth and Replacement Market Demands	88
4.4	Full Flight Simulation with PIANO and Unit Flight Matrix	90
4.5	Inventory Modeling and Stringency Analysis	91
Table of Figures
Figure 4-1 - Regulatory Analysis Flow Chart	83
Figure 4-2 - The Retirement Curve of Narrow-Body Passenger Airplane Based on Ascend fleet data	87
Table of Tables
Table 4-1 - Two-parameter mapping from 2015 Inventory database to Growth Rate forecast databases	85
Table 4-2 - Retirement Curve coefficients by airplane category	88
Table 4-3 - The G&R airplane available in each market segment	89
Table of Equations
Equation 4-1 - Retirement Curve Equation	86
Equation 4-2 - Number of Operations Equation	89
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Airplane Performance Model and Analysis
Chapter 4: Airplane Performance Model and Analysis
4.1	Purpose and Scope
This chapter describes methodologies, assumptions and data sources used to develop the
airplane emissions and fuel burn inventories for the standards and two alternative stringency
scenarios. See chapter 6 for a detailed description of the alternative scenarios. The results of the
emissions inventories and stringency analysis are presented in Chapter 5.
The EPA had participated in the Committee on Aviation Environmental Protection (CAEP) to
analyze the emission impacts of the ICAO Airplane CO2 Emission Standards. CAEP provided a
summary of the results from this analysis in the report of its tenth meeting50, which occurred in
February 2016. However, due to the commercial sensitivity of the data used in the analysis,
much of the underlying information is not available to the public. For the U.S. domestic
standard, however, we are making our analysis, data sources, and model assumptions transparent
to the public so all stakeholders that affected by the standards can understand how the agency
derives its decisions. Thus, the EPA has conducted an independent impact analysis based solely
on publicly available information and data sources. An EPA report detailing the methodology
and results of the emissions inventory analysis51 was peer-reviewed by multiple independent
subject matter experts, including experts from academia and other government agencies, as well
as independent technical experts.52
The EPA analysis focuses primarily on modeling the U.S. GHG emissions inventory. Because
aviation is an international industry, and all major airplane and airplane engine manufacturers
sell their products globally, we also model estimated global GHG emissions for reference, but at
a much less detailed level for traffic growth and fleet evolution outside of the U.S.
In developing the inputs for our model, we contracted with ICF11 to conduct an independent
airplane/engine technology and cost assessment for the EPA rulemaking analysis. The agency
uses this ICF technology and cost forecast as the basis for our impact assessment. We also
conducted sensitivity analyses to evaluate the effects of certain model assumptions.
4.2	Methodology of the EPA Emissions Inventory and Stringency Analysis
The methodologies the EPA uses to assess the impacts of the standards and alternative
stringency scenarios can be summarized in a flow chart shown in Figure 4-1. Essentially, the
approach is to develop a baseline emissions inventory which represents the business as usual
case in the absence of standards. This baseline inventory was then compared with three
"stringency" scenarios, representing the standards and two alternative scenarios.
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Airplane Performance Model and Analysis
EPA Emissions Inventory and Stringency Analysis Flow Chart Diagram
Stringency &
Technology
Response
Spreadsheet

Growth & Retirement Rates of
each base year operation
2015_lnventory
Base Year
Operations
'1
Fleet Evolution Module
Fleet Evolution & Projected
Future Year Operations
- Baseline (No stringency)
Fleet Evolution & Projected
Future Year Operations
- w/Stringency Responses
j'"'"Inventory Module
Fuel Burn and Emissions
Inventory Calculations
PIANO Aircraft
A
Performance
A
W Models &
M
' Databases
M
Unit Flight Matrix for Fuel
Burn and Emissions
Flight Simulation Module
J
Figure 4-1 - Regulatory Analysis Flow Chart
The first step of the EPA analysis is to develop an inventory baseline by evolving the base
year operations to future year operations emulating the market driven fleet renewal process
without any stringency requirements. This "no stringency" baseline is developed for the analysis
period of 2015 to 2040. Our approach to developing the baseline is to estimate the growth and
retirement rates of future year operations based on flights with unique route (origin-destination
or OD-pair) and airplane combinations in the base year operations. The growth and retirement
rates for each of the unique base year operations determine the future year market demand which
is then allocated to available airplanes in a Growth and Replacement (G&R) database53 The
growth and retirement rates over the analysis period are obviously a function of macroeconomic
factors like fuel price, materials prices and economic growth. These economic factors are not
considered explicitly in our analysis, but they are embedded in the traffic growth forecast and
retirement rates data as inputs to the EPA analysis. Together with the residual operations from
the base year airplanes, these G&R operations constitute all the operations of in-service fleet for
every future year. The same method is applied to define fleet evolution under various stringency
scenarios. The only difference is under the stringency scenarios, technology responses need to
be taken into consideration. The airplane impacted by a stringency scenario could either be
modified to meet the standards or removed from production without a response. Once the flight
activities for all analysis scenarios are defined by the fleet evolution module, fuel burn and GHG
emissions inventories for the three stringency scenarios are then modeled with a physics-based
airplane performance model known as PIANO54. The differences between the baseline and the
three stringency scenarios are used for assessing the impacts of the stringency scenarios. The
computational processes are grouped into three distinct modules as shown in Figure 4-1. More
detailed accounts of the methods, assumptions, and data sources used for these three
computational modules are given below. The results of the fleet evolution, emissions inventories
and stringency analyses are discussed in the next chapter.
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Airplane Performance Model and Analysis
4.3 Fleet Evolution Model and Data Sources
The EPA fleet evolution model focuses on U.S. aviation, including both domestic and
international flights. U.S. international flights are defined as flights originating from the U.S. but
landing outside the U.S. Flights originating outside the U.S. are not included in the U.S.
inventory. The EPA fleet evolution model is based on FAA' 2015 Inventory Database55
(2015_Inventory) for base year flight activities and FAA's 2015-2040 Terminal Area Forecast56
(TAF) for future year traffic growth. Section 4.3.1 describes how the base year operations are
mapped into the growth forecast database to determine the future year growth rate. Section 4.3.2
describes how the retirement rates of the base year airplanes are determined from the ASCEND
global fleet database. Section 4.3.3 describes how the future market demands are allocated to
available airplanes for growth and replacement.
4.3.1 Mapping Base Year Operation to the Growth Forecast Database
The FAA 2015 Inventory Database is a comprehensive global flight dataset. Its U.S. based
flights have been used as part of the high-fidelity data sources for EPA's official annual GHG
and Sinks report since 199057. Globally, the 2015 inventory database contains 39,708,418 flights
in which 13,508,800 originated from the U.S. Among the U.S. flights, 1,288,657 are by piston
engine airplanes, 341,078 are military operations and 1,393,125 are by small airplanes with
maximum zero fuel weight1" less than 6000 lbs. In our analysis, we exclude military, piston
engine and small light weight airplanes since they are not covered under this rulemaking.
Excluding flights for these three non-covered airplane categories, the database still contains 10.3
million flights, 1,992.2 billion available seat kilometers (ASK) and 341.6 billion available tonne
kilometers (ATK) in the modeled 2015 U.S. operations.
Likewise, TAF is a comprehensive traffic growth forecast dataset for commercial operations
in both U.S. domestic and U.S. international markets. The 2015-2040 TAF used in this analysis
contains growth forecasts for both passenger and freighter markets based on origin-destination
airport pair and airplane type. In order to determine the growth rate of a base year operation, the
base year operation has to be mapped from the 2015 Inventory Database to a corresponding TAF
market defined by market type (passenger or freighter), origin-destination airport pair, and
airplane type. There is no unique mapping between these two databases. After some iterations
by trial and error and consultation with FAA, we have determined that a two-parameter mapping
using USAGE-CODE and SERVICETYPE works the best.
The two-parameter mapping from the FAA 2015 Inventory Database to TAF for growth rate
type identification is shown Table 4-1. USAGE CODE and SERVICE TYPE are parameters in
the 2015 Inventory database designed to identify the airplane usage category and the service type
of a given flight. Possible USAGE CODEs are P for passenger, B for business, C for cargo, A
for attack/combat, and O for other. Possible SERVICETYPEs are C for commercial, G for
general aviation, F for freighter, M for military, O for other, and T for air taxi. For this analysis,
we filter out SERVICE TYPEs of M (military), O (other), and T (air taxi) and only keep C
lvi The maximum zero fuel weight is the maximum permissible weight of an airplane with no disposable fuel or oil.
It is used as a prescreening filter to exclude individual airplane from further analysis in the absence of precise
maximum takeoff weight information. Maximum takeoff weight thresholds of 5,700 kg for jet airplanes and 8,618
kg for turboprop airplanes are applied by airplane type to limit the analysis to the subset of airplanes covered by
the final GHG standards.
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Airplane Performance Model and Analysis
(commercial), G (general aviation), and F (freighter). Likewise, for USAGE CODE, we filter
out A (attack/combat) and O (other) but keep P (passenger), B (business) and C (cargo) for this
analysis.
Combinations of the remaining USAGECODE and SERVICETYPE subdivide the total
market into nine sub-market categories as shown in Table 4-1. The size of each sub-market
category based on the two-parameter mapping is summarized in Table 4-1 to give a sense of their
relative contributions to the overall fleet operations by available seat kilometer (TOTAL ASK),
available tonne kilometer (TOTAL ATK), and number of operations (2015 OPS). In
consultation with FAA, these nine sub-markets are mapped into three growth rate types (under
the GRMap column in Table 4-1) for the purpose of determining their growth rate forecast for
future year operations. Again, in GR Map, G is for general aviation, F is for freighter and P is
for passenger. For U.S. passenger (P) and freighter (F) operations, TAF is used to determine the
growth rates for U.S. origin-destination (OD) pairs and airplane types from 2015 to 2040.
Table 4-1 - Two-parameter mapping from 2015 Inventory database to Growth Rate forecast databases
USAGE_CODE
SERVICE_TYPE
GR_Map
TOTAL_OPS
TOTAL_ASK
TOTAL_ATK
B - Business
C- Commercial
G - General
5.8148E+05
4.5898E+09
9.8501E+08
B
F - Freight
F - Freight
6.4350E+03
1.4580E+06
1.1399E+07
B
G - General
G
1.3937E+06
1.3166E+10
2.8144E+09
C - Cargo
C
F
2.2645E+05
2.8492E+10
3.7362E+10
C
F
F
4.7665E+05
5.2309E+09
6.6587E+10
C
G
G
9.6400E+03
6.1929E+08
1.8029 E+09
P - Passenger
C
P - Passenger
2.7432E+07
7.0697E+12
1.0836E+12
P
F
F
3.1517E+05
8.8414E+10
2.6023E+10
P
G
G
4.1658E+06
1.2560E+12
2.0427E+11
In mapping the base year operations to TAF to determine their corresponding growth rate, if
there are exact OD-pair and airplane matches between the two databases, the exact TAF year-on-
year growth rates are applied to grow 2015 base year operations to future years. For cases
without exact matches, the growth rates of progressively higher-level aggregates will be used to
grow the future year operations.56 For example, if there is no match in exact origin-destination
airport pair, the airport pair will be mapped to a route group (either domestic or international),
and the growth rate of the route group will be used instead to grow the operation. If there is no
match in airplane type (e.g., B737-8 MAX, B777-9X, etc.), the airplane category (e.g., narrow
body passenger, wide body freighter, etc.) as defined in the TAF will be used to map the growth
rate.
Since general aviation is not covered in TAF, we use the forecasted growth rate of 1.6% for
all turboprop operations based on the FAA Aerospace Forecast (Fiscal Year 2017-2037)58. For
U.S. business jet operations, we use the 3% compound annual growth rate published in the same
FAA Aerospace Forecast (Fiscal Year 2017-2037).58
For non-U. S. flights, we use an average compound annual growth rate of 4.5% for all
passenger operations and 4.2% for all freighter operations based on ICAO long-term traffic
forecast for passenger and freighters.59 For non-U. S. business jet operations, we use the global
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Airplane Performance Model and Analysis
average growth rate of 5.4% based on Bombardier's Business Aircraft Market Forecast 2016-
2025.60
Given the classification of the two-parameter mapping table, we have determined that the
eighth row of the mapping table (where the USAGE CODE = "P" and SERVICE TYPE = "F")
is converted freighters which are freighters converted from used passenger airplanes after the end
of their passenger services. These converted freighters are not subject to the GHG standards, so
they are excluded from all inventory data reported in this TSD.
4.3.2 Retirement Rate
The retirement rate of a specific airplane is determined by the age of the airplane and the
retirement curve associated with the airplane category. The retirement curve is the cumulative
fraction of retirement expected as the airplane ages. It goes from 0 to 1 as the airplane age
increases. The retirement curves can be expressed as a Sigmoid or Logistic function in the form
of
Equation 4-1 - Retirement Curve Equation
RC(x) = 1/(1 + ea~bx)
where RC is the retirement curve function, a and b are coefficients that change with airplane
category and x is the age of the airplane.
The reason to choose this type of retirement function is because it is a well-behaved function
that matches well with historical retirement data of known airplane fleet. Figure 4-2 illustrates
the characteristic "S" shape of a historical survival curve, SC(x), where SC(x) = 1 - RC(x). Note
that the ratio of the two coefficients in Equation 4-1, i.e., a/b, represents the half-life of the
airplane fleet where 50% of the fleet survives and 50% retires. The slope of the retirement curve
(or percent retired per year) at half-life is b/4. So, the larger the coefficient b is, the higher the
rate of retirement will be at half-life. The retirement curve is also an antisymmetric function
with respect to x = a/b and has long tails at both ends of the age distribution (very young and
very old airplanes in the fleet).
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Airplane Performance Model and Analysis
Narrow Body Passenger Retirement Curve
100%
80%
"S 60%
>
3
LO
SO
0s-
40%
20%
0%
0
10	20	30
Airplane Age
40
1970
•
1971
1972
•
1973
1974
•
1975
1976
•
1977
1978
•
1979
1980
•
1981
1982
•
1983
1984
•
1985
1986
•
1987
1988
•
1989
1990
•
1991
1992
•
1993
1994
•
1995
1996

1997
1998
•
1999
2300
•
2001
2302
•
2003
2304
•
2005
2306
•
2007
2308
•
2009
2310
•
2011
2312
•
2013
2314
•
2015
CAEP10 NB
	BFSC
Figure 4-2 - The Retirement Curve of Narrow-Body Passenger Airplane Based on Ascend61 fleet data
Retirement curves of major airplane categories used in this EPA analysis are derived
statistically based on data from the FlightGlobal's Fleets Analyzer database61 (also known as
ASCEND Online Fleets Database — hereinafter "ASCEND"). Table 4-2 lists the numerical
values of these coefficients in the retirement curves for major airplane categories. The retirement
curves so established are consistent with published literature from Boeing and Avolon in terms
of the economic useful life of airplane categories. However, it is recognized from other sectors
(e.g., light duty vehicles) that the retirement curves are not necessarily exogenously fixed but
rather a function of the relative price of new versus used vehicles; fuel prices; repair costs; etc.
Furthermore, when regulations are vintage differentiated (i.e., when new vehicles are subject to
stricter requirements than older vintages), it has been shown that the economically useful life of
the existing fleet can be extended. The higher cost and sometimes diminished performance of
compliant new vehicles makes it economically worthwhile to extend the life of older vehicles
that would otherwise have been retired. These extraneous factors, however, are not considered
in this analysis.
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Airplane Performance Model and Analysis
Table 4-2 - Retirement Curve coefficients by airplane category
LQ
LQF
Ri
SA
SAF
TA
TAF
TP
AirplaneCategory
BJ
Description
Business Jet
Large Quad
a
6.265852341	0.150800149
5.611526057	0.223511259
6.905900732	0.205267334
4.752779141	0.178659236
5.393337195	0.222210782
6.905900732	0.205267334
5.611526057	0.223511259
6.905900732	0.205267334
3.477281304	0.103331799
b
large Quad Freighter
Regional Jet
Single Aisle
Single Aisle Freighter
Twin Aisle
Twin Aisle Freighter
Turboprop
For each operation in the base year database (2015 Inventory), if the airplane tail number is
known, the retirement rate is based on exact age of the airplane from the ASCEND global fleet
database. If the airplane's tail number is not known, the aggregated retirement rate of the next
level matching group (e.g., airplane category or airplane 'type' as defined by ASCEND) will be
used to calculate the retirement rates for future years.
4.3.3 Calculating Future Year Growth and Replacement Market Demands
Combining the growth and retirement rates together, we can determine the total future year
market demands for each base year flight. These market demands are then allocated by equal
product market sharelvu to available G&R airplanes competing in the same market segment as the
base year flight. The available G&R airplanes for various market segments are based on the
technology responses developed by ICF, as described in Chapter 2 of the TSD.62 The G&R
airplanes in each market segment are listed in Table 4-3. ICF technology responses also include
detailed information about the entry-into service year and the end-of-production year for each
current and future in-production airplane out to 2040.
lvn EPA uses equal product market share (for all airplanes present in the G&R database), but attention has been paid
to make sure that competing manufacturers have reasonable representative products in the G&R database.
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Airplane Performance Model and Analysis
Table 4-3 - The G&R airplane available in each market segment
Market
Segment
Description
G&R Airplane
CBJ
Corporate Jet
A318-112/CJ, A319-133/CJ, B737-700IGW (BBJ), B737-8 (BBJ)
FR
Freighter
A330-2F, B747-8F, B767-3ERF, B777-2LRF, TU204-F, AN74-F/PAX, B777-
9xF, A330-800-NEOF
LBJ
Large Business Jet
G-5000, G-6000, GVI, GULF5, Global 7000, Global 8000
MBJ
Medium Business Jet
CL-605, CL-850, FAL900LX, FAL7X, ERJLEG, GULF4
RJ 1
Small Regional Jet
CRJ700, ERJ135-LR, ERJ145, MRJ-70
RJ 2
Medium Regional Jet
CRJ900, ERJ175, AN-148-100E, AN-158, EJ-175 E2
RJ_3
Large Regional Jet
CRJ1000, ERJ190, ERJ195, RRJ-95, RRJ-95LR, TU334, MRJ-90, ERJ-190 E2,
ERJ-195 E2
SA_1
Small Single Aisle
A318-122, A319-133, B737-700, B737-700W, A319-NEO, B737-7MAX,
CS100, CS300, MS-21-200
SA_2
Medium Single Aisle
A320-233, B737-800, B737-800W, A320-NEO, B737-8MAX, MS-21-300,
C919ER
SA_3
Large Single Aisle
A321-211, B737-900ER, B737-900ERW, TU204-300, TU204SM, TU214,
A321-NEO, B737-9MAX
SBJ 1
Small Business Jet 1
CNA515B, CNA515C, EMB505, PC-24
SBJ_2
Small Business Jet_2
Learjet 40XR, Learjet 45XR, Learjet 60XR, CNA560-XLS, Learjet 70, Learjet
75
SBJ 3
Small Business Jet 3
CNA680, GULF150, CNA680-S
SBJ 4
Small Business Jet 4
CL-300, CNA750, FAL2000LX, G280, CNA750-X
TA 1
Small Twin Aisle
A330-203, A330-303, B767-3ER, B787-8, A330-800NEO, A330-900-NEO
TA 2
Medium Twin Aisle
A350-800, A350-900, B787-9, B787-10
TA 3
Large Twin Aisle
B777-200ER, A350-1000, B777-8x
TA_4
Very Large Twin
Aisle
A380-842, B747-8, B777-200LR, B777-300ER, B777-9x
TP 1
Small Turboprop
ATR42-5, 1 LI 14-100, AN-32P, AN 140
TP 2
Medium Turboprop
ATR72-2
TP_3
Large Turboprop
Q400
We allocate the market demand based on available seat kilometer (ASK) for passenger
operations, available tonne kilometer (ATK) for freighter operations and number of operations
for business jets. Of course, given the number of seats for passenger airplane, payload capacity
for freighters and the great circle distance for each flight, all these can be converted to a common
activity measure, i.e., number of operations. The formula for calculating number of operations
for out years is given in Equation 4-2.
Equation 4-2 - Number of Operations Equation
GR(y) + RET(y)
NOP(y) =	 ]y|(c	NOP( 2015)
where NOP(v) is number of operations in year y,
GR(v) is the growth rate in year y
RET(v) is the retirement rate in year y
N(c,v) is the number of available airplanes in market segment c and year v
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As described in Chapter 2 of this TSD (see Table 2-1), ICF technology responses include
continuous improvement in metric value (or fuel efficiency improvement) for all G&R airplanes
from 201063 to 2040. ICF technology responses also include estimated MV improvements for
long-term replacement airplanes (see Table 2-4) beyond the end of production of current in-
production and project airplanes. This is meant to establish a baseline where current in-
production airplanes are continuously improving and new type design airplanes are introduced
periodically to replace airplane models that are going out of production due to market
competition. In order to capture these dynamically changing airplane efficiency improvements,
our fleet evolution model tracks the market share of every new-in-service airplane entering the
fleet each year and applies the annual fuel efficiency improvement via an adjustment factor
according to the vintage year of the airplane in the fleet. For stringency analysis, if an airplane
fails a stringency limit and needs to improve its MV to comply with the standard, we apply the
adjustment factor in the same manner to establish the emissions under the influence of the
stringency limit.
4.4 Full Flight Simulation with PIANO and Unit Flight Matrix
The purpose of the full flight simulation module is to calculate instantaneous and cumulative
fuel burn, flight distance, flight altitude, flight time, and emissions by modeling airplane
performance for standardized flight trajectories and operational modes. PIAN0lvm version 5.4
was used for all the emissions modeling. PIANO is a physics-based airplane performance model
used widely by industry, research institutes, non-governmental organizations and government
agencies to assess airplane performance metrics such as fuel efficiency and emissions
characteristics based on airplane types and engine types. PIANO v5.4 (2017 build) has 591
airplane models (including many project airplanes still under development, e.g., the B777-9X)
and 56 engine types in its airplane and engine databases. We use these comprehensive airplane
and engine data to model airplane performance for all phases of flight from gate to gate including
taxi-out, take-off, climb, cruise, descent, approach, landing, and taxi-in in this analysis.
To simplify the computation, we made the following modeling assumptions: 1) Assume
airplanes fly the great circle distance (which is the shortest distance along surface of the earth
between two airports) for each origin-destination (OD) pair. 2) Assume still air flights and ignore
weather or jet stream effects. 3) Assume no delays in takeoff, landing, en-route, and other flight
related operations. 4) Assume a load factor of 75% maximum payload capacity for all flights
except for business jet where 50% is assumed. 5) Use the PIANO default reserve fuel rulellx for a
given airplane type. 6) Assume a one-to-one relationship between metric value improvement and
fuel burn improvement for airplanes with better fuel efficiency technology insertions (or
technology responses).
When jet fuel is consumed in an engine, the vast majority of the carbon in the fuel reacts with
oxygen to form CO2. To convert fuel consumption to CO2 emissions, we used the conversion
lvm PIANO is the Aircraft Design and Analysis Software by Dr. Dimitri Simos, Lissys Limited, UK, 1990-present;
Available at www.piano.aero (last accessed March 16, 2020). PIANO is a commercially available airplane
design and performance software suite used across the industry and academia.
lK For typical medium/long-haul airplanes, the default reserve settings are 200 nm diversion, 30 minutes hold, plus
5% contingency on mission fuel. Depending on airplane types, other reserve rules such as U.S. short-haul,
European short-haul, NB AA-IFR or Douglas rules are used as well.
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factor of 3.16 kg/kg fuel for CO2 emissions, and to convert to the six well-mixed GHG
emissions, we used a slightly higher conversion factor of 3.19 kg/kg fuel for CO2 equivalent
emissions. It is important to note that in regard to the six well-mixed GHGs (CO2, methane,
nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride), only two of these
gases — CO2 and nitrous oxide (N2O) — are reported (or emitted) for airplanes and airplane
engines.57 The method for calculating CO2 equivalent emissions is based on SAE AIR 5715,
entitled Procedures for the Calculation of Airplane Emissions64 for N2O emissions, and the EPA
publication Emissions Factors for Greenhouse Gas Inventories65 for the 100-year global
warming potential.
Given the flight activities defined by the fleet evolution module in the previous section, we
generate a unit flight matrix to summarize all the PIANO outputs of fuel burn, flight distance,
flight time, emissions, etc. for all flights uniquely defined by a combination of departure and
arrival airports, airplane types, and engine types. This matrix includes millions of flights and
forms the basis for all the regulatory scenarios and sensitivity studies. To reduce the
computational workload of such a huge task in stringency analysis, we pre-calculate these full
flight simulation results and store them in a database of 50 distances and 50 payloads for each
airplane and engine combination. The millions of flights in the unit flight matrix are interpolated
from the 50x50 flight distance/payload database.
4.5 Inventory Modeling and Stringency Analysis
The GHG emissions calculation involves summing the outputs from the first two modules for
every flight in the database. This is done globally, and the U.S. portion is segregated from the
global dataset. The same calculation is done for the baseline and the GHG standards and two
alternative scenarios. When a surrogate airplane is used to model any airplane that is not in the
PIANO database or when a technology response is required for any airplane to pass a stringency
limit, an adjustment factor is also applied to model the expected performance of the intended
airplane and technology responses.
The differences between the GHG standards and alternative scenarios and that of the baseline
provide the quantitative measures for the agency to assess the emissions impacts of the GHG
standards.
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REFERENCES
50	ICAO, 2016: Tenth Meeting Committee on Aviation Environmental Protection Report, 1-12 February 2016,
Committee on Aviation Environmental Protection, Document 10069, 432pp, is found on page 27 of the English
Edition ICAO Products & Services 2020 Catalog and is copyright protected; Order No. 10069. For purchase
available at: https://www.icao.int/publications/catalogue/cat_2020_en.pdf (last accessed March 17, 2020). The
summary of technological feasibility and cost information is located in Appendix C (starting on page 5C-1) of this
report.
51	U.S. EPA, 2020: Technical Report on Aircraft Emissions Inventory and Stringency Analysis, July 2020.
52	RTI International and EnDyna, EPA Technical Report on Aircraft Emissions Inventory and Stringency Analysis:
Peer Review, July 2019, 157pp.
53	The Growth and Replacement database contains all the available in production and in development airplanes
known to the agency for renewing the global in-service fleet in the analysis period of 2015-2040. This G&R
database together with technology responses developed by ICF is available in the 2018 ICF Report.
54	PIANO is the Aircraft Design and Analysis Software by Dr. Dimitri Simos, Lissys Limited, UK, 1990-present;
Available at www.piano.aero (last accessed March 18, 2020). PIANO is a commercially available aircraft design
and performance software suite used across the industry and academia.
55	FAA, Inventory Database is developed by the U.S. Federal Aviation Administration (FAA). Commercial airplane
jet fuel burn and carbon dioxide (CO2) emissions estimates were included in the U.S. Inventory using radar-
informed data from the FAA Enhanced Traffic Management System (ETMS) for 2000 through 2016 as modeled
with the Aviation Environmental Design Tool (AEDT). For this analysis, EPA only uses the operations data from
the 2015 Inventory Database to develop the fleet evolution and emissions modeling as described in this document.
56	FAA, 2015-2040 Terminal Area Forecast, the Terminal Area Forecast (TAF) is the official FAA forecast of
aviation activity for U.S. airports. It contains active airports in the National Plan of Integrated Airport Systems
(NPIAS) including FAA-towered airports, Federal contract-towered airports, nonfederal towered airports, and non-
towered airports. Forecasts are prepared for major users of the National Airspace System including air carrier, air
taxi/commuter, general aviation, and military. The forecasts are prepared to meet the budget and planning needs of
the FAA and provide information for use by state and local authorities, the aviation industry, and the public.
57	EPA, 2019: Inventory of US Greenhouse Gas Emissions and Sinks, EPA develops an annual report that tracks
U.S. greenhouse gas emissions and sinks by source, economic sector, and greenhouse gas going back to 1990. EPA
publishes the draft report in February to allow public comment prior to publishing the final report by April 15 of
every year. The document is available online at the following EPA website.
https://www.epa.gov/ghgeniissions/inventore-ns-green.honse-gas-emissions-and-sinks (last accessed March 17,
2020)
58	FAA, 2018, FAA Aerospace Forecast, Fiscal Years 2017-2037, Table 29 Active General Aviation and Air taxi
Hours Flown, Average Annual Growth 2017-2037. The document is available online at the FAA website.
https://www.faa.gov/data research/aviation/aerospace forecasts/media/FY20.1.7-37 FAA Aerospace Forecast.pdf
(last accessed March 17, 2020)
59	ICAO, 2016, Long Term Traffic Forecasts, Passenger and Cargo, July 2016. The document is available online at
the ICAO website. https://www.icao.int/Meetings/aviationdatasem.inar/Docnments/ICAO-Long-Tenn-Traffic-
Forecasts-Julv-2016.pdf (last accessed March 17. 2020)
60	Bombardier, 2015, 2016-2025 Bombardier's Business Aircraft Market Forecast. The report is available online at
the Bombardier website, https://businessaircraft.bombardier.com/sites/defauit/files/2018-03/market forecast en.pdf
(last accessed March 17, 2020)
61	FlightGlobal Fleets Analyzer is a subscription based online data platform providing comprehensive and
authoritative source of global aircraft fleet data (also known as ASCEND database) for manufacturers, suppliers and
MRO providers, https://sign.in.cirimn.com/ (last accessed March 17, 2020)
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Airplane Performance Model and Analysis
62	ICF, 2018: Aircraft CO2 Cost and Technology Refresh and Industry Characterization, Final Report, EPA Contract
Number EP-C-16-020, September 30, 2018.
63	For this analysis with 2015 as the base year, we only use the continuous improvement data from 2015 to 2040.
64	SAE, 2009: Procedures for the Calculation of Aircraft Emissions', AIR 5715, 2009-07. This document can be
purchased at SAE website, and is copyright protected, https://www.sae.org/standards/content/air5715/.
65	EPA, 2014, Emissions Factors for Greenhouse Gas Inventories, EPA, last modified 4, April 2014.
https://www.epa.gov/sites/production/files/2015-07/documents/emission-factors 2014.pdf
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Table of Contents
Chapter 5: Impacts on Emissions and Fuel Burn	96
5.1	Executive Summary	96
5.2	Introduction	96
5.3	Fleet Evolution Results and Baseline Emissions	97
5.3.1.1 Conclusions of the Fleet Evolution Results	104
5.3.2 Baseline Emissions	105
5.3.2.1 Discussions on baseline modeling	106
5.4	Stringency Analysis of U.S. and Global CO2 Emission Impacts	107
5.5	Sensitivity Case Studies	109
5.5.1	Scenario 3 Sensitivity to Continuous Improvement	109
5.5.2	Scenario 3 Sensitivity to Extending Production of A380 and B767-3ERF to 2030112
5.5.3	Scenario 3 Sensitivity to Combined Effects of Continuous Improvement and
Extended Production	114
5.5.4	Similar Sensitivity Studies for Scenarios 1 and 2	117
Table of Figures
Figure 5-1 - Global total growth and replacement operations in years 2015-2040	98
Figure 5-2 - Comparison of U.S. Passenger fleet Available Seat Kilometer of ICAO, EPA and TAF	100
Figure 5-3 - Comparison of U.S. Turboprop fleet Available Seat Kilometer of ICAO, EPA and TAF	100
Figure 5-4 - Comparison of U.S. Regional Jet fleet Available Seat Kilometer of ICAO, EPA and TAF	101
Figure 5-5 - Comparison of U.S. Freighter fleet number of operations for ICAO, EPA and TAF	102
Figure 5-6 - Comparison of U.S. Freighter fleet Available Tonne Kilometer of ICAO, EPA and TAF	103
Figure 5-7 - Total Available Tonne Kilometer of subsets of flights in EPA and TAF with and without match origin-
destination pair (OD), aircraft type (AC) and airplane category (CAT)	103
Figure 5-8 - Comparison of U.S. Business Jet fleet number of operations for ICAO, EPA and TAF	104
Figure 5-9 - Range of CO2 emissions baselines with various fleet evolution and continuous improvement
assumptions	106
Figure 5-10 - CO2 emissions of A380-8 and market segment TA_4 for the baseline and Scenario 3	108
Figure 5-11 - Cumulative reduction of CO2 emissions from 2023 to 2040 for Scenario 3	108
Figure 5-12 - CO2 Emissions of Baseline and Scenario 3 for ICAO and EPA (w & w/o continuous improvement)
Cases	110
Figure 5-13 - Zoom-in Picture of CO2 Emissions of Impacted Airplane A380-8 and Market Segment TA_4 for EPA
Scenario 3 with and without Continuous Improvement	Ill
Figure 5-14 - Cumulative CO2 Reduction of Scenario 3 for ICAO and EPA (w & w/o continuous improvement)
cases	Ill
Figure 5-15 - Cumulative U.S. CO2 Reduction for EPA Scenario 3 with & without Continuous Improvement	112
Figure 5-16 - CO2 emissions of A380-8 with two different end of production (EOP) assumptions (2025 versus 2030)
for EPA baseline and Scenario 3	113
Figure 5-17 - CO2 emissions of B767-3ERF with two different end of production assumptions (2023 versus 2030)
for EPA baseline and Scenario 3	113
Figure 5-18 - EPA main analysis versus sensitivity study: in cumulative reduction of CO2 emissions from 2023 to
2040 for Scenario 3	114
Figure 5-19 - Zoom-in view of CO2 Emissions of A380-8 and Market Segment TA_4, for Extended Production to
2030, with and without Continuous Improvement	115
Figure 5-20 - Zoom-in view of CO2 Emissions of B767-3ERF and Market Segment FR, for Extended Production to
2030, with and without Continuous Improvement	115
Figure 5-21 - Cumulative CO2 Reduction of Scenario 3 for ICAO and EPA (Sensitivity Study of Extended
Production to 2030 for A3 80 and B767F, with & without continuous improvement)	116
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Impacts on Emissions and Fuel Consumption
Figure 5-22 - Cumulative U.S. C02 Reduction of Scenario 3 for the Sensitivity Study of Extended Production to
2030 for A380 and B767F, with & without continuous improvement	116
Figure 5-23 - Summary of Sensitivity to Model Assumptions for Scenarios I, 2 and 3	118
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Impacts on Emissions and Fuel Consumption
Chapter 5: Impacts on Emissions and Fuel Burn
5.1	Executive Summary
EPA analyzed the costs and emissions reductions for the standards and two alternative
scenarios. The first alternative scenario (Scenario 2) was for a 5-year pull-ahead (or 5-year
earlier effective date) of the in-production standard. The second alternative scenario (Scenario 3)
was for a pull-ahead combined with a more stringent level comparable to the new type standard.
These alternative scenarios are described in more detail later in section 6.1.2 (of Chapter 6).
The main conclusion of the impact analysis for the airplane GHG emissions rule is that it will
result in no costs and no emission reductions. This is because the ICAO standards are
technology-following standards and all manufacturers have products that either already meet the
standards or have new products under development that will meet the standards by their effective
dates. The major effect of the adopted standards is to align with ICAO standards in order to
provide a level playing field for U.S. manufacturers and to prevent future airplanes from
backsliding or incorporating technologies that will have an adverse effect on GHG emissions.
Of the two alternative stringency scenarios the agency has analyzed, the pull-ahead scenario
of the in-production standard also offers no additional benefit but has a much tighter timeline for
manufacturers to certify their engines due to the 5-year pull-ahead from the ICAO production
cut-off date. The other more stringent scenario (Scenario 3) would only result in modest
emission reductions (1.4 Mt of cumulative U.S. CO2 reductions over the period of 2023-2040).lx
This result is because the only airplane that is impacted by Scenario 3 is the A380. None of the
U.S. airlines have the A380 in their fleets, and thus, under Scenario 3 the emissions reduction
impacts from both U.S. domestic and international flights are limited.
5.2	Introduction
Market forces historically have driven fuel efficiency improvements because fuel efficiency is
a major part of the direct operating cost of air carriers, and it influences their airplane purchasing
decisions. EPA's Guidelines for Economic Analysis, OMB's A-4, and standard cost-benefit
analysis all call for a ceteris paribuslxi baseline scenario, against which a policy scenario is
compared. From this perspective, a business as usual (BAU) baseline which includes market-
driven improvements in the absence of the GHG standards will be the best measure for assessing
impact of the standards. In fact, EPA regulatory impact analyses in other sectors all use such
BAU baselines to assess the impacts of emission regulations on the regulated sectors.
It is thus important to determine the BAU baseline as accurately as possible by
knowledgeable and independent third-party experts. EPA contracted with ICF to conduct such
an independent study to develop the best estimates of the BAU improvements for airplanes and
engines in detail by airplane models and engine types for the near- and mid- term (2010-2030)
and long-term (2030-2040) timeframes, based on technology feasibility and economic viability
lx As described later in section 6.4 (of Chapter 6), estimated net benefits (benefits minus costs) range from -$285
million to -$261 million, at 7 and 3 percent discount rates respectively
1x1 Ceteris paribus means with other conditions remaining the same (all other things being equal).
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Impacts on Emissions and Fuel Consumption
for each of airplane/engine types. The main analysis results presented in this chapter are based
on the fleet evolution and technology responses derived from this ICF study66.
Inherent in any modeling of future emissions is the uncertainty associated with predictions of
the future. The agency has conducted a number of sensitivity studies in an attempt to quantify
the effects of certain fleet evolution and technology response parameters, specifically the end-of-
production timing and continuous-improvement (which are improvements expected from BAU
developments) assumptions. These sensitivity studies provide an estimate of the uncertainties
when we vary such parameters one at a time or in combinations.
5.3 Fleet Evolution Results and Baseline Emissions
As described in Chapter 4 of the TSD, the EPA fleet evolution model aims to develop future
operations of the overall airplane fleet based on the base year operations assuming a fixed
network structure (no new routes or time-varying network configurations). We use a very simple
market allocation method in which each competing airplane within a market segment is given an
equal market share. The market allocation is based on airplane types and their operations
measured in available seat kilometer (ASK) or available tonne kilometer (ATK) or number of
operations since they directly determine the emissions output. We are not tracking flights and
airplane deliveries at individual airplane operator or airline level.
In developing future year operations, all growth and replacement (G&R) operations and
residual legacy operations in future years are expressed in fractions of the base year operations in
our analysis. The growth and replacement operations come from new airplanes entering into
service to fill the market demands from increased air traffic and retirement of in-service fleet in
future years. The residual legacy operations are the remaining base year operations expected in
future years after retirement of a portion of the base year fleet.
The market allocation method for G&R operations is applied to each individual flight in the
base year. Together with the residual operations from the base year, the total fleet operations in
any given year are made up of three parts, i.e., growth, retirement and residual operations. This is
true at any aggregate levels from individual flight to total global fleet. To illustrate the
relationship between base year operations, growth, retirement and residual operations in future
years, the overall global fleet growth and replacement operations are depicted as an example in
Figure 5-1 where the lower line defines the residual (or remaining) operations while the upper
line defines the growth projection. The area between the base year operations (the dashed
horizontal line) and the growth line is the growth operations. The area between the base year
operations and the residual line is the retirement operations. The area below the residual line is
the residual operations from the legacy fleet of the base year. The combined growth and
retirement operations in each year will be the total annual market demands that need to be filled
by G&R airplanes. The G&R fleet in any future year though is comprised of G&R airplanes
entering in service from all previous years. The new enter-into-service airplanes themselves will
retire according to their respective retirement curves. Thus, the market share and distribution of
operations among the in-service fleet change from year to year, and our fleet evolution model
tracks these changes for each G&R airplane type and each enter-into-service year. Thus, we are
able to assign proper BAU improvements according to the year a G&R airplane enters into
service. Fleet evolution results and baseline emissions all depend on the exact age distribution of
the G&R fleet.
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le8
Global: Total
Number of Operations
Residual
X.® ?[ o pe rat i 9ns
Growth
Growth
Operations
Replacement
Operations
0.0
2015
2020
2025
2030
2035
Residual Operations
2040
Year
Figure 5-1 - Global total growth and replacement operations in years 2015-2040
Fleet Evolution Results
Fleet evolution defines how the future fleet is composed and how future fleet operations are
distributed based on the operations of a base year and the market growth forecast from the base
year. It is the basis for calculating future year emissions and evaluating the impact of stringency
scenarios. The fleet evolution of the EPA analysis is developed independently of the ICAO
analysis. Per discussions in section 4.3, it is based on FAA's 2015 inventory database for the
base year operations and FAA's 2015-2040 TAFW" for future traffic growth. Since it is
developed independently, it is not directly comparable to the ICAO dataset. Nevertheless, we
will compare our fleet evolution results with ICAO and TAF data for a consistency check. There
is no right or wrong in this comparison, but any outstanding differences may warrant some
discussion to ensure that they will not skew the results and affect the policy decisions in an
unexplainable manner.
Figure 5-2 compares the EPA fleet evolution results with the ICAO results. The EPA analysis
results are close to the ICAO results but differ by up to 10% in the analysis period of 2015-2040.
This is expected because there are many fundamental differences between the two analyses.
1x11 FAA, 2015-2040 Terminal Area Forecast, the Terminal Area Forecast (TAF) is the official FAA forecast of
aviation activity for U.S. airports. It contains active airports in the National Plan of Integrated Airport Systems
(NPIAS) including FAA-towered airports. Federal contract-towered airports, nonfederal towered airports, and
non-towered airports. Forecasts are prepared for major users of the National Airspace System including air
carrier, air taxi/commuter, general aviation, and military. The forecasts are prepared to meet the budget and
planning needs of the FAA and provide information for use by state and local authorities, the aviation industry ,
and the public.
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Impacts on Emissions and Fuel Consumption
First, the EPA fleet evolution for this rule is based on FAA 2015 Inventory Database, while
ICAO's fleet evolution is based on 2010 Common Operations Database (COD)lxui. Second, the
EPA growth forecast is based on FAA 2015-2040 Terminal Area Forecast (TAF), while the
ICAO growth forecast is based on CAEP-FESGlxiv consensus traffic forecast and industry-
provided fleet forecast for passenger, freight and business jets for 2010-2040. So the two fleet
evolution models are based on different data sources in both the base year operation and the
growth rate forecast. Coming within 10% differences in a 25-year span is actually quite
noteworthy considering the EPA fleet evolution for the U.S. operations is very detailed based on
the FAA data while the ICAO model treats all U.S. domestic operation as growing at one
uniform growth rate.
We also compare the EPA fleet evolution results with FAA TAF mainly to confirm that the
growth rates are consistent between the two since EPA analysis growth rates are sourced from
TAF. But because the two databases (2015 Inventory and TAF) are developed and maintained
by different groups for different purposes using different data sources, some differences exist in
the base year operations, most notably, in the international freight operations. Many operations
exist in one database but not in the other and vice versa. Our fleet evolution strategy is to evolve
future year fleet operations solely based on FAA 2015 Inventory for the base year operations.
So, in cases where the base year operations in TAF are different from those in the 2015
Inventory, the TAF operational data are ignored. TAF is only used to determine the growth rate
of the fleet. The challenge for this strategy is in mapping the base year operations correctly onto
TAF to find the proper growth rates forecast for the operations in future years. With this
strategy, we will always get a unique solution for future year operations with a given mapping of
base year operations from 2015 Inventory to TAF, but there is no guarantee that the total
operations so derived in any year will be the same as the TAF. By using a two-parameter
mapping, we were able to refine the grouping of base year operations and improve the mapping
between the two databases. Although some large differences still exist between the two, further
reconciliation is beyond the scope of this project. By using the two-parameter mapping, we can
also isolate the converted freighter operations and exclude them from stringency analysis
because they are not subjected to the GHG standards. This exclusion also makes the EPA
analysis freighter results more comparable to ICAO's, but other differences remain as explained
later.
1x111 Common Operations Database (COD) is a comprehensive global flight database developed and maintained by
the Modeling and Database Group (MDG), which is a technical group under ICAO's Committee on Aviation
Environmental Protection (CAEP). COD is used for trends analysis of aviation environmental impacts and
stringency analysis for ICAO standards.
lxiv CAEP-FESG refers to the Forecasting and Economic Analysis Support Group which is the technical group
tasked to develop fleet growth forecast and cost effectiveness analyses for ICAO standards.
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Passenger Total-ask
lel2
1,7. 	 ICAO
	 EPA
1.6
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2040

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2015
20 20
2023
2025
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7.32E+11
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TAF

6.48E+11
7.67E+11
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9.90E+11
105E+12
119E+12
133E+12
Figure 5-2 - Comparison of U.S. Passenger fleet Available Seat Kilometer of ICAO, EPA and TAF
The U.S. passenger fleet operations of the three datasets match reasonably well as shown in
Figure 5-2. We observe higher growth rate for ICAO in both U.S. domestic and international
operations compared to the results from the EPA analysis. The EPA analysis growth rate is
between the other two.
Turboprops - ASK
US Domestic; Turboprop
US International: Turboprop
v ?¦>

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2020
2025
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2030
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Figure 5-3 - Comparison of U.S. Turboprop fleet Available Seat Kilometer of ICAO, EPA and TAF
The U.S. turboprop fleet operations of the three datasets match less well as shown in Figure
5-3. The EPA analysis and TAF are reasonably close while ICAO is about 50 to 100 percent
Page: 100
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Impacts on Emissions and Fuel Consumption
higher in ASK. The mismatch is not a major concern for fleet-wide emissions because turboprop
emissions are less than 1% of the overall fleet emissions. The mismatch to ICAO data is even
less of a concern to U.S. emissions since the ICAO dataset is less detailed and less refined for the
U.S. domestic and international operations than the FAA-TAF dataset. Since the EPA fleet
evolution results match well with the TAP data, it suggests our fleet evolution results for
turboprop are reasonable, and the emissions and stringency analysis will proceed with the EPA
fleet evolution results on this basis. We intend to resolve this discrepancy with ICAO in the
future.
Regional Jets - ASK
US Domestic: Regional Jets
US International: Regional Jets
1 706*11
?.OSE-»U
2.46E+11
ICAO 1 SlE + kl
ICAO
L41E+11 |13BC+11 jmE+ll ll-TOe-fll E1-79E+11 ILB3E+11 I2.P2E+11 I2.13E411
i lien: 1 ••«»!! fl.fiZE+11 l«8i til "l :!!£•:: 1 S2E+I1 1 '<01 • II |2 141 til
Figure 5-4 - Comparison of U.S. Regional Jet fleet Available Seat Kilometer of ICAO, EPA and TAF
Similar to turboprop, the U.S. regional jet operations of the three datasets match well between
EPA and TAF, but ICAO has about 10% to 30% higher ASK and higher growth rate as shown in
Figure 5-4. This mismatch again is less of a concern for fleet-wide emissions because the
regional jet emissions are a small fraction of the overall passenger fleet emissions. The mismatch
to ICAO data is even less of a concern to U.S. emissions since the ICAO regional jet dataset is
less detailed and less refined than TAF for the U.S. domestic and international operations. Given
that the EPA fleet evolution results match well with the high-fidelity FAA-TAF dataset, the fleet
evolution results for regional jets are fit for purposes of this analysis.
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Impacts on Emissions and Fuel Consumption
Freighter - Number of Operations
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IT}
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2010 2015 2020
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Year
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2040


2010 2015 2020
2025
Year
2030
2035
2040


2010
2015
2020
2023
2025
2028
2030
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2040

2010
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ICAO
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Figure 5-5 - Comparison of U.S. Freighter fleet number of operations for ICAO, EPA and TAF
Figure 5-5 shows that the three datasets for freighters are quite different in terms of number of
operations. To compare fleet evolution results for freighter operations from the three datasets,
there are, however, several factors to be considered. These factors are (1) ICAO freighter
operations are exclusively from widebody purpose-built freighters while EPA and TAF include
smaller freighter types, and (2) between EPA and TAF, TAF has more small airplane operations
in its dataset than the EPA analysis, which is based on the FAA 2015 Inventory. Thus, the
higher number of operations in Figure 5-5 does not necessarily translate into higher freight
capacity in terms of ATK (Available Tonne Kilometer) as shown in Figure 5-6. The ICAO
activity dataset we used does not contain payload capacity information, so we can only compare
the EPA analysis with TAF for ATK. It is clear from Figure 5-6 that EPA results match TAF
results closely for U.S. domestic freighter operations. This close agreement, however, is not
observed in the U.S. international freighter operations. In that case, the ATK of TAF is more
than twice the ATK of the EPA analysis because possibly many operations present in TAF are
missing in FAA 2015 Inventory from which the EPA ATK is derived. Figure 5-7 illustrates
some evidence supporting this hypothesis by separating out the operations in TAF with and
without origin-destination (OD) pair, aircraft (AC), and airplane category (CAT) matches to the
EPA analysis (or FAA 2015 Inventory on which the EPA analysis is based). It is clear from
Figure 5-7 that a large part (the top two lines) of TAF U.S. international freight operations has no
matching OD/AC or OD/CAT in the EPA analysis. Given our methodology to use FAA 2015
Inventory as the basis to grow future year activities with TAF growth forecast, this discrepancy
is not critical to our mission to evolve all FAA 2015 Inventory freighter flights into the future for
this EPA analysis. Further reconciliation between TAF and 2015 Inventory is beyond the scope
of this project. For the purpose of this analysis, the EPA fleet evolution results will be used
exclusively for all the further stringency and impact analysis.
US Domestic: Freighter
US International: Freighter
.if
£ 100000
a> 80000
60QOO
4OQQ0
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Impacts on Emissions and Fuel Consumption
Freighter - ATK
US Domestic: Freighter
US International: Freighter
EPA
TAF
F 2.4-
2-2
4.5-
4.0-
v 3-5-
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< 3.0-
m
o 2.5-
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Figure 5-6 - Comparison of U.S. Freighter fleet Available Tonne Kilometer of ICAO, EPA and TAF
US International: Total (GR_Map=F)
35-
30-
o 25 -
EPA-OD/AC
TAF-OD/AC
TAF-OD/AC
(no match)
EPA-OD/CAT
TAF-OD/CAT
TAF-OD/CAT
(no match)
2015
2020
2025
2030
2035
2040
Year
Figure 5-7 - Total Available Tonne Kilometer of subsets of flights in EPA and TAF with and without match
origin-destination pair (OD), aircraft type (AC) and airplane category (CAT)
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Impacts on Emissions and Fuel Consumption
Business Jet - Number of Operations
US Domestic: Business Jets
US International: Business Jets
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Figure 5-8 - Comparison of U.S. Business Jet fleet number of operations for ICAO, EPA and TAF
The business jet operations of ICAO and EPA analyses have similar 2010/2015 base year
operations but different growth rates as shown in Figure 5-8. Comparing to EPA, ICAO appears
to underestimate the growth rate of U.S. domestic business jet operations and overestimate that
of U.S. international business jet operations. Higher growth rate increases the G&R fleet faster
over time, so it tends to amplify the impact of the standards. Conversely, lower growth rate
depresses G&R fleet growth and tends to lower the impact of the standards. Nevertheless, the
effect of this baseline uncertainty is only secondary since the impact of the stringency scenarios,
as measured by the difference from the baseline, are less sensitive to the baseline uncertainty.
More importantly, the rank order of stringency scenarios in terms of emission reductions is
typically not affected by the uncertainty in baseline. Although the agency recognizes the
problem with the general lack of detailed and reliable growth forecast data sources for
subcategories like turboprop and business jet, we do not believe that uncertainty in these data
alter any conclusion of the analysis.
5.3.1.1 Conclusions of the Fleet Evolution Results
Overall, the EPA fleet evolution results are acceptable with respect to ICAO and TAF for all
passenger operations in terms of ASK. For turboprop and regional jet operations, ICAO appears
to overestimate the U.S. domestic and U.S. international operations, but the EPA analysis agrees
with TAF in all these operations. For freighter operations, the EPA analysis and TAF have many
small airplanes included, while ICAO is limited to widebody purpose-built freighters only. The
EPA analysis agrees well with TAF in U.S. domestic freighter operations in terms of ATK but
contains significantly fewer operations than TAF in U.S. international freighter operations due to
differences in the base year datasets. For business jet operations, the EPA analysis and ICAO
have similar base year operations but different growth rates, which cause significant differences
in out years. In the absence of more reliable data sources for business jet growth forecast, EPA
will proceed with the current forecast sources from FAA58 and Bombardier60 for the EPA rule
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Impacts on Emissions and Fuel Consumption
analysis. The uncertainty in the baseline forecast is noted but deemed secondary for stringency
assessment.
5.3.2 Baseline Emissions
The baseline CO2 emissions inventories are estimated in this EPA analysis for 2015, 2020,
2023, 2025, 2028, 2030, 2035, and 2040 using PIANO (the airplane performance model) and the
emissions inventory method described in Chapter 4 along with each year's activities data derived
from the fleet evolution model. The baseline CO2 emissions for global, U.S. total, U.S.
domestic, and U.S. international flights are shown in Figure 5-9 based on outputs from the fleet
evolution model.
In each of the plots contained in Figure 5-9, there are three baselines plotted. These include
the primary analysis (labeled as "A: fleet turnover w/cont. imp.") and two sensitivity scenarios
(labeled as "B: fleet turnover w/o cont. imp." and "C: frozen fleet"). The top line is the frozen
fleet baseline, which is basically an emission baseline growing at the rate of traffic growth
assuming constant fuel efficiency in the fleet (i.e., no fleet evolution). The second line is the no
continuous improvement baseline where the fuel efficiency of the fleet benefits from the infusion
of newer airplanes from fleet evolution, but the new airplanes entering into the fleet are assumed
to be static and not improving over the entire analysis period (2015-2040). The third line is the
business as usual baseline where the fleet fuel efficiency benefits from both fleet evolution with
new airplanes entering the fleet and business as usual improvement of the new in-production
airplanes.
These emissions inventory baselines provide a quantitative measure for the effects of model
assumptions on fleet evolution and continuous improvement. The business as usual baseline is
the baseline with all market-driven emissions reduction factors incorporated. It is used as the
primary baseline for this EPA rule analysis. The other two baselines are useful references for
illustrating the effects of fleet evolution and continuous improvement.
Comparing the baselines, the difference between the top two baselines is due to fleet
evolution. Even for G&R airplanes without continuous improvement, the powerful effect of
fleet renewal is clearly evident in emissions inventories of all markets (global, U.S. domestic and
U.S. international). The difference between the bottom two baselines is the effect of continuous
improvement since they have identical fleet evolution.
These baselines are established with no stringency inputs; nevertheless, they provide very
powerful insights into the drivers for emissions inventories and trends. The difference in global
CO2 emissions between the BAU and the frozen fleet baselines in 2040 alone is about 400 Mt, a
huge emissions reduction achievable by market force alone.
It is worth noting that the US domestic market is relatively mature with lower growth rate
than most international markets. This slower growth rate has obvious consequences in the
growth rate of the US domestic CO2 emissions baseline, which is projected with a very slow
growth rate by 2040 given the continuous improvement assumptions.
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Impacts on Emissions and Fuel Consumption
Global C02
US Total C02
A: fleet turnover w/ cont. imp.
B: fleet turnover w/o cont. imp.
C: frozen fleet

2015
2020
2025 2030
Year
2035
2040

2015
2020
2023
2025
2028
2030
2035
2040
A
688 75
829.46
913.03
972.51
1064.87
1130.26
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1245.33
1518 95
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A: fleet turnover w/ cont. imp.
B: fleet turnover w/o cont. imp.
C: frozen fleet
2025 2030
Year

2015
2020
2023
2025
2028
2030
2035
2040
A
172.44
192.81
202.8
209.01
217.96
223.59
233.67
242.18
B
172.44
193.37
204.04
210.89
221.1
228.05
245.4
264.38
C
172.44
194.52
208.22
217.4
231.68
241.43
267.45
294.82
US Domestic C02
A: fleet turnover w/ cont. imp.
B: fleet turnover w/o cont. imp.
C: frozen fleet
US International C02
e 140 -
o
u

2015
2020
2025 2030
Year
2035
2040

2015
2020
2023
2025
2028
2030
2035
2040
A
105.1
115.19
119.06
121.41
124.99
127.04
129.6
131.85
B
105.1
115.48
119.68
122.38
126.67
129.5
137.15
145.85
C
105.1
117.34
124.29
128.82
135.87
140.56
153.07
167.06
A: fleet turnover w/ cont. imp.
B: fleet turnover w/o cont. imp.
C: frozen fleet

2015
2020
2025 2030
Year
2035
2040

2015
2020
2023
2025
2028
2030
2035
2040
A
67.33
77.62
83.74
87.6
92.97
96.56
104.07
110.33
B
67.33
77.88
84.36
88.52
94.43
98.55
108.25
118.53
C
67.33
77.18
83.93
88.58
95.81
100.87
114.39
127.76
Figure 5-9 - Range of CO2 emissions baselines with various fleet evolution and continuous improvement
assumptions
5.3.2.1 Discussions on baseline modeling
By modeling fleet evolution variables such as the end-of-production timing and continuous
improvements explicitly, the agency believes that the business as usual baseline provides a more
accurate assessment of the impacts of the standards on emissions. This comprehensive model can
be a powerful tool to understand the effect of these modelled variables.
One might argue that how fast new technology could infuse into the fleet and how much
market-driven business as usual improvement can be assumed are all inherently uncertain. But
given accurate inputs for fleet evolution and continuous improvement, the baseline inventory can
be better assessed for the real-world performance of all fleets (global, domestic or international).
To help develop this baseline, EPA contracted with ICF to conduct an independent analysis to
develop a credible fleet evolution and technology response forecast66. This ICF analysis
considers both near-term and long-term technological feasibility and market viability of available
technologies and costs for all the modeled G&R airplanes at individual airplane type and family
levels.
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Impacts on Emissions and Fuel Consumption
Given these fleet evolution and efficiency improvement estimates, the agency believes that
the emissions inventory baseline so established provides the best possible representation for the
performance of the global and U.S. fleet for assessing the impact of the GHG standards.
It is traditionally assumed that the baseline does not matter for stringency analysis, because as
the impact of the stringency is measured from stringency to baseline, the effects of baseline
choices tend to cancel out when we consider only the delta of stringency and baseline. It can be
shown that this assumption may not be true when some of the fleet evolution assumptions also
affect the estimates of emission reductions and, thus, change the output of the impact analysis
and potentially influence the policy-making decisions.
In conclusion, using the best possible estimate of a baseline leads to a more accurate
assessment of the impact of the standards. The effects of fleet evolution, continuous
improvements, and technology responses on emissions inventory and emissions reductions are
discussed further in the following sections.
5.4 Stringency Analysis of U.S. and Global CO2 Emission Impacts
The EPA main analysis includes three stringency scenarios, the standards and two
alternatives. The primary scenario is the GHG standards, which are equivalent to the ICAO
Airplane CO2 Emission Standards. The two alternative scenarios are either a pull-ahead scenario
at the same stringency level as the ICAO in-production standard (Scenario 2) or a pull-ahead
scenario at a higher stringency level comparable to the ICAO new type standard (Scenario 3).
See Chapter 6 for a detailed description of the three stringency scenarios, including cost
effectiveness discussions for Scenario 3.
Based on the technology response from the ICF technology and cost report66, there are no
reductions projected in fuel consumption and CO2 emissions for both the primary scenario
(Scenario 1) and the pull-ahead scenario (Scenario 2). This is because all the airplanes in the
G&R fleet either meet the stringency or are out of production when the standards take effect
according to our expected technology responses. Thus, under both scenarios 1 and 2, there
would be no cost and no benefit (no emission reduction) for the GHG standards.
Under Scenario 3, there is one airplane (A380-8) that would be impacted by the stringency.
This airplane, however, is projected to go out of production by 2025 according to ICF's end of
production forecast. Figure 5-10 shows the global CO2 emissions baseline for A380-8 increases
sharply between 2020 and 2025 due to the projected end of production of B747-8 in 2020. After
B747-8 ceases production in 2020, A3 80-8 takes over part of the B747-8's market share, causing
the sharp increase of baseline A3 80-8 emissions. After 2025, A3 80-8 itself also goes out of
production, causing its emissions baseline to decline after 2025 due to normal retirement of the
A3 80 in the in-service fleet. Slightly below the solid baseline, one can see a dashed line for CO2
emissions of A3 80 under Scenario 3 between 2025 and 2040. It is less visible between 2023 and
2025, but the table below shows a slight decrease in CO2 emissions for Scenario 3 comparing to
the A3 80-8 baseline from 2023 to 2040. The sharp reversal of the A3 80 baseline emissions
inventory is due to the effect of fleet evolution. If we look at the aggregate level of large twin-
aisle (TA_4) market segment to which both A3 80 and B747 belong, the reversal of the emissions
baseline disappears. The emissions baseline increases monotonically, but the effects of the
stringency is still faintly visible as the rate of increase slows down a little around 2023-2025 due
to the technology responses of the A3 80.
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Impacts on Emissions and Fuel Consumption
C02 Emissions - Scenario 3
ACCODE - A380-8
Market Segment - TA_4
Global; M80-6
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Scenario 3
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Figure 5-10 - CO2 emissions of A380-8 and market segment TA_4 for the baseline and Scenario 3
In summary, the total cumulative CO2 emissions reduction under Scenario 3 for all U.S.
flights (both U.S. domestic and U.S. international) is 1.36 Mega-tonne (Mt), and the reduction
for global flights amounts to 8.16 Mt from 2023 to 2040 as shown below. It is also worth noting
that Scenario 3 has a modest impact (1.24 Mt) on U.S. international emissions but only a very
small impact (0.12 Mt) on U.S. domestic emissions. This is primarily because none of the U.S.
airlines have the A380 in their fleets.
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B: US Domestic
C: US International
Year

2023
2025
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A
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B
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Figure 5-11 - Cumulative reduction of CO2 emissions from 2023 to 2040 for Scenario 3
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Impacts on Emissions and Fuel Consumption
5.5 Sensitivity Case Studies
As explained previously, the fleet evolution and continuous improvement assumptions have a
strong influence on the emissions baseline; likewise these assumptions may also have strong
influences on technology responses and subsequently on the emissions reductions. The
following sensitivity studies are designed to help look into these influences and put the results of
the EPA main analysis in perspective.
Among the three scenarios analyzed for this TSD, only Scenario 3 impacts an airplane and the
emission reductions associated with it. The following sensitivity studies will use Scenario 3 to
analyze the effects of these model variables and gain insight of their impacts on emissions. We
then apply the same concept to Scenarios 1 and 2 and discuss the effects of these variables in a
similar manner. Given the evidence from these sensitivity studies, we will summarize and draw
conclusions about potential impacts of this rulemaking.
5.5.1 Scenario 3 Sensitivity to Continuous Improvement
One of the major stringency analysis assumptions is the continuous improvement of in-
production airplanes. We will examine its effect on emissions reductions by turning off the
assumption in the EPA main analysis. For reference, we will also compare this analysis with the
corresponding ICAO analysis which, although not directly comparable to EPA main analysis as
explained in section 5.3.1, is an important reference to show the effects of various assumptions in
baseline, fleet evolution, and technology response.
Figure 5-12 shows CO2 emissions of baseline and Scenario 3 for these three cases, i.e., ICAO,
EPA analysis with continuous improvements, and EPA analysis without continuous
improvements. In the case of U.S. domestic and U.S. international emissions, the ICAO baseline
is about 4% lower than the EPA baselines due to differences in the base year datasets (2010
ICAO COD versus 2015 FAA Inventory). This baseline discrepancy, however, does not affect
the stringency analysis outcome because the emissions reductions are measured relative to the
baseline, and thus they are insensitive to the baseline shift. The emissions reductions, as
measured by the differences between the baselines and stringency lines, are what is important for
resolving the effects of model assumptions in the three cases.
From Figure 5-15, we observe that the emissions reductions increase by more than threefold
when continuous improvement is turned off. For example, the cumulative U.S. total emissions
reductions from 2023 to 2040 for Scenario 3 increase from 1.36 Mt to 4.78 Mt as shown in the
accompanying table in Figure 5-15. These are small compared to the ICAO reduction of 108.99
Mt (38.49 Mt for U.S. Domestic and 70.5 Mt for U.S. International as shown in Figure 5-14) for
the same stringency scenario. This is the reason the EPA Scenario 3 (dashed) lines are almost
indistinguishable from the baselines in Figure 5-12. Examining the zoom-in graph for the A380
in Figure 5-13, however, shows that there are significant emissions reductions for the no
continuous improvement case. This relatively significant amount of reductions for the A3 80
becomes less significant at the market segment level (the right panel of Figure 5-13). And it is
almost invisible at the total fleet level in Figure 5-12 when the aggregate base becomes
progressively bigger. Nevertheless, the effect of continuous improvement is significant for the
impacted airplane. This result is understandable since the impacted airplane would have to make
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Impacts on Emissions and Fuel Consumption
larger improvement to meet the stringency from a no continuous improvement baseline, while
the impact of stringency would be a lot smaller if improvements have been made year over year
as assumed by the business as usual baseline. Technically, the two cases achieve the same total
improvement, but one attributes the entire amount of improvement to stringency impact while
the other attributes the business as usual improvement to market force impact and only the
remaining improvement to stringency impact.
It is clear that although the continuous improvement is significant to the impacted airplane,
this factor alone cannot explain the huge differences between the emissions reductions of ICAO
and EPA analyses. We will examine the other important fleet evolution assumption, i.e., the end
of production timing, as a sensitivity study in the next section.
Scenario 3
Global: Total
Scenario 3
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2010 2015 2020 2025 2030 2035 2040
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Baseline
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9.19E+02
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ICAO Baseline
EPA Baseline
EPA Baseline (w/o lmp.(
ICAO Scenario 3
EPA Scenario 3
EPA Sen. 3 (wr/o imp.)
US Domestic: Total
Scenario 3
ICAO Baseline
EPA Baseline
EPA Baseline (wto tmp.|
ICAO Scenario 3
EPA Scenario 3
EPA Sen. 3 (w/o Imp.)
2010 2015 2020 2025 2030 2035 2040
Year
US International: Total
Scenario 3
140 	 (CAO Baseline
EPA Baseline (w/o imp I
120
EPA Sen- 3 imp,)
2010 2015 2020 2025 2030 2035 2040
Year
Figure 5-12 - CO2 Emissions of Baseline and Scenario 3 for ICAO and EPA (w & w/o continuous
improvement) Cases
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Impacts on Emissions and Fuel Consumption
Zoom In on C02 Emissions of Impacted
Aircraft and Market Segment for Scenario 3
ACCODE - A380-8
Global: A380-8
	 fiase&ne
	 Basplir* (w/D imp.)
Scenario 3
	Scenario 3 Iwfci imp.)
Market Segment - TA_4
Global: TA 4
—	Basefeie
—	Baseline (w/o imp.)
Scenario 3
—	Scenario 3 Iw/o mp.J
2015
2020
2025
year
2030
2035
2040

2015
2020
2025
Year
2030
2035
2040


2015
2020
2023
2025
2028
2030
3035
2040

2015
2020
2023
2025
202S
2030
2035
2040
Baseline
26.89
37 59
5t.5S
62.92
6GSt
58 74
SO. 76
38.35
Baseline
14 7 62
177 98
197.39
210.77
228.44
241,01
275.24
316.22
Baseline imp.)
26.89
37.77
52.37
64.44
62.32
60.24
52-2
40.65
0*wline (Wo imp)
147.62
178 64
199.03
213.37
232.24
245 96
284.48
332.08
Scenario 3


51.39
62.42
60.31
M.25
50 28
38.91
Scenario 3


197.23
210.27
227.95
240.52
274.76
315.77
Scenario 3 (w/o imp )


51 81
62 69
60.58
58.51
5052
39 1
Scenario 3 Iwta imp.)


193.47
211.62
230.5
244.23
202.78
330.53
Figure 5-13 - Zoom-in Picture of CO2 Emissions of Impacted Airplane A380-8 and Market Segment TA_4 for
EPA Scenario 3 with and without Continuous Improvement
Scenario 3
Cumulative Reduction
2023
2025
Global: Total
C02 (Mt)
2028 2030
.2 -100-
% -200-
V
* -300-
a
5 -400-
ja
| -500
3 -600
ICAO Cum. Reduction
EPA Cum. Reduction
EPA Cum. Red. (w/o imp. J
Year

2023
2025
2028
2030
2035
2040
ICAO



-122.87

-664.22
EPA
4U6
¦0.98
>2.47
3.46
-5,68
*.16
EPA (w/o imp.)
-0.56
-3.46
-8.69
-12.15
-20.66
-28.68
2025
US Domestic: Total
C02 (Mt)
2028
ICAO Cum, Reduction
EPA Cum. Reduction
EPA Cum. Red. (w/o imp.)
2035
2040

2023
2025
2028
2030
2035
2040
1


ICAO



-6,7

-38.49



EPA
0.0
-0.01
jO.04
O.OS
-0.08
•0.12
EPA (wto imp.l
•0.01
•0.05
-0.13
•0.17
-0.3
-0.41
US International Total
C02 (Mt)
2025
2026
ICAO Cum. Reduction
EPA Cum. Reduction
EPA Cum. Red. |w/0 imp.)

2023
2025
2028
2030
2035
2040
ICAO



-14-23

-70.5
EPA
-0.02
0.15
-0.38
•0.53
-0.9
-1.24
EPA (w/o imp.]
-0.09
¦0.53
¦1.33
1.85
-3.15
4.37
Figure 5-14 - Cumulative CO2 Reduction of Scenario 3 for ICAO and EPA (w & w/o continuous
improvement) cases
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Impacts on Emissions and Fuel Consumption
Scenario 3: U.S. C02 Cumulative Reduction
U. S, C02 Cumulative Reduction
2023 2025 2028 2030 2035 2040
o-
-1-
- " " -g -

1
H
-2- ™
A: US Domestic
r4
B


¦¦
B: US International




-3 *
C: US Total

%


MB
O: US Domestic tw/o imp.)

A


-4- Z0
E: US International (w/o imp.)




f : US Total (w/o imp.)


1
Year

2023
2025
2028
2030
2035
2040
A
0.0
¦0.01
-0.04
¦0.05
-0.08
¦0.12
6
-0.02
-0.15
-0.38
-0.53
-0.9
-1.24
C
-0.03
-0.16
-0.41
-0.58
-0.98
-1.36
D
-0.01
-0.05
-0.13
-0.17
-0.3
-0.41
E
-0.09
-0.53
-1.33
-1.85
-3.15
-4.37
F
-0.1
-0.58
-1.45
-2.03
-3.45
-4.78
Figure 5-15 - Cumulative U.S. CO2 Reduction for EPA Scenario 3 with & without Continuous Improvement
5.5.2 Scenario 3 Sensitivity to Extending Production of A380 and B767-3ERF to 2030
Another important fleet evolution variable is the end of production assumption for G&R
airplanes. We will examine the effect of this assumption by extending the end of production of
both A380-8 and B767-3ERF to 2030 from the EPA main analysis' assumption of 2025 and 2023
respectively for the two airplanes in this sensitivity study. The resulting CO2 emissions from this
sensitivity study are shown side by side with the main analysis for A380-8 in Figure 5-16 and for
B767-3ERF in Figure 5-17. Note that Scenario 3 starts to impact A380 in 2023 but not the
B767-3ERF until 2028, due to the 5-year delay in i mplementation of the standards for
freighters.lxv We note that in their comments Boeing, along with Fedex, GE, and the Cargo
Airline Association, expressed that there would continue to be a low volume demand for the
B767 freighter beyond January 1, 2028. These commenters did not indicate the number of
767F's that would be produced after 2028. The EPA did not change the analysis to adjust the
M On February 14,2019. Airbus made an announcement to end A380 production by 2021 after Emirates reduced its
A380 order by 39 airplanes and replaced them with A330 and A350. (The Airbus press release is available at:
https://www.airbus.eom/newsroom/press-releases/en/2019/02/airbus-and-emirates-reach-agreement-on-a380-
fleet--sign-new-widebody-orders.html, last accessed on February 10, 2020). The early exit of A380 fits the
general trend of reduced demands for large quad engine airplanes presented in this TSD, but the exact timing was
not expected at the time when our analysis was completed. Tliis latest A380 production information will affect
the modeled results for Scenario 3. Without redoing the whole analysis, we can conclude that the early exit of
A380 will nullify its GHG emission reductions from Scenario 3 since it won't be affected by Scenario 3's
implementation date. This result, however, is broadly consistent with our prediction of minimum GHG
reductions for all scenarios, and it does not alter our conclusion of no cost and no benefits for the primaiy
scenario analyzed in the rule.
Page: 112
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Impacts on Emissions and Fuel Consumption
baseline to include continued production of the 767F beyond 2030 because insufficient
information to characterize this scenario was provided.
A380-8 C02 Emissions
ICF EOP 2025
EOP 2030
Global: AJBO-8
Baseline
Scenano 3
\
s
2025	2030
Year

2015
2020
2023
2023
202S
2030
2033
2040
Baseline
27.16
38.31
53.25
65.47
63.32
61.22
53.00
41.36
Scenano 3


53.08
64 94
62 8
60.7
52.57
40.69
Global: A380-8
Basr&ne
Scenario 3
2025	2030
Year

2015
2020
2023
2023
2028
2030
2033
2040
Baseline
27.16
38.31
53.25
65.47
85.2
99.22
90.6
?7Ji6
Scenano 3


53.08
64.94
84.06
97.62
89.02
76.07
Figure 5-16 - CO2 emissions of A380-8 with two different end of production (EOP) assumptions (2025 versus
2030) for EPA baseline and Scenario 3
B767-3ERF C02 Emissions
ICF EOP 2023
EOP 2030
Global: B767-3ERF
Baseline
-,i-r mi-
2025	2030
Year
2035 20*0
Global: B767-3ERF
Oascfric
Scenario 3
_ 10-
s
2025	2030
Year
2023 2025
2028 2030
Figure 5-17 - CO2 emissions of B767-3ERF with two different end of production assumptions (2023 versus
2030) for EPA baseline and Scenario 3
It is clear from Figure 5-18 that the cumulative emissions reduction for the extended
production case (right panel of Figure 5-18) is more than 3 times that of the main analysis (left
panel of Figure 5-18). Extendi ng the end of production forecast thus also has a strong effect on
Page: 113
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Impacts on Emissions and Fuel Consumption
the outcome of the impact analysis (about 3 times in terms of cumulative emissions reductions to
2040).
2023
COj Cumulative Reduction
2025 2028 2030 2035 2040
0 -
-2-
-4-
¦II
5 "6
£
3
u
Global
US Domestic
US International
Year
Extended
2023
0 |'|
-s ¦
-10-
-15 ¦
-20-
-25-
Production: C02 Cumulative Reduction
2025 2028 2030 2035 2040
A: Global
B: US Domestic
C: US International
Year

2023
2025
2028
2030
2035
2040

2023
2025
2028
2030
2035
2040
A
¦0.16
-0.98
-2.47
-3.46
-5.88
-8.16
A
-0.16
¦0.98
-3.96
-7.86
-18.72
¦29.3
S
0.0
-0.01
-0.04
-0.05
¦0.08
-0.12
B
0.0
-0.01
-0.09
-0.26
-0.78
¦1.29
C
-0.02
-0.15
-0.38
-0.53
-0.9
-1.24
C
-0.02
•0.15
-0.58
¦1.0s
-2.47
•3.82
Figure 5-18 - EPA main analysis versus sensitivity study: in cumulative reduction of CO2 emissions from
2023 to 2040 for Scenario 3
5.5.3 Scenario 3 Sensitivity to Combined Effects of Continuous Improvement and
Extended Production
Based on the previous two case studies, it is evident that both continuous improvement and
extended production have significant impacts on emissions reductions. Furthermore, these two
important driving factors are independent variables. Thus, in this section we will assess the
combined effects when both extended production and continuous improvement are applied for
Scenario 3.
Figure 5-19 to Figure 5-22 detail the results of this sensitivity study. A key finding of this
sensitivity study is that the effects of continuous improvement and extended production are
largely multiplicative. The two previous sensitivity studies have shown that the extended
production and the lack of continuous improvement each produced about 3 times the emissions
reductions of the EPA main analysis. As shown in Figure 5-21, the ratio of emissions reduction
impact between with and without continuous improvements is again about 3 times (e.g., 29.3 Mt
versus 87.34 Mt for the cumulative global CO2 reduction to 2040). The combined effects of
extended production and continuous improvement increase the ratio of emissions reductions to
more than 10 times (e.g., 87.34 Mt (Figure 5-21) versus 8.16 Mt (Figure 5-14) for the cumulative
global CO2 reduction to 2040).
Page: 114
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Impacts on Emissions and Fuel Consumption
Zoom In on C02 Emissions of Impacted
Aircraft and Market Segment for Scenario 3
ACCODE - A380-8
Global: A380-8
Baseline ItPj
Baseline ItP. w,'o imp.)
Scenario 3 (EPI
Scenario 3 (EP. w/o Imp. I
2025	2030
Year
Market Segment - TA_4
Global: TA 4
Baseline |EP)
Baseline l£ P, w/a imp.)
Scenario 3 (EPI
Scenario 3 (EP. wrt> Imp.
2025	2030
Year

2015
2020
2023
2025
202a
2030
2035
2040

2015
2020
2023
2025
x>2«
2030
2035
2040
Basefeie (EP)
26.89
37.59
51.55
62.92
ai.ie
94.76
86.3
73.66

Baseine (EP)
147.62
177.98
197.39
210.77
232.52
248.12
282-24
322.97
Basekne 
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Impacts on Emissions and Fuel Consumption
Scenario 3
Cumulative Reduction
Global: Total
C02 (Mt)
2023
2025
2028
2030
2035
2040
0-
-100-
-200
-300-
-400-
-500 •
-600-
ICAO Cum. Reduction
EPA Cum. Reduction (EP)
EPA Cum. Red. (EP, w/o imp.)
Year

2023
2025
2028
2030
2035
2040
ICAO



•122.87

664.22
EPA (EP}
*0.16
-0.96
•3.96
-7.66
18.72
-29.3
EPA (EP, w(o imp.)
-0.56
-3.46
-13.3
-24.9
-56.6
-87.34
3 -la-
's
E -SO-
US Domestic: Total
C02 (Mt)
2023 2025 2028 2030 I
¦	ICAO Cum. Reduction
m EPA Cum. Reduction tEPI
¦	EPA Cum. Red. IEP. wfo imp.)

2023
2025
2028
2030
2035
2040
ICAO



-6.7

-38.49
EPAiEP)
0.0
-0.01
.0.0-9
0.2fi
-0.78
-1.29
£PA{£P, w.'o imp.f
-0.01
-0.05
¦0.24
-0.59
-1.59
-2.5S
US International: Total
C02 (Mt)
JB7S 2025 2028 2030 2035
I I CAD Cum. Reduction
i EPA Cum. Reduction |EP) ®
i EPA Cum. Red. 
¦0.02 -0.15
-0-58
-1.08
•2.4?
-3.82
EPA 3.55
7.88
12.07
Figure 5-21 - Cumulative COz Reduction of Scenario 3 for ICAO and EPA (Sensitivity Study of Extended
Production to 2030 for A380 and B767F, with & without continuous improvement)
Scenario 3: U.S. C02 Cumulative Reduction
Extended Production; U. S. C02 Cumulative Reduction
C
£ -2.5 •
2023 2025 2026

	«
u
"o -5,0 -
a*
QC

A: US Domestic (EP)
a* -7.5 -
IB
B: US International (EP)
>
5? -10.0-
¦
C: US Total (EP)
MS
D; US Domestic (EP, w/o imp.)
E
3 -12.5-
u
MM
E: US International (EP, w/o imp.)
F: US Total (EP, w/o imp.)
0
0

Year
2030
2035
2040

2023
2025
202 B
2030
2035
2040
A
0.0
¦0.01
0.09
¦0.26
¦0.78
-1.29
B
-0.02
-0.15
-0.58
-1.08
-2.47
-3.82
C
-0.03
-0.16
-0.67
-1.34
-3.25
-5.11
D
-0.01
-0.05
-0.24
-0.59
-1.59
-2.58
E
-0.09
-0.53
-1.97
-3.55
-7.B8
-12.07
F
-0.1
-0.58
-2.21
-4.14
-9.47
-14.65
Figure 5-22 - Cumulative U.S. CO2 Reduction of Scenario 3 for the Sensitivity Study of Extended Production
to 2030 for A380 and B767F, with & without continuous improvement
Page: 116
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Impacts on Emissions and Fuel Consumption
Extrapolating this finding further, we can clearly see that the projected emissions reductions
can be increased even more by extending the production of current in-production airplanes
further into the future. ICAO's analysis assumed no end of production for current in-production
airplanes. This explains why significantly higher emissions reductions were found in the ICAO
analysis compared to the EPA analysis for the same stringency scenario. The key is in fleet
evolution, technology response, and baseline assumptions. Thus, it is crucial to establish the best
possible estimates for fleet evolution, technology response, and business as usual baseline to
provide a more accurate assessment for the costs and benefits of the standards.
5.5.4 Similar Sensitivity Studies for Scenarios 1 and 2
In summary, the sensitivity studies for Scenario 3 show that the EPA and ICAO analyses of
emissions reductions, although quite different, are results of their respective model assumptions.
As we relax the assumptions in the EPA analysis to be more like ICAO's, the results tend toward
ICAO results. It will eventually reproduce ICAO results when given the same model
assumptions. We also evaluated whether this trend would hold true for Scenarios 1 and 2. We
analyzed emissions reductions for Scenarios 1 and 2 under various model assumptions similar to
what was done in previous sections for Scenario 3. Like the sensitivity studies for Scenario 3,
only A3 80 and 767-3ERF are considered since they are the only airplanes potentially impacted
by the standards and alternative scenarios.
Specifically, without continuous improvement (CI), the A3 80 would not pass the in-
production standards and would need to make about 1% improvements to be compliant and 2%
improvements with the 1% design margin. This is true for both Scenarios 1 and 2 since without
CI, the metric value margin to the stringency line would not change with time and required
improvements would remain the same independent of the standard's effective dates. With CI,
A3 80 would pass the standards in both 2023 and 2028 timeframes and does not require any
additional improvement for Scenarios 1 and 2.
On the other hand, 767-3ERF would not pass the in-production standards with or without CI,
so its response status is mostly driven by the end of production assumption. In other words, in
the normal assumption of end of production in 2023, there would be no need to improve in either
Scenarios 1 or 2 with the standards effective date for freighters starting in 2028. In the extended
production case, 767-3ERF would have a 3-year window from 2028 to 2030 that it would need
to improve to be compliant with the in-production standards.
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Impacts on Emissions and Fuel Consumption
Scenario 3 Sensitivity Studies
w/o CI	LP m LP&w/cfl
Scenario 3
¦ Cibhl ¦ USDorn BlAIrt ¦ Lftlotai
Scenario 1 Sensitivity Studies

w/o CI
EP
E=" a w/o CI
i!""|
Soardrti 1
o
-100
-2W
¦M
aoo
500
-600
-TOO
-LOO
-200
•300
•JOG
•300
¦600
-700
Comparing Sensitivity of Emission Reduction
Estimates to Model Assumptions Between
EPA and "ICAO-like" Analyses, Including
Three Intermediate Case Studies for
Scenarios 1, 2, and 3:
*	Without Continuous Improvement (w/o CI)
*	Extended Production {EP)
*	Combination of the Two Assumptions (EP &
w/o CI)
¦ Global HUSDorn »U5M ¦ USToltf
Scenario 2 Sensitivity Studies
	m
w/oCI	EP	E? EL w/o CI
ilSTJ
a
-uao
-ma
-300
-«a
-KQ
-KG
-7QG
¦ 'Jlubdl ¦ DSDOrYi ¦ US Ml ¦ USTOIil
Figure 5-23 - Summary of Sensitivity to Model Assumptions for Scenarios 1,2 and 3
To put the sensitivity studies in context and compare the general trends for all three scenarios,
we will examine the five cases in each scenario as shown in Figure 5-23. A brief discussion of
the five sensitivity cases is given below.
Case 1 (EPA): For the EPA analysis, both Scenarios 1 and 2 show no emissions
reduction, due to the continuous improvement assumption for A3 80 and the end-of-
production assumption (2023) for 767-3ERF.
Case 2 (w/o CI): In the case of without continuous improvement, Scenario 1 would
still be no emissions reduction because A3 80 would be out of production by
2025. Scenario 2, however would produce a small benefit of 2% fuel efficiency
improvement from A3 80 between the pull-ahead schedule of 2023 and the end-of-
production year of 2025. The C02 reduction would be on the order of 6 Mt globally and
1 Mt in U.S. total for Scenario 2.
Case 3 (EP): In the case of extended production (EP) with continuous improvement,
the benefit would all come from 767-3ERF since A3 80 would be compliant with the in-
production standards with continuous improvement. Since the pull-ahead schedule is not
assumed for freighters, Scenarios 1 and 2 are the same and the estimated C02 reduction
would be on the order of 4 Mt globally and 1 Mt in U.S. total.
Case 4 (EP & w/o CI): In the case of extended production without continuous
improvement, Scenario 1 would be benefitted by 3 years of improvement from A3 80 and
767-3ERF in 2028-2030 and larger improvements required from no continuous
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Impacts on Emissions and Fuel Consumption
improvement baselines. Scenario 2 would be similar except that the A380 benefit would
be from the pull-ahead schedule of 2023. The rough estimate of emissions reductions for
Scenario 1 would be 14 Mt globally and 3 Mt in U.S. total and for Scenario 2, 24 Mt
globally and 4 Mt in U.S. total.
Case 5 (ICAO-like): The ICAO like C02 reductions have been analyzed previously
as 249.75 Mt globally and 45.52 Mt in U.S. total for Scenario 1, and 412.44 Mt globally
and 74.82 in U.S. total for Scenario 2.
Given this sensitivity analysis, we can conclude that the technology response and fleet
evolution (principally continuous improvement and end of production) assumptions drive the
difference between EPA and ICAO analyses. Also, as in Scenario 3, as we modify the
continuous improvement (CI) and extended production (EP) assumptions in Scenarios 1 and 2 to
be closer to that of the ICAO analysis, the emissions reductions results move progressively
closer to ICAO results. These general trends of emissions reductions from EPA analysis to
ICAO analysis for Scenarios 1, 2 and 3 are shown in Figure 5-23.
Although uncertainties around these model assumptions exist, the sensitivity studies clearly
show that even when we remove the continuous improvement assumption and extend the
production of A380 and 767-3ERF to 2030, the emissions reductions for all three scenarios are
still quite modest and in all cases are an order of magnitude smaller than that of the ICAO-like
analysis. Both assumptions of no improvement for 20 years and extending production of current
airplane models indefinitely into the future are highly unlikely to happen in the real world. On
the other hand, the business as usual baseline and the independently developed and peer
reviewed technology response help estimate the true impact of the standards. In terms of
modeling, the agency attributes the business as usual improvements to market competition while
ICAO treats them as part of the impacts from the standards. Both are valid with respect to their
model assumptions.
In summary, the EPA analysis shows the GHG standards, which match the ICAO Airplane
CO2 Emission Standards, have no cost or benefit in Scenarios 1 and 2 but produce a small
environmental benefit (1.4 Mt CO2 reductions in the U.S.) in Scenario 3 that is not enough to
justify deviating from the international standards. Therefore, the agency is matching the U.S.
airplane GHG standards with the ICAO Airplane CO2 Emission Standards. These harmonized
standards will enable U.S. airplane and engine manufacturers to compete internationally on a
level playing field. Chapter 6 provides further discussions on EPA's rationale for this standard.
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Impacts on Emissions and Fuel Consumption
REFERENCES
66 ICF, 2018: Aircraft CO2 Cost and Technology Refresh and Industry Characterization, Final Report, EPA Contract
Number EP-C-16-020, September 30, 2018.
Page: 120
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Analysis of Alternatives
Table of Contents
Chapter 6: Analysis of Alternatives	122
6.1	Overview	122
6.1.1	ICAO/CAEP Stringency Options, International Standards Adopted, and Final
Standards	122
6.1.2	Alternatives Considered in the Context of CAEP Stringency Options, International
Standards Adopted, and Final Standards	127
6.2	GHG Emission Reductions and Costs of Two Alternative Scenarios	133
6.2.1	Scenario 2	133
6.2.2	Scenario 3	134
6.2.2.1	767-3ERF	135
6.2.2.2	A3 80	 135
6.2.2.2.1	A380's GHG Emission Reductions	138
6.2.2.2.2	A380's Costs	138
6.2.2.3	Monetized Benefits for A380	 139
6.3	Sensitivity Case Studies	146
6.3.1	Emission Reductions for Scenario 3	146
6.3.2	Emission Reductions for Scenarios 1 and 2	146
6.3.3	Costs for All Three Scenarios	147
6.4	Summary	148
Table of Figures
Figure 6-1 - Final GHG Emission Standards and CAEP's Ten Stringency Options (MTOM in kilograms)	126
Figure 6-2 - Final GHG Emission Standards and CAEP's Ten Stringency Options	127
Figure 6-3 - In-Production Airplane Stringency Lines for the Three	132
Figure 6-4 - Detail of In-Production Airplane Stringency Lines for Airplane Below 100 tons MTOM	133
Figure 6-5 - A380 Incremental Improvement Technology Supply Curve	138
Table of Tables
Table 6-1 - Coefficients Used in Equation for Ten CAEP Stringency Options	123
Table 6-2 - Percentage Differences Between the Ten CAEP Stringency	123
Table 6-3 - Stringency Levels and Effective Dates for Final GHG Emission Standards	125
Table 6-4 - Final Rule and Alternative Scenarios	129
Table 6-5 - A380 Scenario 3 - Implementation of Technology Response	137
Table 6-6 - Interim Domestic Social Cost of CO2, 2015-2050 (in 2015$ per metric ton)*	140
Table 6-7 - Interim Domestic Social Cost of N2O, 2015-2050 (in 2015$ per metric ton)*	140
Table 6-8 - Detailed Domestic C02-Related Benefits for Scenario 3 (Millions of 2015$)	142
Table 6-9 - Detailed Domestic N20-Related Benefits for Scenario 3 (Millions of 2015$)	143
Table 6-10 - Detailed Domestic Fuel Savings for Scenario 3 (Millions of 2015$)	144
Table 6-11 - Summary of Domestic Climate-Related Benefits and Fuel Savings for Scenario 3	144
Table 6-12 - Summary of Domestic Climate-Related Benefits and Fuel Savings for Scenario 3	145
Table of Equations
Equation 6-1 - Calculation of Metric Values for Ten CAEP Stringency Options	123
Page: 121
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Analysis of Alternatives
Chapter 6: Analysis of Alternatives
This chapter describes the three scenarios, including the two alternative scenarios, that the
EPA analyzed, and it discusses the costs, emission reductions, and benefits of these alternative
scenarios. The agency's methodologies for assessing technological feasibility, costs, and
emission reductions were described earlier in Chapter 2, Chapter 4, and Chapter 5. The same
methodologies were used to analyze the final GHG standards and two alternative scenarios.
6.1 Overview
To give context to the alternative scenarios analyzed by the EPA, we will first provide
background on the stringency options considered by ICAO/CAEP in developing the international
Airplane CO2 Emission Standards. We then describe the alternative scenarios in detail.
6.1.1 ICAO/CAEP Stringency Options, International Standards Adopted, and Final
Standards
As described in the 2015 ANPR, for the international Airplane CO2 Emission Standards,
CAEP analyzed 10 different stringency options (SOs) lxvi for standards of both in-production and
new type design airplanes, comparing airplanes with a similar level of technology on the same
stringency level.67 These stringency options were genetically referred to numerically from "1"
as the least stringent to "10" as the most stringent. The 2015 ANPR described the range of
stringency options under consideration at ICAO/CAEP as falling into three categories as follows:
(1) CO2 stringency options that could impactlxvu only the oldest, least efficient airplanes in-
production around the world, (2) middle range CO2 stringency options that could impact many
airplanes currently in-production and comprising much of the current operational fleet, and (3)
CO2 stringency options that could impact airplanes that have either just entered production or are
in final design phase but would be in-production by the time the international Airplane CO2
Emission Standards become effective.1
In addition, these ten stringency options are described in the report of the CAEP meeting in
February 2016.68 The equation for the ten SOs (or the equation to calculate the SOs' metric
values (MVs)) and the accompanying coefficients that determine each of the distinct SOs are
provided below in Equation 6-1 and Table 6-1. Equation 6-1 is a second order log curve where
the coefficients were derived to match the trends of MVs for airplanes. Table 6-1 shows that
there was a kink point at 60,000 kilograms MTOM for each of the ten stringency options. The
percentage differences between SOs, which are shown in Table 6-2 below, were not constant
because CAEP's intent was for the SOs to affect the full scope of in-production and in-
development airplanes as the SOs increased in stringency.1™11 The CAEP report indicated that
lxvi In this chapter, generally the term, "stringency option" will be used to describe the ten ICAO/CAEP's stringency
options, and the term, "stringency level" will be used to describe the final GHG standards, which match the
international Airplane CO2 Emission Standards that were agreed to by CAEP in February 2016.
lxvu As described in the 2015 ANPR, the airplanes shown in Figures 6-1 and 6-2 are in-production and current in-
development. These airplanes could be impacted by in-production standards in that, if they were above the
standards, they will need to either implement a technology response or go out of production. For standards for
only new type designs, there will be no regulatory requirement for these airplanes to respond,
lxvm -[n Development" airplanes are the airplanes that were in development by manufacturers at the time of the
CAEP cost-effectiveness analysis and the publication of the 2015 ANPR.
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the ten SOs provided a convenient analytical space to perform a cost-effectiveness analysis, but
these SOs had no particular meaning for the stringencies ultimately agreed upon at CAEP for the
international Airplane CO2 Emission Standards.
Equation 6-1 - Calculation of Metric Values for Ten CAEP Stringency Options
MV = 10 (CO + CI * loglO(MTOM) + C2 * (loglO(MTOM))2)
Table 6-1 - Coefficients Used in Equation for Ten CAEP Stringency Options
Coefficients
SOI
S02
S03
S04
S05
S06
S07
S08
S09
SO10

C2
-0.00129488
-0.0111115
-0.0191302
-0.0233739
-0.0277861
-0.0323773
-0.0371585
-0.0409071
-0.0409071
-0.0409071
Below 60t
CI
0.4623490
0.5434880
0.6097660
0.6448410
0.6813100
0.7192570
0.7587750
0.7897580
0.7897580
0.7897580

CO
-2.23839
-2.42424
-2.57535
-2.65507
-2.73780
-2.82370
-2.91298
-2.98395
-3.00564
-3.02627
MTOM at kink point
60000
60000
60000
60000
60000
60000
60000
60000
60000
60000

C2
0.0593831
0.0593831
0.0593831
0.0593831
0.0593831
0.0593831
0.0593831
0.0593831
0.0593831
0.0593831
Above 60t
CI
-0.0205170
-0.0205170
-0.0205170
-0.0205170
-0.0205170
-0.0205170
-0.0205170
-0.0205170
-0.0205170
-0.0205170

CO
-1.31651
-1.33879
-1.35628
-1.36529
-1.37450
-1.38391
-1.39353
-1.40203
-1.42372
-1.44435
Table 6-2 - Percentage Differences Between the Ten CAEP Stringency
CAEP CO2 Stringency
Option
% Difference to SOI
at 60t MTOM
% Difference to
Previous SO at 60t
MTOM
MV at 60t
MTOM
1
-
--
0.8734
2
-5.0%
-5.0%
0.8297
3
-8.7%
-3.9%
0.797
4
-10.6%
-2.1%
0.7806
5
-12.5%
-2.1%
0.7642
6
-14.4%
-2.1%
0.7479
7
-16.2%
-2.2%
0.7315
8
-17.9%
-1.9%
0.7173
9
-21.9%
-4.9%
0.6823
10
-25.5%
-4.6%
0.6507
At this February 2016 meeting, CAEP agreed on an initial set of international standards to
regulate CO2 emissions from airplanes, and the final GHG standards match these international
standards. It was agreed that these international standards should apply to both new type design
and in-production airplanes. The effective date for the in-production standards were agreed to be
later than for the standards for new type designs. This allows manufacturers and certification
authorities additional preparation time to accommodate the standards. The standards for smaller
and larger new type design and in-production airplanes were agreed to be set at different
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stringencies to reflect the range of technology being used and the availability of new fuel burn
reduction technologies that vary across airplanes of differing size and weight. The final
standards and associated effective dates match these provisions for the international standards.
Table 6-3 provides a brief overview of the effective dates and stringency levels (SL) of the final
standards, which are equivalent to the international standards, including the standards' equations
and associated coefficients (as described earlier in Equation 6-1 and Table 6-1). As described
earlier, CAEP considered and analyzed 10 different stringency options for standards of both in-
production and new type designs (from 1 as the least stringent to 10 as the most stringent).
Ultimately, CAEP agreed upon the international Airplane CO2 Emission Standards with a SL8.5
for new type design airplanes greater than about 70,000 kilograms MTOM, which the final
standards match for this applicability criteria, and this SL8.5 is between CAEP's S08 and S09
(described earlier). There is a difference in the shape of lines for the ten CAEP SOs compared to
the final standards. This difference is due to the kink point at 60,000 kilograms MTOM for the
ten CAEP SOs versus the horizontal transition between 60,000 and about 70,000 kilograms
MTOM for the final standards (which are equivalent to the international standards), as described
further below.lxix
lxix When analyzing stringency options, CAEP determined that there were significant performance differences
between large and small airplanes. Airplanes with an MTOM less than 60,000 kilograms are either business jets
or regional jets. Due to the physical size of smaller airplanes, there are scaling challenges which limit technology
improvements on smaller airplanes compared to larger airplanes. This leads to requiring higher capital costs to
implement the technology relative to the sale price of the airplanes. Business jets (generally less than 60,000
kilograms MTOM) tend to operate differently than commercial airplanes by flying at higher altitudes and faster
than commercial traffic. Based on these considerations, when developing stringency options for the international
standard, ICAO further realized that curve shapes of the data differed for large and small airplanes (on MTOM
versus metric value plots). Looking at the dataset, there was originally a gap in the data at 60,000 kilograms.
This natural gap allowed a kink point to be established between larger commercial airplanes and smaller business
jets and regional jets. The kink point provided flexibility at CAEP to consider standards at appropriate levels for
airplanes above and below 60,000 kilograms. (This kink point accommodates a change in slope observed
between large and small airplanes.) The flat section of the curve starting at 60,000 kilograms, for the stringency
options, is used as a transition to connect the curves for larger and smaller airplanes.
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Table 6-3 - Stringency Levels and Effective Dates for Final GHG Emission Standards

Airplane Weight
(MTOM) Thresholds
(KG)
New-Type
Airplane Maximum
Permitted GHG Level
In-Production
Airplane Maximum
Permitted GHG
Level
Stringency Level
>5,700 to <60,000
SL5
a
SL3
A

Horizontal
Transitionlxx
60,000 to ~ 70,000
SL5-SL8.5lxxi
c
SL3-SL7lxxii
D

> -70,000
SL8.5
e
SL7
F
Implementation
Date
Application for a
new-type certificate or a
change to an exi sting-
type certificate
2020
(2023 for planes
with less than 19 seats)
2023

Production Cut-Off
n/a
2028
a. Equation of Stringency Level #5: MV = io"2-73780+ (°-681310 * Wmtom))+ (-0.0277861«(iogio(MToM))2)
Equation	of	Stringency	Level	#3:	MV =
^q—2.57535 + (0.609766 * loglO(MTOM))+ (-0.0191302 * (loglO(MTOM))2^)
Equation of New Type transition - 60,000 to 70,395kg: MV = 0. 764
Equation of In-production transition-60,000 to 70,107kg: MV = 0.797
Equation	of	Stringency	Level	#8.5:	MV =
^Q—1.412742 + (-0.020517 * loglO(MTOM))+ (0.0593831 * (loglO(MTOM))2^)
Equation	of	Stringency	Level	#7:	MV =
^Q—1.39353 + (-0.020517 * loglO(MTOM))+ (0.0593831 * (loglO(MTOM))2^)
Figure 6-1 and Figure 6-2 show a graphical depiction of both the final standards for new type
design and in-production airplanes compared against the 10 CAEP stringency options (described
earlier) and the CO2 metric values (as of February 2017) of in-production and in-
developmentlxxm airplanes. As described in earlier chapters of this TSD, the airplane metric
value data shown were generated by the EPA using a commercially available airplane modeling
tool called PIANO (PIANO version 5.4, dated February 2017).69 Note, a number of the
lxx Stringency lines above and below 60,000 kilograms (MTOM) are connected by a horizontal transition starting at
60,000 kilograms (MTOM) and continuing right (increasing mass) until it intersects with the next level.
lxxi The stringency level for the standards starting at 60,000 kilograms maintains the level of SL5 until it intersects
the SL8.5 at 70,395 kilograms (MTOM).
lxxu The stringency level for the standards starting at 60,000 kilograms maintains the level of SL3 until it intersects
SL7 at 70,107 kilograms (MTOM).
lxxm Airplanes that are currently in-development but will be in production by the applicability dates. These could be
new type design or significant partial redesigned airplanes.
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airplanes currently shown as in-production are expected to go out of production and be replaced
by known in-development airplanes prior to both the final GHG standards for new type design
and the in-production airplanes going into effect.
SOS
S09
SOlO
In-Production
New Type
Piano MV
MTOM (1000 kg)
Figure 6-1 - Final GIIG Emission Standards and CAEP's Ten Stringency Options (MTOM in kilograms)1™
w [n tjie ]egenci of Figure 6-1 and Figure 6-2, "In-Production" and "New Type" refer to the graphical depiction of
the final standards for in-production and new type design airplanes, and the international standards agreed to at
the February 2016 CAEP meeting match these final standards.
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—	SOB
—	SO 9
—	SO10
—	In-Production
-- New Type
• Piano MV
MTOM (1000 kg)
Figure 6-2 - Final GHG Emission Standards and CAEP's Ten Stringency Options
(Zoomed to show <100,000 MTOM in kilograms)
6.1.2 Alternatives Considered in the Context of CAEP Stringency Options, International
Standards Adopted, and Final Standards
As discussed earlier, in the EPA consideration of alternative scenarios, the final GHG
standards, which match the international standards, are designated as the primary scenario,
identified as Scenario 1 (described earlier in Table 6-3). The alternative scenarios considered the
earlier implementation dates and more stringent levels (or more stringent options) that CAEP
analyzed. The two alternative scenarios, identified as Scenarios 2 and 3, were defined to
consider whether moving the implementation date(s) forward (for in-production airplanes) and
tightening the stringency (for both in-production and new type designs) would make a
meaningful difference.lxsv Scenario 2 reflects the earliest implementation date that is practical,
and Scenario 3 represents the most stringent option analyzed by CAEP. All three scenarios are
summarized below in Table 6-4, and all three scenarios are assessed against the (no regulation)
kxv As described earlier. CAEP analyzed stringency options that were less stringent than the standards ICAO
ultimately adopted. As discussed in section II.D. of the Federal Register Notice for this rale, under the Chicago
Convention, we are obligated to adopt standards that are at least as stringent as ICAO standards. Thus, the EPA
did not analyze any CAEP stringency options that are less stringent than the ICAO standards.
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baseline that assumes continuous (2016-2040) annual fuel efficiency improvements and end of
production timing (for some in-production airplanes) —as described in Chapter 5. As described
earlier, for smaller and larger airplanes, under all three scenarios, the stringencies for new type
design and in-production airplanes are assumed to be set at different levels to reflect the range of
technology being used and the availability of new fuel burn reduction technologies that vary
across airplanes of differing size and MTOM.
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Table 6-4 - Final Rule and Alternative Scenarios
Scenario
Option
Description of Stringency and Effective Date
1
Final Rule
(see Table 6-3
above)
-New Tvoe: SL8.5. 2020
(SL5, 2023 for new type airplanes < 60 tonslxxvUxxvu & < 19
seats)
-In-Production: SL7 (5% less stringent vs. newtvoe),
2028lxxviii
(SL3, 4% less stringent vs. new type, 2028 also for in-
production airplanes < 60 tons and dedicated freighters)
(2023 for GHG adverse or significant In-Production type
changes)
2
Pull Ahead Some
In-Production
Dates
-New Tvoe: Same stringencies and same effective dates for
New Type as Scenario 1
-In-Production: Differentiate In-Production effective dates
and move general effective date to 2023
(move in-production airplanes < 60 tons effective date to
2025, but retain 2028 effective date for in-production
dedicated freighters)
3
Pull Ahead Some
New Type and In-
Production
Dates and More
Stringent
Levels
-New Tvpe: Similar to ICAO S09, 2.5% more stringent
than Scenario l's SL8.5
(Matches ICAO S06, 2% more stringent than Scenario l's
SL5 and 2020 for airplanes < 60 tons)
-In-Production: Similar to ICAO S08 or S09lxxix, 2% to
7% more stringent than Scenario l's SL7 lxxx and move
effective date to 2023
(Matches ICAO S05, 3% to 4% more stringent than
Scenario l's SL3 for in-production airplanes <60 tons and
move effective date to 2025, but retain 2028 effective date for
in-production dedicated freighters)
lxxvi In this rulemaking, 60 tons means 60 metric tons, which is equal to 60,000 kilograms (kg). Or, 1 ton means 1
metric ton, which is equal to 1,000 kg.
ixxvn por bod, new type design airplanes and in-production airplanes, the MTOM thresholds for covered airplanes are
as follows: greater than 5.7 tons (or 5,700 kilograms) MTOM for subsonic jet airplanes and greater than 8.618
tons (8,618 kilograms) MTOM for turboprop airplanes,
lxxvm por Scenarios i ancl 2, the 19-seat differentiation (for airplanes less than or equal to 60 tons MTOM) in
effective date only applies to new type design airplanes.
rxlx Scenario 3 includes two stringency options, ICAO S08 and S09, for in-production airplanes greater than 60
tons MTOM.
lxxx For Scenario 3, its more stringent levels also apply to dedicated freighters (including dedicated freighters less
than or equal to 60 tons MTOM), but the 2028 in-production effective date is retained for dedicated freighters.
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Scenario 2 considers whether an earlier implementation date for the final GHG standards will
result in benefits that outweigh the costs. Scenario 2 will have the same stringencies as Scenario
1 (and the final standards, which match the international standards). However, in contrast to
Scenario 1 where the standards will only become effective on or after January 1, 2023, for GHG
adverse or significant in-production type changes,lxxxi Scenario 2 will have this same effective
date for most in-production airplanes, which is five years earlier than Scenario l.lxxx" This
earlier effective date for Scenario 2 is based on expected improvements to airplanes and changes
in their production status in the next five years. For in-production airplanes that are 60 tons or
less MTOM, the Scenario 2 effective date is assumed to be moved to 2025, which is three years
earlier than Scenario 1. Flexibility is provided for airplanes that are 60 tons or less MTOM
because these smaller airplanes have limited technologies available to incorporate in comparison
to larger airplanes (mainly larger passenger commercial airplanes), and smaller airplanes have
different economic viability of technology development relative to larger airplanes.lxxxm But for
dedicated freighters, the Scenario 2 effective date will remain the same as Scenario 1 (January 1,
2028). Flexibility is provided for these dedicated freighters in Scenario 2 because of the unique
aspects of the market for commercial air cargo transport — e.g., the small size of the market for
air cargo transport services and the potentially limited business case for making improvements to
these airplanes.lxxxiv
Scenario 3 considers more stringent standards in addition to an earlier implementation date for
new type design airplanes that are 60 tons or less MTOM and 19 seats or less (in maximum
passenger seating capacity) and the same earlier effective dates for in-production airplanes
considered in Scenario 2. Similar to Scenario 2, Scenario 3 has a January 1, 2023, effective date
(five years earlier than Scenario 1) for in-production airplanes in general, a January 1, 2025,
effective date for in-production airplanes that are 60 tons or less MTOM, and a January 1, 2028,
effective date for in-production airplanes that are dedicated freighters. In addition, Scenario 3
will have more stringent standards for both new type design and in-production airplanes
compared to Scenarios 1 and 2. For new type design airplanes greater than 60 tons MTOM, the
stringency will be similar to ICAO S09 and be 2.5 percent stricter compared to Scenario l's
lxxxi Scenario l's 2028 implementation date for in-production airplanes will be a production cut-off, which means
that in-production airplane that do not comply with the final standards after this date will not be allowed enter
into service or be built. Also, Scenario 1 has a 2023 implementation date for in-production airplanes with adverse
GHG emission changes or significant in-production type changes. This provision means that after 2023,
applications to change a type design of a non-GHG certificated airplane that either increase the Metric Value of
the airplane, increase the MTOM of the airplane, or significantly change the airplane's GHG emissions
(significant decrease in GHG emissions) will be required to comply with the in-production rule. The provision is
meant to capture changes to those non-GHG certificated airplanes built prior to the production cut-off date of
2028.
lxxxn por scenari0 2. the production cut-off date will be 2023.
lxxxm u s United States Position on the ICAO Aeroplane CO2 Emissions Standard, Montreal, Canada, CAEP10
Meeting, February 1-12, 2016, Presented by United States, CAEP/10-WP/59. Available in the docket for this
rulemaking, Docket EPA-HQ-OAR-2018-0276.
lxxxiv in.production airplanes that are dedicated freighters have developed a unique market segment for the business
case of providing air cargo transport services. Demand for new purpose-built freighters is relatively low,
therefore they are produced in smaller volumes than their passenger equivalents. Because of the size of the
market, manufacturers of dedicated freighters may have a potentially limited business case for making
improvements to these airplanes.
ICAO/CAEP, United States Position on the ICAO Aeroplane CO2 Emissions Standard, Tenth Meeting of CAEP,
Montreal, Canada, February 1 to 12, 2016, CAEP/10-WP/59.
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SL8.5 (and Scenario 2). For new type design airplanes 60 tons or less MTOM, the stringency
will match ICAO S06 and be 2 percent stricter than Scenario 1 and Scenario 2's SL5. For in-
production airplanes greater than 60 tons MTOM, we consider a range of stringencies (or two
stringencies) as part of Scenario 3. For these in-production airplanes, the stringency will be
similar to either ICAO S08 or S09 and be 2 to 7 percent stricter (depending on the MTOM)
compared to Scenario 1 and Scenario 2's SL7. For in-production airplanes 60 tons or less
MTOM, the stringency will match ICAO S05 and be 3 to 4 percent stricter than Scenario 1 and
Scenario 2's SL3.
Scenario 3 reflects the position proposed by the U.S. as an ICAO Member country. However,
with U.S. concurrence the tenth meeting of ICAO/CAEP, which occurred in February 2016, did
not adopt the U.S. Scenario 3-equivalent position.lxxxv For harmonizing with the international
standards and providing global consistency of standards, which will ensure all the world's
manufacturers need to comply (or certify) to the same standards and no U.S. manufacturer finds
itself at a competitive disadvantage, we are finalizing standards that match the ICAO standards
(see further rationale for the final standards compared to Scenario 3 later in section 6.4).
Figure 6-3 and Figure 6-4 below show the in-production stringencies for the three scenarios as
plots.lxxxvi Figure 6-3 shows the scenarios over the entire MTOM range, and Figure 6-4 zooms in
on the scenarios below 100 tons MTOM.lxxxvu In Figure 6-3 and Figure 6-4, Scenario 1 is red,
Scenario 2 is blue, and Scenario 3 is green. The lines for Scenarios 1 and 2 are identical in
stringency level, and they only differ in their effective dates. Thus, they overlap in these figures.
Scenario 3 is shown as a range in stringency options for in-production airplanes as described
above (CAEP S08 or S09). Three metric values are plotted for each airplane, corresponding to
the values for each scenario's effective date. For the scenarios with different effective dates, the
projection of constant annual improvement in fuel efficiency metric value applied for each
airplane leads to the difference in metric value for the same airplane — as described earlier in
Chapter 2. Note the metric values for Scenarios 2 and 3 are the same since they have the same
effective dates.
The solid red circles represent the metric value each airplane would have at Scenario l's 2028
in-production applicability date. The open red circles represent the metric value each out of
production airplane would have at 2028 (Scenario 1). The solid blue and green circles represent
the metric value each airplane would have at Scenario 2 and Scenario 3's 2023 in-production
applicability date. The open blue and green circles represent the metric value each out of
production airplane would have at 2023 (Scenarios 2 and 3). With fewer baseline improvement
lxxxv ICAO/CAEP, United States Position on the ICAO Aeroplane CO2 Emissions Standard, Tenth Meeting of
CAEP, Montreal, Canada, Februaiy 1 to 12, 2016, CAEP/10-WP/59.
lxxxv 1 jjlc analysis focused on in-production airplanes because, as described in Chapter 2, a technology response is
not necessary for new type design airplanes to meet the scenarios,
kxxvn scenario 1 (and Scenario 2) will have a constant metric value or stringency level for MTOMs between 60 tons
and 70.107 tons. For the purposes of presenting Scenario 3 in Figure 6-3 and Figure 6-4, Scenario 3 also has a
constant stringency level in this MTOM range. ICF analyzed Scenario 3 with a varying stringency level in this
same MTOM range or a kink point at 60 tons MTOM (similar to the ICAO/CAEP SOs), which is consistent with
the U.S. position proposed by the U.S. ICAO Member at the tenth meeting of ICAO/CAEP. The results of
airplanes affected by Scenario 3 do not change with either having a constant stringency level between 60 tons and
70.107 tons or instead having a kink point at 60 tons MTOM.
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years prior to applicability, the 2023 metric values (blue and green circles) would be expected to
be higher than the corresponding 2028 values (red circles).
3.0
0.5 -
Sen. i
Sen. 2
Sen. 3
Sen. 1 In-Prod. MV
Sen. 1 Out of Prod. MV
Sen. 2,3 In-Prod. MV
Sen. 2,3 Out of Prod. MV
200	300	400
MTOM (1000 kg)
600
Figure 6-3 - In-Production Airplane Stringency Lines for the Three
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1.0
0.8
>
2!
0.6
Sen. 1
Sen. 2
Sen. 3
Sen. 1 In-Prod. MV
Sen. 1 Out of Prod. MV
Sen. 2,3 In-Prod. MV
Sen. 2,3 Out of Prod. MV
0.2
0.0
0
20
40
60
80
100
MTOM (1000 kg)
Figure 6-4 - Detail of In-Production Airplane Stringency Lines for Airplane Below 100 tons MTOM
6.2 GHG Emission Reductions and Costs of Two Alternative Scenarios
The methods used to analyze the GHG costs and emission reductions from the final standards
and the two alternative scenarios are described in Chapter 2, Chapter 4, and Chapter 5. Although
the final standards (Scenario 1) do not have any costs or emission reductions (based on the
rationale provided in the earlier chapters), the effects of the final standards were analyzed using
the same methods as the two alternative scenarios.
6.2.1 Scenario 2
Scenario 2 would not be expected to result in additional GHG reductions or costs relative to
the final standards or Scenario 1. As described earlier in Chapter 2 and Chapter 5 for the final
standards (Scenario 1), under Scenario 2 manufacturers comply through already developed or
developing technologies to respond to ICAO standards. Moreover, as described in Chapter 2,
with the baseline constant annual improvement in fuel efficiency metric value in the absence of
rules, all but one airplane model are still expected to be in production and compliant with the 5-
year pull ahead associated with Scenario 2. The exception is a single dedicated freighter airplane
(Boeing 767-3ERF); however, the 5-year accelerated implementation date will not apply to
dedicated freighters for Scenario 2. This provision would mean that the 767-3ERF is not
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disadvantaged by Scenario 2, and those additional years allow for it to come into compliance
given the assumed baseline constant annual improvement in fuel efficiency metric value.70
However, it is informative to describe the 767-3ERF's metric value compared with Scenario
2's stringency level but without a five-year delay for dedicated freighters (for a 2023 effective
date). The 767-3ERF's metric value would be 7.91 percent greater than Scenario 2 in 2023 (does
not meet level of Scenario 2). With a 1 percent design margin,lxxxvm as described earlier in
Chapter 2, there would need to be an 8.91 percent improvement in the 767-3ERF metric value by
2023 to comply with Scenario 2 (and an 8.91 percent reduction in GHG emissions per 767-
3ERF). With this amount of improvement needed for the 767-3ERF to comply with Scenario 2
in 2023 and the 767-3ERF expected to be end production in 2023, the manufacturer would be
anticipated to pull forward its final year of production by one year (2022) instead of making the
investment for the technology response to comply with Scenario 3. Yet, with the dedicated
freighter delay to 2028 in Scenario 2, this pull forward in the end of production for the 767-3ERF
would not need to occur. As described above, the 767-3ERF would comply with Scenario 2
based on its expected end of production in 2023 in the absence of a standard, and thus, there
would be no emission reductions or costs from Scenario 2 based on the 767-3ERF. In addition,
even if we were to change the above expectations, the manufacturer of the 767-3ERF could
utilize the exemption provisions described in section V.E of the preamble, which are intended for
airplanes at the end of their production life. If Boeing chose to apply for an exemption and it
was granted, the 767-3ERF would not need to respond to Scenario 2, and thus, there would be no
resultant emission reductions or costs for Scenario 2 from the 767-3ERF.
We note that in their comments on the proposed rulemaking Boeing, along with Fedex, GE,
and the Cargo Airline Association, expressed that there would continue to be a low volume
demand for the B767 freighter beyond January 1, 2028. These commenters did not indicate the
number of 767F's that would be produced after 2028. The EPA did not change the analysis to
include continued production of the 767F beyond 2028 because insufficient information to
characterize this scenario was provided.
6.2.2 Scenario 3
Scenario 3 both accelerates the implementation date by 5 years and increases the stringency.
This scenario would be expected to result in additional GHG reductions and costs relative
Scenarios 1 and 2. Using the same assumptions applied to the other scenarios, the baseline
constant annual improvement in fuel efficiency metric value for each airplane and the delay to
2028 for dedicated freighters, there are limited reductions and costs from Scenario 3. These
limited costs and emission reductions are due the impacts on a single airplane model, the Airbus
A380.
As described earlier in a Chapter 5 footnote, on February 14, 2019, Airbus made an
announcement to end A380 production by 2021 after Emirates airlines reduced its A3 80 order by
lxxxvm j]lc 2018 ICF updated analysis indicated that for those airplanes that do not meet a stringency level, an
additional 1 percent design margin above the shortfall would need to be reached. This design margin would
ensure the technology addresses the response to the stringency level (actual CO2 reduction for a given technology
is variable).
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39 airplanes and replaced them with A330s and A350s.lxxxix The early exit of A380 will result in
no costs and no emission reductions from Scenario 3. However, this EPA analysis of Scenario 3
was conducted prior to Airbus's announcement, so the analysis did not consider the effect of the
A380 ending production in 2021. Thus, this analysis results in limited costs and emission
reductions for Scenario 3.
6.2.2.1	767-3ERF
Due to the dedicated freighter 5-year delay in Scenario 3, the 767-3ERF would comply with
Scenario 3 for the same reason described above for Scenario 2. However, it is informative to
describe the 767-3ERF's metric value compared to the stringency level of Scenario 3. The 767-
3ERF's metric value would be 15.7 percent greater than Scenario 3. With a 1 percent design
margin, there would need to be a 16.7 percent improvement in the 767-3ERF metric value by
2023 to comply with Scenario 3 (and a 16.7 percent reduction in GHG emissions per 767-3ERF).
As with Scenario 2, with this greater amount of improvement (for Scenario 3 compared to
Scenario 2) needed for the 767-3ERF to comply with Scenario 3 in 2023 and the 767-3ERF
expected to end production in 2023, the manufacturer would be even more likely (versus
Scenario 2) to pull forward its final year of production by one year (2022) instead of making the
investment to comply with Scenario 3. Yet, with the dedicated freighter delay to 2028 in
Scenario 3, this pull forward in the end of production for the 767-3ERF would not be needed. As
described above, the 767-3ERF would comply with Scenario 3 based on its expected end of
production in 2023 in the absence of a standard, and thus, there would be no emission reductions
or costs from Scenario 3 based on the 767-3ERF. In addition, (as with Scenario 2) even if we
were to change the above expectations, the 767-3ERF could utilize the exemption provisions
described in section V.E of the preamble, which are intended for airplanes at the end of their
production life.
As described earlier, we note that in their comments on the proposed rulemaking Boeing,
along with Fedex, GE, and the Cargo Airline Association, expressed that there would continue to
be a low volume demand for the B767 freighter beyond January 1, 2028. These commenters did
not indicate the number of 767F's that would be produced after 2028. The EPA did not change
the analysis to include continued production of the 767F beyond 2028 because insufficient
information to characterize this scenario was provided.
6.2.2.2	A380
For Scenario 3, with the baseline constant annual improvement, the 5-year earlier effective
date (except dedicated freighters that retain the 2028 effective date), and tighter stringency levels
for in-production airplanes, one in-production airplane model would not comply. Further, the
impacted airplane model would need a technology response to stay in production after the effect
date, and the technology response would lead to GHG reductions and costs (and fuel savings)
compared to Scenarios 1 and 2. This airplane model is the Airbus A380-842/A380-861 (herein
referred to as the "A380"). The A380 does not comply with the in-production level that is 7
percent more stringent than Scenarios 1 and 2 (Scenario 3 will be similar to the level of IC AO
lxxxix The Airbus press release is available at: https://www.airbns.com/newsroom/press-reieases/en/2019/02/airbns-
and-emirates~reach~agreement~on~a380~fieet~~sign~new~widebodv~orders.html. last accessed on February 10,
2020.
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S09 for in-production airplanes greater than 60 tons MTOM and will be effective in 2023). The
A380's metric value would be 3.24 percent greater than Scenario 3. With a 1 percent design
margin, there would need to be a 4.24 percent improvement in the A380 metric value by 2023 to
comply with the Scenario 3 metric value requirement. Applying a constant annual improvement
in fuel efficiency metric value would mean 1.71 percent of these reductions would already have
been obtained by 2023 (by business as usual technology improvements in the absence of a
standard), and the remaining portion of the reductions, 1.53 percent, would be achieved through
technology response. With the 1 percent design margin, the technology response would become
2.53 percent. Table 6-5 shows the result of this method for determining the metric value
reduction for technology response for the A380.
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Table 6-5 - A380 Scenario 3 - Implementation of Technology Response

No Design Margin
1% Design Margin
Percent MV Greater than Scenario 3
3.24%
4.24%
Residual Implemented MV Improvement
(1.71%)
(1.71%)
Technology Response Improvement Target
1.53%
2.53%
Technology Response: Adaptive Trailing Edge
2.00% of A380 baseline MV
2.00% of A380 baseline MV
Technology Response: ECS Aero
N/A
0.63% of A380 baseline MV
Non-Recurring Cost to Implement Technology
Response
$493M
$580M
Based on the supply curve method in the 2018 ICF updated analysis, which is described
earlier in Chapter 2, the anticipated technology response (or the most economical technology
response) for the A3 80 would be the adaptive trailing edge and environmental control system
(ECS) aerodynamic cleanup and on-demand ECS scheduling, if the 1 percent design margin is
necessary (and only adaptive trailing edge if the 1 percent design margin is not needed). These
technology responses are described further in Chapter 2. Figure 6-5 provides the supply curve
for the technology response of the A380 4-xc
xc As described in Chapter 2 and earlier in section 6.2.2.2, for a given future year, a manufacturer's technology
insertion is assumed to have progressed up the supply curve (i.e. technologies with largest improvement and most
economical cost are implemented first). Therefore, these economical technologies would have already been
implemented by the stringency year, and they will not be available for future investment. Then, we overlay the
smoothed forecasted incremental metric value improvement by the stringency year on the airplane model's
discrete supply-curve. From this overlay, ICF identified the most economical technologies that would already
have been implemented by the stringency year, and these technologies represent business as usual improvement
or continuous metric value improvement by the stringency year - or 2023 improvement level. The red-dashed
line in Figure 6-2 shows the continuous metric value improvement by 2023 or the 2023 improvement level.
Subsequently, the remaining technologies not yet implemented, which are those technologies that are to the right
of the red-dashed line, would be available for the technology response needed to meet Scenario 3.
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$6,000
$5,000
I $4/) 00
$3,000
W $2,000
$1,000
Analysis of Alternatives
A380 Incremental Improvement Technology Supply Curve
Gap to scenario (%}
AUO-M1
2023 Improvement Level
Aerodynamic AJ®U Fairing /Aft
body rede sign
Other Aerodynamic Improvements
Other Syftems Improvement*
Hybrid Liminv Sow Control •
Empennage
P»fclet Coatings
Adaptive 'railing Edge
Variable Camber Trailing Edge -
Mcrphirg
ECS Aero and On Demand ECS
Scheduling
SHI fteduong Profile ot the light*
i i Engine Technologies
Advanced Wing Op Devices -
Retrofit
—A— MV Supply Curve tine
10% 12% 14%
Metric Value Improvement
Figure 6-5 - A380 Incremental Improvement Technology Supply Curve
6.2.2.2.1	A380's GHG Emission Reductions
For Scenario 3, we also estimated that the U.S. covered airplane GHG emissions would be
reduced in 2030 and 2040 from the anticipated technology response for the A3 80s built after
January 1, 2023 (Scenario 3's effective date for in-production airplanes over 60 tons MTOM).
(Note, as described in section III of the preamble, CO2 represents 99 percent of all GHGs emitted
from both total U.S. airplanes and U.S. covered airplanes (in megatonnes of CO2 equivalent),
and nitrous oxide (N2O) represents 1 percent of GHGs emitted from total airplanes and U.S.
covered airplanes.) However, the emissions reductions from such a response would be limited
since the 2018 ICF updated analysis projects that the number of A3 80s that would be built after
January 1, 2023, would be about 40 airplanes. The cumulative reductions in U.S. covered
airplane GHG emissions for Scenario 3XC1 would be as follows (percentage and absolute
reductions): about 0.7 percent and 0.6 Mt CO2 equivalent for 2030 and about 0.8 percent and 1.4
Mt CO2 equivalent for 2040. Further details about the emissions impacts of Scenario 3 are
provided in Chapter 5.
6.2.2.2.2	A380's Costs
Based on the same reasons as discussed earlier in this section there would be limited
technology response costs from only the A380 needing to respond to Scenario 3. As described
earlier, the technology response for the A380 to comply would be the adaptive trailing edge and
™ ICF projected that about 40 A3 80s would be built globally after January 1, 2023. The cumulative reductions in
U.S. covered airplane GHG emissions would be from about 40 A380s receiving a technology response for
Scenario 3 from 2023 to 2030. However, as discussed earlier in Chapter 5, we did not comiect these cumulative
GHG reductions to a specific number of A380s used in the EPA analysis, but instead we connected the reductions
to a specific amount of operations.
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ECS aerodynamic cleanup and on-demand ECS scheduling. We estimated that the non-recurring
cost to apply this technology response to the A380 would be about $415 million and $501
million (in 2015$), at 7 and 3 percent discount rates respectively.™11 Chapter 2 provides the
details of the cost methodology.
Similar to the earlier discussion in Chapter 2, the 2018 ICF updated analysis indicates that if
technologies would add significant recurring costs (recurring operating and maintenance costs)
to an airplane and/or an operator (e.g., an air carrier), an air carrier would likely not add these
technologies to their airplanes. Thus, the 2018 ICF updated analysis estimates that there would
be no recurring costs for the projected technology response of the A3 80 to Scenario 3.
In addition, for Scenario 3, the A380 could apply to utilize the exemption provisions
(described in section V.E of the preamble), which are intended for airplanes at the end of their
production life. If Airbus chose to apply for an exemption and it was granted, the A3 80 would
not need to respond to Scenario 3, and thus, there would be no resultant emission reductions or
costs for Scenario 3.
6.2.2.3 Monetized Benefits for A3 80
We estimate the climate benefits associated with alternative regulatory Scenario 3 using a
measure of the domestic social cost of carbon and nitrous oxide (SC-CO2 and SC-N2O).
Scenario 3 is the only alternative scenario with potential SC-CO2 and SC-N2O emission
reductions. The social cost of these greenhouse gases is a metric that estimates the monetary
value of impacts associated with marginal changes in CO2 emissions in a given year. It includes
a wide range of anticipated climate impacts, such as net changes in agricultural productivity and
human health, property damage from increased flood risk, and changes in energy system costs,
such as reduced costs for heating and increased costs for air conditioning. It is typically used to
assess the avoided damages as a result of regulatory actions (i.e., benefits of rulemakings that
lead to an incremental reduction in cumulative global CO2 emissions). The SC-CO2 and SC-N2O
estimates used in this TSD focus on the direct impacts of climate change that are anticipated to
occur within U.S. borders.
The SC-CO2 and SC-N2O estimates used in this TSD are interim values developed under
E.O. 13783 — for use in regulatory analyses until an improved estimate of the impacts of climate
change to the U.S. can be developed based on the best available science and economics.™111 See
xcn We began by using the ICF's estimate for undiscounted non-recurring costs of $580 million for this technology
response (of these two technologies together). Subsequently, we allocated a fifth of these NRC costs to each of
the five years preceding 2023 since the costs would typically be spent over a five-year period (instead of all in
one year). Next, we discounted these annual costs back to 2015 at 7 percent and 3 percent discount rates to
calculate the resulting total present value of non-recurring costs of $415 million and $501 million (in 2015$),
respectively.
xcm Such improved domestic estimates would take into considerations the recent recommendations from the National
Academies of Sciences, Engineering, and Medicine for a comprehensive update to the current methodology to
ensure that the social cost of greenhouse estimates reflect the best available science. While the Academies'
review focused on the methodology to estimate the social cost of carbon (SC-CO2), the recommendations on how
to update many of the underlying modeling assumptions also pertain to the SC-N20 estimates since the
framework used to estimate SC-N20 is the same as that used for SC-CO2. See National Academies of Sciences,
Engineering, and Medicine, Valuing Climate Damages: Updating Estimation of the Social Cost of Carbon
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the Appendix71 for additional discussion of E.O. 13783 and an explanation of the modeling steps
involved in estimating the domestic estimates used in this TSD.
Table 6-6 and Table 6-7 present the average domestic SC-CO2 and SC-N2O estimates,
respectively, across all the model runs using both 3 and 7 percent discount rates for the years
2015 to 2050. As with the global social cost of greenhouse gas estimates, the domestic estimates
increase over time because future emissions are expected to produce larger incremental damages
as physical and economic systems become more stressed in response to greater climatic change,
and because gross domestic product (GDP) is growing over time and many damage categories
are modeled as proportional to gross GDP.
Table 6-6 - Interim Domestic Social Cost of CO2,2015-2050 (in 2015$ per metric ton)*

Discount Rate and Statistic
Year
3% Average
7% Average
2015
$6
$1
2020
6
1
2025
7
1
2030
8
1
2035
8
2
2040
9
2
2045
10
2
2050
10
2
* These SC-CO2 values are stated in $/metric ton CO2 and rounded to the nearest dollar. The estimates vary
depending on the year of CO2 emissions and are defined in real terms, i.e., adjusted for inflation using the GDP
implicit price deflator.
Table 6-7 - Interim Domestic Social Cost of N20,2015-2050 (in 2015$ per metric ton)*
Year
Discount Rate and Statistic
3% Average
7% Average
2015
$1900
$310
2020
2100
360
2025
2300
440
2030
2600
510
2035
2800
600
2040
3100
700
2045
3400
810
2050
3700
920
* These SC-N2O values are stated in $/metric ton N20 and rounded to two significant digits. The estimates vary
depending on the year of N20 emissions and are defined in real terms, i.e., adjusted for inflation using the GDP
implicit price deflator
The estimates in Table 6-6 and Table 6-7 are used to monetize the domestic climate benefits.
Forecasted changes in CO2 and N2O emissions in a given year, expected as a result of Scenario
3, are multiplied by the SC-CO2 and SC-N2O estimates, respectively, for that year.
Dioxide, Washington, D.C., January 2017. http://www.nap.edu/catalog/24651/valuing-climate-changes-updating-
estimation-of-the-social-cost-of.
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Table 6-8 provides annual estimates of SC-CO2 benefits associated with Scenario 3, as well as
the total present value of SC-CO2 benefits. Table 6-9 provides annual estimates of the SC-N2O
benefits, as well as the total present value of SC-N2O benefits. As described earlier, N2O
represents 1 percent of GHGs emitted from U.S. covered airplanes, and therefore contributes a
small portion of climate benefits compared to C02.XC1V Table 6-10 provides annual estimates of
fuel savings, as well as the total present value of fuel savings.
Fuel savings, domestic climate benefits, and total benefits associated with Scenario 3 are
presented in Table 6-11 and Table 6-12.xcv
XC1V Global warming potential (GWP) is a quantified measure of the globally averaged relative radiative forcing
impacts of a particular greenhouse gas. It is the accumulated radiative forcing within a specific time horizon,
relative to that of the reference gas CO2. GWP-weighted emissions are measured in megatonnes of CO2
equivalent (Mt C02 Eq.), and GWPs are based upon a 100-year time horizon.
U.S. EPA, 2020: Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2018, 733 pp., U.S. EPA Office
of Air and Radiation, EPA 430-R-20-002, April 2020. Available at:
https://www.epa.gov/ghgemissions/inventorv-us-greenhouse-gas-emissions-and-sinks-1990-2018 (last accessed
June 18, 2020).
xcv The airplane GHG emission reductions in the U.S. described earlier in this section for Scenario 3 directly relate to
airplane fuel savings in the U.S. For Scenario 3, the EPA approximated the value of airplane fuel burn savings
from the reduced demand attributable to improved airplane fuel efficiency, due to the technology response
described earlier. To estimate these airplane fuel savings for Scenario 3, we used the average jet fuel price per
year (2023 through 2040) from the Annual Energy Outlook 2018. The jet fuel prices were in 2017$, and we
converted these jet fuel prices to 2015$.
U.S. Energy Information Administration (EIA), 2018: Annual Energy Outlook 2018, #AEO2018, Table 12 -
Petroleum and Other Liquids Prices, Available at www.eia.gov/aeo (last accessed April 11, 2018).
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Table 6-8 - Detailed Domestic CCh-Related Benefits for Scenario 3x'vi-xcvii-"viii (Millions of 2015$)
Year
Domestic
Domestic Climate
Domestic Climate

Reductions
Benefits
Benefits

C02
SC-COz
SC-COz


(3%)
(7%)
2023*™
0.03
$0.19
$0.03
2024
0.06
0.38
0.06
2025
0.08
0.59
0.10
2026
0.08
0.60
0.10
2027
0.08
0.61
0.10
2028
0.08
0.62
0.10
2029
0.08
0.63
0.11
2030
0.08
0.63
0.11
2031
0.08
0.64
0.11
2032
0.08
0.65
0.12
2033
0.08
0.66
0.12
2034
0.08
0.66
0.12
2035
0.08
0.67
0.13
2036
0.08
0.67
0.13
2037
0.08
0.67
0.13
2038
0.07
0.67
0.13
2039
0.07
0.67
0.13
2040

0.67
0.13
Total Present Value (3%)

$6.60
-
Total Present Value (7%)

--
$0.63
XCV1 Estimates are rounded to two significant figures.
xcvu The SC-CO2 and SC-N20 estimates used in this TSD are interim values developed under E.O. 13783 and are
based on assumed 3 and 7 percent discount rates used in their estimation. Consistent with OMB Circular A-4
guidance, the present value of the stream of annual climate and fuel savings benefits also use a 3 and 7 percent
discount rate.
xcv" Global SC-CO2 results are provided in the appendix of this TSD.
XC1X Since Scenario 3's implementation date for most in-production airplanes will be 2023, this is the first year that
benefits will begin to occur.
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Table 6-9 - Detailed Domestic N20-Related Benefits for Scenario 3C (Millions of 2015$)
Year
Domestic Climate
Domestic Climate

Benefits
Benefits

SC-NzO
SC-NzO

(3%)
(7%)
2023
$0,002
$0.0003
2024
0.004
0.001
2025
0.01
0.001
2026
0.01
0.001
2027
0.01
0.001
2028
0.01
0.001
2029
0.01
0.001
2030
0.01
0.001
2031
0.01
0.001
2032
0.01
0.001
2033
0.01
0.001
2034
0.01
0.001
2035
0.01
0.002
2036
0.01
0.002
2037
0.01
0.002
2038
0.01
0.002
2039
0.01
0.002
2040
0.01
0.002
Total Present Value (3%)
T—1
0
-
Total Present Value (7%)
--
$0.01
0 Global SC-N2O results are provided in the appendix of this TSD.
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Table 6-10 - Detailed Domestic Fuel Savings for Scenario 3 (Millions of 2015$)
Year
Fuel Savings
2023
$6.8
2024
14
2025
21
2026
21
2027
22
2028
22
2029
22
2030
23
2031
23
2032
23
2033
23
2034
23
2035
23
2036
23
2037
23
2038
23
2039
23
2040
23
Total Present Value (3%)
$230
Total Present Value (7%)
$130
Table 6-11 - Summary of Domestic Climate-Related Benefits and Fuel Savings for Scenario 3ci
(3% Discount Rate, Millions of 2015$)
Year
Domestic Climate Benefits
(3%)
Fuel Savings
Total Benefits
Domestic Climate Benefits @ 3%
2023
$0.2
$6.8
$7
2025
0.6
21
22
2030
0.6
23
23
2035
0.7
23
24
2040
0.7
23
24
Total Present Value (3%)
$6.7
$230
$240
01 Domestic climate benefits in this table includes SC-CO2 and SC-N2O benefits.
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Table 6-12 - Summary of Domestic Climate-Related Benefits and Fuel Savings for Scenario 3cii
(7% Discount Rate, Millions of 2015$)
Year
Domestic Climate Benefits
(7%)
Fuel Savings
Total Benefits
Domestic Climate Benefits @ 7%
2023
$0.03
$6.8
$6.9
2025
0.1
21
21
2030
0.1
23
23
2035
0.1
23
24
2040
0.1
23
23
Total Present Value (7%)
$0.6
$130
$130
The limitations and uncertainties associated with the global social cost of greenhouse gas
estimates, which were discussed at length in recent rules, likewise apply to the domestic social
cost of greenhouse gas estimates presented in this TSD.cm Some uncertainties are captured
within the analysis, as discussed in detail in the Appendix, while other areas of uncertainty have
not yet been quantified in a way that can be modeled. For example, limitations include the
incomplete way in which the integrated assessment models capture catastrophic and non-
catastrophic impacts, their incomplete treatment of adaptation and technological change, the
incomplete way in which inter-regional and inter-sectoral linkages are modeled, uncertainty in
the extrapolation of damages to high temperatures, and inadequate representation of the
relationship between the discount rate and uncertainty in economic growth over long time
horizons. The science incorporated into these models understandably lags behind the most
recent research, and the limited amount of research linking climate impacts to economic damages
makes the modeling exercise even more difficult.
These individual limitations and uncertainties do not all work in the same direction in terms of
their influence on the estimates. In accordance with guidance in OMB Circular A-4 on the
treatment of uncertainty, the Appendix provides a detailed discussion of the ways in which the
modeling underlying the development of the social cost of greenhouse gas estimates used in this
TSD addressed quantified sources of uncertainty, and presents a sensitivity analysis to show
consideration of the uncertainty surrounding discount rates over long time horizons.
In addition to requiring reporting of impacts at a domestic level, OMB Circular A-4 states that
when an agency "evaluate[s] a regulation that is likely to have effects beyond the borders of the
United States, these effects should be reported separately" (page 15). This guidance is relevant
to the valuation of damages from CO2 and other GHGs, given that GHGs contribute to damages
around the world independent of the country in which they are emitted. Therefore, in accordance
with this guidance in OMB Circular A-4, the Appendix presents the global climate benefits from
this rulemaking using global SC-CO2, SC-CH4, and SC-N2O estimates based on both 3 and 7
percent discount rates. Note EPA did not quantitatively project the full impact of the final action
on international trade and the ultimate distribution of compliance costs, so it is not possible to
present estimates of global costs resulting from the final action.
011 Domestic climate benefits in this table includes SC-CO2 and SC-N2O benefits.
0111 See e.g., the EPA's 2019 Affordable Clean Energy (ACE) rulemaking (84 FR 32520, July 8, 2019).
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6.3 Sensitivity Case Studies
As described earlier in Chapter 5, for the three scenarios, we conducted sensitivity studies on
the emissions reductions effect of 1) not having continuous annual improvement (continuous
improvement was assumed in our main analysis) and 2) having extended production of the A3 80
and 767-3ERF to 2030 (instead of using the main analysis' assumption of 2025 and 2023,
respectively). These sensitivity study criteria are nearer to the assumptions in the ICAO/CAEP
analysis.
(As described earlier, we note that in their comments on the proposed rulemaking Boeing,
along with Fedex, GE, and the Cargo Airline Association, expressed that there would continue to
be a low volume demand for the B767 freighter beyond January 1, 2028. These commenters did
not indicate the number of 767F's that would be produced after 2028. The EPA did not change
the analysis to include continued production of the 767F beyond 2030 because insufficient
information to characterize this scenario was provided.)
6.3.1	Emission Reductions for Scenario 3
Under the combined sensitivity studies for Scenario 3, the A3 80 would not comply with the
scenario by its effective dates and therefore would need a technology response of about 4 percent
in improvements to the metric value (with the 1% design margin). The 767-3ERF (dedicated
freighter) would not meet Scenario 3 with or without continuous annual improvement, and its
technology response status would be mostly driven by the end of production assumption (thus
needing a technology response of about 17 percent in improvements to the metric value in 2028).
The total U.S. CO2 cumulative reductions from the combination of these two sensitivity case
studies would be as follows: about 4.2 Mt CO2 equivalent for 2030 and about 15 Mt CO2
equivalent for 2040. As indicated in Chapter 5, these results show that 7 to 11 times greater (or
600 percent to 1000 percent greater) emission reductions for Scenario 3 would occur with the
assumptions in the combined sensitivity studies compared to the main analysis (4.2 Mt CO2
equivalent versus 0.6 Mt CO2 equivalent in 2030 and 15 Mt CO2 equivalent versus 1.4 Mt CO2
equivalent in 2040, respectively).
Separate from these combined sensitivity studies, we also analyzed the emission reductions
using ICAO/CAEP's assumptions of airplane fleet evolution and airplane operations (used
PIANO for airplane CO2 emission rates). Using these same assumptions as ICAO, the total U.S.
CO2 cumulative reductions would be about 110 Mt CO2 equivalent for Scenario 3.
6.3.2	Emission Reductions for Scenarios 1 and 2
For the combined sensitivity studies of Scenarios 1 and 2, the A3 80 would not comply with
either scenario by their effective dates and therefore would need a technology response of about
2 percent in improvements to the metric value (with the 1% design margin). The 767-3ERF
(dedicated freighter) would not meet Scenarios 1 and 2 with or without continuous annual
improvement, and its technology response status would be mostly driven by the end of
production assumption. For the results of this combined sensitivity study, the total U.S. CO2
cumulative reductions in 2040 would be about 3 Mt CO2 equivalent for Scenario 1 and about 4
Mt CO2 equivalent for Scenario 2.
In the sensitivity case of no continuous annual improvement but no extended production,
Scenario 1 would result in no emission reductions because the A3 80 would be out of production
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by 2025. However, in this case, Scenario 2 would result in limited emission reductions from the
technology response improvement of 2 percent for the A3 80 due to the 5-year accelerated
implementation date (2023). The total U.S. CO2 cumulative reductions in 2040 would be about 1
Mt CO2 equivalent in the U.S.
In the sensitivity case of extended production but with continuous improvement, the emission
reductions would result from only the 767-3ERF since the A380 would meet the scenarios.
Since the 5-year accelerated implementation date is not adopted for freighters, Scenarios 1 and 2
would have the same emission reductions effect, and the estimated the total U.S. CO2 cumulative
reductions in 2040 would be about 1 Mt CO2 equivalent in the U.S.
Separate from these sensitivity studies and using the same assumptions as ICAO/CAEP,clv the
total U.S. CO2 cumulative reductions would be about 50 Mt CO2 equivalent for Scenario 1 and
about 75 Mt CO2 equivalent for Scenario 2.
However, as discussed in Chapter 5 for all three scenarios, we believe that the EPA main
analysis assumptions of business as usual improvements in the absence of standards (continuous
annual improvement) and the independently developed and peer reviewed technology responses
(including expected end of production expectations) are based on more up to date inputs and
assumptions, in comparison to these sensitivity studies.
6.3.3 Costs for All Three Scenarios
We did not conduct specific sensitivity case studies for costs based on the above criteria for
the three scenarios, but a rough approximation of such sensitivity case studies is a comparison of
our non-recurring costs (NRC) to ICAO/CAEP analysis' NRC (see Chapter 2 of this TSD,
particularly refer to Table 2-12 and
Table 2-13 for a comparison of NRC for a range of percent metric value improvements). We
can draw insight from this rough approximation even though the criteria in our sensitivity case
studies do not exactly match the assumptions in the ICAO/CAEP analysis. Similar to our
sensitivity studies for emissions reductions, the methodology for the ICAO/CAEP's NRC
analysis assumed no continuous annual improvement and included extended production of the
A380 and 767-3ERF (as well as numerous other airplanes). Thus, it is informative to compare
our NRC results to ICAO/CAEP results since they may serve as a general sensitivity analysis of
our costs. As with emission reductions from our sensitivity studies, the NRC results from
ICAO/CAEP are typically much greater than our NRC results (on average about 170 percent
greater for representative airplanes in the various airplane categories). Also, section 2.6 of this
TSD describes fuel savings based on our analysis and the ICAO/CAEP analysis, and
ICAO/CAEP's results are much greater. The magnitude of these differences is expected.
ICAO/CAEP's technology responses were based on technology frozen in 2016-2017 compared
to the EPA's responses that considered technologies available in 2017, but with continuous
improvement of metric values for in-production and in-development (or on-order) airplanes from
2010 to 2040 based on the incorporation of these technologies onto these airplanes (over this
same timeframe). Also, as discussed in Chapter 2, ICAO/CAEP's top-down approach likely
included all airplane development costs (type certification, noise, in-flight entertainment, etc.)
C1V We analyzed the emission reductions using ICAO/CAEP's assumptions of airplane fleet evolution and airplane
operations (used PIANO for airplane CO2 emission rates).
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instead of only those costs for CO2 improvements. Thus, we believe the assumptions in our cost
analysis are based on more up to date inputs and assumptions.
In addition, for the extended production criteria (for the scenarios), manufacturers could apply
to use the exemption provisions (described in section V.E of the preamble), which are intended
for airplanes at the end of their production life. If manufacturers chose to apply for an exemption
and it was granted, the A3 80 and 767-3ERF would not need to respond, and thus, there would be
no resultant emission reductions or costs.
6.4 Summary
As described earlier in this TSD, for harmonizing with the international standards and
providing global consistency, which would ensure all the world's manufacturers comply (or
certify) to the same standards and no U.S. manufacturer finds itself at a competitive
disadvantage, the EPA is issuing standards (Scenario 1) that match the international standards.
As discussed earlier, according to the EPA analysis, Scenario 2 (accelerated implementation
dates) has no costs and benefits, which is the same impact as Scenario 1. Scenario 3 (both
accelerated implementation dates and stricter stringency levels) has limited costs, which
outweigh the limited benefits. As shown in Table 6-13, for Scenario 3, the present value of non-
recurring costs would be about $415 million and $501 million (in 2015$), at 7 and 3 percent
discount rates respectively. The present value of total benefits would be about $130 million and
$240 million (in 2015$), at 7 and 3 percent discount rates respectively. Estimated net benefits
(benefits minus costs) therefore range from -$285 million to -$261 million, at 7 and 3 percent
discount rates respectively.
Table 6-13 - Present Value of Total Benefits, Total Costs, and Net Benefits for Scenario 3
(Millions of 2015$)
Present Value
3% Discount Rate
7% Discount Rate
Benefits
240
130
Costs
501
415
Net Benefits (benefits minus costs)
-261
-285
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Appendix A.
A.l Overview of Methodology Used to Develop Interim Domestic SC-CO2 and SC-
N2O Estimates
E.O. 13783 directed agencies to ensure that estimates of the social cost of greenhouse gases
used in regulatory analyses "are based on the best available science and economics" and are
consistent with the guidance contained in OMB Circular A-4, "including with respect to the
consideration of domestic versus international impacts and the consideration of appropriate
discount rates" (E.O. 13783, Section 5(c)). In addition, E.O. 13783 withdrew the technical
support documents (TSDs) describing the global social cost of greenhouse gas estimates
developed under the prior Administration as no longer representative of government policy. The
withdrawn TSDs were developed by an interagency working group (IWG) that included the
DOT, EPA and other executive branch entities.
Regarding the two analytical considerations highlighted in E.O. 13783 - how best to consider
domestic versus international impacts and appropriate discount rates - current guidance in OMB
Circular A-4 is as follows. Circular A-4 states that analysis of economically significant proposed
and final regulations "should focus on benefits and costs that accrue to citizens and residents of
the United States." We follow this guidance by adopting a domestic perspective in our central
analysis. Regarding discount rates, Circular A-4 states that regulatory analyses "should provide
estimates of net benefits using both 3 percent and 7 percent." The 7 percent rate is intended to
represent the average before-tax rate of return to private capital in the U.S. economy. The 3
percent rate is intended to reflect the rate at which society discounts future consumption, which
is particularly relevant if a regulation is expected to affect private consumption directly. EPA
follows this guidance by presenting estimates based on both 3 and 7 percent discount rates in the
main analysis.
The domestic social cost of greenhouse gas estimates presented in this TSD rely on the same
ensemble of three integrated assessment models (IAMs) that were used to develop the IWG
global SC-CO2 and SC-N2O estimates: DICE 2010, FUND 3.8, and PAGE 2009.cv The three
IAMs translate emissions into changes in atmospheric greenhouse concentrations, atmospheric
concentrations into changes in temperature, and changes in temperature into economic damages.
The emissions projections used in the models are based on specified socio-economic (GDP and
population) pathways. These emissions are translated into atmospheric concentrations, and
concentrations are translated into warming based on each model's simplified representation of
the climate and a key parameter, equilibrium climate sensitivity. The effect of these Earth
system changes is then translated into consumption-equivalent economic damages. As in the
IWG exercise, these key inputs were harmonized across the three models: a probability
distribution for equilibrium climate sensitivity; five scenarios for economic, population, and
emissions growth; and discount rates.CV1 All other model features were left unchanged. Future
cv The full model names are as follows: Dynamic Integrated Climate and Economy (DICE); Climate Framework for
Uncertainty, Negotiation, and Distribution (FUND); and Policy Analysis of the Greenhouse Gas Effect (PAGE).
CV1 In order to develop SC-CH4 and SC-N20 estimates consistent with the methodology underlying the SC-CO2
estimates also required augmenting the climate model of two of the IAMs to explicitly consider the path of
additional radiative forcing from a CH4 or N20 perturbation, and adding more specificity to the assumptions
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damages are discounted using constant discount rates of both 3 and 7 percent, as recommended
by OMB Circular A-4.
The domestic share of the global SC-CO2 and SC-N2O—i.e., an approximation of the climate
change impacts that occur within U.S. bordersCV11—is calculated directly in both FUND and
PAGE. However, DICE 2010 generates only global estimates. Therefore, the U.S. damages are
approximated as 10 percent of the global values from the DICE model runs, based on the results
from a regionalized version of the model (RICE 2010) reported in Table 2 of Nordhaus (2017).
Although the regional shares reported in Nordhaus (2017) are specific to SC-CO2, they still
provide a reasonable interim approach for approximating the U.S. share of marginal damages
from emissions of other greenhouse gases.
The steps involved in estimating the social cost of each gas are described below. The three
integrated assessment models (FUND, DICE, and PAGE) are run using the harmonized
equilibrium climate sensitivity distribution, five socioeconomic and emissions scenarios, and two
constant discount rates described above. Because the climate sensitivity parameter is modeled
probabilistically, and because PAGE and FUND incorporate uncertainty in other model
parameters, the final output from each model run is a distribution over the SC-CO2 or SC-N2O in
year t based on a Monte Carlo simulation of 10,000 runs. For each of the IAMs, the basic
computational steps for calculating the social cost estimate in a particular year t are the
following: 1.) calculate the temperature effects and (consumption-equivalent) damages in each
year resulting from the baseline path of emissions; 2.) adjust the model to reflect an additional
unit of emissions in year t; 3.) recalculate the temperature effects and damages expected in all
years beyond t resulting from this adjusted path of emissions, as in step 1; and 4.) subtract the
damages computed in step 1 from those in step 3 in each model period and discount the resulting
path of marginal damages back to the year of emissions. In PAGE and FUND step 4 focuses on
the damages attributed to the US region in the models. As noted above, DICE does not explicitly
include a separate US region in the model and therefore, U.S. damages are approximated in step
4 as 10 percent of the global values based on the results of Nordhaus (2017). This exercise
produces 30 separate distributions of the SC-CO2 and SC-N2O for a given year, the product of 3
models, 2 discount rates, and 5 socioeconomic scenarios. Following the approach used by the
IWG, the estimates are equally weighted across models and socioeconomic scenarios in order to
consolidate the results into one distribution for each gas for each discount rate.
A.2-Treatment of Uncertainty in Interim Domestic SC-C02 and SC-N20 Estimates
There are various sources of uncertainty in the social cost of greenhouse gas estimates used in
this analysis. Some uncertainties pertain to aspects of the natural world, such as quantifying the
physical effects of greenhouse gas emissions on Earth systems. Other sources of uncertainty are
regarding post-2100 baseline CH4 and N20 emissions. See the IWG's summary of its methodology in the docket,
document ID number EPA-HQ-OAR-2015-0827-5886, "Addendum to Technical Support Document on Social
Cost of Carbon for Regulatory Impact Analysis under Executive Order 12866: Application of the Methodology to
Estimate the Social Cost of Methane and the Social Cost of Nitrous Oxide (August 2016)". See also National
Academies (2017) for a detailed discussion of each of these modeling assumptions.
cvn Note that inside the U.S. borders is not the same as accruing to U.S. citizens, which may be higher or lower.
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associated with current and future human behavior and well-being, such as population and
economic growth, GHG emissions, the translation of Earth system changes to economic
damages, and the role of adaptation. It is important to note that even in the presence of
uncertainty, scientific and economic analysis can provide valuable information to the public and
decision makers, though the uncertainty should be acknowledged and when possible taken into
account in the analysis (National Academies 2013). OMB Circular A-4 also requires a thorough
discussion of key sources of uncertainty in the calculation of benefits and costs, including more
rigorous quantitative approaches for higher consequence rules. This section summarizes the
sources of uncertainty considered in a quantitative manner in the domestic SC-CO2 and SC-N2O
estimates.
The domestic SC-CO2 and SC-N2O estimates consider various sources of uncertainty through
a combination of a multi-model ensemble, probabilistic analysis, and scenario analysis. We
provide a summary of this analysis here; more detailed discussion of each model and the
harmonized input assumptions can be found in National Academies (2017). For example, the
three IAMs used collectively span a wide range of Earth system and economic outcomes to help
reflect the uncertainty in the literature and in the underlying dynamics being modeled. The use of
an ensemble of three different models at least partially addresses the fact that no single model
includes all of the quantified economic damages. It also helps to reflect structural uncertainty
across the models, which stems from uncertainty about the underlying relationships among GHG
emissions, Earth systems, and economic damages that are included in the models. Bearing in
mind the different limitations of each model and lacking an objective basis upon which to
differentially weight the models, the three integrated assessment models are given equal weight
in the analysis.
Monte Carlo techniques were used to run the IAMs a large number of times. In each
simulation the uncertain parameters are represented by random draws from their defined
probability distributions. In all three models the equilibrium climate sensitivity is treated
probabilistically based on the probability distribution from Roe and Baker (2007) calibrated to
the IPCC AR4 consensus statement about this key parameter.cvm The equilibrium climate
sensitivity is a key parameter in this analysis because it helps define the strength of the climate
response to increasing GHG concentrations in the atmosphere. In addition, the FUND and
PAGE models define many of their parameters with probability distributions instead of point
estimates. For these two models, the model developers' default probability distributions are
maintained for all parameters other than those superseded by the harmonized inputs (i.e.,
equilibrium climate sensitivity, socioeconomic and emissions scenarios, and discount rates).
More information on the uncertain parameters in PAGE and FUND is available upon request.
For the socioeconomic and emissions scenarios, uncertainty is included in the analysis by
considering a range of scenarios selected from the Stanford Energy Modeling Forum exercise,
EMF-22. Given the dearth of information on the likelihood of a full range of future
socioeconomic pathways at the time the original modeling was conducted, and without a basis
for assigning differential weights to scenarios, the range of uncertainty was reflected by simply
weighting each of the five scenarios equally for the consolidated estimates. To better understand
cvm Specifically, the Roe and Baker distribution for the climate sensitivity parameter was bounded between 0 and 10
with a median of 3 °C and a cumulative probability between 2 and 4.5 °C of two-thirds.
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how the results vary across scenarios, results of each model run are available in the docket
(Docket ID No. EPA-HQ-OAR-2017-0355, which is for the EPA Affordable Clean Energy
(ACE) rulemaking).
The outcome of accounting for various sources of uncertainty using the approaches described
above is a frequency distribution of the SC-CO2 and SC-N2O estimates for emissions occurring
in a given year for each discount rate. Unlike the approach taken for consolidating results across
models and socioeconomic and emissions scenarios, the SC-CO2 and SC-N2O estimates are not
pooled across different discount rates because the range of discount rates reflects both
uncertainty and, at least in part, different policy or value judgements; uncertainty regarding this
key assumption is discussed in more detail below. The frequency distributions reflect the
uncertainty around the input parameters for which probability distributions were defined, as well
as from the multi-model ensemble and socioeconomic and emissions scenarios where
probabilities were implied by the equal weighting assumption. It is important to note that the set
of SC-CO2 and SC-N2O estimates obtained from this analysis does not yield a probability
distribution that fully characterizes uncertainty about the SC-CO2 and SC-N2O due to impact
categories omitted from the models and sources of uncertainty that have not been fully
characterized due to data limitations.
Figure 6-6 and Figure 6-7 present the frequency distribution of the domestic SC-CO2 and SC-
N2O estimates, respectively, for emissions in 2030 for each discount rate. Each distribution
represents 150,000 estimates based on 10,000 simulations for each combination of the three
models and five socioeconomic and emissions scenarios.C1X In general, the distributions are
skewed to the right and have long right tails, which tend to be longer for lower discount rates.
To highlight the difference between the impact of the discount rate and other quantified sources
of uncertainty, the bars below the frequency distributions provide a symmetric representation of
quantified variability in the SC-CO2 and SC-N2O estimates conditioned on each discount rate.
The full set of SC-CO2 and SC-N2O results through 2050 is available as part of the TSD analysis
materials.
CK Although each distribution in Figure 6-6 and Figure 6-7 is based on the full set of model results (150,000
estimates for each discount rate), for display purposes the horizontal axis is truncated with a small percent of the
estimates lying below the lowest bin displayed and above the highest bin displayed, depending on the discount
rate.
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un
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0	4	8 12 16 20 24 28 32 36 40
Interim U.S. Domestic Social Cost of Carbon in 2030 [2015$ / metric ton C02]
Figure 6-6 - Frequency Distribution of Interim Domestic SC-CO2 Estimates for 2030 (in 2015$ per metric ton
CO2)
LO
CO
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0
J3
1
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LO
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1
lllIllIlInTnTTTrnTrTTTrrrn ¦ n ¦ ¦. —
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"i r
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2000	4000	6000	8000	10000 12000
Interim U.S. Domestic Social Cost of Nitrous Oxide in 2030 [2015$ / metric ton N20]
i i r
14000
Figure 6-7 - Frequency Distribution of Interim Domestic SC-NiO Estimates for 2030 (in 2015$ per metric ton
NzO)
As illustrated by the frequency distributions in Figure 6-6 and Figure 6-7, the assumed
discount rate plays a critical role in the ultimate estimate of the social cost of greenhouse gases.
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This is because CO2 and N2O emissions today continue to impact society far out into the future,cx
so with a higher discount rate, costs that accrue to future generations are weighted less, resulting
in a lower estimate. Circular A-4 recommends that costs and benefits be discounted using the
rates of 3 percent and 7 percent to reflect the opportunity cost of consumption and capital,
respectively. Circular A-4 also recommends quantitative sensitivity analysis of key
assumptions'^1, and offers guidance on what sensitivity analysis can be conducted in cases where
a rule will have important intergenerational benefits or costs. To account for ethical
considerations of future generations and potential uncertainty in the discount rate over long time
horizons, Circular A-4 suggests "further sensitivity analysis using a lower but positive discount
rate in addition to calculating net benefit using discount rates of 3 and 7 percent" (page 36) and
notes that research from the 1990s suggests intergenerational rates "from 1 to 3 percent per
annum" (OMB 2003). We consider the uncertainty in this key assumption by calculating the
domestic SC-CO2 and SC-N2O based on a 2.5 percent discount rate, in addition to the 3 and 7
percent used in the main analysis. Using a 2.5 percent discount rate, the average domestic SC-
CO2 and SC-N2O estimates across all the model runs for emissions occurring in 2030 is $11 per
metric ton of CO2 (2015$) and $3,600 per metric ton of N2O, respectivelycxu; in this case the
total domestic climate benefits of Scenario 3 are $0.9 million in 2030 under a 2.5 percent
discount rate. The total present value of the domestic climate benefits under a 2.5 percent
discount rate is $10 million.
In addition to the approach to accounting for the quantifiable uncertainty described above, the
scientific and economics literature has further explored known sources of uncertainty related to
estimates of the social cost of carbon and other greenhouse gases. For example, researchers have
examined the sensitivity of IAMs and the resulting estimates to different assumptions embedded
in the models (see, e.g., Hope 2013, Anthoff and Tol 2013, Nordhaus 2014, and Waldhoff et al.
2011, 2014). However, there remain additional sources of uncertainty that have not been fully
characterized and explored due to remaining data limitations. Additional research is needed to
expand the quantification of various sources of uncertainty in estimates of the social cost of
carbon and other greenhouse gases (e.g., developing explicit probability distributions for more
inputs pertaining to climate impacts and their valuation). On the issue of intergenerational
discounting, some experts have argued that a declining discount rate is appropriate to analyze
impacts that occur far into the future (Arrow et al., 2013). However, additional research and
analysis is still needed to develop a methodology for implementing a declining discount rate and
to understand the implications of applying these theoretical lessons in practice.
Recognizing the limitations and uncertainties associated with estimating the social cost of
greenhouse gases, the research community is continuing to explore opportunities to improve
cx Although the atmospheric lifetime of CH4 is notably shorter than that of CO2 or N20, the impacts of changes in
contemporary CH4 emissions are also expected to occur over long time horizons that cover multiple generations.
For more discussion, see document ID number EPA-HQ-OAR-2015-0827-5886, "Addendum to Technical
Support Document on Social Cost of Carbon for Regulatory Impact Analysis under Executive Order 12866:
Application of the Methodology to Estimate the Social Cost of Methane and the Social Cost of Nitrous Oxide
(August 2016)".
0X1 "If benefit or cost estimates depend heavily on certain assumptions, you should make those assumptions explicit
and carry out sensitivity analyses using plausible alternative assumptions." (OMB 2003, page 42).
0X11 The estimates are adjusted for inflation using the GDP implicit price deflator. SC-CO2 estimates are rounded to
the nearest dollar and SC-CH4 and SC-N20 estimates are rounded to two significant digits.
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estimates of SC-CO2 and other greenhouse gases. Notably, the National Academies of Sciences,
Engineering, and Medicine conducted a multi-discipline, multi-year assessment to examine
potential approaches, along with their relative merits and challenges, for a comprehensive update
to the current methodology. The task was to ensure that the SC-CO2 estimates that are used in
Federal analyses reflect the best available science, focusing on issues related to the choice of
models and damage functions, climate science modeling assumptions, socioeconomic and
emissions scenarios, presentation of uncertainty, and discounting. In January 2017, the
Academies released their final report, Valuing Climate Damages: Updating Estimation of the
Social Cost of Carbon Dioxide,cxm and recommended specific criteria for future updates to the
SC-CO2 estimates, a modeling framework to satisfy the specified criteria, and both near-term
updates and longer-term research needs pertaining to various components of the estimation
process (National Academies 2017). Since the framework used to estimate SC-N2O is the same
as that used for SC-CO2, the Academies' recommendations on how to update many of the
underlying modeling assumptions also apply to the SC-N2O estimates.
The 2017 National Academies report also provides recommendations pertaining to
discounting, emphasizing the need to more explicitly model the uncertainty surrounding discount
rates over long time horizons, its connection to uncertainty in economic growth, and, in turn, to
climate damages using a Ramsey-like formula (National Academies 2017). These and other
research needs are discussed in detail in the 2017 National Academies' recommendations for a
comprehensive update to the current methodology, including a more robust incorporation of
uncertainty.
The Academies' report also discussed the challenges in developing domestic SC-CO2
estimates, noting that current integrated assessment models do not model all relevant regional
interactions - i.e., how climate change impacts in other regions of the world could affect the
United States, through pathways such as global migration, economic destabilization, and political
destabilization. The Academies concluded that it "is important to consider what constitutes a
domestic impact in the case of a global pollutant that could have international implications that
impact the United States. More thoroughly estimating a domestic SC-CO2 therefore needs to
consider the potential implications of climate impacts on, and actions by, other countries, which
also have impacts on the United States." (National Academies 2017, pg. 12-13). This challenge
is equally applicable to the estimation of the domestic SC-CH4 and SC-N2O.
A.3- Global Climate Benefits
In addition to requiring reporting of impacts at a domestic level, OMB Circular A-4 states that
when an agency "evaluate[s] a regulation that is likely to have effects beyond the borders of the
United States, these effects should be reported separately" (page 15).CX1V This guidance is
0X111 National Academies of Sciences, Engineering, and Medicine. 2017. Valuing Climate Damages: Updating
Estimation of the Social Cost of Carbon Dioxide. National Academies Press. Washington, DC Available at
https://www.nap.edu/cataiog/24651/vaiuing-dimate-damages-npdating-estimation-of-the-social-cost-of (last
accessed March 20, 2020).
CX1V While Circular A-4 does not elaborate on this guidance, the basic argument for adopting a domestic only
perspective for the central benefit-cost analysis of domestic policies is based on the fact that the authority to
regulate extends only, or principally, to a nation's own residents who have consented to adhere to the same set of
rules and values for collective decision-making, as well as the assumption that most domestic policies will have
negligible effects on the welfare of other countries' residents (EPA 2010; Kopp et al. 1997; Whittington et al.
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relevant to the valuation of damages from GHGs, given that most GHGs contribute to damages
around the world independent of the country in which they are emitted. Therefore, in this section
we present the global climate benefits from this rulemaking using the global SC-CO2 and SC-
N2O estimates - i.e., reflecting quantified impacts occurring in both the U.S. and other
countries—corresponding to the model runs that generated the domestic SC-CO2 and SC-N2O
estimates used in the main analysis. The average global SC-CO2 and SC-N2O estimate across
all the model runs for emissions occurring in 2030 are $7/mtC02 (in 2015 dollars) and
$3,500/mtN20, respectively, using a 7 percent discount rate, and $57/mtC02 and $21,000/mtN20
using a 3 percent discount rate.cxv The domestic estimates presented above are approximately
15-19 percent and 12-14 percent of the global estimates for the 7 percent and 3 percent discount
rates, respectively, depending on the gas. Applying these estimates to the changes in CO2 and
N2O emissions results from Scenario 3 in estimated total global climate benefits of $0.6 million
in 2030, using a 7 percent discount rate. The total present value of the global climate benefits
using a 7 percent discount rate is $3.5 million. The estimated total global climate benefits are
$4.7 million in 2030 using a 3 percent rate. The total present value of the global climate benefits
using a 3 percent discount rate is $49 million. Under the sensitivity analysis considered above
using a 2.5 percent discount rate, the average global estimates across all the model runs for
emissions occurring in 2030 are $82/mtC02 (in 2015 dollars) and $30,000/mtN20. The total
global climate benefits are estimated to be $6.8 million in 2030 using a 2.5 percent discount rate.
The total present value of the global climate benefits using a 2.5 percent discount rate is $77
million. All estimates are reported in 2015 dollars.
1986). In the context of policies that are expected to result in substantial effects outside of U.S. borders, an active
literature has emerged discussing how to appropriately treat these impacts for purposes of domestic policymaking
(e.g., Gayer and Viscusi 2016, 2017; Anthoff and Tol, 2010; Fraas et al. 2016; Revesz et al. 2017). This discourse
has been primarily focused on the regulation of greenhouse gases (GHGs), for which domestic policies may result
in impacts outside of U.S. borders due to the global nature of the pollutants.
cxv The estimates are adjusted for inflation using the GDP implicit price deflator and then rounded to two significant
digits.
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Regulatory Flexibility Analysis
Table of Contents
Chapter 7: Regulatory Flexibility Analysis	160
7.1	Requirements of the Regulatory Flexibility Act	160
7.2	Need for the Rulemaking and Rulemaking Objectives	160
7.3	Definition and Description of Small Entities	161
7.4	Summary of Small Entities to Which the Rulemaking Will Apply	161
7.5	Related Federal Rules	161
7.6	Projected Effects of the Rulemaking on Small Entities	161
Table of Tables
Table 7-1 - Small Business Definitions	161
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Chapter 7: Regulatory Flexibility Analysis
This chapter presents our Small Business Flexibility Analysis (SBFA) which evaluates the
potential impacts of the rule on small entities. The Regulatory Flexibility Act (RFA), as
amended by the Small Business Regulatory Enforcement Fairness Act of 1996 (SBREFA),
generally requires an agency to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative Procedure Act or any
other statute unless the agency certifies that the rule will not have a significant economic impact
on a substantial number of small entities.
7.1	Requirements of the Regulatory Flexibility Act
When proposing and promulgating rules subject to notice and comment under the Clean Air
Act, we are generally required under the RFA to conduct a regulatory flexibility analysis unless
we certify that the requirements of a regulation will not cause a significant impact on a
substantial number of small entities. The key elements of the RFA include:
•	a description of and, where feasible, an estimate of the number of small entities to
which the rule will apply;
•	the projected reporting, record keeping, and other compliance requirements of the rule,
including an estimate of the classes of small entities which will be subject to the
requirements and the type of professional skills necessary for preparation of the report
or record;
•	an identification to the extent practicable, of all other relevant Federal rules which
may duplicate, overlap, or conflict with the rule; and,
•	any significant alternatives to the rule which accomplish the stated objectives of
applicable statutes and which minimize any significant economic impact of the rule on
small entities.
The RFA was amended by SBREFA to ensure that concerns regarding small entities are
adequately considered during the development of new regulations that affect them. Although we
are not required by the Clean Air Act to provide special treatment to small businesses, the RFA
requires us to carefully consider the economic impacts that our rules will have on small entities.
Specifically, the RFA requires us to determine, to the extent feasible, our rule's economic impact
on small entities, explore regulatory options for reducing any significant economic impact on a
substantial number of such entities, and explain our ultimate choice of regulatory approach.
In developing this rule, we concluded that the airplane and airplane engine GHG program
does not have a significant impact on a substantial number of small entities. We based this on
the fact that the rule does not place any burden on small governmental jurisdictions or small
nonprofit organizations. Further, there is only one small business in the group of potentially
affected entities - an airplane engine manufacturer. There is no economic burden associated with
this rule. Thus, this rule does not place any burden on small entities.
7.2	Need for the Rulemaking and Rulemaking Objectives
A detailed discussion on the need for and objectives of this rule is located in the preamble to
the rule. The standards in this rule are the equivalent of the ICAO standards, consistent with
U.S. efforts to secure the highest practicable degree of uniformity in aviation regulations and
standards In addition, EPA is required by Clean Air Act section 231 to propose and promulgate
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Regulatory Flexibility Analysis
emission standards regulating GHG emissions from the classes of aircraft engines identified in
EPA's 2016 final endangerment and cause/contribute findings for those emissions. EPA is
meeting the Clean Air Act obligation by adopting GHG standards which are equivalent to the
Airplane CO2 Emission Standards adopted by ICAO.
7.3 Definition and Description of Small Entities
Small entities include small businesses, small organizations, and small governmental
jurisdictions. For the purposes of assessing the impacts of the rule on small entities, a small
entity is defined as: (1) a small business that meets the definition for business based on the Small
Business Administration's (SBA) size standards (see Table 7-1); (2) a small governmental
jurisdiction that is a government of a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is any not-for-profit enterprise
which is independently owned and operated and is not dominant in its field. Table 7-1 provides
an overview of the primary SBA small business categories potentially affected by this regulation.
Table 7-1 - Small Business Definitions
Industry
Defined as small entity by
SBA if:
NAICS
Codes3
Manufacturers of new airplane
engines
<1,500 employees
336412
Manufacturers of new airplanes
<1,500 employees
336411
a. North American Industry Classification System (NAICS)
7.4	Summary of Small Entities to Which the Rulemaking Will Apply
The businesses that are potentially affected by this rule are those that manufacture new
airplanes and new airplane engines. As outlined in Chapter 1, we performed an industry
characterization of potentially affected airplane and airplane engine manufacturers.
The industry characterization was used to determine which airplane and airplane engine
manufacturers also meet the SBA definition of a small business under this rule. From the
industry characterization, we determined that there is only a single airplane engine manufacturer
that meets the definition of a small business. Given the small number of businesses overall that
are potentially affected by this rule as well as the relative stability of the commercial aviation
market, the EPA is confident that this accounting of the number of potentially affected small
businesses is both correct and unlikely to change in the near future.
7.5	Related Federal Rules
We are not aware of any area where the regulations directly duplicate or overlap with the
existing federal, state, or local regulations; however, one small engine manufacturer is also
subject to the airplane engine smoke emissions control requirements. The FAA will follow this
with its own rulemaking to incorporate the adopted standards into its certification and
compliance framework.
7.6	Projected Effects of the Rulemaking on Small Entities
After considering the economic impacts of today's rule on small entities, we do not believe
that this action will have a significant economic impact on a substantial number of small entities.
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There is no economic burden associated with this rule.
Regulatory Alternatives to Accommodate Small Entities
Given that the EPA does not believe the rule has any impact on even a single small entity, it
does not believe there is a need for regulatory alternatives to help minimize such a burden on
small entities.
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REFERENCES
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