`[Federal Register Volume 86, Number 6 (Monday, January 11, 2021)]
[Rules and Regulations]
[Pages 2136-2174]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-28882]



[[Page 2135]]

Vol. 86

Monday,

No. 6

January 11, 2021

Part IV





 Environmental Protection Agency





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40 CFR Parts 87 and 1030





Control of Air Pollution From Airplanes and Airplane Engines: GHG 
Emission Standards and Test Procedures; Final Rule

  Federal Register / Vol. 86 , No. 6 / Monday, January 11, 2021 / Rules 
and Regulations  

[[Page 2136]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 87 and 1030

[EPA-HQ-OAR-2018-0276; FRL-10018-45-OAR]
RIN 2060-AT26


Control of Air Pollution From Airplanes and Airplane Engines: GHG 
Emission Standards and Test Procedures

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is adopting 
greenhouse gas (GHG) emission standards applicable to certain classes 
of engines used by certain civil subsonic jet airplanes with a maximum 
takeoff mass greater than 5,700 kilograms and by certain civil larger 
subsonic propeller-driven airplanes with turboprop engines having a 
maximum takeoff mass greater than 8,618 kilograms. These standards are 
equivalent to the airplane carbon dioxide (CO2) standards 
adopted by the International Civil Aviation Organization (ICAO) in 2017 
and apply to both new type design airplanes and in-production 
airplanes. The standards in this rule reflect U.S. efforts to secure 
the highest practicable degree of international uniformity in aviation 
regulations and standards. The standards also meet the EPA's obligation 
under section 231 of the Clean Air Act (CAA) to adopt GHG standards for 
certain classes of airplanes as a result of the 2016 ``Finding That 
Greenhouse Gas Emissions From Aircraft Cause or Contribute to Air 
Pollution That May Reasonably Be Anticipated To Endanger Public Health 
and Welfare'' (hereinafter ``2016 Findings'')--for six well-mixed GHGs 
emitted by certain classes of airplane engines. Airplane engines emit 
only two of the six well-mixed GHGs, CO2 and nitrous oxide 
(N2O). Accordingly, EPA is adopting the fuel-efficiency-
based metric established by ICAO, which will control both the GHGs 
emitted by airplane engines, CO2 and N2O.

DATES: This final rule is effective on January 11, 2021. The 
incorporation by reference of certain publications listed in this 
regulation is approved by the Director of the Federal Register as of 
January 11, 2021.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OAR-2018-0276. All documents are listed on the http://www.regulations.gov website. Although listed in the index, some 
information is not publicly available, e.g., confidential business 
information (CBI) or other information whose disclosure is restricted 
by statute. Certain other material, such as copyrighted material, is 
not placed on the internet and will be publicly available only in hard 
copy form. Publicly available docket materials are available either 
electronically through http://www.regulations.gov or in hard copy at 
Air and Radiation Docket and Information Center, EPA Docket Center, 
EPA/DC, EPA WJC West Building, 1301 Constitution Ave. NW, Room 3334, 
Washington, DC. Note that the EPA Docket Center and Reading Room were 
closed to public visitors on March 31, 2020, to reduce the risk of 
transmitting COVID-19. The Docket Center staff will continue to provide 
remote customer service via email, phone, and webform. The telephone 
number for the Public Reading Room is (202) 566-1744, and the telephone 
number for the Air Docket is (202) 566-1742. For further information on 
EPA Docket Center services and the current status, go to https://www.epa.gov/dockets.

FOR FURTHER INFORMATION CONTACT: Bryan Manning, Office of 
Transportation and Air Quality, Assessment and Standards Division 
(ASD), Environmental Protection Agency, 2000 Traverwood Drive, Ann 
Arbor, MI 48105; telephone number: (734) 214-4832; email address: 
[email protected].

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
    A. Does this action apply to me?
    B. Did EPA conduct a peer review before issuing this action?
    C. Basis for Immediate Effective Date
    D. Judicial Review and Adminstrative Reconsideration
    E. Executive Summary
II. Introduction: Overview and Context for This Action
    A. Summary of Final Rule
    B. EPA Statutory Authority and Responsibilities Under the Clean 
Air Act
    C. Background Information Helpful to Understanding This Action
    D. U.S. Airplane Regulations and the International Community
    E. Consideration of Whole Airplane Characteristics
III. Summary of the 2016 Findings
IV. EPA's Final GHG Standards for Covered Airplanes
    A. Airplane Fuel Efficiency Metric
    B. Covered Airplane Types and Applicability
    C. GHG Standard for New Type Designs
    D. GHG Standard for In-Production Airplane Types
    E. Exemptions From the GHG Standards
    F. Application of Rules for New Version of an Existing GHG-
Certificated Airplane
    G. Test and Measurement Procedures
    H. Controlling Two of the Six Well-Mixed GHGs
    I. Response to Key Comments
V. Aggregate GHG and Fuel Burn Methods and Results
    A. What methodologies did the EPA use for the emissions 
inventory assessment?
    B. What are the baseline GHG emissions?
    C. What are the projected effects in fuel burn and GHG 
emissions?
VI. Technological Feasibility and Economic Impacts
    A. Market Considerations
    B. Conceptual Framework for Technology
    C. Technological Feasibility
    D. Costs Associated With the Program
    E. Summary of Benefits and Costs
VII. Aircraft Engine Technical Amendments
VIII. Statutory Authority and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Executive Order 13771: Reducing Regulation and Controlling 
Regulatory Costs
    C. Paperwork Reduction Act (PRA)
    D. Regulatory Flexibility Act (RFA)
    E. Unfunded Mandates Reform Act (UMRA)
    F. Executive Order 13132: Federalism
    G. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    H. Executive Order 13045: Protection of Children From 
Environmental Health Risks and Safety Risks
    I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use
    J. National Technology Transfer and Advancement Act (NTTAA) and 
1 CFR Part 51
    K. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low-Income 
Populations
    L. Congressional Review Act

I. General Information

A. Does this action apply to me?

    This action will affect companies that manufacture civil subsonic 
jet airplanes that have a maximum takeoff mass (MTOM) of greater than 
5,700 kilograms and civil subsonic propeller driven airplanes (e.g., 
turboprops) that have a MTOM greater than 8,618 kilograms, including 
the manufacturers of the engines used on these airplanes. Affected 
entities include the following:

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                                                         Examples of
             Category               NAICS code \a\       potentially
                                                      affected entities
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Industry..........................          336412  Manufacturers of new
                                                     aircraft engines.

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Industry..........................          336411  Manufacturers of new
                                                     aircraft.
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\a\ North American Industry Classification System (NAICS)

    This table lists the types of entities that EPA is now aware could 
potentially be affected by this action. Other types of entities not 
listed in the table might also be subject to these regulations. To 
determine whether your activities are regulated by this action, you 
should carefully examine the relevant applicability criteria in 40 CFR 
parts 87 and 1030. If you have any questions regarding the 
applicability of this action to a particular entity, consult the person 
listed in the preceding FOR FURTHER INFORMATION CONTACT section.
    For consistency purposes across the United States Code of Federal 
Regulations (CFR), the terms ``airplane,'' ``aircraft,'' and ``civil 
aircraft'' have the meanings found in title 14 CFR 1.1 and are used as 
appropriate throughout the new regulation under 40 CFR part 1030.

B. Did EPA conduct a peer review before issuing this action?

    This regulatory action is supported by influential scientific 
information. Therefore, the EPA conducted peer reviews consistent with 
the Office of Management and Budget's (OMB's) Final Information Quality 
Bulletin for Peer Review.\1\ Two different reports used in support of 
this action underwent peer review; a report detailing the technologies 
likely to be used in compliance with the standards and their associated 
costs \2\ and a report detailing the methodology and results of the 
emissions inventory modeling.\3\ These reports were each peer-reviewed 
through external letter reviews by multiple independent subject matter 
experts (including experts from academia and other government agencies, 
as well as independent technical experts).4 5 The peer 
review reports and the Agency's response to the peer review comments 
are available in Docket ID No. EPA-HQ-OAR-2018-0276.
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    \1\ OMB, 2004: Memorandum for Heads of Departments and Agencies, 
Final Information Quality Bulletin for Peer Review. Available at 
https://www.whitehouse.gov/sites/whitehouse.gov/files/omb/memoranda/2005/m05-03.pdf.
    \2\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
    \3\ U.S. EPA, 2020: Technical Report on Aircraft Emissions 
Inventory and Stringency Analysis, July 2020, 52pp.
    \4\ RTI International and EnDyna, Aircraft CO2 Cost and 
Technology Refresh and Aerospace Industry Characterization: Peer 
Review, June 2018, 114pp.
    \5\ RTI International and EnDyna, EPA Technical Report on 
Aircraft Emissions Inventory and Stringency Analysis: Peer Review, 
July 2019, 157pp.
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C. Basis for Immediate Effective Date

    This rule is subject to the rulemaking procedures in section 307(d) 
of the Clean Air Act (CAA). See CAA section 307(d)(1)(F). Section 
307(d)(1) of the CAA states that: ``The provisions of section 553 
through 557 * * * of Title 5 shall not, except as expressly provided in 
this subsection, apply to actions to which this subsection applies.'' 
Thus, section 553(d) of the Administrative Procedure Act (APA), which 
requires publication of a substantive rule to be made ``not less than 
30 days before its effective date'' subject to limited exceptions, does 
not apply to this action. In the alternative, the EPA concludes that it 
is consistent with APA section 553(d) to make this action effective 
January 11, 2021.
    Section 553(d)(3) of the APA, 5 U.S.C. 553(d)(3), provides that 
final rules shall not become effective until 30 days after publication 
in the Federal Register ``except . . . as otherwise provided by the 
agency for good cause found and published with the rule.'' ``In 
determining whether good cause exists, an agency should `balance the 
necessity for immediate implementation against principles of 
fundamental fairness which require that all affected persons be 
afforded a reasonable amount of time to prepare for the effective date 
of its ruling.'' Omnipoint Corp. v. Fed. Commc'n Comm'n, 78 F.3d 620, 
630 (D.C. Cir. 1996) (quoting United States v. Gavrilovic, 551 F.2d 
1099, 1105 (8th Cir. 1977)). The purpose of this provision is to ``give 
affected parties a reasonable time to adjust their behavior before the 
final rule takes effect.'' Id.; see also Gavrilovic, 551 F.2d at 1104 
(quoting legislative history).
    As discussed in the notice of proposed rulemaking, and below, the 
standards adopted here are meant to be technology following standards 
that align with international standards that were previously adopted in 
2017 by ICAO. This means the rule reflects the performance and 
technology achieved by existing airplanes. Moreover, the EPA is not 
aware of any manufacturers who would seek certification of any new type 
design airplanes in the near future, such that making the rule 
effective immediately upon publication could disrupt their 
certification plans. The EPA is determining that in light of the nature 
of this action, good cause exists to make this final rule effective 
immediately because the Agency seeks to provide regulatory certainty as 
soon as possible and no party will be harmed by an immediate effective 
date since there is no need to provide a delay of 30 days after 
publication for parties to adjust their behavior prior to the effective 
date. Accordingly, the EPA is making this rule effective immediately 
upon publication.

D. Judicial Review and Administrative Reconsideration

    Under Clean Air Act (CAA) section 307(b)(1), judicial review of 
this final action is available only by filing a petition for review in 
the United States Court of Appeals for the District of Columbia Circuit 
by March 12, 2021. Under CAA section 307(b)(2), the requirements 
established by this final rule may not be challenged separately in any 
civil or criminal proceedings brought by the EPA to enforce the 
requirements.
    Section 307(d)(7)(B) of the CAA further provides that only an 
objection to a rule or procedure which was raised with reasonable 
specificity during the period for public comment (including any public 
hearing) may be raised during judicial review. This section also 
provides a mechanism for the EPA to reconsider the rule if the person 
raising an objection can demonstrate to the Administrator that it was 
impracticable to raise such objection within the period for public 
comment or if the grounds for such objection arose after the period for 
public comment (but within the time specified for judicial review) and 
if such objection is of central relevance to the outcome of the rule. 
Any person seeking to make such a demonstration should submit a 
Petition for Reconsideration to the Office of the Administrator, U.S. 
EPA, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW, 
Washington, DC 20460, with a copy to both the person(s) listed in the 
preceding FOR FURTHER INFORMATION CONTACT section, and the Associate 
General Counsel for the Air and Radiation Law Office, Office of General 
Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW, 
Washington, DC 20460

E. Executive Summary

1. Purpose of This Regulatory Action
    One of the core functions of the International Civil Aviation 
Organization (ICAO) is to adopt Standards and Recommended Practices on 
a wide range of aviation-related matters, including aircraft emissions. 
As

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a member State of ICAO, the United States seeks to secure the highest 
practicable degree of international uniformity in aviation regulations 
and standards.\6\ ICAO adopted airplane CO2 standards in 
2017. The adoption of these aviation standards into U.S. law will align 
with the ICAO standards. For reasons discussed herein, the EPA is 
adopting standards for GHG emissions from certain classes of engines 
used on covered airplanes (hereinafter ``covered airplanes'' or 
``airplanes'') that are equivalent in scope, stringency and timing to 
the CO2 standards adopted by ICAO.
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    \6\ ICAO, 2006: Convention on International Civil Aviation, 
Ninth Edition, Document 7300/9, Article 37, 114 pp. Available at: 
http://www.icao.int/publications/Documents/7300_9ed.pdf (last 
accessed October 27, 2020).
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    These standards will ensure control of GHG emissions, maintain 
international uniformity of airplane standards, and allow U.S. 
manufacturers of covered airplanes to remain competitive in the global 
marketplace. In the absence of U.S. standards for implementing the ICAO 
Airplane CO2 Emission Standards, U.S. civil airplane 
manufacturers could be forced to seek CO2 emissions 
certification from an aviation certification authority of another 
country (not the Federal Aviation Administration (FAA)) in order to 
market and operate their airplanes internationally. We anticipate U.S. 
manufacturers would be at a significant disadvantage if the U.S. failed 
to adopt standards that are harmonized with the ICAO standards for 
CO2 emissions. The ICAO Airplane CO2 Emission 
Standards have been adopted by other ICAO member states that certify 
airplanes. The action to adopt in the U.S. GHG standards that match the 
ICAO Airplane CO2 Emission Standards will help ensure 
international consistency and acceptance of U.S. manufactured airplanes 
worldwide.
    In August 2016, the EPA issued two findings regarding GHG emissions 
from aircraft engines (the 2016 Findings).\7\ First, the EPA found that 
elevated concentrations of GHGs in the atmosphere endanger the public 
health and welfare of current and future generations within the meaning 
of section 231(a)(2)(A) of the CAA. Second, EPA found that emissions of 
GHGs from certain classes of engines used in certain aircraft are 
contributing to the air pollution that endangers public health and 
welfare under CAA section 231(a)(2)(A). Additional details of the 2016 
Findings are described in Section III. As a result of the 2016 
Findings, CAA sections 231(a)(2)(A) and (3) obligate the EPA to propose 
and adopt, respectively, GHG standards for these covered aircraft 
engines.
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    \7\ U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
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2. Summary of the Major Provisions of This Regulatory Action
    The EPA is regulating GHG emissions from covered airplanes through 
the adoption of domestic GHG regulations that match international 
standards to control CO2 emissions. The GHG standards 
finalized in this action are equivalent to the CO2 standards 
adopted by ICAO and will be implemented and enforced in the U.S. The 
standards apply to covered airplanes: Civil subsonic jet airplanes 
(those powered by turbojet or turbofan engines and with a MTOM greater 
than 5,700 kilograms), as well as larger civil subsonic propeller-
driven airplanes (those powered by turboprop engines and with a MTOM 
greater than 8,618 kilograms). The timing and stringencies of the 
standards differ depending on whether the covered airplane is a new 
type design (i.e., a design that has not previously been type 
certificated under title 14 CFR) or an in-production model (i.e., an 
existing design that had been type certificated under title 14 CFR 
prior to the effective date of the GHG standards). The standards for 
new type designs apply to covered airplanes for which an application 
for certification is submitted to the FAA on or after January 11, 2021 
(January 1, 2023, for new type designs that have a maximum takeoff mass 
(MTOM) of 60,000 kilograms MTOM or less and have 19 passenger seats or 
fewer). The in-production standards apply to covered airplanes 
beginning January 1, 2028. Additionally, consistent with ICAO 
standards, before the in-production standards otherwise apply in 2028, 
certain modifications made to airplanes (i.e., changes that result in 
an increase in GHG emissions) will trigger a requirement to certify to 
the in-production regulation beginning January 1, 2023. Some minor 
technical corrections have been made to the proposed regulatory text in 
this action to further clarify that the standards do not apply to in-
service airplanes or military airplanes.
    The EPA is adopting the ICAO CO2 metric, which measures 
fuel efficiency, for demonstrating compliance with the GHG emission 
standards. This metric is a mathematical function that incorporates the 
specific air range (SAR) of an airplane/engine combination (a 
traditional measure of airplane cruise performance in units of 
kilometer/kilogram of fuel) and the reference geometric factor (RGF), a 
measure of fuselage size. The metric is further discussed in Section 
IV.A.
    To measure airplane fuel efficiency, the EPA is adopting the ICAO 
test procedures whereby the airplane/engine SAR value is measured at 
three specific operating test points, and a composite of those results 
is used in the metric to determine compliance with the GHG standards. 
The test procedures are discussed in Section IV.G.
    The EPA proposed an annual reporting provision which would have 
required manufacturers of covered airplanes to submit to the EPA 
information on airplane characteristics, emissions characteristics and 
production volumes. Commenters raised several issues such as 
duplicative reporting burdens with FAA and ICAO, risks to confidential 
business information, and higher costs associated with the reporting 
requirement than EPA projections. The Agency is not adopting the 
proposed annual reporting provisions. Further information on those 
comments and the EPA's response can be found in the Response to 
Comments (RTC) document accompanying this action. Further information 
on all aspects of the GHG standards can be found in Section IV.
    Finally, as proposed, the EPA is updating the existing 
incorporation by reference of the ICAO test procedures for hydrocarbons 
(HC), carbon monoxide (CO), oxides of nitrogen (NOX) and 
smoke to reference the most recent edition of the ICAO procedures. This 
update will improve clarity in the existing test procedures and 
includes a minor change to the composition of the test fuel used for 
engine certification. Further details on this technical amendment can 
be found in Section VII.
3. Costs and Benefits
    Given the significant international market pressures to continually 
improve the fuel efficiency of their airplanes, U.S. manufacturers have 
already developed or are developing technologies that will allow 
affected airplanes to comply with the ICAO standards, in advance of 
EPA's adoption of standards. Many airplanes manufactured by U.S. 
manufacturers already met the ICAO standards at the time of their 
adoption and thus already meet the standards contained in this action. 
Furthermore, based on the manufacturers' expectation that the ICAO 
standards will be implemented globally, the EPA anticipates nearly all 
affected airplanes to be compliant by the respective effective dates 
for new type designs and for in-production airplanes

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(see Section IV.I.2 for further information on affected airplanes). The 
EPA's business as usual baseline projects that even independent of the 
ICAO standards, nearly all airplanes produced by U.S. manufacturers 
will meet the ICAO in-production standards in 2028. This result is not 
surprising, given the significant market pressure on airplane 
manufacturers to continually improve the fuel efficiency of aircraft, 
the significant annual research and development expenditures from the 
aircraft industry (much of which is focused on fuel efficiency), and 
the more than 50 year track record of the industry in developing and 
selling aircraft which have shown continuous improvement in fuel 
efficiency. EPA's assessment includes the expectation that existing in-
production airplanes that are non-compliant will either be modified and 
re-certificated as compliant, will likely go out of production before 
the production compliance date of January 1, 2028, or will seek 
exemptions from the GHG standard. For these reasons, the EPA is not 
projecting emission reductions associated with these GHG regulations. 
However, the EPA does note that consistency with the international 
standards will prevent backsliding by ensuring that all new type design 
and in-production airplanes are at least as efficient as today's 
airplanes. For further details on the benefits and costs associated 
with these GHG standards, see Sections V and VI, respectively.

II. Introduction: Overview and Context for this Action

    This section provides a summary of the final rule. This section 
describes the EPA's statutory authority, the U.S. airplane engine 
regulations and the relationship with ICAO's international standards, 
and consideration of the whole airplane in addressing airplane engine 
GHG emissions.

A. Summary of Final Rule

    In February 2016, ICAO's Committee on Aviation Environmental 
Protection (CAEP) agreed to international Airplane CO2 
Emission Standards, which ICAO approved in 2017. The EPA is adopting 
GHG standards that are equivalent to the international Airplane 
CO2 Emission Standards promulgated by ICAO in Annex 16.\8\
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    \8\ ICAO, 2006: Convention on International Civil Aviation, 
Ninth Edition, Document 7300/9, 114 pp. Available at: http://www.icao.int/publications/Documents/7300_9ed.pdf (last accessed 
October 27, 2020).
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    As a result of the 2016 Findings,9 10 the EPA is 
obligated under section 231(a) of the CAA to issue emission standards 
applicable to GHG emissions from the classes of engines used by covered 
aircraft included in the 2016 Findings. As described later in further 
detail in Section III, we are regulating the air pollutant that is the 
aggregate of the six well-mixed GHGs. Only two of the six well-mixed 
GHGs--CO2 and N2O --have non-zero emissions for 
total civil subsonic airplanes and U.S. covered airplanes. 
CO2 represents 99 percent of all GHGs emitted from both 
total U.S. civil airplanes and U.S. covered airplanes, and 
N2O represents 1 percent of GHGs emitted from total 
airplanes and U.S. covered airplanes. Promulgation of the GHG emission 
standards for the certain classes of engines used by covered airplanes 
will fulfill EPA's obligations under the CAA and is the next step for 
the United States in implementing the ICAO standards promulgated in 
Annex 16 under the Chicago Convention. We are issuing a new rule that 
controls aircraft engine GHG emissions through the use of the ICAO 
regulatory metric that quantifies airplane fuel efficiency.
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    \9\ U.S. EPA, 2016: 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; Final Rule, 81 FR 54422 (August 15, 2016).
    \10\ Covered airplanes are those airplanes to which the 
international CO2 standards and the GHG standards apply: 
subsonic jet airplanes with a maximum takeoff mass (MTOM) greater 
than 5,700 kilograms and subsonic propeller-driven (e.g., turboprop) 
airplanes with a MTOM greater than 8,618 kilograms. Section IV 
describes covered and non-covered airplanes in further detail.
    ICAO, 2016: Tenth Meeting Committee on Aviation Environmental 
Protection Report, Doc 10069, CAEP/10, 432 pp, Available at: http://www.icao.int/publications/Pages/catalogue.aspx (last accessed 
October 27, 2020). The ICAO CAEP/10 report is found on page 27 of 
the English Edition 2020 catalog and is copyright protected; Order 
No. 10069.
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    The rule will establish GHG standards applicable to U.S. airplane 
manufacturers that are no less stringent than the Airplane 
CO2 Emission Standards adopted by ICAO.\11\ This rule 
incorporates the same compliance schedule as the ICAO Airplane 
CO2 Emission Standards. The standards will apply to both new 
type designs and in-production airplanes. The in-production standards 
have later applicability dates and different emission levels than do 
the standards for new type designs. The different emission levels for 
new type designs and in-production airplanes depend on the airplane 
size, weight, and availability of fuel efficiency technologies.
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    \11\ ICAO's certification standards and test procedures for 
airplane CO2 emissions are based on the consumption of 
fuel (or fuel burn) under prescribed conditions at optimum cruise 
altitude. ICAO uses the term, CO2, for its standards and 
procedures, but ICAO is actually regulating or measuring the rate of 
an airplane's fuel burn (fuel efficiency). For jet fuel, the 
emissions index or emissions factor for CO2 is 3.16 
kilograms of CO2 per kilogram of fuel burn (or 3,160 
grams of CO2 per kilogram of fuel burn). Thus, to convert 
an airplane's rate of fuel burn to a CO2 emissions rate, 
this emission index needs to be applied.
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    Apart from the GHG requirements, we are updating the engine 
emissions testing and measurement procedures applicable to HC, 
NOX, CO, and smoke in current regulations. The updates will 
implement recent amendments to ICAO standards in Annex 16, Volume II, 
and these updates will be accomplished by incorporating provisions of 
the Annex by reference, as has historically been done in previous EPA 
rulemakings.\12\
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    \12\ Previous EPA rulemakings for aircraft engine regulations 
are described later in section II.D.2.
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B. EPA Statutory Authority and Responsibilities Under the Clean Air Act

    Section 231(a)(2)(A) of the CAA directs the Administrator of the 
EPA to, from time to time, propose aircraft engine emission standards 
applicable to the emission of any air pollutant from classes of 
aircraft engines which in the Administrator's judgment causes or 
contributes to air pollution that may reasonably be anticipated to 
endanger public health or welfare. (See 42 U.S.C. 7571(a)(2)(A)). 
Section 231(a)(2)(B) directs the EPA to consult with the Administrator 
of the FAA on such standards, and it prohibits the EPA from changing 
aircraft engine emission standards if such a change would significantly 
increase noise and adversely affect safety (see 42 U.S.C. 
7571(a)(2)(B)(i)-(ii)). Section 231(a)(3) provides that after we 
propose standards, the Administrator shall issue such standards ``with 
such modifications as he deems appropriate.'' (see 42 U.S.C. 
7571(a)(3)). The U.S. Court of Appeals for the D.C. Circuit has held 
that this provision confers an unusually broad degree of discretion on 
the EPA to adopt aircraft engine emission standards that the Agency 
determines are reasonable. Nat'l Ass'n of Clean Air Agencies v. EPA, 
489 F.3d 1221, 1229-30 (D.C. Cir. 2007) (NACAA).
    In addition, under CAA section 231(b) the EPA is required to 
ensure, in consultation with the U.S. Department of Transportation 
(DOT), that the effective date of any standard provides the necessary 
time to permit the development and application of the requisite 
technology, giving appropriate consideration to the cost of compliance

[[Page 2140]]

(see 42 U.S.C. 7571(b)). Section 232 then directs the Secretary of 
Transportation to prescribe regulations to ensure compliance with the 
EPA's standards (see 42 U.S.C. 7572). Finally, section 233 of the CAA 
vests the authority to promulgate emission standards for aircraft 
engines only in the Federal Government. States are preempted from 
adopting or enforcing any standard respecting emissions from aircraft 
or aircraft engines unless such standard is identical to the EPA's 
standards (see 42 U.S.C. 7573).

C. Background Information Helpful to Understanding This Action

    Civil airplanes and associated engines are international 
commodities that are manufactured and sold around the world. The member 
States of ICAO and the world's airplane and airplane engine 
manufacturers participated in the deliberations leading up to ICAO's 
adoption of the international Airplane CO2 Emission 
Standards. However, ICAO's standards are not directly applicable to nor 
enforceable against member States' airplane and engine manufacturers. 
Instead, after adoption of the standards by ICAO, a member State is 
required (as described later in Section II.D.1) to adopt domestic 
standards at least as stringent as ICAO standards and apply them, as 
applicable, to subject airplane and airplane engine manufacturers in 
order to ensure recognition of their airworthiness and type certificate 
by other member State's civil aviation authorities. This rulemaking is 
a necessary step to meet this obligation for the United States.

D. U.S. Airplane Regulations and the International Community

    The EPA and the FAA work within the standard-setting process of 
ICAO's CAEP to help establish international emission standards and 
related requirements, which individual member States adopt into 
domestic law and regulations. Historically, under this approach, 
international emission standards have first been adopted by ICAO, and 
subsequently the EPA has initiated rulemakings under CAA section 231 to 
establish domestic standards that are harmonized with ICAO's standards. 
After EPA promulgates aircraft engine emission standards, CAA section 
232 requires the FAA to issue regulations to ensure compliance with the 
EPA aircraft engine emission standards when issuing airworthiness 
certificates pursuant to its authority under Title 49 of the United 
States Code. This rule continues this historical rulemaking approach.
1. International Regulations and U.S. Obligations
    The EPA has worked with the FAA since 1973, and later with ICAO, to 
develop domestic and international standards and other recommended 
practices pertaining to aircraft engine emissions. The Convention on 
International Civil Aviation (commonly known as the `Chicago 
Convention') was signed in 1944 at the Diplomatic Conference held in 
Chicago. The Chicago Convention establishes the legal framework for the 
development of international civil aviation. The primary objective is 
``that international civil aviation may be developed in a safe and 
orderly manner and that international air transport services may be 
established on the basis of equality of opportunity and operated 
soundly and economically.'' \13\ In 1947, ICAO was established, and 
later in that same year ICAO became a specialized agency of the United 
Nations (UN). ICAO sets international standards for aviation safety, 
security, efficiency, capacity, and environmental protection and serves 
as the forum for cooperation in all fields of international civil 
aviation. ICAO works with the Chicago Convention's member States and 
global aviation organizations to develop international Standards and 
Recommended Practices (SARPs), which member States reference when 
developing their domestic civil aviation regulations. The United States 
is one of 193 currently participating ICAO member 
States.14 15
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    \13\ ICAO, 2006: Convention on International Civil Aviation, 
Ninth Edition, Document 7300/9, 114 pp. Available at: http://www.icao.int/publications/Documents/7300_9ed.pdf (last accessed 
October 27, 2020).
    \14\ Members of ICAO's Assembly are generally termed member 
States or contracting States. These terms are used interchangeably 
throughout this preamble.
    \15\ There are currently 193 contracting states according to 
ICAO's website: https://www.icao.int/MemberStates/Member%20States.English.pdf (last accessed March 16, 2020).
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    In the interest of global harmonization and international air 
commerce, the Chicago Convention urges its member States to 
``collaborate in securing the highest practicable degree of uniformity 
in regulations, standards, procedures and organization in relation to 
aircraft, . . . in all matters which such uniformity will facilitate 
and improve air navigation.'' The Chicago Convention also recognizes 
that member States may adopt national standards that are more or less 
stringent than those agreed upon by ICAO or standards that are 
different in character or that comply with the ICAO standards by other 
means. Any member State that finds it impracticable to comply in all 
respects with any international standard or procedure, or that 
determines it is necessary to adopt regulations or practices differing 
in any particular respect from those established by an international 
standard, is required to give notification to ICAO of the differences 
between its own practice and that established by the international 
standard.\16\
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    \16\ ICAO, 2006: Doc 7300-Convention on International Civil 
Aviation, Ninth Edition, Document 7300/9, 114 pp. Available at 
http://www.icao.int/publications/Documents/7300_9ed.pdf (last 
accessed October 27, 2020).
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    ICAO's work on the environment focuses primarily on those problems 
that benefit most from a common and coordinated approach on a worldwide 
basis, namely aircraft noise and engine emissions. SARPs for the 
certification of aircraft noise and aircraft engine emissions are 
contained in Annex 16 to the Chicago Convention. To continue to address 
aviation environmental issues, in 2004, ICAO established three 
environmental goals: (1) Limit or reduce the number of people affected 
by significant aircraft noise; (2) limit or reduce the impact of 
aviation emissions on local air quality; and (3) limit or reduce the 
impact of aviation GHG emissions on the global climate.
    The Chicago Convention has a number of other features that govern 
international commerce. First, member States that wish to use aircraft 
in international transportation must adopt emission standards that are 
at least as stringent as ICAO's standards if they want to ensure 
recognition of their airworthiness certificates. Member States may ban 
the use of any aircraft within their airspace that does not meet ICAO 
standards.\17\ Second, the Chicago Convention indicates that member 
States are required to recognize the airworthiness certificates issued 
or rendered valid by the contracting State in which the aircraft is 
registered provided the requirements under which the certificates were 
issued are equal to or above ICAO's minimum standards.\18\ Third, to 
ensure that international commerce is not unreasonably constrained, a 
member State that cannot meet or deems it necessary to adopt 
regulations differing from the international standard is obligated to 
notify ICAO of the differences between

[[Page 2141]]

its domestic regulations and ICAO standards.\19\
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    \17\ ICAO, 2006: Convention on International Civil Aviation, 
Article 33, Ninth Edition, Document 7300/9, 114 pp. Available at 
http://www.icao.int/publications/Documents/7300_9ed.pdf(last 
accessed October 27, 2020).
    \18\ ICAO, 2006: Convention on International Civil Aviation, 
Article 33, Ninth Edition, Document 7300/9, 114 pp. Available at 
http://www.icao.int/publications/Documents/7300_9ed.pdf (last 
accessed October 27, 2020).
    \19\ ICAO, 2006: Convention on International Civil Aviation, 
Article 38, Ninth Edition, Document 7300/9, 114 pp. Available at 
http://www.icao.int/publications/Documents/7300_9ed.pdf (last 
accessed October 27, 2020).
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    ICAO's CAEP, which consists of members and observers from States, 
intergovernmental and non-governmental organizations representing the 
aviation industry and environmental interests, undertakes ICAO's 
technical work in the environmental field. The Committee is responsible 
for evaluating, researching, and recommending measures to the ICAO 
Council that address the environmental impacts of international civil 
aviation. CAEP's terms of reference indicate that ``CAEP's assessments 
and proposals are pursued taking into account: Technical feasibility; 
environmental benefit; economic reasonableness; interdependencies of 
measures (for example, among others, measures taken to minimize noise 
and emissions); developments in other fields; and international and 
national programs.'' \20\ The ICAO Council reviews and adopts the 
recommendations made by CAEP. It then reports to the ICAO Assembly, the 
highest body of the organization, where the main policies on aviation 
environmental protection are adopted and translated into Assembly 
Resolutions. If ICAO adopts a CAEP proposal for a new environmental 
standard, it then becomes part of ICAO standards and recommended 
practices (Annex 16 to the Chicago Convention).21 22
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    \20\ ICAO: CAEP Terms of Reference. Available at http://www.icao.int/environmental-protection/Pages/Caep.aspx#ToR (last 
accessed March 16, 2020).
    \21\ ICAO, 2017: Aircraft Engine Emissions, International 
Standards and Recommended Practices, Environmental Protection, Annex 
16, Volume II, Fourth Edition, July 2017, 174 pp. Available at 
http://www.icao.int/publications/Pages/catalogue.aspx (last accessed 
March 16, 2020). The ICAO Annex 16 Volume II is found on page 16 of 
the ICAO Products & Services English Edition of the 2020 catalog, 
and it is copyright protected; Order No. AN16-2. Also see: ICAO, 
2020: Supplement No.7, August 2020, Annex 16 Environmental 
Protection--Volume II--Aircraft Engine Emissions, Amendment 10 (20/
7/20).76pp. Available at https://www.icao.int/publications/catalogue/cat_2020_Sup07_en.pdf (last accessed October 27, 2020). 
The ICAO Annex 16, Volume II, Amendment 10 is found on page 3 of 
Supplement No. 7--August 2020; English Edition, Order No. AN16-2/E/
12.
    \22\ CAEP develops new emission standards based on an assessment 
of the technical feasibility, cost, and environmental benefit of 
potential requirements.
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    The FAA plays an active role in ICAO/CAEP, including serving as the 
representative (member) of the United States at annual ICAO/CAEP 
Steering Group meetings, as well as the ICAO/CAEP triennial meetings, 
and contributing technical expertise to CAEP's working groups. The EPA 
serves as an advisor to the U.S. member at the annual ICAO/CAEP 
Steering Group and triennial ICAO/CAEP meetings, while also 
contributing technical expertise to CAEP's working groups and assisting 
and advising the FAA on aviation emissions, technology, and 
environmental policy matters. In turn, the FAA assists and advises the 
EPA on aviation environmental issues, technology and airworthiness 
certification matters.
    CAEP's predecessor at ICAO, the Committee on Aircraft Engine 
Emissions (CAEE), adopted the first international SARPs for aircraft 
engine emissions that were proposed in 1981.\23\ These standards 
limited aircraft engine emissions of hydrocarbons (HC), carbon monoxide 
(CO), and oxides of nitrogen (NOX). The 1981 standards 
applied to newly manufactured engines, which are those engines built 
after the effective date of the regulations--also referred to as in-
production engines. In 1993, ICAO adopted a CAEP/2 proposal to tighten 
the original NOX standard by 20 percent and amend the test 
procedures.\24\ These 1993 standards applied both to newly certificated 
turbofan engines (those engine models that received their initial type 
certificate after the effective date of the regulations, referred to as 
newly certificated engines or new type design engines) and to in-
production engines; the standards had different effective dates for 
newly certificated engines and in-production engines. In 1995, CAEP/3 
recommended a further tightening of the NOX standards by 16 
percent and additional test procedure amendments, but in 1997 the ICAO 
Council rejected this stringency proposal and approved only the test 
procedure amendments. At the CAEP/4 meeting in 1998, the Committee 
adopted a similar 16 percent NOX reduction proposal, which 
ICAO approved in 1998. Unlike the CAEP/2 standards, the CAEP/4 
standards applied only to new type design engines after December 31, 
2003, and not to in-production engines, leaving the CAEP/2 standards 
applicable to in-production engines. In 2004, CAEP/6 recommended a 12 
percent NOX reduction, which ICAO approved in 
2005.25 26 The CAEP/6 standards applied to new engine 
designs certificated after December 31, 2007, again leaving the CAEP/2 
standards in place for in-production engines before January 1, 2013. In 
2010, CAEP/8 recommended a further tightening of the NOX 
standards by 15 percent for new engine designs certificated after 
December 31, 2013.27 28 The Committee also recommended that 
the CAEP/6 standards be applied to in-production engines on or after 
January 1, 2013, which cut off the production of CAEP/2 and CAEP/4 
compliant engines with the exception of spare engines; ICAO adopted 
these as standards in 2011.\29\
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    \23\ ICAO, 2017: Aircraft Engine Emissions: Foreword, 
International Standards and Recommended Practices, Environmental 
Protection, Annex 16, Volume II, Fourth Edition, July 2017, 174pp. 
Available at https://www.icao.int/publications/Pages/catalogue.aspx 
(last accessed March 16, 2020). The ICAO Annex 16 Volume II is found 
on page 16 of the ICAO Products & Services English Edition 2020 
catalog and is copyright protected; Order No. AN16-2. Also see: 
ICAO, 2020: Supplement No. 7, August 2020, Annex 16 Environmental 
Protection-Volume II-Aircraft Engine Emissions, Amendment 10 (20/7/
20).76pp. Available at https://www.icao.int/publications/catalogue/cat_2020_Sup07_en.pdf (last accessed October 27, 2020). The ICAO 
Annex 16, Volume II, Amendment 10 is found on page 3 of Supplement 
No. 7--August 2020; English Edition, Order No. AN16-2/E/12.
    \24\ CAEP conducts its work triennially. Each 3-year work cycle 
is numbered sequentially and that identifier is used to 
differentiate the results from one CAEP meeting to another by 
convention. The first technical meeting on aircraft emission 
standards was CAEP's predecessor, i.e., CAEE. The first meeting of 
CAEP, therefore, is referred to as CAEP/2.
    \25\ CAEP/5 did not address new airplane engine emission 
standards.
    \26\ ICAO, 2017: Aircraft Engine Emissions, International 
Standards and Recommended Practices, Environmental Protection, Annex 
16,Volume II, Fourth Edition, July 2017, 174pp. Available at https://www.icao.int/publications/Pages/catalogue.aspx (last accessed March 
16, 2020). The ICAO Annex 16 Volume II is found on page 16 of the 
ICAO Products & Services English Edition of the 2020 catalog, and it 
is copyright protected; Order No. AN16-2. Also see: ICAO, 2020: 
Supplement No. 7, August 2020, Annex 16 Environmental Protection-
Volume II-Aircraft Engine Emissions, Amendment 10 (20/7/20).76pp. 
Available at https://www.icao.int/publications/catalogue/cat_2020_Sup07_en.pdf (last accessed October 27, 2020). The ICAO 
Annex 16, Volume II, Amendment 10 is found on page 3 of Supplement 
No. 7--August 2020; English Edition, Order No. AN16-2/E/12.
    \27\ CAEP/7 did not address new aircraft engine emission 
standards.
    \28\ ICAO, 2010: Committee on Aviation Environmental Protection 
(CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 2010, 
CAEP/8-WP/80 Available in Docket EPA-HQ-OAR-2010-0687.
    \29\ ICAO, 2017: Aircraft Engine Emissions, International 
Standards and Recommended Practices, Environmental Protection, Annex 
16, Volume II, Fourth Edition, July 2017, Amendment 9, 174 pp. CAEP/
8 corresponds to Amendment 7 effective on July 18, 2011. Available 
at https://www.icao.int/publications/Pages/catalogue.aspx (last 
accessed March 16, 2020). The ICAO Annex 16 Volume II is found on 
page 16 of the ICAO Products & Services English Edition of the 2020 
catalog, and it is copyright protected; Order No. AN16-2. Also see: 
ICAO, 2020: Supplement No. 7, August 2020, Annex 16 Environmental 
Protection--Volume II--Aircraft Engine Emissions, Amendment 10 (20/
7/20).76pp. Available at https://www.icao.int/publications/catalogue/cat_2020_Sup07_en.pdf (last accessed October 27, 2020). 
The ICAO Annex 16, Volume II, Amendment 10 is found on page 3 of 
Supplement No. 7--August 2020; English Edition, Order No. AN16-2/E/
12.

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[[Page 2142]]

    At the CAEP/10 meeting in 2016, the Committee agreed to the first 
airplane CO2 emission standards, which ICAO approved in 
2017. The CAEP/10 CO2 standards apply to new type design 
airplanes for which the application for a type certificate will be 
submitted on or after January 1, 2020, some modified in-production 
airplanes on or after January 1, 2023, and all applicable in-production 
airplanes built on or after January 1, 2028.
2. EPA's Regulation of Aircraft Engine Emissions and the Relationship 
to International Aircraft Standards
    As required by the CAA, the EPA has been engaged in reducing 
harmful air pollution from airplane engines for over 40 years, 
regulating gaseous exhaust emissions, smoke, and fuel venting from 
engines.\30\ We have periodically revised these regulations. In a 1997 
rulemaking, for example, we made our emission standards and test 
procedures more consistent with those of ICAO's CAEP for turbofan 
engines used in commercial aviation with rated thrusts greater than 
26.7 kilonewtons.\31\ These ICAO requirements are generally referred to 
as CAEP/2 standards.\32\ The 1997 rulemaking included new 
NOX emission standards for newly manufactured commercial 
turbofan engines 33 34 and for newly certificated commercial 
turbofan engines.35 36 It also included a CO emission 
standard for in-production commercial turbofan engines.\37\ In 2005, we 
promulgated more stringent NOX emission standards for newly 
certificated commercial turbofan engines.\38\ That final rule brought 
the U.S. standards closer to alignment with ICAO CAEP/4 requirements 
that became effective in 2004. In 2012, we issued more stringent two-
tiered NOX emission standards for newly certificated and in-
production commercial and non-commercial turbofan engines, and these 
NOX standards align with ICAO's CAEP/6 and CAEP/8 standards 
that became effective in 2013 and 2014, respectively.39 40 
The EPA's actions to regulate certain pollutants emitted from aircraft 
engines come directly from the authority in section 231 of the CAA, and 
we have aligned the U.S. emissions requirements with those promulgated 
by ICAO. All of these previous ICAO emission standards, and the EPA's 
standards reflecting them, have generally been considered anti-
backsliding standards (most aircraft engines meet the standards), which 
are technology following.
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    \30\ U.S. EPA, 1973: Emission Standards and Test Procedures for 
Aircraft; Final Rule, 38 FR 19088 (July 17, 1973).
    \31\ U.S. EPA, 1997: Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures; Final 
Rule, 62 FR 25355 (May 8, 1997).
    \32\ The full CAEP membership meets every three years and each 
session is denoted by a numerical identifier. For example, the 
second meeting of CAEP is referred to as CAEP/2, and CAEP/2 occurred 
in 1994.
    \33\ This does not mean that in 1997 we promulgated requirements 
for the re-certification or retrofit of existing in-use engines.
    \34\ Those engines built after the effective date of the 
regulations that were already certificated to pre-existing standards 
are also referred to as in-production engines.
    \35\ In the existing EPA regulations, 40 CFR part 87, newly 
certificated aircraft engines are described as engines of a type or 
model of which the date of manufacture of the first individual 
production model was after the implementation date. Newly 
manufactured aircraft engines are characterized as engines of a type 
or model for which the date of manufacturer of the individual engine 
was after the implementation date.
    \36\ Those engine models that received their initial type 
certificate after the effective date of the regulations are also 
referred to as new engine designs.
    \37\ U.S. EPA, 1997: Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures; Final 
Rule, 62 FR 25355 (May 8, 1997).
    \38\ U.S. EPA, 2005: Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures; Final 
Rule, 70 FR 69664 (November 17, 2005).
    \39\ U.S. EPA, 2012: Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures; Final 
Rule, 77 FR 36342 (June 18, 2012).
    \40\ While ICAO's standards were not limited to ``commercial'' 
airplane engines, our 1997 standards were explicitly limited to 
commercial engines, as our finding that NOX and carbon 
monoxide emissions from airplane engines cause or contribute to air 
pollution which may reasonably be anticipated to endanger public 
health or welfare was so limited. See 62 FR 25358 (May 8, 1997). In 
the 2012 rulemaking, we expanded the scope of that finding and of 
our standards pursuant to CAA section 231(a)(2)(A) to include such 
emissions from both commercial and non-commercial airplane engines 
based on the physical and operational similarities between 
commercial and noncommercial civilian airplane and to bring our 
standards into full alignment with ICAO's.
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    The EPA and the FAA worked from 2009 to 2016 within the ICAO/CAEP 
standard-setting process on the development of the international 
Airplane CO2 Emission Standards. In this action, we are 
adopting GHG standards equivalent to the ICAO Airplane CO2 
Emission Standards. As stated earlier in this Section II, the standards 
established in the United States need to be at least as stringent as 
the ICAO Airplane CO2 Emission Standards in order to ensure 
global acceptance of FAA airworthiness certification. Also, as a result 
of the 2016 Findings, as described later in Section IV, the EPA is 
obligated under section 231 of the CAA to propose and issue emission 
standards applicable to GHG emissions from the classes of engines used 
by covered aircraft included in the 2016 Findings.
    When the EPA proposed the aircraft GHG findings in 2015, we 
included an aircraft GHG emission standards advance notice of proposed 
rulemaking (henceforth the ``2015 ANPR'') \41\ that provided 
information on the international process for setting the ICAO Airplane 
CO2 Emission Standards. Also, the 2015 ANPR described and 
sought input on the potential use of section 231 of the CAA to adopt 
and implement the corresponding international Airplane CO2 
Emission Standards domestically as a CAA section 231 GHG standard.
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    \41\ 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).
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E. Consideration of Whole Airplane Characteristics

    In addressing CO2 emissions, ICAO adopted an approach 
that measures the fuel efficiency from the perspective of whole 
airplane design--an airframe and engine combination. Specifically, ICAO 
adopted CO2 emissions test procedures based on measuring the 
performance of the whole airplane rather than the airplane engines 
alone.\42\ The ICAO standards account for three factors: Aerodynamics, 
airplane weight, and engine propulsion technologies. These airplane 
performance characteristics determine the overall CO2 
emissions. Rather than measuring a single chemical compound, the ICAO 
CO2 emissions test procedures measure fuel efficiency based 
on how far an airplane can fly on a single unit of fuel at the optimum 
cruise altitude and speed.
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    \42\ ICAO, 2016: Report of Tenth Meeting, Montreal, 1-12 
February 2016, Committee on Aviation Environmental Protection, 
Document 10069, 432pp. Available at: https://www.icao.int/publications/Pages/catalogue.aspx (last accessed March 16, 2020). 
ICAO Document 10069 is found on page 27 of the ICAO Products & 
Services English Edition 2020 Catalog, and it is copyright 
protected; Order No. 10069. See Appendix C (starting on page 5C-1) 
of this report.
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    The three factors--and technology categories that improve these 
factors--are described as follows: \43\
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    \43\ ICAO, Environmental Report 2010--Aviation and Climate 
Change, 2010, which is located at http://www.icao.int/environmental-protection/Pages/EnvReport10.aspx (last accessed March 16, 2020).
---------------------------------------------------------------------------

     Weight: Reducing basic airplane weight \44\ via structural 
changes to

[[Page 2143]]

increase the commercial payload or extend range for the same amount of 
thrust and fuel burn;
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    \44\ Although weight reducing technologies affect fuel burn, 
they do not affect the metric value for the GHG standard. The 
standard is a function of maximum takeoff mass (MTOM). Reductions in 
airplane empty weight (excluding usable fuel and the payload) can be 
canceled out or diminished by a corresponding increase in payload, 
fuel, or both--when MTOM is kept constant. Section IV and VI provide 
a further description of the metric value and the effects of weight 
reducing technologies.
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     Propulsion (thermodynamic and propulsion efficiency): 
Advancing the overall specific performance of the engine, to reduce the 
fuel burn per unit of delivered thrust; and
     Aerodynamic: Advancing the airplane aerodynamics to reduce 
drag and its associated impacts on thrust.
    As examples of technologies that support addressing aircraft engine 
CO2 emissions accounting for the airplane as a whole, 
manufacturers have already achieved significant weight reduction with 
the introduction of advanced alloys and composite materials and lighter 
weight control systems (e.g., fly-by-wire) \45\ and aerodynamic 
improvements with advanced wingtip devices such as winglets.
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    \45\ Fly-by-wire refers to a system which transmits signals from 
the cockpit to the airplane's control surfaces electronically rather 
than mechanically. AirlineRatings.com, Available at https://www.airlineratings.com/did-you-know/what-does-the-term-fly-by-wire-mean/ (last accessed on March 16, 2020).
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    The EPA agrees with ICAO's approach to measure the fuel efficiency 
based on the performance of the whole airplane. Accordingly, under 
section 231 of the CAA, the EPA is adopting regulations that are 
consistent with this approach. We are also adopting GHG test procedures 
that are the same as the ICAO CO2 test procedures. (See 
Section IV.G for details on the test procedures.)
    As stated earlier in Section II, section 231(a)(2)(A) of the CAA 
directs the Administrator of the EPA to, from time to time, propose 
aircraft engine emission standards applicable to the emission of any 
air pollutant from classes of aircraft engines which in the 
Administrator's judgment causes or contributes to air pollution that 
may reasonably be anticipated to endanger public health or welfare. For 
a standard promulgated under CAA section 231(a)(2)(A) to be 
``applicable to'' emissions of air pollutants from aircraft engines, it 
could take many forms and include multiple elements in addition to a 
numeric permissible engine exhaust rate. For example, EPA rules adopted 
pursuant to CAA section 231 have addressed fuel venting to prevent the 
discharge of raw fuel from the engine and have adopted test procedures 
for exhaust emission standards. See 40 CFR part 87, subparts B and G.
    Given both the absence of a statutory directive on what form a CAA 
section 231 standard must take (in contrast to, for example, CAA 
section 129(a)(4), which requires numerical emissions limitations for 
emissions of certain pollutants from solid waste incinerators) and the 
D.C. Circuit's 2007 NACAA ruling that section 231 of the CAA confers an 
unusually broad degree of discretion on the EPA in establishing 
airplane engine emission standards, the EPA is controlling GHG 
emissions in a manner identical to how ICAO's standards control 
CO2 emissions--with a fuel efficiency standard based on the 
characteristics of the whole airplane. While this standard incorporates 
characteristics of airplane design as adopted by ICAO, the EPA is not 
asserting independent regulatory authority over airplane design.

III. Summary of the 2016 Findings

    On August 15, 2016,\46\ the EPA issued two findings regarding GHG 
emissions from aircraft engines. First, the EPA found that elevated 
concentrations of GHGs in the atmosphere endanger the public health and 
welfare of current and future generations within the meaning of section 
231(a)(2)(A) of the CAA. The EPA made this finding specifically with 
respect to the same six well-mixed GHGs--CO2, methane, 
N2O, hydrofluorocarbons, perfluorocarbons, and sulfur 
hexafluoride--that together were defined as the air pollution in the 
2009 Endangerment Finding \47\ under section 202(a) of the CAA and that 
together were found to constitute the primary cause of climate change. 
Second, the EPA found that emissions of those six well-mixed GHGs from 
certain classes of engines used in certain aircraft \48\ cause or 
contribute to the air pollution--the aggregate group of the same six 
GHGs--that endangers public health and welfare under CAA section 
231(a)(2)(A).
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    \46\ U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
    \47\ U.S. EPA, 2009: Endangerment and Cause or Contribute 
Findings for Greenhouse Gases Under Section 202(a) of the Clean Air 
Act; Final Rule, 74 FR 66496 (December 15, 2009).
    \48\ Certain aircraft in this context are referred to 
interchangeably as ``covered airplanes,'' ``US covered airplanes,'' 
or airplanes throughout this rulemaking.
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    The EPA identified U.S. covered aircraft as subsonic jet aircraft 
with a maximum takeoff mass (MTOM) greater than 5,700 kilograms and 
subsonic propeller-driven (e.g., turboprop) aircraft with a MTOM 
greater than 8,618 kilograms. See Section IV of this final rulemaking 
for examples of airplanes that correspond to the U.S. covered aircraft 
identified in the 2016 Findings.\49\ The EPA did not at that time make 
findings regarding whether other substances emitted from aircraft 
engines cause or contribute to air pollution which may reasonably be 
anticipated to endanger public health or welfare. The EPA also did not 
make a cause or contribute finding regarding GHG emissions from engines 
not used in U.S. covered aircraft (i.e., those used in smaller 
turboprops, smaller jet aircraft, piston-engine aircraft, helicopters 
and military aircraft). Consequently, the 2016 Findings did not trigger 
the EPA's authority or duty under the CAA to regulate these other 
substances or aircraft types.
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    \49\ 81 FR 54423, August 15, 2016.
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    The EPA explained that the collective GHG emissions from the 
classes of engines used in U.S. covered aircraft contribute to the 
national GHG emission inventories \50\ and estimated global GHG 
emissions.51 52 53 54 The 2016 Findings

[[Page 2144]]

accounted for the majority (89 percent) of total U.S. aircraft GHG 
emissions.55 56
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    \50\ In 2014, classes of engines used in U.S. covered airplanes 
contribute to domestic GHG inventories as follows: 10 percent of all 
U.S. transportation GHG emissions, representing 2.8 percent of total 
U.S. emissions.
     U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
     U.S. EPA, 2016: Inventory of U.S. Greenhouse Gas Emissions and 
Sinks: 1990-2014, 1,052 pp., U.S. EPA Office of Air and Radiation, 
EPA 430-R-16-002, April 2016. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014 (last accessed March 16, 2020).
     ERG, 2015: U.S. Jet Fuel Use and CO2 Emissions 
Inventory for Aircraft Below ICAO CO2 Standard 
Thresholds, Final Report, EPA Contract Number EP-D-11-006, 38 pp.
    \51\ In 2010, classes of engines used in U.S. covered airplanes 
contribute to global GHG inventories as follows: 26 percent of total 
global airplane GHG emissions, representing 2.7 percent of total 
global transportation emissions and 0.4 percent of all global GHG 
emissions.
     U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
     U.S. EPA, 2016: Inventory of U.S. Greenhouse Gas Emissions and 
Sinks: 1990-2014, 1,052 pp., U.S. EPA Office of Air and Radiation, 
EPA 430-R-16-002, April 2016. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014 (last accessed March 16, 2020).
     ERG, 2015: U.S. Jet Fuel Use and CO2 Emissions 
Inventory for Aircraft Below ICAO CO2 Standard 
Thresholds, Final Report, EPA Contract Number EP-D-11-006, 38 pp.
     IPCC, 2014: Climate Change 2014: Mitigation of Climate Change. 
Contribution of Working Group III to the Fifth Assessment Report of 
the Intergovernmental Panel on Climate Change [Edenhofer, O., R. 
Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, A. 
Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. 
Savolainen, S. Schl[ouml]mer, C. von Stechow, T. Zwickel and J.C. 
Minx (eds.)]. Cambridge University Press, 1435 pp.
    \52\ U.S. EPA, 2016: Inventory of U.S. Greenhouse Gas Emissions 
and Sinks: 1990-2014, 1,052 pp., U.S. EPA Office of Air and 
Radiation, EPA 430-R-16-002, April 2016. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014 (last accessed March 16, 2020).
    \53\ IPCC, 2014: Climate Change 2014: Mitigation of Climate 
Change. Contribution of Working Group III to the Fifth Assessment 
Report of the Intergovernmental Panel on Climate Change [Edenhofer, 
O., R. Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, 
A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. 
Savolainen, S. Schl[ouml]mer, C. von Stechow, T. Zwickel and J.C. 
Minx (eds.)]. Cambridge University Press, 1435 pp.
    \54\ The domestic inventory comparisons are for the year 2014, 
and global inventory comparisons are for the year 2010. The 
rationale for the different years is described in section IV.B.4 of 
the 2016 Findings, 81 FR 54422 (August 15, 2016).
    \55\ Covered U.S. aircraft GHG emissions in the 2016 Findings 
were from airplanes that operate in and from the U.S. and thus 
contribute to emissions in the U.S. This includes emissions from 
U.S. domestic flights, and emissions from U.S. international bunker 
flights (emissions from the combustion of fuel used by airplanes 
departing the U.S., regardless of whether they are a U.S. flagged 
carrier--also described as emissions from combustion of U.S. 
international bunker fuels). For example, a flight departing Los 
Angeles and arriving in Tokyo, regardless of whether it is a U.S. 
flagged carrier, is considered a U.S. international bunker flight. A 
flight from London to Hong Kong is not.
    \56\ U.S. EPA, 2016: Inventory of U.S. Greenhouse Gas Emissions 
and Sinks: 1990-2014, 1,052 pp., U.S. EPA Office of Air and 
Radiation, EPA 430-R-16-002, April 2016. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014 (last accessed March 16, 2020).
---------------------------------------------------------------------------

    As explained in the 2016 Findings,\57\ only two of the six well-
mixed GHGs, CO2 and N2O, are emitted from covered 
aircraft. CO2 represents 99 percent of all GHGs emitted from 
both total U.S. aircraft and U.S. covered aircraft, and N2O 
represents 1 percent of GHGs emitted from total U.S. aircraft and U.S. 
covered aircraft.\58\ Modern aircraft are overall consumers of 
methane.\59\ Hydrofluorocarbons, perfluorocarbons, and sulfur 
hexafluoride are not products of aircraft engine fuel combustion. 
(Section IV.H discusses controlling two of the six well-mixed GHGs--
CO2 and N2O-- in the context of the details of 
this rule.)
---------------------------------------------------------------------------

    \57\ U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
    \58\ U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
     U.S. EPA, 2016: Inventory of U.S. Greenhouse Gas Emissions and 
Sinks: 1990-2014, 1,052 pp., U.S. EPA Office of Air and Radiation, 
EPA 430-R-16-002, April 2016. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2014 (last accessed March 16, 2020).
     ERG, 2015: U.S. Jet Fuel Use and CO2 Emissions 
Inventory for Aircraft Below ICAO CO2 Standard 
Thresholds, Final Report, EPA Contract Number EP-D-11-006, 38 pp.
    \59\ Methane emissions are no longer considered to be emitted 
from aircraft gas turbine engines burning jet fuel A at higher power 
settings. Modern aircraft jet engines are typically net consumers of 
methane (Santoni et al. 2011). Methane is emitted at low power and 
idle operation, but at higher power modes aircraft engines consume 
methane. Over the range of engine operating modes, aircraft engines 
are net consumers of methane on average.
---------------------------------------------------------------------------

IV. EPA's Final GHG Standards for Covered Airplanes

    This section describes the fuel efficiency metric that will be used 
as a measure of airplane GHG emissions, the size and types of airplanes 
that will be affected, the emissions levels, and the applicable test 
procedures. As explained earlier in Section III and in the 2016 
Findings,\60\ only two of the six well-mixed GHGs--CO2 and 
N2O--are emitted from covered aircraft. Both CO2 
and N2O emissions scale with fuel burn, thus allowing them 
to be controlled through fuel efficiency.
---------------------------------------------------------------------------

    \60\ U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
---------------------------------------------------------------------------

    The GHG emission regulations for this rule are being specified in a 
new part in title 40 of the CFR--40 CFR part 1030. The existing 
aircraft engine regulations applicable to HC, NOX, CO, and 
smoke remain in 40 CFR part 87.
    In order to promote international harmonization of aviation 
standards and to avoid placing U.S. manufacturers at a competitive 
disadvantage that would result if EPA were to adopt standards different 
from the standards adopted by ICAO, the EPA is adopting standards for 
GHG emissions from certain classes of engines used on airplanes that 
match the scope, stringency, and timing of the CO2 standards 
adopted by ICAO. The EPA and the FAA worked within ICAO to help 
establish the international CO2 emission standards, which 
under the Chicago Convention individual member States then adopt into 
domestic law and regulations in order to implement and enforce them 
against subject manufacturers. A member State that adopts domestic 
regulations differing from the international standard--in either scope, 
stringency or timing--is obligated to notify ICAO of the differences 
between its domestic regulations and the ICAO standards.\61\
---------------------------------------------------------------------------

    \61\ ICAO, 2006: Convention on International Civil Aviation, 
Article 38, Ninth Edition, Document 7300/9, 114 pp. Available at 
http://www.icao.int/publications/Documents/7300_9ed.pdf (last 
accessed March 16, 2020).
---------------------------------------------------------------------------

    Under the longstanding EPA and FAA rulemaking approach to regulate 
airplane emissions (as described earlier in Section II.D), 
international emission standards have been adopted by ICAO, with 
significant involvement from the FAA and the EPA, and subsequently the 
EPA has undertaken rulemakings under CAA section 231 to establish 
domestic standards that are harmonized with ICAO's standards. Then, CAA 
section 232 requires the FAA to issue regulations to ensure compliance 
with the EPA standards. In 2015, EPA issued an advance notice of 
proposed rulemaking \62\ which noted EPA and FAA's engagement in ICAO 
to establish an international CO2 emissions standard and 
EPA's potential use of section 231 to adopt corresponding airplane GHG 
emissions standards domestically. This rulemaking continues this 
statutory paradigm.
---------------------------------------------------------------------------

    \62\ 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; Proposed Rule, 80 FR 
37758 (July 1, 2015).
---------------------------------------------------------------------------

    The rule will facilitate the acceptance of U.S. manufactured 
airplanes and airplane engines by member States and airlines around the 
world. We anticipate that U.S. manufacturers would be at a significant 
competitive disadvantage if the U.S. failed to adopt standards that are 
aligned with the ICAO standards for CO2 emissions. Member 
States may ban the use of any airplane within their airspace that does 
not meet ICAO standards.\63\ If the EPA were to adopt no standards or 
standards that were not as stringent as ICAO's standards, U.S. civil 
airplane manufacturers could be forced to seek CO2 emissions 
certification from an aviation certification authority of another 
country (other than the FAA) in order to market their airplanes for 
international operation.
---------------------------------------------------------------------------

    \63\ ICAO, 2006: Convention on International Civil Aviation, 
Article 33, Ninth Edition, Document 7300/9, 114 pp. Available at 
http://www.icao.int/publications/Documents/7300_9ed.pdf (last 
accessed March 16, 2020).
---------------------------------------------------------------------------

    Having invested significant effort and resources, working with FAA 
and the Department of State, to gain international consensus to adopt 
the first-ever CO2 standards for airplanes, the EPA believes 
that meeting the United States' obligations under the Chicago 
Convention by aligning domestic standards with the ICAO standards, 
rather than adopting more stringent standards, will have substantial 
benefits for future

[[Page 2145]]

international cooperation on airplane emission standards, and such 
cooperation is the key for achieving worldwide emission reductions. 
Nonetheless, the EPA also analyzed the impacts of two more stringent 
alternatives, and the results of our analyses are described in chapters 
4, 5, and 6 of the Technical Support Document (TSD) which can be found 
in the docket for this rulemaking. The analyses show that one 
alternative would result in limited additional costs, but no additional 
costs or GHG emission reductions compared to the final standards. The 
other alternative would have further limited additional costs and some 
additional GHG emission reductions compared to the final standards, but 
the additional emission reductions are relatively small from this 
alternative and do not justify deviating from the international 
standards and disrupting international harmonization. ICAO 
intentionally established its 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. Thus, the additional emission reductions 
associated with the more stringent alternatives are relatively small 
because all but one of the affected airplanes either meet the 
stringency levels or are expected to go out of production by the 
effective dates. In addition, requiring U.S. manufacturers to certify 
to a different standard than has been adopted internationally (even one 
more stringent) could have disruptive effects on manufacturers' ability 
to market planes for international operation. Consequently, the EPA did 
not choose to finalize either of these alternatives.

A. Airplane Fuel Efficiency Metric

    For the international Airplane CO2 Emission Standards, 
ICAO developed a metric system to allow the comparison of a wide range 
of subsonic airplane types, designs, technology, and uses. While ICAO 
calls this a CO2 emissions metric, it is a measure of fuel 
efficiency, which is directly related to CO2 emitted by 
aircraft engines. The ICAO metric system was designed to differentiate 
between fuel-efficiency technologies of airplanes and to equitably 
capture improvements in propulsive and aerodynamic technologies that 
contribute to a reduction in the airplane CO2 emissions. In 
addition, the ICAO metric system accommodates a wide range of 
technologies and designs that manufacturers may choose to implement to 
reduce CO2 emissions from their airplanes. However, because 
of an inability to define a standardized empty weight across 
manufacturers and types of airplanes, the ICAO CO2 emissions 
metric is based on the MTOM of the airplane. This metric does not 
directly reward weight reduction technologies because the MTOM of an 
airplane will not be reduced when weight reduction technologies are 
applied so that cargo carrying capacity or range can be increased. 
Further, while weight reduction technologies can be used to improve 
airplane fuel efficiency, they may also be used to allow increases in 
payload,\64\ equipment, and fuel load.\65\ Thus, even though weight 
reducing technologies increase the airplane fuel efficiency, this 
improvement in efficiency may not be reflected in operation.
---------------------------------------------------------------------------

    \64\ Payload is the weight of passengers, baggage, and cargo. 
FAA Airplane Weight & Balance Handbook (Chapter 9, page 9-10, file 
page 82) https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/media/FAA-H-8083-1.pdf (x)(last accessed on March 16, 
2020).
    \65\ ICF, 2018: Aircraft CO2 Cost and Technology Refresh and 
Industry Characterization, Final Report, EPA Contract Number EP-C-
16-020, September 30, 2018.
---------------------------------------------------------------------------

    The ICAO metric system consists of a CO2 emissions 
metric (Equation IV-1) and a correlating parameter.\66\
---------------------------------------------------------------------------

    \66\ Annex 16 Volume III Part II Chapter 2 sec. 2.2. ICAO, 2017: 
Annex 16 Volume III--Environmental Protection--Aeroplane CO2 
Emissions, First Edition, 40 pp. Available at: http://www.icao.int/publications/Pages/catalogue.aspx (last accessed July 15, 2020). The 
ICAO Annex 16 Volume III is found on page 16 of the English Edition 
of the 2020 catalog, and it is copyright protected; Order No. AN 16-
3. Also see: ICAO, 2020, Supplement No. 6--July 2020, Annex 16 
Environmental Protection-Volume III-Aeroplane CO2 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--July 2020, English Edition, Order No. 
AN16-3/E/01.
[GRAPHIC] [TIFF OMITTED] TR11JA21.001

    The ICAO CO2 emissions metric uses an average of three 
Specific Air Range (SAR) test points that is normalized by a geometric 
factor representing the physical size of an airplane. SAR is a measure 
of airplane cruise performance, which measures the distance an airplane 
can travel on a unit of fuel. Here the inverse of SAR is used (1/SAR), 
which has the units of kilograms of fuel burned per kilometer of 
flight; therefore, a lower metric value represents a lower level of 
airplane CO2 emissions (i.e., better fuel efficiency). The 
SAR data are measured at three gross weight points used to represent a 
range of day-to-day airplane operations (at cruise).\67\ For the ICAO 
CO2 emissions metric, (1/SAR)avg \68\ is 
calculated at 3 gross weight fractions of Maximum Takeoff Mass (MTOM): 
\69\
---------------------------------------------------------------------------

    \67\ ICAO, 2016: Tenth Meeting Committee on Aviation 
Environmental Protection Report, Doc 10069, CAEP/10, 432 pp, AN/192, 
Available at: https://www.icao.int/publications/Pages/catalogue.aspx 
(last accessed March 16, 2020). The ICAO Report of the Tenth Meeting 
report is found on page 27 of the ICAO Products & Services English 
Edition 2020 catalog and is copyright protected; Order No. 10069.
    \68\ Avg means average.
    \69\ Annex 16 Vol. III Part II Chapter 2 sec. 2.3. ICAO, 2017: 
Annex 16 Volume III--Environmental Protection--Aeroplane 
CO2 Emissions, First Edition, 40 pp. Available at: http://www.icao.int/publications/Pages/catalogue.aspx (last accessed July 
15, 2020). The ICAO Annex 16 Volume III is found on page 16 of the 
English Edition of the 2020 catalog, and it is copyright protected; 
Order No. AN 16-3. Also see: ICAO, 2020, Supplement No. 6--July 
2020, Annex 16 Environmental Protection-Volume III-Aeroplane CO2 
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--July 2020, English 
Edition, Order No. AN16-3/E/01.
---------------------------------------------------------------------------

     High gross mass: 92% MTOM.
     Mid gross mass: Average of high gross mass and low gross 
mass.
     Low gross mass: (0.45 * MTOM) + (0.63 * 
(MTOM[caret]0.924)).
    The Reference Geometric Factor (RGF) is a non-dimensional measure 
of the fuselage \70\ size of an airplane

[[Page 2146]]

normalized by 1 square meter, generally considered to be the shadow 
area of the airplane's pressurized passenger compartment.\71\
---------------------------------------------------------------------------

    \70\ The fuselage is an aircraft's main body section. It holds 
crew, passengers, and cargo.
    \71\ Annex 16 Vol. III Appendix 2. ICAO, 2017: Annex 16 Volume 
III--Environmental Protection--Aeroplane CO2 Emissions, 
First Edition, 40 pp. Available at: http://www.icao.int/publications/Pages/catalogue.aspx (last accessed July 15, 2020). The 
ICAO Annex 16 Volume III is found on page 16 of the English Edition 
2020 catalog, and it is copyright protected; Order No. AN 16-3. Also 
see: ICAO, 2020, Supplement No. 6--July 2020, Annex 16 Environmental 
Protection-Volume III-Aeroplane CO2 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--July 2020, English Edition, Order No. AN16-3/E/01.
---------------------------------------------------------------------------

    When the ICAO CO2 emissions metric is correlated against 
MTOM, it has a positive slope. The international Airplane 
CO2 Emission Standards use the MTOM of the airplane as an 
already certificated reference point to compare airplanes. In this 
action, we are adopting MTOM as the correlating parameter as well.
    We are adopting ICAO's airplane CO2 emissions metric 
(shown in Equation IV-1) as the measure of airplane fuel efficiency as 
a surrogate for GHG emissions from covered airplanes (hereafter known 
as the ``fuel efficiency metric'' or ``fuel burn metric''). This is 
because the fuel efficiency metric controls emissions of both 
CO2 and N2O, the only two GHG emitted by airplane 
engines (see Section IV.H for further information). Consistent with 
ICAO, we are also adopting MTOM as the correlating parameter to be used 
when setting emissions limits.

B. Covered Airplane Types and Applicability

1. Maximum Takeoff Mass Thresholds
    This GHG rule applies to civil subsonic jet airplanes (turbojet or 
turbofan airplanes) with certificated MTOM over 5,700 kg (12,566 lbs.) 
and propeller-driven civil airplanes (turboprop airplanes) over 8,618 
kg (19,000 lbs.). These applicability criteria are the same as those in 
the ICAO Airplane CO2 Emission Standards and correspond to 
the scope of the 2016 Findings. The applicability of this rule is 
limited to civil subsonic airplanes and does not extend to civil 
supersonic airplanes.\72\ Through this action, as described earlier in 
Section II, the EPA is fully discharging its obligations under the CAA 
that were triggered by the 2016 Findings. Once the EPA and the FAA 
fully promulgate the airplane GHG emission standards and regulations 
for their implementation and enforcement domestically, the United 
States regulations will align with ICAO Annex 16 standards.
---------------------------------------------------------------------------

    \72\ Currently, civilian supersonic airplanes are not in 
operation. The international standard did not consider the inclusion 
of supersonic airplanes in the standard. More recently, there has 
been renewed interest in the development of civilian supersonic 
airplanes. This has caused ICAO to begin considering how existing 
emission standards should be revised for new supersonic airplanes. 
The US is involved in these discussions and at this point plans to 
work with ICAO to develop emission standards on the international 
stage prior to adopting them domestically.
---------------------------------------------------------------------------

    Examples of covered airplanes under this GHG rule include smaller 
civil jet airplanes such as the Cessna Citation CJ3+, up to and 
including the largest commercial jet airplanes--the Boeing 777 and the 
Boeing 747. Other examples of covered airplanes include larger civil 
turboprop airplanes, such as the ATR 72 and the Viking 
Q400.73 74 The GHG rule does not apply to smaller civil jet 
airplanes (e.g., Cessna Citation M2), smaller civil turboprop airplanes 
(e.g., Beechcraft King Air 350i), piston-engine airplanes, helicopters, 
and military airplanes.
---------------------------------------------------------------------------

    \73\ This was previously owned by Bombardier and was sold to 
Viking in 2018, November 8, 2018 (Forbes).
    \74\ It should be noted that there are no US domestic 
manufacturers that produce turboprops that meet the MTOM thresholds. 
These airplanes are given as examples but will be expected to be 
certificated by their national aviation certification authority.
---------------------------------------------------------------------------

2. Applicability
    The rule applies to all covered airplanes, in-production, and new 
type designs produced after the respective effective dates of the 
standards except as provided in IV.B.3. There are different regulatory 
emissions levels and/or applicability dates depending on whether the 
covered airplane is in-production before the applicability date or is a 
new type design.
    The in-production standards are only applicable to previously type 
certificated airplanes, newly-built on or after the applicability date 
(described in IV.D.1), and do not apply retroactively to airplanes that 
are already in-service. For example, converting a passenger airplane 
built prior to the 2028 in-production (and/or after 2023 if applicable) 
applicability date into a freight airplane would not trigger the change 
criteria described later in section IV.D.1.i (Changes for non-GHG 
Certificated Airplane Types), which apply only to newly produced 
airplanes (airplanes receiving their first airworthiness certificate) 
incorporating such modifications.
3. Exceptions
    Consistent with the applicability of the ICAO standards, the EPA is 
adopting applicability language that excepts the following airplanes 
from the scope of the standards: Amphibious airplanes, airplanes 
initially designed or modified and used for specialized operational 
requirements, airplanes designed with an RGF of zero,\75\ and those 
airplanes specifically designed or modified and used for fire-fighting 
purposes. Airplanes in these excepted categories are generally designed 
or modified in such a way that their designs are well outside of the 
design space of typical passenger or freight carrying airplanes. For 
example, amphibious airplanes are, by necessity, designed with 
fuselages that resemble boats as much as airplanes. As such, their 
aerodynamic efficiency characteristics fall well outside of the range 
of airplanes used in developing the ICAO Airplane CO2 
Emission Standards and our GHG rules.
---------------------------------------------------------------------------

    \75\ RGF refers to the pressurized compartment of an airplane, 
generally meant for passengers and/or cargo. If an airplane is 
unpressurized, the calculated RGF of the airplane is zero (0). These 
airplanes are very rare, and the few that are in service are used 
for special missions. An example is Boeing's Dreamlifter.
---------------------------------------------------------------------------

    Airplanes designed or modified for specialized operational 
requirements could include a wide range of activities, but many are 
outside the scope of the 2017 ICAO Airplane CO2 standards. 
Airplanes that may be out of scope could include:
     Airplanes that require capacity to carry cargo that is not 
possible by using less specialized airplanes (e.g. civil variants of 
military transports); \76\
---------------------------------------------------------------------------

    \76\ This is not expected to include freight versions of 
passenger airplanes such as the Boeing 767F, Boeing 747-8F, or 
Airbus A330F. Rather, this is intended to except airplanes such as 
the Lockheed L-100 which is a civilian variant of the military C-
130.
---------------------------------------------------------------------------

     Airplanes that require capacity for very short or vertical 
takeoffs and landings;
     Airplanes that require capacity to conduct scientific, 
\77\ research, or humanitarian missions exclusive of commercial 
service; or
---------------------------------------------------------------------------

    \77\ For example, the NASA SOFIA airborne astronomical 
observatory.
---------------------------------------------------------------------------

     Airplanes that require similar factors.
    The EPA is finalizing the exceptions to the rule as proposed. 
Comments on this issue and our responses can be found in the RTC 
document included in the docket for this rulemaking.
4. New Airplane Types and In-Production Airplane Designations
    The final rule recognizes differences between previously type 
certificated

[[Page 2147]]

airplanes that are in production and new type designs presented for 
original certification.
     In-production airplanes: Those airplane types which have 
already received a type certificate \78\ from the FAA, and for which 
manufacturers either have existing undelivered sales orders or would be 
willing and able to accept new sales orders. The term can also apply to 
the individual airplane manufactured according to the approved design 
type certificate, and for which an Airworthiness Certificate is 
required before the airplane is permitted to operate.79 80
---------------------------------------------------------------------------

    \78\ A type certificate is a design approval whereby the FAA 
ensures that the manufacturer's designs meet the minimum 
requirements for airplane safety and environmental regulations. 
According to ICAO Cir 337, a type certificate is ``[a] document 
issued by a Contracting State to define the design of an airplane 
type and to certify that this design meets the appropriate 
airworthiness requirements of that State.'' A type certificate is 
issued once for each new type design airplane and modified as an 
airplane design is changed over the course of its production life.
    \79\ 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/catalogue.aspx 
(last accessed March 16, 2020). The ICAO Report of the Tenth Meeting 
report is found on page 27 of the ICAO Products & Services English 
Edition 2020 catalog and is copyright protected; Order No. 10069.
    \80\ In existing U.S. aviation emissions regulations, in-
production means newly-manufactured or built after the effective 
date of the regulations--and already certificated to pre-existing 
rules. This is similar to the current ICAO definition for in-
production airplane types for purposes of the international 
CO2 standard.
---------------------------------------------------------------------------

     New type designs: Airplane types for which original 
certification is applied for on or after the compliance date of a rule, 
and which have never been manufactured prior to the compliance date of 
a rule.
    Certificated designs may subsequently undergo design changes such 
as new wings, engines, or other modifications that would require 
changes to the type certificated design. These modifications happen 
more frequently than applications for a new type design. For example, a 
number of airplanes have undergone significant design changes 
(including the Boeing 747-8, Boeing 737 Max, Airbus 320 Neo, Airbus 
A330 Neo, and Boeing 777-X). As with a previous series of redesigns 
from 1996-2006, which included the Boeing 777-200LR in 2004, Boeing 
777-300ER in 2006, Airbus 319 in 1996, and Airbus 330-200 in 1998, 
incremental improvements are expected to continue to be more frequent 
than major design changes over the next decade--following these more 
recent major programs (or more recent significant design 
changes).81 82
---------------------------------------------------------------------------

    \81\ ICF International, 2015: CO2 Analysis of 
CO2-Reducing Technologies for Airplane, Final Report, EPA 
Contract Number EP-C-12-011, March 17, 2015.
    \82\ Insofar as we are going through a wave of major redesign 
and service entry now, prospects for further step-function 
improvements will be low in the coming 10-15 years. (ICF 
International, CO2 Analysis of CO2-Reducing 
Technologies for Airplane, Final Report, EPA Contract Number EP-C-
12-011, March 17, 2015.)
---------------------------------------------------------------------------

    New type designs are infrequent, and it is not unusual for new type 
designs to take 8-10 years to develop, from preliminary design to entry 
into service.\83\ The most recent new type designs introduced in 
service were the Airbus A350 in 2015, \84\ the Airbus A220 (formerly 
known as the Bombardier C-Series) in 2016, \85\ and the Boeing 787 in 
2011.86, 87 However, it is unlikely more than one new type 
design will be presented for certification in the next ten years.\88\ 
New type designs (and some redesigns) typically yield large fuel burn 
reductions--10 percent to 20 percent--over the prior generation they 
replace (considered a step-change in fuel burn improvement). As one 
might expect, these significant fuel burn reductions do not happen 
frequently. Also, airplane development programs are expensive.\89\
---------------------------------------------------------------------------

    \83\ ICF International, 2015: CO2 Analysis of CO2-
Reducing Technologies for Airplane, Final Report, EPA Contract 
Number EP-C-12-011, March 17, 2015.
    \84\ The Airbus A350 was announced in 2006 and received its type 
certification in 2014. The first model, the A350-900 entered service 
with Qatar Airways in 2015.
    \85\ The Bombardier C-series was announced in 2005 and received 
its type certification in 2015. The first model, the C100 entered 
service with Swiss Global Air Lines in 2016.
    \86\ Boeing, 2011: Boeing Unveils First 787 to Enter Service for 
Japan Airlines, December 14. Available at http://boeing.mediaroom.com/2011-12-14-Boeing-Unveils-First-787-to-Enter-Service-for-Japan-Airlines (last accessed March 16, 2020).
    \87\ ICF International, 2015: CO2 Analysis of 
CO2-Reducing Technologies for Airplane, Final Report, EPA 
Contract Number EP-C-12-011, March 17, 2015.
    \88\ Ibid.
    \89\ Analysts estimate a new single aisle airplane would have 
cost $10-12 billion to develop. The A380 and 787 are estimated to 
each have cost around $20 billion to develop; the A350 is estimated 
to have cost $15 billion, excluding engine development. Due to the 
large development cost of a totally new airplane design, 
manufacturers are opting to re-wing or re-engine their airplane. 
Boeing is said to have budgeted $5 billion for the re-wing of the 
777, and Airbus and Boeing have budgeted $1-2 billion each for the 
re-engine of the A320 and the 737, respectively (excluding engine 
development costs). Embraer has publicly stated that it will need to 
spend $1-2 billion to re-wing the EMB-175 and variants. (ICF 
International, CO2 Analysis of CO2-Reducing 
Technologies for Airplane, Final Report, EPA Contract Number EP-C-
12-011, March 17, 2015.)
---------------------------------------------------------------------------

    At ICAO, the difference between in-production airplanes and new 
type designs has been used to differentiate two different pathways by 
which fuel efficiency technologies can be introduced into civil 
airplane designs.
    When a new requirement is applied to an in-production airplane, 
there may be a real and immediate effect on the manufacturer's ability 
to continue to build and deliver it in its certificated design 
configuration and to make business decisions regarding future 
production of that design configuration. Manufacturers need sufficient 
notice to make design modifications that allow for compliance to the 
new standards and to have those modifications certificated by their 
certification authorities. In the United States, applying a new 
requirement to an in-production airplane means that a newly produced 
airplane subject to this rule that does not meet the GHG standards 
would likely be denied an airworthiness certificate after January 1, 
2028. As noted above in IV.B.2, in-service airplanes are not subject to 
the ICAO CO2 standards and likewise are not subject to these 
GHG standards.
    For new type designs, this rule has no immediate effect on airplane 
production or certification for the manufacturer. The standards that a 
new type design must meet are those in effect when the manufacturer 
applies for type certification. The applicable design standards at the 
time of application remain frozen over the typical 5-year time frame 
provided by certification authorities for completing the type 
certification process. Because of the investments and resources 
necessary to develop a new type design, manufacturers have indicated 
that it is important to have knowledge of the level of future standards 
at least 8 years in advance of any new type design entering 
service.\90\ Because standards are known early in the design and 
certification process, there is more flexibility in how and what 
technology can be incorporated into a new type design. (See Section VI 
describing the Technology Response for more information on this).
---------------------------------------------------------------------------

    \90\ ICAO policy is that the compliance date of an emissions 
standard must be at least 3 years after it has been agreed to by 
CAEP. Adding in the 5-year certification window, this means that the 
level of the standard can be known 8 years prior to entry into 
service date for a new type design. Manufacturers also have 
significant involvement in the standard development process at ICAO, 
which begins at least 3 years before any new standard is agreed to.
---------------------------------------------------------------------------

    To set standards at levels that appropriately reflect the 
feasibility to incorporate technology and lead time, the level and 
timing of the standards are different for in-production airplanes and 
new type designs. This is discussed further in Sections IV.C and IV.D 
below, describing standards for new type designs and in-production 
airplanes,

[[Page 2148]]

and Section VI, discussing the technology response.

C. GHG Standard for New Type Designs

1. Applicability Dates for New Type Designs
    The EPA is adopting GHG standards that apply to civil airplanes 
within the scope of the international standards adopted by ICAO in 2017 
that meet maximum takeoff weight thresholds, passenger capacity, and 
dates of applications for original type certificates. In this way, 
EPA's standards align with ICAO's in defining those airplanes that are 
now subject to the standards finalized in this action. Consequently, 
for subsonic jet airplanes over 5,700 kg MTOM and certificated with 
more than 19 passenger seats, and for turboprop airplanes over 8,618 kg 
MTOM, the regulations apply to all airplanes for which application for 
an original type certificate is made to the FAA as the first 
certificating authority on or after January 11, 2021. For subsonic jet 
airplanes over 5,700 kg MTOM and less than 60,000 kg MTOM and a type 
certificated maximum passenger seating capacity of 19 seats or fewer, 
the regulations apply to all airplanes for which an original type 
certification application was made to the FAA as the first 
certificating authority on or after January 1, 2023.
    Consistency with international standards is important for 
manufacturers, as they noted in comments to our ANPR in 2015 and in 
their comments to this rulemaking. Airplane manufacturers and engine 
manufacturers would have been surprised if the EPA had adopted criteria 
to identify airplanes covered by our GHG standards that resulted in 
different coverage than that of ICAO's standards--either in terms of 
maximum takeoff mass, passenger capacity, or dates of applications for 
new original type certificates. Additionally, if the EPA diverged from 
ICAO's criteria for CO2 standards applicability, it would 
have introduced unnecessary uncertainty into the airplane type 
certification process. Also, as described earlier for the 2016 
Findings, covered airplanes accounted for the majority (89 percent) of 
total U.S. aircraft GHG emissions.
    In order to harmonize with the ICAO standards to the maximum extent 
possible, the EPA proposed the same effective date as ICAO, January 1, 
2020, for defining those type certification applications subject to the 
standards, noting in the NPRM that it was a date that had already 
passed. However, to avoid potential concerns raised by commenters and 
because it does not affect harmonization with ICAO standards, we are 
adopting standards that are effective upon the effective date of this 
rule January 11, 2021. No airplane manufacturer has in fact yet 
submitted an application for a new type design certification since 
January 1, 2020, no manufacturer will currently need to amend any 
already submitted application to address the GHG standards. Further, 
neither the EPA nor the FAA is aware of any anticipated original new 
type design application to be submitted before the EPA's standards are 
promulgated and effective. Thus, there is no practical impact of 
changing the effective date for the new type design standards from 
January 1, 2020, as proposed, to the effective date of this rule 
January 11, 2021.
    The EPA recognizes that new regulatory requirements have differing 
impacts on items that are already in production and those yet to be 
built. Airplane designs that have yet to undergo original type 
certification can more easily be adapted for new regulatory 
requirements, compared with airplanes already being produced subject to 
older, existing design standards. The agency has experience adopting 
regulations that acknowledge these differences, such as in issuing 
emission standards for stationary sources of hazardous air pollutants 
(which often impose more stringent standards for new sources, defined 
based on dates that precede dates of final rule promulgation, than for 
existing sources). See, e.g., 42 U.S.C. 7412(a)(4), defining ``new 
source'' to mean a stationary source the construction or reconstruction 
of which is commenced after the EPA proposes regulations establishing 
an emission standard.
2. Regulatory limit for New Type Designs
    The EPA is adopting the GHG emissions limit for new type designs 
that is a function of the airplane certificated MTOM and consists of 
three levels described below in Equation IV-2, Equation IV-3, and 
Equation IV-4.\91\
---------------------------------------------------------------------------

    \91\ Annex 16 Vol. III Part II Chapter 2 sec. 2.4.2 (a), (b), 
and (c). ICAO, 2017: Annex 16 Volume III--Environmental Protection--
Aeroplane CO2 Emissions, First Edition, 40 pp. Available 
at: http://www.icao.int/publications/Pages/catalogue.aspx (last 
accessed July 15, 2020). The ICAO Annex 16 Volume III is found on 
page 16 of the English Edition of the 2020 catalog and it is 
copyright protected; Order No. AN 16-3. Also see: ICAO, 2020, 
Supplement No.6--July 2020, Annex 16 Environmental Protection-Volume 
III-Aeroplane CO2 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--July 2020, English Edition, Order No. AN16-3/E/01.
[GRAPHIC] [TIFF OMITTED] TR11JA21.002

[GRAPHIC] [TIFF OMITTED] TR11JA21.003

[GRAPHIC] [TIFF OMITTED] TR11JA21.004


[[Page 2149]]


    Figure IV-1 and Figure IV-2 show the numerical limits of the 
adopted new type design rules and how the airplane types analyzed in 
Sections V and VI relate to this limit. Figure IV-2 shows only the 
lower MTOM range of Figure IV-1 to better show the first two segments 
of the limit line. These plots below show the airplane fuel efficiency 
metric values as they were modeled. This includes all anticipated/
modeled technology responses, improvements, and production assumptions 
in response to the market and this rule. (See Section V and VI for more 
information about this.) These final GHG emission limits are the same 
as the limits of the ICAO Airplane CO2 Emission Standards.
[GRAPHIC] [TIFF OMITTED] TR11JA21.005


[[Page 2150]]


[GRAPHIC] [TIFF OMITTED] TR11JA21.006

    After analyzing potential levels of the standard, ICAO determined, 
based on assessment of available data, that there were significant 
performance differences between large and small airplanes. Jet 
airplanes with an MTOM less than 60 tons \92\ are either business jets 
or regional jets. The physical size of smaller airplanes presents 
scaling challenges that limit technology improvements that can readily 
be made on larger airplanes.\93\ This leads to requiring higher capital 
costs to implement the technology relative to the sale price of the 
airplanes.\94\ Business jets (generally less than 60 tons MTOM) tend to 
operate at higher altitudes and faster speeds than larger commercial 
traffic.
---------------------------------------------------------------------------

    \92\ In this rulemaking, 60 tons means 60 metric tons (or 
tonnes), which is equal to 60,000 kilograms (kg). 1 ton means 1 
metric ton (or tonne), which is equal to 1,000 kg.
    \93\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
    \94\ U.S., United States Position on the ICAO Aeroplane 
CO2 Emissions Standard, Montr[eacute]al, 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.
---------------------------------------------------------------------------

    Based on these considerations, when developing potential levels for 
the international standards, 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 tons.\95\ This natural gap allowed a ``kink'' point (i.e., 
change in the slope of the standard) to be established between larger 
commercial airplanes and smaller business jets and regional jets. The 
identification of this kink point provided flexibility at ICAO to 
consider standards at appropriate levels for airplanes above and below 
60 tons.
---------------------------------------------------------------------------

    \95\ Initial data that were reviewed at ICAO did not include 
data on the Bombardier C-Series (now the Airbus A220) airplane. Once 
data were provided for this airplane, it was determined by ICAO that 
while the airplane did cross the 60 tons kink point, this did not 
pose a problem for analyzing stringency options, because the 
airplane passes all options considered.
---------------------------------------------------------------------------

    The level adopted for new type designs was set to reflect the 
performance for the latest generation of airplanes. The CO2 
emission standards agreed to at ICAO, and the GHG standards adopted 
here, are meant to be technology following standards. This means the 
rule reflects the performance and technology achieved by existing 
airplanes (in-production and in-development airplanes \96\).\97\
---------------------------------------------------------------------------

    \96\ In-development airplanes are airplanes that were in-
development when setting the standard at ICAO but will be in 
production by the applicability dates. These could be new type 
designs (e.g. Airbus A350) or redesigned airplanes (e.g. Boeing 
737Max).
    \97\ Note: Figure IV-1 and Figure IV-2 show the metric values 
used in the EPA modeling for this action. These values differ from 
those used at ICAO. The rationale for this difference is discussed 
below in section VI of this rule, and in chapter 2 of the TSD.
---------------------------------------------------------------------------

    Airplanes of less than 60 tons with 19 or fewer passenger seats 
have additional economic challenges to technology development compared 
with similarly sized commercial airplanes. ICAO sought to reduce the 
burden on manufacturers of airplanes with 19 or fewer seats, and thus 
ICAO agreed to delay the applicability of the new type designs for 3 
years. In maintaining consistency with the international decision, the 
applicability dates adopted in this rule reflect this difference 
determined by ICAO (see Section VI for further information).
    As described earlier in Section II, consistency with the 
international standards will facilitate the acceptance of U.S. 
airplanes by member States and airlines around the world, and it will 
help to ensure that U.S. manufacturers

[[Page 2151]]

will not be at a competitive disadvantage compared with their 
international competitors. Consistency with the international standards 
will also prevent backsliding by ensuring that all new type design 
airplanes are at least as efficient as today's airplanes.

D. GHG Standard for In-Production Airplane Types

1. Applicability Dates for In-Production Airplane Types
    The EPA is adopting the same compliance dates for the GHG rule as 
those adopted by ICAO for its CO2 emission standards. 
Section IV.D.2 below describes the rationale for these dates and the 
time provided to in-production types.
    All airplanes type certificated prior to January 11, 2021, and 
receiving its first certificate of airworthiness after January 1, 2028, 
will be required to comply with the in-production standards. This GHG 
regulation will function as a production cutoff for airplanes that do 
not meet the fuel efficiency levels described below.
i. 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% \98\ will be required to demonstrate that newly 
produced airplanes comply with the in-production standard. This earlier 
applicability date for in-production airplanes, 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 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.
---------------------------------------------------------------------------

    \98\ Note that IV.D.1.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.1.i only applies only to 
airplane types that have not been certificated for GHG.
---------------------------------------------------------------------------

    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.
2. Regulatory Limit for In-Production Type Designs
    The EPA is adopting an emissions limit for in-production airplanes 
that is a function of airplane certificated MTOM and consists of three 
MTOM ranges as described below in Equation IV-5, Equation IV-6, and 
Equation IV-7.\99\
---------------------------------------------------------------------------

    \99\ Annex 16 Vol. III Part II Chapter 2 sec. 2.4.2(d), (e), and 
(f). ICAO, 2017: Annex 16 Volume III--Environmental Protection--
Aeroplane CO2 Emissions, First Edition, 40 pp. Available 
at: http://www.icao.int/publications/Pages/catalogue.aspx (last 
accessed July 15, 2020). The ICAO Annex 16 Volume III is found on 
page 16 of the English Edition of the 2020 catalog, and it is 
copyright protected; Order No. AN 16-3. Also see: ICAO, 2020, 
Supplement No. 6--July 2020, Annex 16 Environmental Protection-
Volume III-Aeroplane CO2 Emissions, Amendment 1 (20/7/
20). 22 pp. 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--July 2020, English Edition, Order No. AN16-3/E/01.
[GRAPHIC] [TIFF OMITTED] TR11JA21.007

[GRAPHIC] [TIFF OMITTED] TR11JA21.008

[GRAPHIC] [TIFF OMITTED] TR11JA21.009


[[Page 2152]]


    Figure IV-3 and Figure IV-4 show the numerical limits of the 
adopted in-production rules and the relationship of the airplane types 
analyzed in Sections V and VI to this limit. Figure IV-4 shows only the 
lower MTOM range of Figure IV-3 to better show the first two segments 
of the limit line. These plots below show the airplane CO2 
metric values as they were modeled. This includes all anticipated/
modeled technology responses, improvements, and production assumptions 
in response to the market and the final rule. (See Sections V and VI 
for more information about this.) These GHG emission limits are the 
same as the limits of the ICAO Airplane CO2 Emission 
Standards.
[GRAPHIC] [TIFF OMITTED] TR11JA21.010


[[Page 2153]]


[GRAPHIC] [TIFF OMITTED] TR11JA21.011

    As discussed in Section IV.C above, the kink point was included in 
the ICAO Aircraft CO2 standards at 60 tons to account for a 
change in slope that is observed between large and small airplanes. The 
flat section starting at 60 tons is used as a transition to connect the 
curves for larger and smaller airplanes.
    While the same technology is considered for both new type design 
and in-production airplanes, there will be a practical difference in 
compliance for in-production airplanes. Manufacturers will need to test 
and certify each type design to the GHG standard prior to January 1, 
2028, or else newly produced airplanes will likely be denied an 
airworthiness certificate. In contrast, new type design airplanes have 
yet to go into production, but these airplanes will need to be designed 
to comply with the standards for new type designs (for an application 
for a new type design certificate on or after January 11, 2021). This 
poses a challenge for setting the level of the in-production standard 
because sufficient time needs to be provided to allow for the GHG 
certification process and the engineering and airworthiness 
certifications needed for improvements. The more stringent the in-
production standard is, the more time that is necessary to provide 
manufacturers to modify production of their airplanes. ICAO determined 
that while the technology to meet the in-production level is available 
in 2020 (the ICAO standards new type design applicability date), 
additional time beyond the new type design applicability date was 
necessary to provide sufficient time for manufacturers to certify all 
of their products. The EPA agrees that additional time for in-
production airplanes beyond the new type design applicability date is 
necessary to allow sufficient time to certify airplanes to the GHG 
standards.
    Section VI describes the analysis that the EPA conducted to 
determine the cost and benefits of adopting this standard. Consistent 
with the ICAO standard, this rule applies to all in-production 
airplanes built on or after January 1, 2028, and to all in-production 
airplanes that have any modification that trigger the change criteria 
after January 1, 2023.
    The levels of the in-production GHG standards are the same as 
ICAO's CO2 standards, and they reflect the emission 
performance of current in-production and in-development airplanes. As 
discussed in Section IV.B.4 above and in Section VI, the regulations 
reflect differences in economic feasibility for introducing 
modifications to in-production airplanes and new type designs. The 
standards adopted by ICAO, and here, for in-production airplanes were 
developed to reflect these differences.

E. Exemptions From the GHG Standards

    On occasion, manufacturers may need additional time to comply with 
a standard. The reasons for needing a temporary exemption from 
regulatory requirements vary and may include circumstances beyond the 
control of the manufacturer. The FAA is familiar with these actions, as 
it has handled the similar engine emission standards under its CAA 
authority to enforce the standards adopted by the EPA. The FAA has 
considerable authority under its authorizing legislation and its 
regulations to deal with these events.\100\
---------------------------------------------------------------------------

    \100\ Title 49 of the United States Code, sec. 44701(f), vests 
power in the FAA Administrator to issue exemptions as long as the 
public interest condition is met, and, pursuant to sec. 232(a) of 
the CAA, the Administrator may use that power ``in the execution of 
all powers and duties vested in him under this section'' ``to insure 
compliance'' with emission standards.
---------------------------------------------------------------------------

    Since requests for exemptions are requests for relief from the 
enforcement

[[Page 2154]]

of these standards (as opposed to a request to comply with a different 
standard than set by the EPA), this rule will continue the relationship 
between the agencies by directing any request for exemption be filed 
with the FAA under its established regulatory paradigm. The 
instructions for submitting a petition for exemption to the FAA can be 
found in 14 CFR part 11, specifically Sec.  11.63. Section 11.87 lists 
the information that must be filed in a petition, including a reason 
``why granting your petition is in the public interest.'' Any request 
for exemption will need to cite the regulation that the FAA will adopt 
to carry out its duty of enforcing the standard set by the EPA. A list 
of requests for exemption received by the FAA is routinely published in 
the Federal Register.
    The primary criterion for any exemption filed with the FAA is 
whether a grant of exemption will be in the public interest. The FAA 
will continue to consult with the EPA on all petitions for exemption 
that the FAA receives regarding the enforcement of aircraft engine and 
emission standards adopted under the CAA.

F. Application of Rules for New Version of an Existing GHG-Certificated 
Airplane

    Under the international Airplane CO2 Emission Standards, 
a new version of an existing CO2-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-
CO2-Change Threshold (described in IV.F.1 below). ICAO's 
standards provide that once an airplane is CO2 certificated, 
all subsequent changes to that 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 would also apply 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 new type 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 adopting provisions for new versions of 
existing GHG-certificated airplanes that are 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.
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,\101\ 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.
---------------------------------------------------------------------------

    \101\ A fairing is ``a structure on the exterior of an aircraft 
or boat, for reducing drag.'' https://www.dictionary.com/browse/fairing (last accessed November 30, 2020).
---------------------------------------------------------------------------

    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 takeoff 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 IV-5: \102\
---------------------------------------------------------------------------

    \102\ 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/publications/Pages/catalogue.aspx (last accessed July 15, 2020). The 
ICAO Annex 16 Volume III is found on page 16 of the English Edition 
of the 2020 catalog, and it is copyright protected; Order No. AN 16-
3. Also see: ICAO, 2020. Supplement No. 6--July 2020, Annex 16 
Environmental Protection--Volume III--Aeroplane CO2 
Emissions, Amendment 1 (20/7/20). 22 pp. Available at https://
www.icao.int/publications/catalogue/CAT_2020_Sup06_en.pdf (last 
accessed October 28, 2020). The ICAO Annex 16, Volume III, Amendment 
1 is found on page 2 of Supplement No. 6--July 2020; English 
Edition, Order No. AN 16-3/E/01.
---------------------------------------------------------------------------

     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.

[[Page 2155]]

[GRAPHIC] [TIFF OMITTED] TR11JA21.012

    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.
    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.\103\
---------------------------------------------------------------------------

    \103\ ETM Vol. III sec. 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/publications/Pages/catalogue.aspx (last accessed July 15, 2020). The ICAO Environmental 
Technical Manual Volume III is found on page 77 of the English 
Edition of the 2020 catalog, and it is copyright protected; Order 
No. 9501-3. Also see: ICAO, 2020: Doc 9501--Environmental Technical 
Manual Volume III--Procedures for the CO2 Emissions 
Certification of Aeroplanes, 2nd Edition, 2020. 90 pp. Available at 
https://www.icao.int/publications/catalogue/cat_2020_sup06_en.pdf 
(last accessed October 28, 2020). The ICAO Environmental Technical 
Manual Volume III, 2nd Edition is found on page 3 of Supplement No. 
6--July 2020, English Edition, Order No. 9501-3.
---------------------------------------------------------------------------

    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.

G. Test and Measurement Procedures

    The international certification test procedures have been developed 
based upon industry's current best practices for establishing the 
cruise performance of their airplanes and on input from

[[Page 2156]]

certification authorities. These procedures include specifications for 
airplane conformity, weighing, fuel specifications, test condition 
stability criteria, required confidence intervals, measurement 
instrumentation required, and corrections to reference conditions. In 
this action, we are incorporating by reference the test procedures for 
the ICAO Airplane CO2 Emission Standards. Adoption of these 
test procedures will maintain consistency among all ICAO member States.
    Airplane flight tests, or FAA approved performance models, will be 
used to determine SAR values that form the basis of the GHG metric 
value. Under the adopted rule, flight testing to determine SAR values 
shall be conducted within the approved normal operating envelope of the 
airplane, when the airplane is steady, straight, level, and trim, at 
manufacturer-selected speed and altitude.\104\ The rule will provide 
that flight testing must be conducted at the ICAO-defined reference 
conditions where possible,\105\ and that when testing does not align 
with the reference conditions, corrections for the differences between 
test and reference conditions shall be applied.\106\
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    \104\ It is expected that manufacturers will choose conditions 
that result in the highest SAR value for a given certification mass. 
Manufacturers may choose other than optimum conditions to determine 
SAR; however, doing so will be at their detriment.
    \105\ Annex 16, Vol. III, sec. 2.5. ICAO, 2017: Annex 16 Volume 
III--Environmental Protection--Aeroplane CO2 Emissions, 
First Edition, 40 pp. Available at: http://www.icao.int/publications/Pages/catalogue.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 CO2 Emissions, 
Amendment 1 (20/7/20) 22 pp. Available at http://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--July 2020, English Edition, Order No. AN 
16-3/E/01.
    \106\ Annex 16, Vol. III, Appendix 1. ICAO, 2017: Annex 16 
Volume III--Environmental Protection--Aeroplane CO2 
Emissions, First Edition, 40 pp. Available at: http://www.icao.int/publications/Pages/catalogue.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 CO2 Emissions, 
Amendment 1 (20/7/20) 22 pp. Available at http://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--July 2020, English Edition, Order No. AN 
16-3/E/01.
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    We are incorporating by reference, in 40 CFR 1030.23(d), certain 
procedures found in ICAO Annex 16, Volume III.

H. Controlling Two of the Six Well-Mixed GHGs

    As described earlier in Section IV.A and IV.G, we are adopting the 
ICAO test procedures and fuel efficiency metric.\107\ The ICAO test 
procedures for the international Airplane CO2 Emission 
Standards measure fuel efficiency (or fuel burn), and ICAO uses fuel 
efficiency in the metric (or equation) for determining compliance. As 
explained earlier in Section III and in the 2016 Findings,\108\ only 
two of the six well-mixed GHGs--CO2 and N2O--are 
emitted from covered aircraft. Although there is not a standardized 
test procedure for directly measuring airplane CO2 or 
N2O emissions, the test procedure for fuel efficiency scales 
with the limiting of both CO2 and N2O emissions, 
as they both can be indexed on a per-unit-of-fuel-burn basis. 
Therefore, both CO2 and N2O emissions are 
controlled as airplane fuel burn is limited.\109\ Since limiting fuel 
burn is the only means by which airplanes control their GHG emissions, 
the fuel-burn-based metric (or fuel-efficiency-based metric) reasonably 
serves as a means for controlling both CO2 and 
N2O.
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    \107\ ICAO's certification standards and procedures for airplane 
CO2 emissions are based on the consumption of fuel (or 
fuel burn). ICAO uses the term CO2 for its standards and 
procedures, but ICAO is actually regulating or measuring the rate of 
an airplane's fuel burn (or fuel efficiency). As described earlier, 
to convert an airplane's rate of fuel burn (for jet fuel) to a 
CO2 emissions rate, a 3.16 kilograms of CO2 
per kilogram of fuel burn emission index needs to be applied.
    \108\ U.S. EPA, 2016: Finding That Greenhouse Gas Emissions From 
Aircraft Cause or Contribute To Air Pollution That May Reasonably Be 
Anticipated To Endanger Public Health and Welfare; Final Rule, 81 FR 
54422 (August 15, 2016).
    \109\ For jet fuel, the emissions index or emissions factor for 
CO2 is 3.16 kilograms of CO2 per kilogram of 
fuel burn (or 3,160 grams of CO2 per kilogram of fuel 
burn). For jet fuel, the emissions index for nitrous oxide is 0.1 
grams of nitrous oxide per kilogram of fuel burn (which is 
significantly less than the emissions index for CO2). 
Since CO2 and nitrous oxide emissions are indexed to fuel 
burn, they are both directly tied to fuel burn. Controlling 
CO2 emissions means controlling fuel burn, and in turn 
this leads to limiting nitrous oxide emissions. Thus, controlling 
CO2 emissions scales with limiting nitrous oxide 
emissions.
    SAE, 2009, Procedure for the Calculation of Airplane Emissions, 
Aerospace Information Report, AIR5715, 2009-07 (pages 45-46). The 
nitrous oxide emissions index is from this report.
    ICAO, 2016: ICAO Environmental Report 2016, Aviation and Climate 
Change, 250 pp. The CO2 emissions index is from this 
report. Available at https://www.icao.int/environmental-protection/Documents/ICAO%20Environmental%20Report%202016.pdf (last accessed 
March 16, 2020).
---------------------------------------------------------------------------

    Since CO2 emissions represent nearly all GHG emissions 
from airplanes and ICAO's CO2 test procedures measure fuel 
efficiency by using a fuel-efficiency-based metric, we are adopting 
rules that harmonize with the ICAO CO2 standard--by adopting 
an aircraft engine GHG \110\ standard that employs a fuel efficiency 
metric that will also scale with both CO2 and N2O 
emissions. The aircraft engine GHG standard will control both 
CO2 and N2O emissions, without the need for 
adoption of engine exhaust emissions rates for either CO2 or 
N2O. However, the air pollutant regulated by these standards 
will remain the aggregate of the six well-mixed GHGs.\111\
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    \110\ See section II.E (Consideration of Whole Airplane 
Characteristics) of this rule for a discussion on regulating 
emissions from the whole airplane.
    \111\ Although compliance with the final GHG standard will be 
measured in terms of fuel efficiency, the EPA considers 
the six well-mixed GHGs to be the regulated pollutant for the 
purposes of the final standard.
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I. Response to Key Comments

    The EPA received numerous comments on the proposed rulemaking which 
are presented in the Response to Comments document along with the EPA's 
responses to those comments. Below is a brief discussion of some of the 
key comments received.
1. Stringency of the Standards
    Several commenters stated that the proposed rulemaking satisfies 
the requirements in the CAA, is consistent with the precedent for 
setting airplane emission standards in coordination with ICAO, and is 
supported by the administrative record for this rulemaking. The 
establishment of aircraft engine GHG standards that match the ICAO 
airplane CO2 standards into U.S. law is consistent with the 
authority given to the EPA under section 231 of the CAA, and it clearly 
meets the criteria for adoption of aircraft engine standards specified 
in section 231. In addition, the proposed GHG standards align with the 
following CAEP terms of reference (described earlier in section II.D.1) 
that were assessed for the international airplane CO2 
standards: Technical feasibility, environmental benefit, economic 
reasonableness, and interdependencies of measures (i.e., measures taken 
to minimize noise and emissions). These CAEP terms of reference are 
consistent with the criteria the EPA must adhere to under section 
231(b) of the CAA that requires the EPA to allow enough lead time ``to 
permit the development and application of the requisite technology, 
giving appropriate consideration to the cost of compliance within such 
period''--when adopting aircraft engine emission standards.
    In addition, these commenters expressed that the EPA adopting

[[Page 2157]]

standards that match ICAO standards is vital to competitiveness of the 
U.S. industry and certainty in the regulatory landscape. This approach 
provides international harmonization regulatory uniformity throughout 
the world. Adopting ICAO standards will protect U.S. jobs and 
strengthen the American aviation industry by ensuring the worldwide 
acceptance of U.S. manufactured airplanes. Adopting more stringent 
standards would place U.S. airplane manufacturers at a competitive 
disadvantage compared to their international competitors. Reciprocity 
and consistency are essential, specifically the worldwide mutual 
recognition of the sufficiency of ICAO's standards and the avoidance of 
any unnecessary difference from those standards in each Member State's 
law. Aviation is a global industry, and airplanes are assets that can 
fly anywhere in the world and cross international borders. Within this 
context, alignment of domestic and international standards levels the 
playing field for the aviation industry, and it makes sure that 
financial resources can be focused on improvement for the benefit of 
the environment (including investments creating CO2 
emissions reductions via carrying out the non-airplane-technology 
elements of ICAO's basket of measures). In addition, reciprocity and 
consistency of international standards decrease administrative 
complexity for airplane manufacturers and air carriers. Some commenters 
stated that aligning with ICAO standards ensures that U.S. 
manufacturers' airplanes are available to U.S. air carriers, while 
encouraging global competition and enabling U.S. air carriers to obtain 
airplanes and airplane engines at competitive prices.
    In contrast, several commenters stated that the EPA's lack of 
consideration of feasible standards that result in GHG emission 
reductions is unlawful and arbitrary, and that the EPA should adopt 
more stringent standards. Under the authority that the EPA is provided 
in Clean Air Act section 231, the EPA is obligated to account for the 
danger to public health and welfare of the pollutant and the 
technological feasibility to control the pollutant. All in-production 
and new type design airplanes will meet the standards because existing 
non-compliant airplanes are anticipated to end production by 2028, the 
applicability date for in-production airplanes. More stringent 
standards are feasible for in-production and new type design airplanes, 
and the EPA should adopt technology-forcing instead of technology 
following standards to make sure the rulemaking will result in needed 
reductions in GHG emissions.
    In response to these comments, we refer to Section II.B and the 
introductory paragraphs of Section IV which present our reasons for 
finalizing GHG standards that are aligned with the international 
CO2 standards. Section 231(a)(2)(A) of the CAA directs the 
Administrator of the EPA to, from time to time, propose aircraft engine 
emission standards applicable to the emission of any air pollutant from 
classes of aircraft engines which in the Administrator's judgment 
causes or contributes to air pollution that may reasonably be 
anticipated to endanger public health or welfare. Section 231(a)(3) 
provides that after we propose standards, the Administrator shall issue 
such standards ``with such modifications as he deems appropriate.'' 
Section 231(b) requires that any emission standards ``take effect after 
such period as the Administrator finds necessary . . . to permit the 
development and application of the requisite technology, giving 
appropriate consideration to the cost of compliance during such 
period.'' The U.S. Court of Appeals for the D.C. Circuit has held that 
these provisions confer an unusually broad degree of discretion on the 
EPA to adopt aircraft engine emission standards as the Agency 
determines are reasonable. Nat'l Ass'n of Clean Air Agencies v. EPA, 
489 F.3d 1221, 1229-30 (D.C. Cir. 2007) (NACAA). As described in the 
2005 EPA rule on aircraft engine NOx standards,\112\ while 
the statutory language of section 231 is not identical to other 
provisions in title II of the CAA that direct the EPA to establish 
technology-based standards for various types of engines, the EPA 
interprets its authority under section 231 to be somewhat similar to 
those provisions that require us to identify a reasonable balance of 
specified emissions reduction, cost, safety, noise, and other factors. 
See, e.g., Husqvarna AB v. EPA, 254 F.3d 195 (D.C. Cir. 2001) 
(upholding the EPA's promulgation of technology-based standards for 
small non-road engines under section 213(a)(3) of the CAA). However, we 
are not compelled under section 231 to obtain the ``greatest degree of 
emission reduction achievable'' as per sections 213 and 202(a)(3)(A) of 
the CAA, and so the EPA does not interpret the Act as requiring the 
agency to give subordinate status to factors such as cost, safety, and 
noise in determining what standards are reasonable for aircraft 
engines. Rather, the EPA has greater flexibility under section 231 in 
determining what standard is most reasonable for aircraft engines, and 
the EPA is not required to achieve a technology-forcing result. 
Moreover, in light of the United States' ratification of the Chicago 
Convention, EPA has historically given significant weight to uniformity 
with international requirements as a factor in setting aircraft engine 
standards. The fact that most airplanes already meet the standards does 
not in itself mean that the standards are inappropriate, provided the 
agency has a reasonable basis after considering all the relevant 
factors for setting the standards at a level that results in no actual 
emission reductions. By the same token, the EPA believes a technology-
forcing standard would not be precluded by section 231, in light of 
section 231(b)'s forward-looking language. However, the EPA would, 
after consultation with the Secretary of Transportation, need to 
provide manufacturers sufficient lead time to develop and implement 
requisite technology. Also, there is an added emphasis on the 
consideration of safety in section 231 (see, e.g., sections 
231(a)(2)(B)(ii) (``The Administrator shall not change the aircraft 
engine emission standards if such change would [* * *] adversely affect 
safety''), 42 U.S.C. 7571(a)(2)(B)(ii), and 231(c) (``Any regulations 
in effect under this section [* * *] shall not apply if disapproved by 
the President, after notice and opportunity for public hearing, on the 
basis of a finding by the Secretary of Transportation that any such 
regulation would create a hazard to aircraft safety''), 42 U.S.C. 
7571(c). Thus, it is reasonable for the EPA to give greater weight to 
considerations of safety in this context than it might in balancing 
emissions reduction, cost, and energy factors under other title II 
provisions.
---------------------------------------------------------------------------

    \112\ U.S. EPA, 2005: Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures; Final 
Rule, 70 FR 69664 (November 17, 2005). See page 69676 of this 
Federal Register notice.
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    In order to promote international cooperation on GHG emissions 
regulation and international harmonization of aviation standards and to 
avoid placing U.S. manufacturers at a competitive disadvantage that 
likely would result if the EPA were to adopt standards different from 
the standards adopted by ICAO, as discussed further above, the EPA is 
adopting standards for GHG emissions from certain classes of engines 
used on airplanes that match the stringency of the CO2 
standards adopted by ICAO. This rule will facilitate the acceptance of 
U.S. manufactured airplanes and airplane

[[Page 2158]]

engines by member States and airlines around the world. In addition, 
requiring U.S. manufacturers to certify to different or more stringent 
standards than have been adopted internationally could have disruptive 
effects on manufacturers' ability to market planes for international 
operation. Having invested significant effort and resources, working 
with the FAA and the Department of State, to gain international 
consensus within ICAO to adopt the first-ever international 
CO2 standards for airplanes, the EPA believes that meeting 
the United States' obligations under the Chicago Convention by aligning 
domestic standards with the ICAO standards, rather than adopting more 
stringent standards, will have substantial benefits for future 
international cooperation on airplane emission standards, and such 
cooperation is the key for achieving worldwide emission reductions. 
This EPA rule to promulgate airplane GHG standards equivalent to 
international standards is consistent with U.S. obligations under ICAO. 
By issuing standards that meet or exceed the minimum stringency levels 
of ICAO standards, we satisfy these obligations.
    Also, these final standards are the first-ever airplane GHG 
standards and test procedures for U.S. manufacturers, and international 
regulatory uniformity and certainty are key elements for these 
manufacturers as they become familiar with adhering to these standards 
and test procedures. Consistency with the international standards will 
prevent backsliding by ensuring that all new type design and in-
production airplanes are at least as efficient as today's airplanes. 
CAEP meets triennially, and in the future, we anticipate ICAO/CAEP 
considering more stringent airplane CO2 standards. The U.S. 
Interagency Group on International Aviation (IGIA) facilitates 
coordinated recommendations to the Secretary of State on issues 
pertaining to international aviation (and ICAO/CAEP), and the FAA is 
the chair of IGIA. Representatives of domestic states, NGOs, and 
industry can participate in IGIA to provide input into future standards 
for ICAO/CAEP. U.S. manufacturers will be prepared for any future 
standard change due to their experience with the first-ever standards. 
Moreover, the manufacturers anticipation of future ICAO standards will 
be another factor for them to consider in continually improving the 
fuel efficiency of their airplanes in addition to the business-as-usual 
market forces (i.e., in addition to business-as-usual continually 
improving fuel efficiency for airplanes), as described later in section 
V.
2. Timing of the Standard--Extension of In Production Applicability 
Date for Some Freight Airplanes
    Some commenters requested that the EPA deviate from the ICAO 
standards (and the EPA proposed implementation dates) and delay the 
2028 in-production applicability date for a class of widebody purpose-
built (or dedicated) freighters such as the Boeing 767F and Airbus 
A330-220F. These commenters requested that the in-production 
applicability date for purpose-built freight airplanes with MTOMs 
between 180,000 kg and 240,000 kg be extended by 10 years, from January 
1, 2028 to January 1, 2038.
    Boeing argued that significant unexpected economic factors arising 
after the ICAO CO2 standard was established, including the 
COVID-19 pandemic, have affected and continue to severely affect 
Boeing, its supply chain, and its customers, and warrant additional 
time for Boeing to upgrade or replace the 767F in a practicable and 
economically feasible manner, consistent with the ICAO terms of 
reference and the mandatory factors in CAA section 231(b). Additional 
details on these comments can be found in the Response to Comments 
document under section 6.2.1.
    The EPA recognizes the significant financial hardships the aviation 
industry is experiencing as a result of the COVID-19 pandemic. The 
challenges the industry now faces were not anticipated when the 
standards were agreed by ICAO in 2017. However, ICAO recognized that 
unexpected hardships may arise in the future and included language to 
allow certification authorities to grant exemptions when it may be 
appropriate to provide relief from the standards.
    Consistent with ICAO, the EPA proposed to include exemption 
provisions (40 CFR 1030.10 of the regulations) by pointing to the FAA's 
existing exemption process to provide relief when unforeseen 
circumstances or hardships result in the need for additional time to 
comply with the GHG standards. These provisions are similar to those 
exemption provisions that have been in 40 CFR part 87 of the 
regulations for decades. Manufacturers will be able to apply to the FAA 
for exemptions in accordance with the regulations of 14 CFR part 11, 
and the FAA will consult with the EPA on each exemption application 
prior to granting relief from certification to the GHG standards.
    Boeing provided a list of historical examples where they say the 
EPA delayed aircraft engine emission standards, adopted standards after 
ICAO implementation dates, or granted exemptions.\113\ Boeing 
characterizes the examples of exemptions as the most relevant to their 
current situation with the 767F. However, neither Boeing nor other 
commenters provided any information or rationale to justify why the 
exemption provisions proposed in part 1030.10, which point to the FAA's 
existing exemption process, would be insufficient to resolve their 
concerns. Thus, there is not a sufficient basis for the EPA to conclude 
that the exemption provisions would not resolve this issue for the 
commenters.
---------------------------------------------------------------------------

    \113\ Boeing stated that the EPA granted exemptions, but the FAA 
granted the exemptions after consultation with the EPA, as EPA is 
not authorized under the CAA to grant exemptions.
---------------------------------------------------------------------------

    As we noted at the beginning of Section IV and above in IV.J.1, 
there are significant benefits to industry and future international 
cooperation to adopting standards that to the highest practicable 
degree match ICAO standards, in terms of scope, timing, stringency, 
etc. If less stringent or delayed standards were adopted, it would have 
a disruptive impact on the manufacturers' ability to market their 
airplanes internationally. Boeing recognized this disruption in their 
proposed addition to the regulatory text, 1030.1(a)(8)(ii), where they 
stated the airworthiness certificate would be limited to U.S. domestic 
operation. Commenters did not provide any rationale, or make any 
statements, about this suggested revision to limit the operation of 
these freighters to the U.S., nor did they state why such an 
operational requirement would be in EPA's purview. To include limits as 
this on an airworthiness certificate would seem to impose operational 
restrictions on air carriers. Imposing a restriction such as that 
suggested by Boeing would be unprecedented for the EPA, and it is not 
clear how it could be accomplished. Further, such a significant change 
was not proposed for comment by interested parties. Operational 
restrictions would typically be the purview of the FAA under its 
enabling legislation.
    Finally, although Boeing's request purported to also cover an 
Airbus airplane of the same weight class, the EPA received no comments 
from Airbus seconding the request, and therefore it does not appear 
that the problem identified by Boeing is universal to all airplanes of 
the same class that may be put into freighter service.

[[Page 2159]]

    Given that no information was provided to show why the proposed 
exemptions would be insufficient, that the would-be affected airplane 
manufacturers do not seem to be universally in favor of or need a 10-
year compliance extension, and that significant challenges and adverse 
impacts would arise if timely harmonization with international 
standards did not occur, the EPA is finalizing the standards and timing 
proposed in the NPRM. The EPA, in consultation with the FAA, believes 
that the exemption process should provide an appropriate avenue for 
manufacturers to seek relief.

V. Aggregate GHG and Fuel Burn Methods and Results

    This section describes the EPA's emission impacts analysis for the 
final standards. This section also describes the assumptions and data 
sources used to develop the baseline GHG emissions inventories and the 
potential consequences of the final standards on aviation emissions. 
Consistent with Executive Order 12866, we analyzed the impacts of 
alternatives (using similar methodologies), and the results for these 
alternatives are described in chapters 4 and 5 of the Technical Support 
Document (TSD).
    As described earlier in Section II, the manufacturers of affected 
airplanes and engines have already developed or are developing 
technologies that meet the 2017 ICAO Airplane CO2 Emission 
Standards. The EPA expects that the manufacturers will comply with the 
ICAO Airplane CO2 Emission Standards even in advance of 
member States' adoption into domestic regulations. Therefore, the EPA 
expects that the final GHG standards will not impose an additional 
burden on manufacturers. In keeping with the ICAO/CAEP need to consider 
technical feasibility in standard setting, the ICAO Airplane 
CO2 Emission Standards reflect demonstrated technology that 
will be available in 2020.
    As described below, the analysis for the final GHG standards 
considered individual airplane types and market forces. We have 
assessed GHG emission reductions needed for airplane types (or airplane 
models) to meet the final GHG standards compared to the improvements 
that are driven by market competition and are expected to occur in the 
absence of any standard (business as usual improvements). A summary of 
these results is described later in this section. Additional details 
can be found in chapter 5 of the accompanying TSD for the final 
standards.

A. What methodologies did the EPA use for the emissions inventory 
assessment?

    The EPA participated in ICAO/CAEP's standard-setting process for 
the international Airplane CO2 Emission Standards. CAEP 
provided a summary of the results from this analysis in the report of 
its tenth meeting,\114\ 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 GHG standards, however, we are making our analysis, data 
sources, and model assumptions transparent to the public so all 
stakeholders affected by the final 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 analysis \115\ was peer-reviewed 
by multiple independent subject matter experts, including experts from 
academia and other government agencies, as well as independent 
technical experts.\116\
---------------------------------------------------------------------------

    \114\ ICAO, 2016: Doc 10069--Report of the Tenth Meeting, 
Montreal,1-12 February 2016, Committee on Aviation Environmental 
Protection, CAEP 10, 432 pp., pages 271 to 308, is found on page 27 
of the ICAO Products & Services English Edition 2020 Catalog and is 
copyright protected. For purchase available at: https://www.icao.int/publications/Pages/catalogue.aspx (last accessed March 
16, 2020). The summary of technological feasibility and cost 
information is located in Appendix C (starting on page 5C-1) of this 
report.
    \115\ U.S. EPA, 2020: Technical Report on Aircraft Emissions 
Inventory and Stringency Analysis, July 2020, 52 pp.
    \116\ RTI International and EnDyna, EPA Technical Report on 
Aircraft Emissions Inventory and Stringency Analysis: Peer Review, 
July 2019, 157 pp.
---------------------------------------------------------------------------

    The methodologies the EPA uses to assess the impacts of the final 
GHG standards are summarized in a flow chart shown in Figure V-1. This 
section describes the impacts of the final GHG standards. Essentially, 
the approach is to compare the GHG emissions of the business as usual 
baseline in the absence of standards with those emissions under the 
final GHG standards.

[[Page 2160]]

[GRAPHIC] [TIFF OMITTED] TR11JA21.013

    The first step of the EPA analysis is to create a baseline, which 
is constructed from the unique airport origin-destination (OD) pairs 
and airplane combinations in the 2015 base year. As described further 
in the next section, these base year operations are then evolved to 
future year operations, 2016-2040, by emulating the market driven fleet 
renewal process to define the baseline (without the final GHG 
regulatory requirements). The same method then is applied to define the 
fleet evolution under the final GHG standards, except that different 
potential technology responses are defined for the airplanes impacted 
by the final GHG standards. Specifically, they are either modified to 
meet the standards or removed from production. Once the flight 
activities for all analysis scenarios are defined by the fleet 
evolution module, then fuel burn and GHG \117\ emissions are modelled 
for all the scenarios with a physics-based airplane performance model 
known as PIANO.\118\ A brief account of the methods, assumptions, and 
data sources used is given below, and more details can be found in 
chapter 4 of the TSD.
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    \117\ To convert fuel burn to CO2 emissions, we used 
the conversion factor of 3.16 kg/kg fuel for CO2 
emissions, and to convert to the six well-mixed GHG emissions, we 
used 3.19 kg/kg fuel for CO2 equivalent emissions. Our 
method for calculating CO2 equivalent emissions is based 
on SAE AIR 5715, 2009: Procedures for the Calculation of Aircraft 
Emissions and the EPA publication: 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 (last accessed March 16, 2020).
    \118\ 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.
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1. Fleet Evolution Module
    To develop the baseline, the EPA used FAA 2015 operations data as 
the basis from which to project future fleet operations out to 2040. 
The year-to-year activity growth rate was determined by the FAA 2015-
2040 Terminal Area Forecast \119\ (TAF) based on airport OD-pairs, 
route groups (domestic or international), and airplane types. The 
retirement rate of a specific airplane is determined by the age of the 
airplane and the retirement curve of its associated airplane type. 
Retirement curves of major airplane types are derived statistically 
based on data from the FlightGlobal Fleets Analyzer database \120\ 
(also known as ASCEND Online Fleets Database--hereinafter ``ASCEND'').
---------------------------------------------------------------------------

    \119\ 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, non-Federal 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.
    \120\ FlightGlobal Fleets Analyzer is a subscription based 
online data platform providing comprehensive and authoritative 
source of global airplane fleet data (also known as ASCEND database) 
for manufacturers, suppliers and Maintenance, Repair, Overhaul (MRO) 
providers. https://signin.cirium.com (last accessed December 16, 
2019).
---------------------------------------------------------------------------

    The EPA then linked the 2015 FAA operations data to the TAF and 
ASCEND-based growth and retirement rates by matching the airport and 
airplane parameters. Where the OD-pair and airplane match between the 
operations data and the TAF, then the exact TAF year-on-year growth 
rates were applied to grow 2015 base year activities to future years. 
For cases without exact matches, growth rates from progressively more 
aggregated levels were used to grow the future year activities.\121\
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    \121\ For example, in the absence of exact airplane match, the 
aggregated growth rate of airplane category is used; in case of no 
exact OD-pair match, the growth rate of route group is used. Outside 
the U.S. the non-US flights were modelled with global average growth 
rates from ICAO for passenger and freighter operations and from the 
Bombardier forecast for business jets. See chapter 5 of the TSD for 
details.
---------------------------------------------------------------------------

    The retirement rate was based on the exact age of the airplane from 
ASCEND for airplanes with a known tail number. When the airplane tail 
number was not known, the aggregated retirement rate of the next level 
matching fleet (e.g., airplane type or category as defined by

[[Page 2161]]

ASCEND) was used to calculate the retirement rates for future years.
    Combining the growth and retirement rates together, we calculate 
the future year growth and replacement (G&R) market demands. These 
future year G&R market demands are aligned to each base year flight, 
and the future year flights are allocated with available G&R airplanes 
\122\ using an equal-product market-share selection process.\123\ The 
market demand allocation is made based on ASK (Available Seat 
Kilometer) for passenger operations, ATK (Available Tonne Kilometer) 
for freighter operations, and number of operations for business jets.
---------------------------------------------------------------------------

    \122\ The airplane G&R database contains all the EPA-known in-
production and in-development airplanes that are projected to grow 
and replace the global base-year fleet over the 2015-2040 analysis 
period. This airplane G&R database, the annual continuous 
improvements, and the technology responses are available in the 2018 
ICF Report.
    \123\ The EPA uses equal product market share (for all airplane 
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.
---------------------------------------------------------------------------

    For the 2015 base-year analysis, the baseline (no regulation) 
modelling includes continuous (2016-2040) annual fuel efficiency 
improvements. The modelling tracks the year airplanes enter the fleet 
and applies the type-specific fuel efficiency improvement \124\ via an 
annual adjustment factor based on the makeup of the fleet in a 
particular year. Since there is uncertainty associated with the fuel-
efficiency improvement assumption, the analysis also includes a 
sensitivity scenario without this assumption in the baseline. This 
sensitivity scenario applied the ICAO Constant Technology Assumption to 
the baseline, which meant that no technology improvements were 
projected beyond what was known in 2016. Specifically, current airplane 
types were assumed to have the same metric value in 2040 as they did in 
2016. ICAO used this simplifying assumption because they conducted 
their stringency analysis on comparative basis and did not attempt to 
include future emission trends in their stringency analysis. ICAO 
stated that its analysis was ``. . .not suitable for application to any 
other purpose of any kind, and any attempt at such application would be 
in error.'' \125\ In contrast to how ICAO used the Constant Technology 
Assumption, as a simplification, the EPA is using this as a worst case 
scenario in our sensitivity studies to provide an estimate of the range 
of uncertainty to our main analysis in extreme cases.
---------------------------------------------------------------------------

    \124\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
    \125\ ICAO, 2016: Doc 10069--Report of the Tenth Meeting, 
Montreal,1-12 February 2016, Committee on Aviation Environmental 
Protection, CAEP 10, 432 pp., pages 271 to 308, is found on page 27 
of the ICAO Products & Services English Edition 2020 Catalog and is 
copyright protected. For purchase available at: https://www.icao.int/publications/Pages/catalogue.aspx (last accessed March 
16, 2020). The summary of technological feasibility and cost 
information is located in Appendix C (starting on page 5C-1) of this 
report. In particular, see paragraph 2.3 for the caveats, 
limitations and context of the ICAO analysis.
---------------------------------------------------------------------------

    The EPA fleet evolution model focuses on U.S. aviation, including 
both domestic and international flights (with U.S. international 
flights defined as flights departing from the U.S. but landing outside 
the U.S.). This is the same scope of operations used for the EPA 
Inventory of U.S. Greenhouse Gas Emissions and Sinks.\126\ However, 
because aviation is an international industry and manufacturers of 
covered airplanes sell their products globally, the analysis also 
covers the global fleet evolution and emissions inventories for 
reference (but at a much less detailed level for traffic growth and 
fleet evolution outside of the U.S.).
---------------------------------------------------------------------------

    \126\ U.S. EPA, 2018: Inventory of U.S. Greenhouse Gas Emissions 
and Sinks: 1990-2016, 1,184 pp., U.S. EPA Office of Air and 
Radiation, EPA 430-R-18-003, April 2018. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2016 (last accessed March 16, 2020).
---------------------------------------------------------------------------

    The fleet evolution modelling for the final regulatory scenarios 
defines available G&R airplanes for various market segments based on 
the technology responses identified by ICF, a contractor for the EPA, 
as described later in Section VI.\127\
---------------------------------------------------------------------------

    \127\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
---------------------------------------------------------------------------

2. Full Flight Simulation Module
    PIANO version 5.4 was used for all the emissions modelling. 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. PIANO is a physics-based 
airplane performance model used widely by industry, research 
institutes, non-governmental organizations and government agencies to 
model airplane performance metrics such as fuel consumption and 
emissions characteristics based on specific airplane and engine types. 
We use it to model airplane performance for all phases of flight from 
gate to gate including taxi-out, takeoff, 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 great circle distance (which is 
the shortest distance along the 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 percent maximum payload capacity for all 
flights except for business jet where 50 percent is assumed. (5) Use 
the PIANO default reserve fuel rule \128\ 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).
---------------------------------------------------------------------------

    \128\ 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, National 
Business Aviation Association--Instrument Flight Rules (NBAA-IFR) or 
Douglas rules are used as well.
---------------------------------------------------------------------------

    Given the flight activities defined by the fleet evolution module 
in the previous section, we generated 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 (OD-pairs), airplane types, and engine 
types. This matrix includes millions of flights and forms the basis for 
our analysis (including the sensitivity studies).
3. Emissions Module
    The GHG emissions calculation involves summing the outputs from the 
first two modules for every flight in the database. This is done 
globally, and then the U.S. portion is segregated from the global 
dataset. The same calculation is done for the baseline and the final 
GHG standard. When a surrogate airplane is used to model an airplane 
that is not in the PIANO database, or when a technology response is 
required for an airplane to pass a standard level, an adjustment factor 
is also applied to model the expected performance of the intended 
airplane and technology responses.
    The differences between the final GHG standards and the baseline 
provide quantitative measures to assess the emissions impacts of the 
final GHG standards. A brief summary of these results is described in 
the next two sections. More details can be found in chapter 5 of the 
TSD.

[[Page 2162]]

B. What are the baseline GHG emissions?

    The commercial aviation marketplace is continually changing, with 
new origin-destination markets and new, more fuel-efficient airplanes 
growing in number and replacing existing airplanes in air carrier (or 
airline) fleets. This behavior introduces uncertainty to the future 
implications of this rulemaking. Since there is uncertainty, multiple 
baseline/scenarios may be analyzed to explore a possible range of 
implications of the rule.
    For the analysis in this rulemaking and consistent with our 
regulatory impact analyses for many other mobile source 
sectors,\129,130\ the EPA is analyzing additional baseline/scenarios 
that reflect a business-as-usual continually improving baseline with 
respect to fleet fuel efficiency. We also evaluated a baseline scenario 
that is fixed to reflect 2016 technology levels (i.e., no continual 
improvement in fuel-efficient technology), and this baseline scenario 
is consistent with the approach used by ICAO.\131\
---------------------------------------------------------------------------

    \129\ U.S. EPA, 2016: Regulatory Impact Analysis: Greenhouse Gas 
Emissions and Fuel Efficiency Standards for Medium- and Heavy-Duty 
Engines and Vehicles--Phase 2, EPA-420-R-16-900, August 2016.
    \130\ U.S. EPA, 2009: Regulatory Impact Analysis: Control of 
Emissions of Air Pollution from Category 3 Marine Diesel Engines, 
EPA-420-R-09-019, December 2009.
    \131\ A comparison of the EPA and ICAO modeling approaches and 
results is available in chapter 5 and 6 of the TSD.
---------------------------------------------------------------------------

    For the EPA analysis, the baseline GHG emissions are assessed for 
2015, 2020, 2023, 2025, 2028, 2030, 2035, and 2040. The projected 
baseline GHG emissions for all U.S. flights (domestic and 
international) are shown in Figure V-2 and Figure V-3, both with and 
without the continuous (2016-2040) fuel-efficiency improvement 
assumption. More detailed breakdowns for the passenger, freighter, and 
business market segments can be found in chapter 5 of the TSD. It is 
worth noting that the U.S. domestic market is relatively mature, with a 
lower growth rate than those for most international markets. The 
forecasted growth rate for the U.S. domestic market combined with the 
Continuous Improvement Assumption results in a low GHG emissions growth 
rate in 2040 for the U.S. domestic market. However, it should be noted 
that this is one set of assumptions combined with a market forecast. 
Actual air traffic and emissions growth may vary as a result of a 
variety of factors.
---------------------------------------------------------------------------

    \132\ To convert fuel burn to CO2 emissions, we used 
the conversion factor of 3.16 kg/kg fuel for CO2 
emissions, and to convert to the six well-mixed GHG emissions, we 
used 3.19 kg/kg fuel for CO2 equivalent emissions. Our 
method for calculating CO2 equivalent emissions is based 
on SAE AIR 5715, 2009: Procedures for the Calculation of Aircraft 
Emissions and the EPA publication: 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 (last accessed March 16, 2020).
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[[Page 2163]]


[GRAPHIC] [TIFF OMITTED] TR11JA21.015

    Conceptually, the difference between the EPA and ICAO analysis 
baselines is illustrated in Figure V-4. The solid line represents the 
historical growth of emissions from the dawn of the jet age in 1960s to 
the present (2016). In this time, air traffic and operations have 
increased and offset the technology improvements. The long-dashed line 
(_ _) and dot-dash-dot (_ . _) lines represent different assumptions 
used by the EPA and ICAO to create baseline future inventories to 
compare the benefits of potential standards. The two baselines start in 
2016, but their different assumptions lead to very different long-term 
forecasts. The EPA method (long dash) uses the input from an 
independent analysis conducted by ICF \133\ to develop a Projected 
Continuous Improvement baseline to model future improvements similar to 
historical trends. The ICAO method creates a baseline using a Constant 
Technology Assumption that freezes the airplane technology going 
forward. This means that the in-production airplanes after that date 
will be built with no changes indefinitely into the future, i.e. the 
baseline assumes airplanes will have the same metric value in 2040 as 
they did in 2016. The dot-dot-dash (_ . _) line compares this Constant 
Technology Assumption to the solid historical emissions growth. ICAO 
used this simplifying assumption because they conducted their 
stringency analysis on comparative basis and did not attempt to include 
future emission trends in their stringency analysis. Comparative basis 
means ICAO looked at the difference in emission reductions between 
stringency options in isolation and did not attempt to factor in future 
business as usual improvements or fleet changes. The projected benefits 
of any standards will be different depending upon the baseline that is 
assumed. Note that ICAO stated that its analysis was ``. . . not 
suitable for application to any other purpose of any kind, and any 
attempt at such application would be in error.'' \134\ To understand 
the true meaning of the analysis and make well-informed policy 
decisions, one must consider the underlying assumptions carefully. For 
example, if the EPA were to use the ICAO Constant Technology Assumption 
in our main analysis, the impact of the rulemaking would be 
overestimated, i.e., these results would not be able to differentiate 
the effect of the standards from the expected business as usual 
improvements.
---------------------------------------------------------------------------

    \133\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
    \134\ ICAO, 2016: Doc 10069--Report of the Tenth Meeting, 
Montreal,1-12 February 2016, Committee on Aviation Environmental 
Protection, CAEP 10, 432pp., pages 271 to 308, is found on page 27 
of the ICAO Products & Services English Edition 2020 Catalog and is 
copyright protected. For purchase available at: https://www.icao.int/publications/Pages/catalogue.aspx (last accessed March 
16, 2020). The summary of technological feasibility and cost 
information is located in Appendix C (starting on page 5C-1) of this 
report. In particular, see paragraph 2.3 for the caveats, 
limitations and context of the ICAO analysis.

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[[Page 2164]]

[GRAPHIC] [TIFF OMITTED] TR11JA21.016

BILLING CODE 6560-50-C

C. What are the projected effects in fuel burn and GHG emissions?

    EPA's analysis projects that the final GHG standards will not 
result in reductions in fuel burn and GHG emissions beyond the 
baseline. This result makes sense because all of the airplanes in the 
G&R fleet either will meet the standard level associated with the final 
GHG standards or are expected to be out of production by the time the 
standards take effect, according to our technology responses.\135\ In 
other words, the existing or expected fuel efficiency technologies from 
airplane and engine manufacturers that were the basis of the ICAO 
standards, which match the final standards, demonstrate technological 
feasibility. Thus, we do not project a cost or benefit for the final 
GHG standards (further discussion on the rationale for no expected 
reductions and no costs is provided later in this section and Section 
VI).
---------------------------------------------------------------------------

    \135\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
---------------------------------------------------------------------------

    The EPA projected reduction in GHG emissions is different from the 
results of the ICAO analysis mentioned in V.A, which bounds the range 
of analysis exploration given the uncertainties involved with 
predicting the implications of this rule. The agency has conducted 
sensitivity studies around our main analysis to understand the 
differences \136\ between our analysis and ICAO's (further detail on 
the differences in the analyses and the sensitivity studies is provided 
in the TSD). These sensitivity studies show that the no cost-no benefit 
conclusion is quite robust. For example, even if we assume no 
continuous improvement, the projected GHG emissions reductions for the 
final standards will still be zero since all the non-compliant 
airplanes (A380 \137\ and 767 freighters) are

[[Page 2165]]

projected to be out of production by 2028 (according to ICF analysis), 
the final standard effective year. We note that in their public 
comments on the proposal 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 baseline 
to include continued production of the 767F beyond 2028 because 
insufficient information to characterize this scenario was provided.
---------------------------------------------------------------------------

    \136\ The differences in the analyses include different 
assumptions. Our analysis assumes continuous improvement and ICAO's 
analysis does not. Also, we make different projections about the end 
of production of the A380 and 767 compared to ICAO.
    \137\ On February 14, 2019, Airbus made an announcement to end 
A380 production by 2021 after Emirates airlines reduced its A380 
order by 39 and replaced them with A330 and A350. (The Airbus press 
release is available at: https://www.airbus.com/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). EPA's analysis was conducted prior to Airbus's announcement, 
so the analysis does not consider the impact of the A380 ending 
production in 2021. The early exit of A380, compared to the modeled 
scenarios, fits the general trend of reduced demands for large quad 
engine airplanes projected by the ICF technology responses and is 
consistent with our conclusion of no cost and no benefit for this 
rule.
---------------------------------------------------------------------------

    Furthermore, we analyzed a sensitivity case where A380 and 767 
freighters comply with the standards in 2028 and continue production 
until 2030 and not make any improvement between 2015 and 2027, the GHG 
emissions reductions will still be an order of magnitude lower than the 
ICAO results since all emissions reductions will come from just 3 
years' worth of production (2028 to 2030) of A380 and 767 freighters. 
Considering that both airplanes are close to the end of their 
production life cycle by 2028 and low market demands for them, these 
limited emissions reductions may not be realized if the manufacturers 
are granted exemptions. Thus, the agency analysis results in a no cost-
no benefit conclusion that is reasonable for the final GHG standards.
    In summary, the ICAO Airplane CO2 Emission Standards, 
which match the final EPA GHG standards, were predicated on 
technologies that manufacturers of affected airplanes and engines had 
already demonstrated to be safe and airworthy to the advanced 
technology readiness level 8 \138\ when they were adopted in 2017. The 
EPA expects that the manufacturers will comply with the ICAO Airplane 
CO2 Emission Standards even before member States' adoption 
into domestic regulations. Therefore, the EPA expects that the final 
airplane GHG standards will not impose an additional burden on 
manufacturers.
---------------------------------------------------------------------------

    \138\ As described later in section VI.B for Technology 
Readiness Level 8 (TRL8), this refers to having been proven to be 
``actual system completed and `flight qualified' through test and 
demonstration.''
---------------------------------------------------------------------------

VI. Technological Feasibility and Economic Impacts

    This section describes the technological feasibility and costs of 
the airplane GHG rule. This section describes the agency's 
methodologies for assessing technological feasibility and estimated 
costs of the final standards. Consistent with Executive Order 12866, we 
analyzed the technological feasibility and costs of alternatives (using 
similar methodologies), and the results for these alternatives are 
described in chapter 6 of the TSD.
    The EPA and the FAA participated in the ICAO analysis that informed 
the adoption of the international Airplane CO2 Emission 
Standards. A summary of that analysis was published in the report of 
ICAO/CAEP's tenth meeting,\139\ which occurred in February 2016. 
However, due to the commercial sensitivity of much of the underlying 
data used in the ICAO analysis, the ICAO-published report (which is 
publicly available) provides only limited supporting data for the ICAO 
analysis. The EPA TSD for this rulemaking compares the ICAO analysis to 
the EPA analysis.
---------------------------------------------------------------------------

    \139\ ICAO, 2016: Report of Tenth Meeting, Montreal, 1-12 
February 2016, Committee on Aviation Environmental Protection, 
Document 10069, CAEP/10, 432pp, is found on page 27 of the English 
Edition of the ICAO Products & Services 2020 Catalog and is 
copyright protected; Order No. 10069. For purchase available at: 
https://www.icao.int/publications/Pages/catalogue.aspx (last 
accessed March 16, 2020). The summary of technological feasibility 
and cost information is located in Appendix C (starting on page 5C-
1) of this report.
---------------------------------------------------------------------------

    For the purposes of evaluating the final GHG regulations based on 
publicly available and independent data, the EPA had an analysis 
conducted of the technological feasibility and costs of the 
international Airplane CO2 Emission Standards through a 
contractor (ICF) study.140 141 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 regulations 
were analyzed and compared to the improvements that are anticipated to 
occur in the absence of regulation. The methods used in and the results 
from the analysis are described in the following paragraphs--and in 
further detail in chapter 2 of the TSD for this rulemaking.
---------------------------------------------------------------------------

    \140\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
    \141\ ICF International, 2015: CO2 Analysis of 
CO2-Reducing Technologies for Aircraft, Final Report, EPA 
Contract Number EP-C-12-011, March 17, 2015.
---------------------------------------------------------------------------

A. Market Considerations

    Prior to describing our technological feasibility and cost 
analysis, potential market impacts of the final GHG regulations are 
discussed in this section. As described earlier, airplanes and airplane 
engines are sold around the world, and international airplane emission 
standards help ensure the worldwide acceptability of these products. 
Airplane and airplane engine manufacturers make business decisions and 
respond to the international market by designing and building products 
that conform to ICAO's international standards. However, ICAO's 
standards need to be implemented domestically for products to prove 
such conformity. Domestic action through EPA rulemaking and subsequent 
FAA rulemaking enables U.S. manufacturers to obtain internationally 
recognized FAA certification, which for the adopted GHG standards will 
ensure type certification consistent with the requirements of the 
international Airplane CO2 Emission Standards. This is 
important, as compliance with the international standards (via FAA type 
certification) is a critical consideration in airlines' purchasing 
decisions. By implementing the requirements that conform to ICAO 
requirements in the United States, we will remove any question 
regarding the compliance of airplanes certificated in the United 
States. The rule will facilitate the acceptance of U.S. airplanes and 
airplane engines by member States and airlines around the world. 
Conversely, U.S. manufacturers will be at a competitive disadvantage 
compared with their international competitors without this domestic 
action.
    In considering the aviation market, it is important to understand 
that the international Airplane CO2 Emission Standards were 
predicated on demonstrating technological feasibility; i.e., that 
manufacturers have already developed or are developing improved 
technology that meets the 2017 ICAO CO2 standards, and that 
the new technology will be integrated in airplanes throughout the fleet 
in the time frame provided before the implementation of the standards' 
effective date. Therefore, as described in Section V.C, the EPA 
projects that these final standards will impose no additional burden on 
manufacturers.
    While recognizing that the international agreement was predicated 
on demonstrated technological feasibility, without access to the

[[Page 2166]]

underlying ICAO/CAEP data it is informative to evaluate individual 
airplane models relative to the equivalent U.S. regulations. Therefore, 
the technologies and costs needed for airplane types to meet the rule 
were compared to the improvements that are expected to occur in the 
absence of standards (business as usual improvements). A summary of 
these results is described later in this section.

B. Conceptual Framework for Technology

    As described in the 2015 ANPR, 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.\142\ Subsequently, for this 
rulemaking, the EPA contracted with ICF to update its analysis (herein 
referred to as the ``2018 ICF updated analysis'').\143\ It had been 
three years since the initial 2015 ICF analysis was completed, and the 
EPA had ICF update the assessment to ensure that the analysis included 
in this rulemaking reflects the current status of airplane GHG 
technology improvements. Therefore, ICF's assessment of technology 
improvements was updated since the 2015 ANPR was issued.\144\
---------------------------------------------------------------------------

    \142\ ICF International, 2015: CO2 Analysis of 
CO2-Reducing Technologies for Aircraft, Final Report, EPA 
Contract Number EP-C-12-011, March 17, 2015.
    \143\ ICF, 2018: Aircraft CO2 Cost and Technology 
Refresh and Industry Characterization, Final Report, EPA Contract 
Number EP-C-16-020, September 30, 2018.
    \144\ As described earlier in section IV, the ICAO test 
procedures for the international airplane CO2 standards 
measure fuel efficiency (or fuel burn). Only two of the six well-
mixed GHGs--CO2 and N2O are emitted from 
airplanes. The test procedures for fuel efficiency scale with the 
limiting of both CO2 and N2O emissions, as 
they both can be indexed on a per-unit-of-fuel-burn basis. 
Therefore, both CO2 and N2O 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 N2O.
---------------------------------------------------------------------------

    The long-established ICAO/CAEP terms of reference were taken into 
account when deciding the international Airplane CO2 
Emission Standards, principal among these being technical feasibility. 
For the ICAO CO2 certification standard setting, technical 
feasibility refers to any technology expected to be demonstrated to be 
safe and airworthy proven to Technology Readiness Level \145\ (TRL) 8 
by 2016 or shortly thereafter (per CAEP member guidance; approximately 
2017), and expected to be available for application in the short term 
(approximately 2020) over a sufficient range of newly certificated 
airplanes.\146\ This means that the analysis that informed the 
international standard considered the emissions performance of in-
production and on-order or in-development \147\ airplanes, including 
types that first enter into service by about 2020. (ICAO/CAEP's 
analysis was completed in 2015 for the February 2016 ICAO/CAEP 
meeting.)
---------------------------------------------------------------------------

    \145\ 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, CO2 Analysis of 
CO2-Reducing Technologies for Aircraft, Final Report, EPA 
Contract Number EP-C-12-011, see page 40, March 17, 2015.
    \146\ ICAO, 2016: Report of the Tenth Meeting, Montreal, 1-12 
February 2016, Committee on Aviation Environmental Protection, 
Document 10069, CAEP10, 432pp, is found on page 27 of the English 
Edition of the ICAO Products & Services 2020 Catalog and is 
copyright protected: Order No. 10069. For purchase available at: 
https://www.icao.int/publications/Pages/catalogue.aspx (last 
accessed March 16, 2020). The statement on technological feasibility 
is located in Appendix C (page 5C-15, paragraph 6.2.1) of this 
report.
    \147\ Aircraft that are currently in-development but were 
anticipated to be in production by about 2020.
---------------------------------------------------------------------------

    In assessing the airplane GHG rule, the 2018 ICF updated analysis, 
which was completed a few years after the ICAO analysis, was able to 
use a different approach for technology responses. ICF based these 
responses on technology available at TRL8 by 2017 and projected 
continuous improvement of CO2 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, ICF considered the end of production of 
airplanes based on the expected business-as-usual status of airplanes 
(with the continuous improvement assumptions). This approach is 
described in further detail later in Section VI.C. The ICF approach 
differed from ICAO's analysis for years 2016 to 2020 and diverged even 
more for years 2021 and after. Since ICF was able to use the final 
effective dates in their analysis of the final airplane GHG standard 
(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 
occur in the absence of the final standard (business as usual 
improvements) compared against technology improvements/responses needed 
to comply with the final standard. ICF's approach is appropriate for 
the EPA-final GHG standard because it is based on more up-to-date 
inputs and assumptions.

C. Technological Feasibility

1. Technology Principles and Application
i. 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 (upcoming short and mid-
term). This framework included five steps to estimate annual metric 
value (baseline metric values were generated using PIANO data \148\) 
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 amount of potential GHG reduction and 
the mechanisms by which this reduction could be achieved. These first 
two steps were analyzed by airplane category. Third and fourth, the 
technologies were passed through technical success probability and 
commercial success probability screenings, respectively. Finally, 
individual airplane differences were assessed within each airplane 
category to generate GHG emission reduction projections by technology 
by airplane model--at the airplane family level (e.g., 737 family). 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 improvement \149\ from

[[Page 2167]]

2015-2029 for all the technologies that would be applied to each 
airplane (or business as usual improvement in the absence of a 
standard).
---------------------------------------------------------------------------

    \148\ 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 16, 2020). PIANO is 
a commercially available aircraft design and performance software 
suite used across the industry and academia.
    \149\ Also referred to as the constant annual improvement in 
CO2 metric value.
---------------------------------------------------------------------------

    As a modification to the 2015 ICF analysis, the 2018 ICF updated 
analysis extended the metric value improvements at the airplane family 
level (e.g., 737 family) to the more specific airplane variant level 
(e.g., 737-700, 737-800, etc.). Thus, to estimate whether each airplane 
variant 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. ICF used this approach to estimate 
metric values for 125 airplane models allowing for a comparison of the 
estimated metric value for each airplane model to the level of the 
final GHG standard at the time the standard goes into effect.
    In addition, ICF projected which airplane models will end their 
production runs (or production cycle) prior to the effective date of 
the final GHG standard. These estimates of production status, at the 
time the standard will go into effect, further informed the projected 
response of airplane models to the final standard. Further details of 
the short- and mid-term methodology are provided in chapter 2 of the 
TSD.
ii. Long-Term Methodology
    To project metric value improvements for the long-term, years 2030-
2040, ICF generated a different methodology compared with the short- 
and mid-term methodology. The short- and mid-term methodology is based 
on forecasting metric value improvements contributed by specific 
existing technologies that are implemented, and ICF projects that about 
the 2030 timeframe a new round of technology implementation will begin 
that leads to developing 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. 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 \150\ was 
estimated on a scale of 1 to 5 for each technical factor (chapter 2 of 
the TSD describes these technical factors in detail). 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 its metric value improvements. A low overall index 
score indicates that the airplane type will have a reduced annual 
metric value reduction (the metric value decreases yearly at a slower 
rate relative to an extrapolated short- and mid-term annual metric 
value improvement), and a high overall index score indicates an 
accelerated annual metric value improvement (the metric value decreases 
yearly at a quicker rate relative to an extrapolated short- and mid-
term annual metric value improvement). Further details of the long-term 
methodology are provided in chapter 2 of the TSD.
---------------------------------------------------------------------------

    \150\ 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.
---------------------------------------------------------------------------

2. What technologies did the EPA consider to reduce GHG emissions?
    ICF identified and analyzed seventy different aerodynamic, weight, 
and engine (or propulsion) technologies for fuel burn reductions. 
Although weight-reducing technologies affect fuel burn, they do not 
affect the metric value for the GHG rule.\151\ 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. In addition, based on the methodology described 
earlier in Section VI.C, ICF utilized a subset of the about fifty 
aerodynamic and engine technologies they evaluated to account for the 
improvements to the metric value for the final standard (for in-
production and in-development airplanes \152\).
---------------------------------------------------------------------------

    \151\ 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. 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.
    \152\ Airplanes that are currently in-development but will be in 
production by the applicability dates. These could be new type 
designs or redesigned airplanes.
---------------------------------------------------------------------------

    A short list of the aerodynamic and engine technologies that were 
considered to improve the metric value of the rule is provided below. 
Chapter 2 of the TSD provides a more detailed description of these 
technologies.
     Aerodynamic technologies: The airframe technologies that 
accounted for the improvements to the metric values from airplanes 
included aerodynamic technologies that reduce drag. These technologies 
included advance wingtip devices, adaptive trailing edge, laminar flow 
control, and riblet coatings.
     Engine technologies: The engine technologies that 
accounted for reductions to the metric values from airplanes included 
architecture and cooling technologies. Architecture technologies 
included ultra-high bypass engines and the fan drive gear, and cooling 
technologies included compressor airfoil coating and turbine air 
cooling.
3. Technology Response and Implications of the Final Standard
    The EPA does not project that the GHG rule will cause manufacturers 
to make technical improvements to their airplanes that would not have 
occurred in the absence of the rule. The EPA projects that the 
manufacturers will meet the standards independent of the EPA standards, 
for the following reasons (as was described earlier in Section VI.A):
     Manufacturers have already developed or are developing 
improved technology in response to the ICAO standards that match the 
final GHG regulations;
     ICAO decided on the international Airplane CO2 
Emission Standards, which are equivalent to the final GHG standards, 
based on 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;
     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 or

[[Page 2168]]

seek an exemption from the final standards; and
     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 compared 
to the in-production airplane model they are replacing.
    Based on the approach described above in Sections VI.C.1 and 
VI.C.2, ICF assessed the need for manufacturers to develop technology 
responses for in-production and in-development airplane models to meet 
the final GHG standards (for airplane models that were projected to be 
in production by the effective dates of the final standards and would 
be modified to meet these standards, instead of going out of 
production). After analyzing the results of the approach/methodology, 
ICF estimated that all airplane models (in-production and in-
development airplane models) will meet the levels of the final standard 
or be out of production by the time the standard became effective. 
Thus, a technology response is not necessary for airplane models to 
meet the final rule. This result confirms that the international 
Airplane CO2 Emission Standards are technology following 
standards, and that the EPA's final GHG standards as they will apply to 
in-production and in-development airplane models will also be 
technology following.\153\
---------------------------------------------------------------------------

    \153\ As described earlier, this result is different from the 
ICAO analysis, which did not use continuous improvement 
CO2 metric values nor production end dates for products.
---------------------------------------------------------------------------

    For the same reasons, a technology response is not necessary for 
new type design airplanes to meet the GHG rule. The EPA is currently 
not aware of a specific model of a new type design airplane that is 
expected to enter service after 2020. 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 rule.

D. Costs Associated With the Program

    This section provides the elements of the cost analysis for 
technology improvements, including certification costs, and recurring 
costs. As described, above, the EPA does not anticipate new technology 
costs due to the GHG rule. While recognizing that the GHG rule does not 
have non-recurring costs (NRC), certification costs, or recurring 
costs, it is informative to describe the elements of these costs.
1. Non-Recurring Costs
    Non-recurring cost (NRC) consists of the cost of engineering and 
integration,\154\ testing (flight and ground testing) and tooling, 
capital equipment, and infrastructure. 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 CO2 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 briefly listed earlier in Section VI.C.2.
---------------------------------------------------------------------------

    \154\ Engineering and Integration includes the engineering and 
Research & Development (R&D) needed to progress a technology from 
its current level to a level where it can be integrated onto a 
production airframe. It also includes all airframe and technology 
integration costs.
---------------------------------------------------------------------------

    The methodology for the development of the NRC for in-production 
airplanes consisted of six steps. First, technologies were categorized 
either as minor performance improvement packages (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. Second, the 
elements of non-recurring cost were identified (e.g., engineering and 
integration costs), as described earlier. Third, these elements of non-
recurring cost are apportioned by incremental technology category for 
single-aisle airplanes (e.g., for the category of an airframe minor 
PIP, 85 percent of NRC is for engineering of integration costs, 10 
percent is for testing, and 5 percent is for tooling, capital 
equipment, and infrastructure). \155\ Fourth, the NRC elements were 
scaled to the other airplane size categories (from the baseline single-
aisle airplane category). Fifth, we estimated the NRC costs for single-
aisle airplane and applied the scaled costs to the other airplane size 
categories.\156\ Sixth, we compiled technology supply curves by 
airplane model, which enabled us to rank incremental technologies from 
most cost effective to the least cost effective. For determining 
technical responses by these supply curves, it was assumed that the 
manufacturer invests in and incorporates the most cost-effective 
technologies first and go on to the next most cost-effective technology 
to attain the metric value improvements needed to meet the standard. 
Chapter 2 of the TSD provides a more detailed description of this NRC 
methodology for technology improvements and results.
---------------------------------------------------------------------------

    \155\ For the incremental technology category of an engine minor 
PIP, 35 percent of NRC is for engineering of integration costs, 50 
percent is for testing, and 15 percent is for tooling, capital 
equipment, and infrastructure. For the category of a large 
incremental upgrade, 55 percent of NRC is for engineering of 
integration costs, 40 percent is for testing, and 5 percent is for 
tooling, capital equipment, and infrastructure.
    \156\ Engineering and integration costs and tooling, capital 
equipment, and infrastructure costs were scaled by airplane realized 
sale price from the single-aisle airplane category to the other 
airplane categories. Testing costs were scaled by average airplane 
operating costs.
---------------------------------------------------------------------------

2. Certification Costs
    Following this final 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 estimated 
by FAA and 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 airplane (via 
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.\157\ Thus, there are 
no new certification costs for the rule. However, it is informative to

[[Page 2169]]

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 
(i.e., test instrumentation, infrastructure, and program management).
---------------------------------------------------------------------------

    \157\ In addition, European authorities charge fees to airplane 
manufacturers for the certification of their airplanes, but FAA does 
not charge fees for certification.
---------------------------------------------------------------------------

    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 to measure high-speed cruise performance).\158\ Therefore, 
some manufacturers already have or will have airplane test data (or 
data from high-speed cruise performance modelling) to certify their 
airplane to the standard, and they will not need to conduct flight 
testing for certification to the standard. Also, these data will 
already be part of the manufacturers' fuel burn or high-speed 
performance models, which they can use to demonstrate compliance with 
the international Airplane CO2 Emission Standards. In the 
absence of the standard, 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. Also, the EPA is not making any attempt to quantify the 
costs associated with certification by the FAA.
---------------------------------------------------------------------------

    \158\ ICAO, 2016: Report of Tenth Meeting, Montreal, 1-12 
February 2016, Committee on Aviation Environmental Protection, 
Document 10069, CAEP/10, 432pp, is found on page 27 of the English 
Edition of the ICAO Products & Services 2020 Catalog and is 
copyright protected; Order No. 10069. See Appendix C of this report. 
For purchase available at: https://www.icao.int/publications/Pages/catalogue.aspx (last accessed March 16, 2020).
---------------------------------------------------------------------------

3. Recurring Operating Costs
    For the same reasons there are no NRC and certification costs for 
the rule as discussed earlier, there will be no recurring costs 
(recurring operating and maintenance costs) for the rule; however, it 
is informative to describe elements of recurring costs. The elements of 
recurring costs for incorporating fuel saving technologies will include 
additional maintenance, material, labor, and tooling costs. Our 
analysis shows that airplane fuel efficiency improvements typically 
result in net cost savings through the reduction in the amount of fuel 
consumed. If technologies add significant recurring costs to an 
airplane, operators (e.g., airlines) will likely reject these 
technologies.

E. 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.\159\ 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.
---------------------------------------------------------------------------

    \159\ ATAG, 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-efficiency/ .
---------------------------------------------------------------------------

VII. Aircraft Engine Technical Amendments

    The EPA, through the incorporation by reference of ICAO Annex 16, 
Volume II, Third Edition (July 2008), requires the same test and 
measurement procedures as ICAO for emissions from aircraft engines. See 
our regulations at 40 CFR 87.8(b)(1). At the CAEP/10 meeting in 
February 2016, several minor technical updates and corrections to the 
test and measurement procedures were approved and ultimately included 
in a Fourth Edition of ICAO Annex 16, Volume II (July 2017). Further 
technical updates and corrections were approved at the CAEP/11 meeting 
in February 2019 and included in Amendment 10 (July 20, 2020). The EPA 
played an active role in the CAEP process during the development of 
these revisions and concurred with their adoption. Thus, we are 
updating the incorporation by reference in Sec.  87.8(b) of our 
regulations to refer to the new Fourth Edition of ICAO Annex 16, Volume 
II (July 2017), Amendment 10 (July 20, 2020), replacing the older Third 
Edition.
    Most of these ICAO Annex 16 updates and corrections to the test and 
measurement procedures were editorial in nature and merely served to 
clarify the procedures rather than change them in any substantive 
manner. Additionally, some updates served to correct typographical 
errors and incorrect formula formatting. However, there is one change 
contained in these ICAO Annex 16 updates that warrants additional 
discussion here: a change to the certification test fuel 
specifications.
    Fuel specification bodies establish limits on jet fuels properties 
for commercial use so that aircraft are safe and environmentally 
acceptable in operation. For engine emissions certification testing, 
the ICAO fuel specification prior to CAEP10 was a minimum 1 percent 
volume of naphthalene content and a maximum content of 3.5 percent 
(1.0-3.5%). However, the ASTM International specification is 0.0-3.0 
percent naphthalene, and an investigation found that it is challenging 
to source fuels for engine emissions certification testing that meet 
the minimum 1% naphthalene level. In many cases, engine manufacturers 
were forced to have fuels custom blended for certification testing 
purposes at a cost premium well above that of commercial jet fuel. 
Additionally, such custom blended fuels needed to be ordered well in 
advance and shipped by rail or truck to the testing facility. In order 
to potentially alleviate the cost and logistical burden that the 
naphthalene specification of certification fuel presented, CAEP 
undertook an effort to analyze and consider whether it would be 
appropriate to align the ICAO Annex 16 naphthalene specification for 
certification fuel with that of in-use commercial fuel.
    Prior to the CAEP10 meeting, technical experts (including the EPA) 
reviewed potential consequences of a test fuel specification change and 
concluded that there would be no effect on gaseous emissions levels and 
a negligible effect on the `Smoke Number' (SN) level as long as the 
aromatic and

[[Page 2170]]

hydrogen content remains within the current emissions test fuel 
specification limits. ICAO subsequently adopted the ASTM International 
specification of 0.0-3.0 percent naphthalene for the engine emissions 
test fuel specification and no change to the aromatic and hydrogen 
limits, which was incorporated into the Fourth Edition of ICAO Annex 
16, Volume II, (July 2017).
    The EPA is adopting, through the incorporation of the Annex 
revisions in 40 CFR 87.8(b), the new naphthalene specification for 
certification testing into U.S. regulations. This change will have the 
benefit of more closely aligning the certification fuel specification 
for naphthalene with actual in-use commercial fuel properties while 
reducing the cost and logistical burden associated with certification 
fuel procurement for engine manufacturers. As previously mentioned, all 
the other changes associated with updating the incorporation by 
reference of ICAO Annex 16, Volume II, are editorial or typographical 
in nature and merely intended to clarify the requirements or correct 
mistakes and typographical errors in the Annex.

VIII. Statutory Authority and Executive Order Reviews

    Additional information about these statutes and Executive orders 
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is a significant regulatory action that was submitted 
to the Office of Management and Budget (OMB) for review. The OMB has 
determined that this action raises ``. . . novel legal or policy issues 
arising out of legal mandates, the President's priorities, or the 
principles set forth in this Executive Order.'' This action addresses 
novel policy issues due to it being the first ever GHG standards 
promulgated for airplanes and airplane engines. Accordingly, the EPA 
submitted this action to the OMB for review under E.O. 12866 and E.O. 
13563. Any changes made in response to OMB recommendations have been 
documented in the docket. Sections I.C.3 and VI.E of this preamble 
summarize the cost and benefits of this action. The supporting 
information is available in the docket.

B. Executive Order 13771: Reducing Regulation and Controlling 
Regulatory Costs

    This action is expected to be an Executive Order 13771 regulatory 
action. Sections I.C.3. and VI.E. of this preamble summarize the cost 
and benefits of this action. The supporting information is available in 
the Final Technical Support Document and the docket.

C. Paperwork Reduction Act (PRA)

    The EPA proposed a reporting requirement, along with an associated 
Information Collection Request (ICR), in the NPRM. However, the EPA is 
not adopting the proposed reporting requirement, and therefore not 
submitting a final ICR to OMB for approval. Thus, this action does not 
impose any new information collection burden under the PRA.

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. In 
making this determination, the impact of concern is any significant 
adverse economic impact on small entities. An agency may certify that a 
rule will not have a significant economic impact on a substantial 
number of small entities if the rule relieves regulatory burden, has no 
net burden or otherwise has a positive economic effect on the small 
entities subject to the rule. Among the potentially affected entities 
(manufacturers of covered airplanes and engines for those airplanes), 
there is one small business potentially affected by this action. This 
one small business is a manufacturer of aircraft engines. However, we 
did not project any costs associated with this action. We have 
therefore concluded that this action will have no net regulatory burden 
for all directly regulated small entities.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or 
more as described in UMRA, 2 U.S.C. 1531-1538, and does not 
significantly or uniquely affect small governments. The action imposes 
no enforceable duty on any state, local or tribal governments or the 
private sector.

F. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the National Government and the states, or on the distribution of power 
and responsibilities among the various levels of government.

G. Executive Order 13175: Consultation and Coordination With Indian 
Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. This action regulates the manufacturers of 
airplanes and aircraft engines and will not have substantial direct 
effects on one or more Indian tribes, on the relationship between the 
Federal Government and Indian tribes, or on the distribution of power 
and responsibilities between the Federal Government and Indian tribes. 
Thus, Executive Order 13175 does not apply to this action.

H. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    This action is not subject to Executive Order 13045 because it is 
not economically significant as defined in Executive Order 12866, and 
because the EPA does not believe the environmental health or safety 
risks addressed by this action present a disproportionate risk to 
children.

I. Executive Order 13211: Actions Concerning Regulations That 
Significantly Affect Energy Supply, Distribution or Use

    This action is not a ``significant energy action'' because it is 
not likely to have a significant adverse effect on the supply, 
distribution or use of energy and has not otherwise been designated by 
OIRA as a significant energy action. These airplane GHG regulations are 
not expected to result in any changes to airplane fuel consumption 
beyond what would have otherwise occurred in the absence of this rule, 
as discussed in Section V.C.

J. National Technology Transfer and Advancement Act (NTTAA) and 1 CFR 
Part 51

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113, 12(d) (15 U.S.C. 272 note) 
directs EPA to use voluntary consensus standards in its regulatory 
activities unless to do so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies. NTTAA directs agencies to provide 
Congress, through OMB, explanations when the Agency decides

[[Page 2171]]

not to use available and applicable voluntary consensus standards. This 
action involves technical standards.
    In accordance with the requirements of 1 CFR 51.5, we are 
incorporating by reference the use of test procedures contained in 
ICAO's International Standards and Recommended Practices Environmental 
Protection, Annex 16, Volumes II and III, along with the modifications 
contained in this rulemaking. This includes the following standards and 
test methods:

------------------------------------------------------------------------
   Standard or test method         Regulation              Summary
------------------------------------------------------------------------
ICAO 2017, Aircraft Engine    40 CFR 87.1, 40 CFR   Test method
 Emissions, Annex 16, Volume   87.42(c), and 40      describes how to
 II, Fourth Edition, July      CFR 87.60(a) and      measure gaseous and
 2017, as amended by           (b).                  smoke emissions
 Amendment 10, July 20, 2020.                        from airplane
                                                     engines.
ICAO 2017, Aeroplane CO2      40 CFR 1030.23(d),    Test method
 Emissions, Annex 16, Volume   40 CFR 1030.25(d),    describes how to
 III, First Edition, July      40 CFR 1030.90(d),    measure the fuel
 2017, as amended by           and 40 CFR 1030.105.  efficiency of
 Amendment 1, July 20, 2020.                         airplanes.
------------------------------------------------------------------------

    The material from the ICAO Annex 16, Volume II is an updated 
version of the document that is already incorporated by reference in 40 
CFR 87.1, 40 CFR 87.42(c), and 40 CFR 87.60(a) and (b).
    The referenced standards and test methods may be obtained through 
the International Civil Aviation Organization, Document Sales Unit, 999 
University Street, Montreal, Quebec, Canada H3C 5H7, (514) 954-8022, 
www.icao.int, or [email protected].

K. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA believes that this action does not have disproportionately 
high and adverse human health or environmental effects on minority 
populations, low-income populations and/or indigenous peoples, as 
specified in Executive Order 12898 (59 FR 7629, February 16, 1994). It 
provides similar levels of environmental protection for all affected 
populations without having any disproportionately high and adverse 
human health or environmental effects on any population, including any 
minority or low-income population.

L. Congressional Review Act

    This action is subject to the CRA, and the EPA will submit a rule 
report to each House of the Congress and to the Comptroller General of 
the United States. This action is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects

40 CFR Part 87

    Environmental protection, Air pollution control, Aircraft, 
Incorporation by reference.

40 CFR Part 1030

    Environmental protection, Air pollution control, Aircraft, 
Greenhouse gases, Incorporation by reference.

Andrew Wheeler,
Administrator.

    For the reasons set forth in the preamble, EPA amends 40 CFR 
chapter I as follows:

PART 87--CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT 
ENGINES

0
1. The authority citation for part 87 continues to read as follows:

    Authority:  42 U.S.C. 7401 et seq.


0
2. Section 87.8 is amended by revising paragraphs (a) and (b)(1) to 
read as follows:


Sec.  87.8  Incorporation by reference.

    (a) Certain material is incorporated by reference into this part 
with the approval of the Director of the Federal Register under 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, the Environmental Protection Agency must 
publish a document in the Federal Register and the material must be 
available to the public. All approved material is available for 
inspection at U.S. EPA, Air and Radiation Docket Center, WJC West 
Building, Room 3334, 1301 Constitution Ave. NW, Washington, DC 20004, 
www.epa.gov/dockets, (202) 202-1744, and is available from the sources 
listed in this section. It is also available for inspection at the 
National Archives and Records Administration (NARA). For information on 
the availability of this material at NARA, email [email protected] 
or go to www.archives.gov/federal-register/cfr/ibr-locations.html.
    (b) * * *
    (1) Annex 16 to the Convention on International Civil Aviation, 
Environmental Protection, as follows:
    (i) Volume II--Aircraft Engine Emissions, Fourth Edition, July 
2017. IBR approved for Sec. Sec.  87.1, 87.42(c), and 87.60(a) and (b).
    (ii) Amendment 10 to Annex 16, Volume II, to the Convention on 
International Civil Aviation, effective July 20, 2020 (ICAO Annex 16, 
Volume II). IBR approved for Sec. Sec.  87.1, 87.42(c), and 87.60(a) 
and (b).
* * * * *

0
3. Add part 1030 to read as follows:

PART 1030--CONTROL OF GREENHOUSE GAS EMISSIONS FROM ENGINES 
INSTALLED ON AIRPLANES

Scope and Applicability

1030.1 Applicability.
1030.5 State standards and controls.
1030.10 Exemptions.

Subsonic Airplane Emission Standards and Measurement Procedures

1030.20 Fuel efficiency metric.
1030.23 Specific air range (SAR).
1030.25 Reference geometric factor (RGF).
1030.30 GHG emission standards.
1030.35 Change criteria.
1030.98 Confidential business information.

Reference Information

1030.100 Abbreviations.
1030.105 Definitions.
1030.110 Incorporation by reference.

    Authority:  42 U.S.C. 7401-7671q.

Scope and Applicability


Sec.  1030.1  Applicability.

    (a) Except as provided in paragraph (c) of this section, when an 
aircraft engine subject to 40 CFR part 87 is installed on an airplane 
that is described in this section and subject to title 14 of the Code 
of Federal Regulations, the airplane may not exceed the Greenhouse Gas 
(GHG) standards of this part when original civil certification under 
title 14 is sought.
    (1) A subsonic jet airplane that has--
    (i) A type certificated maximum passenger seating capacity of 20 
seats or more;
    (ii) A maximum takeoff mass (MTOM) greater than 5,700 kg; and

[[Page 2172]]

    (iii) An application for original type certification that is 
submitted on or after January 11, 2021.
    (2) A subsonic jet airplane that has--
    (i) A type certificated maximum passenger seating capacity of 19 
seats or fewer;
    (ii) A MTOM greater than 5,700 kg, but not greater than 60,000 kg; 
and
    (iii) An application for original type certification that is 
submitted on or after January 1, 2023.
    (3) A propeller-driven airplane that has--
    (i) A MTOM greater than 8,618 kg; and
    (ii) An application for original type certification that is 
submitted on or after January 1, 2020.
    (4) A subsonic jet airplane--
    (i) That is a modified version of an airplane whose original type 
certificated version was not required to have GHG emissions 
certification under this part;
    (ii) That has a MTOM greater than 5,700 kg;
    (iii) For which an application for the modification in type design 
is submitted on or after January 1, 2023; and
    (iv) For which the first certificate of airworthiness is issued for 
an airplane built with the modified design.
    (5) A propeller-driven airplane--
    (i) That is a modified version of an airplane whose original type 
certificated version was not required to have GHG emissions 
certification under this part;
    (ii) That has a MTOM greater than 8,618 kg;
    (iii) For which an application for certification that is submitted 
on or after January 1, 2023; and
    (iv) For which the first certificate of airworthiness is issued for 
an airplane built with the modified design.
    (6) A subsonic jet airplane that has--
    (i) A MTOM greater than 5,700 kg; and
    (ii) Its first certificate of airworthiness issued on or after 
January 1, 2028.
    (7) A propeller-driven airplane that has--
    (i) A MTOM greater than 8,618 kg; and
    (ii) Its first certificate of airworthiness issued on or after 
January 1, 2028.
    (b) An airplane that incorporates modifications that change the 
fuel efficiency metric value of a prior version of airplane may not 
exceed the GHG standards of this part when certification under 14 CFR 
is sought. The criteria for modified airplanes are described in Sec.  
1030.35. A modified airplane may not exceed the metric value limit of 
the prior version under Sec.  1030.30.
    (c) The requirements of this part do not apply to:
    (1) Subsonic jet airplanes having a MTOM at or below 5,700 kg.
    (2) Propeller-driven airplanes having a MTOM at or below 8,618 kg.
    (3) Amphibious airplanes.
    (4) Airplanes initially designed, or modified and used, for 
specialized operations. These airplane designs may include 
characteristics or configurations necessary to conduct specialized 
operations that the EPA and the FAA have determined may cause a 
significant increase in the fuel efficiency metric value.
    (5) Airplanes designed with a reference geometric factor of zero.
    (6) Airplanes designed for, or modified and used for, firefighting.
    (7) Airplanes powered by piston engines


Sec.  1030.5  State standards and controls.

    No State or political subdivision of a State may adopt or attempt 
to enforce any airplane or aircraft engine standard with respect to 
emissions unless the standard is identical to a standard that applies 
to airplanes under this part.


Sec.  1030.10  Exemptions.

    Each person seeking relief from compliance with this part at the 
time of certification must submit an application for exemption to the 
FAA in accordance with the regulations of 14 CFR parts 11 and 38. The 
FAA will consult with the EPA on each exemption application request 
before the FAA takes action.

Subsonic Airplane Emission Standards and Measurement Procedures


Sec.  1030.20  Fuel efficiency metric.

    For each airplane subject to this part, including an airplane 
subject to the change criteria of Sec.  1030.35, a fuel efficiency 
metric value must be calculated in units of kilograms of fuel consumed 
per kilometer using the following equation, rounded to three decimal 
places:
[GRAPHIC] [TIFF OMITTED] TR11JA21.017

Where:

SAR = specific air range, determined in accordance with Sec.  
1030.23.
RGF = reference geometric factor, determined in accordance with 
Sec.  1030.25.

Sec.  1030.23  Specific air range (SAR).

    (a) For each airplane subject to this part the SAR of an airplane 
must be determined by either:
    (1) Direct flight test measurements; or
    (2) Using a performance model that is:
    (i) Validated by actual SAR flight test data; and
    (ii) Approved by the FAA before any SAR calculations are made.
    (b) For each airplane model, establish a 1/SAR value at each of the 
following reference airplane masses:
    (1) High gross mass: 92 percent maximum takeoff mass (MTOM).
    (2) Low gross mass: (0.45 * MTOM) + (0.63 * (MTOM-0.924)).
    (3) Mid gross mass: Simple arithmetic average of high gross mass 
and low gross mass.
    (c) Calculate the average of the three 1/SAR values described in 
paragraph (b) of this section to calculate the fuel efficiency metric 
value in Sec.  1030.20. Do not include auxiliary power units in any 1/
SAR calculation.
    (d) All determinations under this section must be made according to 
the procedures applicable to SAR in Paragraphs 2.5 and 2.6 of ICAO 
Annex 16, Volume III and Appendix 1 of ICAO Annex 16, Volume III 
(incorporated by reference in Sec.  1030.110).


Sec.  1030.25  Reference geometric factor (RGF).

    For each airplane subject to this part, determine the airplane's 
nondimensional reference geometric factor (RGF) for the fuselage size 
of each airplane model, calculated as follows:
    (a) For an airplane with a single deck, determine the area of a 
surface (expressed in m[caret]2) bounded by the maximum 
width of the fuselage outer mold line projected to a flat plane 
parallel with the main deck floor and the forward and aft pressure 
bulkheads except for the crew cockpit zone.
    (b) For an airplane with more than one deck, determine the sum of 
the areas (expressed in m[caret]2) as follows:
    (1) The maximum width of the fuselage outer mold line, projected to 
a flat plane parallel with the main deck

[[Page 2173]]

floor by the forward and aft pressure bulkheads except for any crew 
cockpit zone.
    (2) The maximum width of the fuselage outer mold line at or above 
each other deck floor, projected to a flat plane parallel with the 
additional deck floor by the forward and aft pressure bulkheads except 
for any crew cockpit zone.
    (c) Determine the non-dimensional RGF by dividing the area defined 
in paragraph (a) or (b) of this section by 1 m[caret]2.
    (d) All measurements and calculations used to determine the RGF of 
an airplane must be made according to the procedures for determining 
RGF in Appendix 2 of ICAO Annex 16, Volume III (incorporated by 
reference in Sec.  1030.110).


Sec.  1030.30  GHG emission standards.

    (a) The greenhouse gas emission standards in this section are 
expressed as maximum permitted values fuel efficiency metric values, as 
calculated under Sec.  1030.20.
    (b) The fuel efficiency metric value may not exceed the following, 
rounded to three decimal places:

------------------------------------------------------------------------
For airplanes defined in . . .                     the standard is . . .
                                 with MTOM . . .
------------------------------------------------------------------------
(1) Section 1030.1(a)(1) and    5,700 < MTOM <     10(-2.73780 +
 (2).                            60,000 kg.         (0.681310 *
                                                    log10(MTOM))
                                                   + (-0.0277861 *
                                                    (log10(MTOM))[caret]
                                                    2))
(2) Section 1030.1(a)(3)......  8,618 < MTOM <     10(-2.73780 +
                                 60,000 kg.         (0.681310 *
                                                    log10(MTOM))
                                                   + (-0.0277861 *
                                                    (log10(MTOM))[caret]
                                                    2))
(3) Section 1030.1(a)(1) and    60,000 < MTOM <    0.764
 (3).                            70,395 kg.
(4) Section 1030.1(a)(1) and    MTOM > 70,395 kg.  10(-1.412742 + (-
 (3).                                               0.020517 *
                                                    log10(MTOM))
                                                   + (0.0593831 *
                                                    (log10(MTOM))[caret]
                                                    2))
(5) Section 1030.1(a)(4) and    5,700 < MTOM <     10(-2.57535 +
 (6).                            60,000 kg.         (0.609766 *
                                                    log10(MTOM))
                                                   + (-0.0191302 *
                                                    (log10(MTOM))[caret]
                                                    2))
(6) Section 1030.1(a)(5) and    8,618 < MTOM <     10(-2.57535 +
 (7).                            60,000 kg.         (0.609766 *
                                                    log10(MTOM))
                                                   + (-0.0191302 *
                                                    (log10(MTOM))[caret]
                                                    2))
(7) Section 1030.1(a)(4)        60,000 < MTOM <    0.797
 through (7).                    70,107 kg.
(8) Section 1030.1(a)(4)        MTOM > 70,107 kg.  10(-1.39353 + (-
 through (7).                                       0.020517 *
                                                    log10(MTOM))
                                                   + (0.0593831 *
                                                    (log10(MTOM))[caret]
                                                    2))
------------------------------------------------------------------------

Sec.  1030.35  Change criteria.

    (a) For an airplane that has demonstrated compliance with Sec.  
1030.30, any subsequent version of that airplane must demonstrate 
compliance with Sec.  1030.30 if the subsequent version incorporates a 
modification that either increases--
    (1) The maximum takeoff mass; or
    (2) The fuel efficiency metric value by more than:
    (i) For airplanes with a MTOM greater than or equal to 5,700 kg, 
the value decreases linearly from 1.35 to 0.75 percent for an airplane 
with a MTOM of 60,000 kg.
    (ii) For airplanes with a MTOM greater than or equal to 60,000 kg, 
the value decreases linearly from 0.75 to 0.70 percent for airplanes 
with a MTOM of 600,000 kg.
    (iii) For airplanes with a MTOM greater than or equal to 600,000 
kg, the value is 0.70 percent.
    (b) For an airplane that has demonstrated compliance with Sec.  
1030.30, any subsequent version of that airplane that incorporates 
modifications that do not increase the MTOM or the fuel efficiency 
metric value in excess of the levels shown in paragraph (a) of this 
section, the fuel efficiency metric value of the modified airplane may 
be reported to be the same as the value of the prior version.
    (c) For an airplane that meets the criteria of Sec.  1030.1(a)(4) 
or (5), after January 1, 2023 and until January 1, 2028, the airplane 
must demonstrate compliance with Sec.  1030.30 if it incorporates any 
modification that increases the fuel efficiency metric value by more 
than 1.5 per cent from the prior version of the airplane.


Sec.  1030.98  Confidential business information.

    The provisions of 40 CFR 1068.10 apply for information you consider 
confidential.

Reference Information


Sec.  1030.100  Abbreviations.

    The abbreviations used in this part have the following meanings:

                       Table 1 to Sec.   1030.100
------------------------------------------------------------------------
 
------------------------------------------------------------------------
EPA....................................  U.S. Environmental Protection
                                          Agency.
FAA....................................  U.S. Federal Aviation
                                          Administration.
GHG....................................  greenhouse gas.
IBR....................................  incorporation by reference.
ICAO...................................  International Civil Aviation
                                          Organization.
MTOM...................................  maximum takeoff mass.
RGF....................................  reference geometric factor.
SAR....................................  specific air range.
------------------------------------------------------------------------

Sec.  1030.105  Definitions.

    The following definitions in this section apply to this part. Any 
terms not defined in this section have the meaning given in the Clean 
Air Act. The definitions follow:
    Aircraft has the meaning given in 14 CFR 1.1, a device that is used 
or intended to be used for flight in the air.
    Aircraft engine means a propulsion engine that is installed on or 
that is manufactured for installation on an airplane for which 
certification under 14 CFR is sought.
    Airplane has the meaning given in 14 CFR 1.1, an engine-driven 
fixed-wing aircraft heavier than air, that is supported in flight by 
the dynamic reaction of the air against its wings.
    Exempt means to allow, through a formal case-by-case process, an 
airplane to be certificated and operated that does not meet the 
applicable standards of this part.
    Greenhouse Gas (GHG) means an air pollutant that is the aggregate 
group of six greenhouse gases: carbon dioxide, nitrous oxide, methane, 
hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride.
    ICAO Annex 16, Volume III means Volume III of Annex 16 to the 
Convention on International Civil Aviation (see Sec.  1030.110).
    Maximum takeoff mass (MTOM) is the maximum allowable takeoff mass 
as stated in the approved certification basis for an airplane type 
design. Maximum takeoff mass is expressed in kilograms.
    Performance model is an analytical tool (or a method) validated 
using corrected flight test data that can be used to determine the 
specific air range values for calculating the fuel efficiency metric 
value.
    Reference geometric factor is a non-dimensional number derived from 
a two-dimensional projection of the fuselage.
    Round has the meaning given in 40 CFR 1065.1001.
    Specific air range is the distance an airplane travels per unit of 
fuel consumed. Specific air range is

[[Page 2174]]

expressed in kilometers per kilogram of fuel.
    Subsonic means an airplane that has not been certificated under 14 
CFR to exceed Mach 1 in normal operation.
    Type certificated maximum passenger seating capacity means the 
maximum number of passenger seats that may be installed on an airplane 
as listed on its type certificate data sheet, regardless of the actual 
number of seats installed on an individual airplane.


Sec.  1030.110  Incorporation by reference.

    (a) Certain material is incorporated by reference into this part 
with the approval of the Director of the Federal Register under 5 
U.S.C. 552(a) and 1 CFR part 51. To enforce any edition other than that 
specified in this section, the Environmental Protection Agency must 
publish a document in the Federal Register and the material must be 
available to the public. All approved material is available for 
inspection at EPA Docket Center, WJC West Building, Room 3334, 1301 
Constitution Ave. NW, Washington, DC 20004, www.epa.gov/dockets, (202) 
202-1744, and is available from the sources listed in this section. It 
is also available for inspection at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, email [email protected] or go to: 
www.archives.gov/federal-register/cfr/ibr-locations.html.
    (b) International Civil Aviation Organization, Document Sales Unit, 
999 University Street, Montreal, Quebec, Canada H3C 5H7, (514) 954-
8022, www.icao.int, or [email protected].
    (1) ICAO Annex 16, Volume III, Annex 16 to the Convention on 
International Civil Aviation, Environmental Protection, Volume III--
Aeroplane CO2 Emissions, as follows:
    (i) First Edition, July 2017. IBR approved for Sec. Sec.  
1030.23(d) and 1030.25(d).
    (ii) Amendment 1, July 20, 2020. IBR approved for Sec. Sec.  
1030.23(d) and 1030.25(d).
    (2) [Reserved]

[FR Doc. 2020-28882 Filed 1-8-21; 8:45 am]
BILLING CODE 6560-50-P`