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.

[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

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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

    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.
---------------------------------------------------------------------------

    \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\
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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

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.
---------------------------------------------------------------------------

    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

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.

    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.

[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.
---------------------------------------------------------------------------

    \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.
---------------------------------------------------------------------------

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\
---------------------------------------------------------------------------

    \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

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.

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).
---------------------------------------------------------------------------

BILLING CODE 6560-50-P
[GRAPHIC] [TIFF OMITTED] TR11JA21.014

[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.

---------------------------------------------------------------------------

[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

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

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

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

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

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

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

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,<PHONE_NUMBER>,
www.icao.int, or<EMAIL_ADDRESS>
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,<PHONE_NUMBER>, 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_ADDRESS>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

    (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

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.