
[Federal Register Volume 77, Number 117 (Monday, June 18, 2012)]
[Rules and Regulations]
[Pages 36341-36386]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-13828]



[[Page 36341]]

Vol. 77

Monday,

No. 117

June 18, 2012

Part II





Environmental Protection Agency





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





40 CFR Parts 87 and 1068





Control of Air Pollution From Aircraft and Aircraft Engines; Emission 
Standards and Test Procedures; Final Rule

  Federal Register / Vol. 77 , No. 117 / Monday, June 18, 2012 / Rules 
and Regulations  

[[Page 36342]]


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

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 87 and 1068

[EPA-HQ-OAR-2010-0687; FRL-9678-1]
RIN 2060-AO70


Control of Air Pollution From Aircraft and Aircraft Engines; 
Emission Standards and Test Procedures

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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

SUMMARY: EPA is adopting several new aircraft engine emission standards 
for oxides of nitrogen (NOX), compliance flexibilities, and 
other regulatory requirements for aircraft turbofan or turbojet engines 
with rated thrusts greater than 26.7 kilonewtons (kN). We also are 
adopting certain other requirements for gas turbine engines that are 
subject to exhaust emission standards as follows. First, we are 
clarifying when the emission characteristics of a new turbofan or 
turbojet engine model have become different enough from its existing 
parent engine design that it must conform to the most current emission 
standards. Second, we are establishing a new reporting requirement for 
manufacturers of gas turbine engines that are subject to any exhaust 
emission standard to provide us with timely and consistent emission-
related information. Third, and finally, we are establishing amendments 
to aircraft engine test and emissions measurement procedures. EPA 
actively participated in the United Nations' International Civil 
Aviation Organization (ICAO) proceedings in which most of these 
requirements were first developed. These regulatory requirements have 
largely been adopted or are actively under consideration by its member 
states. By adopting such similar standards, therefore, the United 
States maintains consistency with these international efforts.

DATES: These final rules are effective on July 18, 2012. The 
incorporation by reference of certain publications listed in this 
regulation is approved by the Director of the Federal Register as of 
July 18, 2012.

ADDRESSES: EPA has established a docket for this action under Docket ID 
No. EPA-HQ-OAR-2010-0687. All documents in the docket are listed on the 
http://www.regulations.gov Web site. Although listed in the index, some 
information is not publicly available, e.g., confidential business 
information or other information whose disclosure is restricted by 
statute. Certain other material, such as copyrighted material, is not 
placed on the Internet and will be publicly available only in hard copy 
form. Publicly available docket materials are available electronically 
through http://www.regulations.gov or in hard copy at the EPA Docket 
Center, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave. NW., 
Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 
p.m., Monday through Friday, excluding legal holidays. The telephone 
number for the Public Reading Room is (202) 566-1744, and the telephone 
number for the Air Docket is 202-566-1742.

FOR FURTHER INFORMATION CONTACT: Richard Wilcox, Office of 
Transportation and Air Quality, Office of Air and Radiation, 
Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 
48105; telephone number: (734) 214-4390; fax number: (734) 214-4816; 
email address: wilcox.rich@epa.gov.

SUPPLEMENTARY INFORMATION:

 Does this action apply to me?

    Entities potentially regulated by this action are those that 
manufacture and sell aircraft engines and aircraft in the United 
States. Regulated categories include:

----------------------------------------------------------------------------------------------------------------
                                                                                      Examples of potentially
                  Category                    NAICS \a\ Codes     SIC \b\ Codes          affected entities
----------------------------------------------------------------------------------------------------------------
Industry...................................             336412               3724  Manufacturers of new aircraft
                                                                                    engines.
Industry...................................             336411               3721  Manufacturers of new
                                                                                    aircraft.
----------------------------------------------------------------------------------------------------------------
\a\ North American Industry Classification System (NAICS).
\b\ Standard Industrial Classification (SIC) system code.

    This table lists the types of entities that EPA is now aware could 
potentially be regulated by this action. Other types of entities not 
listed in the table could also be regulated. To determine whether your 
activities are regulated by this action, you should carefully examine 
the applicability criteria in 40 CFR 87.1 (part 87). If you have any 
questions regarding the applicability of this action to a particular 
entity, consult the person listed in the preceding FOR FURTHER 
INFORMATION CONTACT section.

Table of Contents

I. Executive Summary
II. Overview and Background
    A. Contents of the Final Rule
    B. EPA's Authority and Responsibilities Under the Clean Air Act
    C. Interaction With the International Community
    D. Brief History of EPA's Regulation of Aircraft Engine 
Emissions
    E. Brief History of ICAO Regulation of Aircraft Engine Emissions
III. Why is EPA taking this action?
    A. Inventory Contribution
    B. Health, Environmental and Air Quality Impacts
    1. Background on Ozone, PM and NOX
    a. What is ozone?
    b. What is particulate matter?
    c. What is NOX?
    2. Health Effects Associated With Exposure to Ozone, PM and 
NOX
    a. What are the health effects of ozone?
    b. What are the health effects of PM?
    c. What are the health effects of NOX?
    3. Environmental Effects Associated With Exposure to Ozone, PM 
and NOX
    a. Deposition of Nitrogen
    b. Visibility Effects
    c. Plant and Ecosystem Effects of Ozone
    4. Impacts on Ambient Air Quality
IV. Details of the Final Rule
    A. NOX Standards for Newly-Certified Engines
    1. Tier 6 NOX Standards for Newly-Certified Engines
    a. Numerical Emission Limits for Higher Thrust Engines
    b. Numerical Emission Limits for Lower Thrust Engines
    2. Tier 8 NOX Standards for Newly-Certified Engines
    a. Numerical Emission Limits for Higher Thrust Engines
    b. Numerical Emission Limits for Lower Thrust Engines
    B. Application of NOX Standards for Newly-
Manufactured Engines
    1. Phase-In of the Tier 6 NOX Standards for Newly-
Manufactured Engines
    2. Carryover of Previously Generated Emission Data
    3. Exemptions and Exceptions From the Tier 6 Production Cutoff
    a. New Provisions for Spare Engines
    b. New Provisions for Engines Installed in New Aircraft
    i. Time-Frame and Scope
    ii. Production Limit
    iii. Exemption Requests
    iv. Coordination of Exemption Requests
    v. Low-Volume, Time-Limited Transitional Exception Program
    c. Voluntary Emission Offsets
    4. Potential Phase-In of New Tier 8 NOX Standards for 
Newly-Manufactured Engines

[[Page 36343]]

    C. Application of Standards for Derivative Engines
    D. Annual Reporting Requirement
    E. Standards for Supersonic Aircraft Turbine Engines
    F. Amendments to Test and Measurement Procedures
    G. Possible Future Revisions to Emission Standards for New 
Technology Turbine Engines and Supersonic Aircraft Turbine Engines
V. Description of Other Revisions to the Regulatory Text
    A. Applicability Issues
    1. Military Engines
    2. Noncommercial Engines
    B. Non-Substantive Revisions
    C. Clarifying Language for Regulatory Text
VI. Technical Feasibility and Cost Impacts
VII. Consultation With FAA
VIII. Public Participation
IX. Statutory Provisions and Legal Authority
X. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review, and 
Executive Order 13563: Improving Regulation and Regulatory Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Analysis
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health & Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Executive Order 12898: Federal Actions To Address 
Environmental Justice in Minority Populations and Low Income 
Populations
    K. Congressional Review Act
    L. Executive Order 13609: Promoting International Regulatory 
Cooperation

I. Executive Summary

A. Purpose of the Regulatory Action

    The primary purpose of this rule is to adopt new oxides of nitrogen 
(NOX) emission standards for aircraft engines with rated 
thrusts greater than 26.7 kN thrust. These are mostly commercial 
passenger and freighter aircraft in common use at airports across the 
U.S. It does not include engines used on military aircraft. 
NOX is strongly correlated with NO2, for which 
EPA has established National Ambient Air Quality Standards (NAAQS), 
i.e., a criteria pollutant, and it is an important precursor gas in the 
formation of tropospheric ozone and secondary particulate matter which 
are common air pollutants in urban areas where airports are located. 
Currently, approximately 154 million people live in areas designated 
nonattainment for one or more of the current NAAQS. This rule will 
allow us to enforce in the U.S. the emission standards adopted by ICAO, 
and will be useful to states in attaining or maintaining the ozone, 
PM2.5, and NO2 NAAQS standards. This rule also 
contains several provisions to facilitate the implementation of EPA's 
aircraft engine emission regulations and related requirements. It is 
also important to note that adoption of the provisions in this rule 
meets U.S. treaty obligations under the Chicago Convention of 1944 by 
aligning our regulations with those in the International Civil Aviation 
Organization Annex 16, Volume II (adopted in 2010) that the U.S. helped 
to develop and support as part of the international process. This rule 
is being implemented under the authority provided in section 231 of the 
Clean Air Act (42 U.S.C. 7571), which directs the Administrator of 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 her judgment causes or contributes to air 
pollution that may reasonably be anticipated to endanger public health 
or welfare.

B. Summary of Major Provisions of the Regulatory Action

    The rule contains six major provisions. The first two provisions 
are new NOX emission standards for newly certified-engine 
models. The first standards, Tier 6, take effect when this rule becomes 
effective. These represent approximately a 12 percent reduction from 
current Tier 4 levels. They were actually adopted by ICAO in 2005 with 
an implementation date in 2008. The second standards, Tier 8, were 
adopted by ICAO in 2008 and take effect in 2014. These represent 
approximately a 15 percent reduction from Tier 6 levels. As noted 
above, both tiers of emission standards are needed to address local air 
quality concerns (NAAQS) and to meet U.S. treaty obligations under the 
Chicago Convention. The third major provision is a production cut-off 
for newly-manufactured engines (as opposed to newly-certified engines) 
which basically requires that after December 31, 2012 all newly-
manufactured engines must meet at least Tier 6 NOX emission 
standards. This is also needed to meet our obligations under the 
Chicago Convention. The production cut-off is needed to ensure that the 
emission reductions envisioned by the emission standards are achieved 
on new production engines. The fourth major provision is related to 
potential exemptions or exceptions to the production cut-off 
requirement. These include revised provisions allowing manufacturers to 
request that FAA in consultation with EPA grant exemptions from the 
production cut-off for a designated number of engines within a 
prescribed time frame. These also include a low-volume, time-limited 
exception provision that will exclude several engines from the 
production cutoff. Both of these provisions help to assure an orderly 
transition to the new standards for engines needing more time to comply 
or for a few engines at the end of their production life. Finally, the 
rule includes a set of provisions which may be considered as minor if 
viewed separately, but collectively are important in upgrading EPA's 
regulations by incorporating some related agreements from our ICAO 
process and clarifying and improving existing provisions. Examples of 
this include special provisions for spare engines, provisions related 
to derivative engine models, test procedure specifications and 
reporting requirements. These changes are important for an effective 
implementation of the new requirements, and in many cases are also 
needed to meet our obligations under the Chicago Convention.

C. Costs and Benefits

    This is not an economically significant regulatory action. Aircraft 
engines are international commodities used on aircraft manufactured and 
sold around the world. When developing new engine models manufacturers 
not only consider current emission requirements but also try to 
anticipate the stringency of future standards and respond 
appropriately. Engine manufacturers participated in the deliberations 
leading up to ICAO decisions on the aircraft engine NOX 
emission standards and after the ICAO decisions they incorporated 
engine technology changes as needed to meet the new ICAO requirements. 
This helps to ensure the world wide acceptability of their products. 
Essentially all of these changes are now complete. Thus, while there is 
some cost to a manufacturer for responding to the new ICAO provisions, 
there is no significant further direct cost to the manufacturers 
created by EPA's adopting the requirements into U.S regulations. In 
fact, it is likely that our adopting these requirements facilitates the 
acceptance of U.S. type certificates by aircraft manufacturers and 
airlines around the world.

II. Overview and Background

    This section summarizes the major provisions of the final rule for 
aircraft gas turbine engines. It also contains

[[Page 36344]]

background on the EPA's standard setting authority and responsibilities 
under the Clean Air Act, the connection between our emission standards 
and those of the international community, and a brief regulatory 
history for this source of emissions.

A. Contents of the Final Rule

    We are adopting several new emission standards and other regulatory 
requirements for aircraft turbofan and turbojet engines \1\ with rated 
thrusts greater than 26.7 kilonewtons (kN). First, we are establishing 
two new tiers of more stringent emission standards for oxides of 
nitrogen (NOX).\2\ The standards apply differently to two 
classes of these engines, i.e., ``newly-certified engines'' and 
``newly-manufactured engines.'' The newly-certified engine standards 
apply to aircraft engines that have received a new type certificate and 
have never been manufactured prior to the effective date of the new 
emission standards. Requirements for newly-manufactured engines apply 
to aircraft engines that were previously certified and manufactured in 
compliance with preexisting standards, and they require manufacturers 
to either comply with the newer standards by a specified future date or 
cease production of the affected engine models. Newly-manufactured 
engine standards are also sometimes referred to as ``production 
cutoff'' standards. Second, we are adopting certain time-limited 
flexibilities, i.e., the potential for exemptions or exceptions as 
defined in the regulations for newly-manufactured engines that may not 
be able to comply with the first tier of the NOX standards 
because of specific technical or economic reasons.\3\
---------------------------------------------------------------------------

    \1\ Turbofan and turbojet engines will be collectively referred 
to as turbofan engines hereafter for convenience.
    \2\ As previously mentioned, these new NOX standards 
are identical to requirements established by ICAO. The stringency of 
any new emission standard is selected based on an assessment of the 
technical feasibility, cost, and environmental benefit of potential 
requirements. The NOX standards we are promulgating today 
will not affect fuel economy or have any practical effect on 
CO2 emissions. (See International Civil Aviation 
Organization (ICAO), ``Committee on Aviation Environmental 
Protection (CAEP), Eighth Meeting, Montreal, 1 to 12 February 2010, 
CAEP/8 NOX Stringency Cost-Benefit Analysis Demonstration 
Using APMT-IMPACTS,'' CAEP/8-IP/30, December 1, 2010. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.)
    \3\ These exemption or exception provisions are conceptually the 
same as the ICAO exemption provisions and provide the same 
regulatory flexibilities to all engine manufacturers.
---------------------------------------------------------------------------

    We are also making a number of additional changes that would apply 
to a wider range of aircraft gas turbine engines \4\ than those that 
would be subject to the new emission standards.\5\ First, we are 
defining the meaning of a derivative engine for emissions certification 
purposes. The intent of this definition is to distinguish when the 
emission characteristics of a new turbofan engine model vary 
sufficiently from its existing parent engine design, and must show 
compliance with the emission standard for a newly-certificated engine. 
Second, we are establishing new reporting requirements for 
manufacturers that produce gas turbine engines subject to any exhaust 
emission standard. This will provide us with timely and consistent 
emission data and other information that is necessary to conduct 
emission inventory and air quality analyses and develop appropriate 
public policy for the aviation sector. Specifically, reports are 
required for turbofan engines with rated thrusts greater than 26.7 kN, 
which are subject to gaseous emission and smoke standards, in addition 
to turbofans less than or equal to 26.7 kN, and all turboprop engines, 
that are only subject to smoke standards.\6\ Third, we are adopting 
minor amendments to the test and measurement procedures for aircraft 
engines. Finally, as described in section IV, we are making minor 
amendments to regulator provisions addressing definitions, acronyms and 
abbreviations, general applicability and requirements, exemptions, and 
incorporation by reference.
---------------------------------------------------------------------------

    \4\ The term gas turbine engine includes turbofan, turbojet, and 
turboprop engines designs. The rated output for turbofan and 
turbojet engines is normally expressed as kilonewtons (kN) thrust. 
The rated output for turboprop engines is normally expressed as 
shaft horsepower (hp) or shaft kilowatt (kW).
    \5\ This includes turbofan and turbojet engines less than 26.7 
kN thrust and all turboprop engines that are subject to any emission 
standard, e.g., smoke.
    \6\ As discussed further in section III.D., the voluntary 
emission data report to ICAO does not include turbofans at or below 
26.7 kN or turboprops subject to any emission standard.
---------------------------------------------------------------------------

    Most of these new regulatory requirements have already been adopted 
by the United Nation's International Civil Aviation Organization 
(ICAO). The requirements contained in this final rule bring the United 
States into alignment with the international standards and recommended 
practices.

B. EPA's Authority and Responsibilities Under the Clean Air Act

    Section 231(a)(2)(A) of the Clean Air Act (CAA) directs the 
Administrator of 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 her judgment causes or contributes 
to air pollution that may reasonably be anticipated to endanger public 
health or welfare. (See 42 U.S.C. 7571(a)(2)(A).) Section 231(a)(2)(B) 
directs EPA to consult with the Administrator of the Federal Aviation 
Administration (FAA) on such standards, and prohibits EPA from changing 
aircraft emission standards if such a change would significantly 
increase noise and adversely affect safety. 42 U.S.C. 7571(a)(2)(B)(i)-
(ii). Section 231(a)(3) provides that after we propose standards, the 
Administrator shall issue such standards ``with such modifications as 
he deems appropriate.'' 42 U.S.C. 7571(a)(3). The U.S. Court of Appeals 
for the D.C. Circuit has held that this provision confers an unusually 
broad degree of discretion on EPA to adopt aircraft engine emission 
standards as the Agency determines are reasonable. NACAA v. EPA, 489 
F.3d 1221 (D.C. Cir. 2007).
    In addition, under CAA section 231(b) EPA is required to ensure, in 
consultation with the U.S. Department of Transportation (DOT), that the 
effective date of any standard provides the necessary time to permit 
the development and application of the requisite technology, giving 
appropriate consideration to the cost of compliance. 42 U.S.C. 7571(b). 
Section 232 then directs the FAA to prescribe regulations to ensure 
compliance with EPA's standards. 42 U.S.C. 7572. Finally, section 233 
of the CAA vests the authority to promulgate emission standards for 
aircraft or aircraft engines only in EPA. States are preempted from 
adopting or enforcing any standard respecting aircraft engine emissions 
unless such standard is identical to EPA's standards. 42 U.S.C. Sec.  
7573. Section VI of today's final rule further discusses our 
coordination with DOT through the FAA.\7\ It also describes DOT's 
responsibility under the CAA to enforce the aircraft emission standards 
established by EPA.
---------------------------------------------------------------------------

    \7\ The functions of the Secretary of Transportation under part 
B of title II of the Clean Air Act (Sec. Sec.  231-234, 42 U.S.C. 
7571-7574) have been delegated to the Administrator of the FAA. 49 
CFR 1.47(g).
---------------------------------------------------------------------------

C. Interaction With the International Community

    We began regulating the air pollution emissions from aircraft 
engines in 1973. Since that time, we have worked with the FAA and later 
with the International Civil Aviation Organization (ICAO) to develop 
international standards and other recommended practices pertaining to 
aircraft engine emissions. ICAO was established in 1944 by the United 
Nations (by the Convention on International Civil Aviation, the

[[Page 36345]]

``Chicago Convention'') ``* * * in order that international civil 
aviation may be developed in a safe and orderly manner and that 
international air transport services may be established on the basis of 
equality of opportunity and operated soundly and economically.'' \8\ 
ICAO's responsibilities include developing aircraft technical and 
operating standards, recommending practices, and generally fostering 
the growth of international civil aviation. The United States is 
currently one of 191 participating member States of 
ICAO.9 10
---------------------------------------------------------------------------

    \8\ ICAO, ``Convention on International Civil Aviation,'' Ninth 
Edition, Document 7300/9, 2006. Copies of this document can be 
obtained from the ICAO Web site located at www.icao.int.
    \9\ Members of ICAO's Assembly are generally termed member 
States or contracting States. These terms are used interchangeably 
throughout this preamble.
    \10\ There are currently 191 Contracting States according to 
ICAO Web site located at www.icao.int.
---------------------------------------------------------------------------

    In the interests of global harmonization and international air 
commerce, the Chicago Convention urges a high degree of uniformity by 
its member States. Nonetheless, the Convention also recognizes that 
member States may adopt their own unique airworthiness standards and 
that some may adopt standards that are more stringent than those agreed 
upon by ICAO.
    The Convention has a number of other features that govern 
international commerce. First, States that wish to use aircraft in 
international transportation must adopt emission standards and other 
recommended practices that are at least as stringent as ICAO's 
standards. States may ban the use of any aircraft within their airspace 
that does not meet ICAO standards.\11\ Second, States are required to 
recognize the airworthiness certificates of any State whose standards 
are at least as stringent as ICAO's standards, thereby assuring that 
aircraft of any member State will be permitted to operate in any other 
member State.\12\ Third, and finally, to ensure that international 
commerce is not unreasonably constrained, a participating nation which 
elects to adopt more stringent standards is obligated to notify ICAO of 
the differences between its standards and ICAO standards.\13\ However, 
if a nation sets tighter standards than ICAO, air carriers not based in 
that nation would only be required to comply with ICAO standards or 
more stringent standards imposed by their own nations, if applicable.
---------------------------------------------------------------------------

    \11\ ICAO, ``Convention on International Civil Aviation,'' 
Article 87, Ninth Edition, Document 7300/9, 2006. Copies of this 
document can be obtained from the ICAO Web site located at 
www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
    \12\ ICAO, ``Convention on International Civil Aviation,'' 
Article 33, Ninth Edition, Document 7300/9, 2006. Copies of this 
document can be obtained from the ICAO Web site located at 
www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
    \13\ ICAO, ``Convention on International Civil Aviation,'' 
Articles 38, Ninth Edition, Document 7300/9, 2006. Copies of this 
document can be obtained from the ICAO Web site located at 
www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
---------------------------------------------------------------------------

    ICAO's Committee on Aviation Environmental Protection (CAEP) 
undertakes ICAO's technical work in the environmental field. The 
Committee is responsible for evaluating, researching, and recommending 
measures to the ICAO Council that address the environmental impact of 
international civil aviation. CAEP is composed of various task groups, 
work groups, and other committees whose contributing members include 
atmospheric, economic, aviation, environmental, and other professionals 
interested in aviation and environmental protection. At CAEP meetings, 
the United States is represented by the FAA, which plays an active role 
at these meetings.\14\ EPA has historically been a principal 
participant in the development of U.S. policy in various ICAO/CAEP 
working groups and other international venues, assisting and advising 
FAA on aviation emissions, technology, and policy matters. If ICAO 
adopts a CAEP proposal for a new environmental standard, it then 
becomes part of ICAO standards and recommended practices (Annex 16 to 
the Chicago Convention).15 16
---------------------------------------------------------------------------

    \14\ Pursuant to the President's memorandum of August 11, 1960 
(and related Executive Order No. 10883 from 1960), the Interagency 
Group on International Aviation (IGIA) was established to facilitate 
coordinated recommendations to the Secretary of State on issues 
pertaining to international aviation. The DOT/FAA is the chair of 
IGIA, and as such, the FAA represents the U.S. on environmental 
matters at CAEP.
    \15\ ICAO, ``Aircraft Engine Emissions,'' International 
Standards and Recommended Practices, Environmental Protection, Annex 
16, Volume II, Second Edition, July 2008. A copy of this document is 
in docket number EPA-HQ-OAR-2010-0687.
    \16\ CAEP develops new emission standards based on an assessment 
of the technical feasibility, cost, and environmental benefit of 
potential requirements.
---------------------------------------------------------------------------

D. Brief History of EPA's Regulation of Aircraft Engine Emissions

    As mentioned above, we initially regulated gaseous exhaust 
emissions, smoke, and fuel venting from aircraft engines in 1973.\17\ 
Since that time, we have occasionally revised those regulations. Two of 
these revisions are most pertinent to today's final rule. First, in a 
1997 rulemaking, we made our emission standards and test procedures 
more consistent with those of ICAO for turbofan engines used in 
commercial aviation with rated thrusts greater than 26.7kN.\18\ These 
ICAO requirements are generally referred to as CAEP/2 standards. (The 
numbering nomenclature for CAEP requirements is discussed in the next 
section.) That action included new NOX emission standards 
for newly-manufactured commercial turbofan engines (those engines built 
after the effective date of the regulations that were already certified 
to pre-existing standards) \19\ and for newly-certified commercial 
turbofan engines (those engine models that received their initial type 
certificate after the effective date of the regulations). It also 
included a CO emission standard for newly-manufactured commercial 
turbofan engines. Second, in our most recent rulemaking in 2005, we 
promulgated more stringent NOX emission standards for newly-
certified commercial turbofan engines.\20\ That final rule brought the 
U.S. standards closer to alignment with ICAO CAEP/4 requirements that 
were effective in 2004. In ruling on a petition for judicial review of 
the 2005 rule filed by the National Association of Clean Air Agencies 
(NACAA), the U.S. Court of Appeals held that EPA's approach of tracking 
the ICAO standards was reasonable and permissible under the CAA. NACAA 
v. EPA, 489 F.3d 1221, 1230-32 (D.C. Cir. 2007).
---------------------------------------------------------------------------

    \17\ U.S. EPA, ``Emission Standards and Test Procedures for 
Aircraft;'' Final Rule, 38 FR 19088, July 17, 1973.
    \18\ U.S. EPA, ``Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures;'' Final 
Rule, 62 FR 25356, May 8, 1997. While ICAO's standards were not 
limited to ``commercial'' aircraft engines, our 1997 standards were 
explicitly limited to commercial engines, as our finding that 
NOX and CO emissions from aircraft engines cause or 
contribute to air pollution which may reasonably be anticipated to 
endanger public health or welfare was so limited, See 62 FR 25358. 
As explained later in section IV.A.2. of today's notice, we are 
expanding the scope of that finding and of our standards pursuant to 
section 231(a)(2)(A) of the Clean Air Act to include such emissions 
from both commercial and non-commercial aircraft engines based on 
the physical and operational similarities between commercial and 
noncommercial civilian aircraft and to bring our standards into full 
alignment with ICAO's.
    \19\ This does not mean that in 2005 we promulgated requirements 
for the re-certification or retrofit of existing in-use engines.
    \20\ U.S. EPA, ``Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures;'' Final 
Rule, 70 FR 2521, November 17, 2005.
---------------------------------------------------------------------------

E. Brief History of ICAO Regulation of Aircraft Engine Emissions

    The first international standards and recommended practices for 
aircraft engine emissions was recommended by CAEP's predecessor, the 
Committee on Aircraft Engine Emissions (CAEE), and

[[Page 36346]]

adopted by ICAO in 1981.\21\ These standards limited aircraft engine 
emissions of HC, CO, and NOX. In 1994, ICAO adopted a CAEP/2 
proposal to tighten the original NOX standard by 20 percent 
and amend the test procedures.\22\ At the next CAEP meeting (CAEP/3) in 
1995, the Committee recommended a further tightening of 16 percent and 
additional test procedure amendments, but in 1997 the ICAO Council 
rejected this stringency proposal and approved only the test procedure 
amendments. At the CAEP/4 meeting in 1998, the Committee adopted a 
similar 16 percent NOX reduction proposal, which ICAO 
approved on 1998. The CAEP/4 standards applied only to new engine 
designs certified after December 31, 2003 (i.e., the requirements did 
not also apply to previously certified, newly-manufactured engines 
unlike the CAEP/2 standards). In 2004, CAEP/6 recommended a 12 percent 
NOX reduction, which ICAO approved in 2005.23 24 
The CAEP/6 standards applied to new engine designs (newly-certified 
models) certified after December 31, 2007. At the most recent meeting, 
CAEP/8 recommended a further tightening of the NOX standards 
by 15 percent for newly-certified engines.25 26 The 
Committee also recommended that the CAEP/6 standards be applied to 
newly-manufactured engines. ICAO approved these recommendations in 
2011.\27\
---------------------------------------------------------------------------

    \21\ ICAO, Foreword of ``Aircraft Engine Emissions,'' 
International Standards and Recommended Practices, Environmental 
Protection, Annex 16, Volume II, Third Edition, July 2008. Copies of 
this document can be obtained from the ICAO Web site at 
www.icao.int.
    \22\ CAEP conducts its work over a period of years. Each work 
cycle is numbered sequentially and that identifier is used to 
differentiate the results from one CAEP to another by convention. 
The first technical meeting on aircraft emission standards was 
CAEP's successor, i.e., CAEE. The first meeting of CAEP, therefore, 
is referred to as CAEP/2.
    \23\ CAEP/5 did not address new aircraft engine emission 
standards.
    \24\ ICAO, ``Aircraft Engine Emissions,'' Annex 16, Volume II, 
Third Edition, July 2008, Amendment 4 effective on July 20, 2008. 
Copies of this document can be obtained from the ICAO Web site at 
www.icao.int.
    \25\ CAEP/7 did not address new aircraft engine emission 
standards.
    \26\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 
2010,'' CAEP/8-WP/80. A copy of this document is in docket number 
EPA-HQ-OAR-2010-0687.
    \27\ ICAO, ``Aircraft Engine Emissions,'' Annex 16, Volume II, 
Third Edition, July 2008, Amendment 7 effective on July 18, 2011. 
Copies of this document can be obtained from the ICAO Web site at 
www.icao.int.
---------------------------------------------------------------------------

III. Why is EPA taking this action?

    As mentioned above, section 231(a)(2)(A) of the CAA authorizes the 
EPA Administrator to ``from time to time, issue proposed emission 
standards applicable to the emission of any air pollution from any 
class or classes of aircraft or aircraft engines which in his judgment 
causes, or contributes to air pollution which may reasonably be 
anticipated to endanger public health or welfare.'' 42 U.S.C. 
7571(a)(2)(A).
    One of the principal components of aircraft exhaust emissions is 
NOX, a precursor to the formation of tropospheric ozone and 
secondary PM.\28\ Most commercial airports are located in urbanized 
areas \29\ and many urbanized areas have ambient pollutant levels above 
the National Ambient Air Quality Standards (NAAQS) for ozone and fine 
particulate matter (PM2.5) (i.e., they are in nonattainment 
for ozone and PM2.5).\30\ This section discusses the 
contribution of aircraft engines used in commercial service with rated 
thrusts greater than 26.7kN to the national NOX emissions 
inventory and to NOX emission inventories in selected ozone 
and PM2.5 nonattainment areas, the potential effect of 
NOX emissions in the upper atmosphere on ground level 
PM2.5 in addition to the health and welfare impacts of 
NOX and PM emissions.
---------------------------------------------------------------------------

    \28\ Ground-level ozone, the main ingredient in smog, is formed 
by complex chemical reactions of volatile organic compounds (VOC) 
and NOX in the presence of heat and sunlight. Standards 
that reduce NOX emissions will help address ambient ozone 
levels. They can also help reduce particulate matter (PM) levels as 
NOX emissions can also be part of the secondary formation 
of PM. See Section II.B below.
    \29\ According to Airport Council International--North America 
and similar FAA databases, most commercial operations occur at 
airports that are in or near large cities or urbanized areas. There 
are about 130 commercial airports in 78 ozone and fine particulate 
nonattainment areas (based on the nonattainment areas status of 
2008). There are about 325 commercial airports in the U.S.
    \30\ For a current list of nonattainment areas see: http://www.epa.gov/oar/oaqps/greenbk/index.html.
---------------------------------------------------------------------------

A. Inventory Contribution

    In contrast to all other mobile sources, whose emissions occur 
completely at ground level, the emissions from aircraft and aircraft 
engines can be divided into two flight regimes. The first regime 
includes the emissions that are released in the lower layer of the 
atmosphere and directly affect local and regional ambient air quality. 
These emissions generally occur at or below 3,000 feet above ground 
level, i.e., during the landing and takeoff (LTO) cycle. The aircraft 
operations that comprise an LTO cycle are: engine idle at the terminal 
gate (and sometimes during ground delays while holding for the active 
runway); taxiing between the terminal and the runway; take-off; climb-
out; and approach to the airport. The second regime includes emissions 
that occur above 3,000 feet above ground level, known as non-LTO 
emissions. Collectively, the emissions associated with all ground and 
flight operations are generally referred to as full flight emissions.
    In this section, we will discuss NOX emission 
inventories for commercial turbine-engine aircraft, both nationally and 
for selected ozone and PM2.5 nonattainment areas (NAAs). 
These inventories reflect emissions during the landing and takeoff 
cycle only. The most recent comprehensive analysis of historical and 
current LTO emissions from aircraft engines comes from a study 
undertaken for us by Eastern Research Group (ERG).\31\ The study 
analyzed the national emissions of commercial aircraft operations in 
the United States, and showed that in the most recent year studied 
(2008), such aircraft LTO operations contributed about 97 thousand tons 
to the national NOX inventory.\32\ A summary of the national 
inventory of LTO NOX emissions is shown in Table 1.
---------------------------------------------------------------------------

    \31\ ``Historical Assessment of Aircraft Landing and Take-off 
Emissions (1986-2008),'' Eastern Research Group, May 2011. A copy of 
this document can be found in public docket EPA-HQ-OAR-2010-0687.
    \32\ The cumulative LTO NOX reduction associated with 
the new NOX standards is projected to be about 100,000 
tons from 2014 to 2030 (2014 is the implementation date of the CAEP/
8 NOX standards). See ``Historical Assessment of Aircraft 
Landing and Take-off Emissions (1986-2008),'' Eastern Research 
Group, May 2011. A copy of this document can be found in public 
docket EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    When these nationwide LTO emissions are compared to the total U.S. 
mobile source inventory for 2009, they account for less than one 
percent of the total. However, such a comparison may be a bit 
misleading, as it only includes those aircraft emissions that occur 
below 3,000 feet altitude, while comparing them to the entirety of 
other mobile source emissions. In the U.S., LTO emissions account for 
only about ten percent of full flight NOX emissions. When 
considering full flight aircraft emissions (i.e., including both LTO 
and non-LTO emissions), the contribution of aircraft to the total 
mobile source NOX inventory is approximately 7.7 
percent.\33\ It is also worth noting that these LTO emissions are more 
localized in that they occur near airports, which are mostly within 
urban areas.
---------------------------------------------------------------------------

    \33\ U.S. EPA, ``Comparison of Aircraft LTO and Full Flight 
NOX Emissions to Total Mobile Source NOX 
Emissions,'' memorandum from John Mueller, Assessment and Standards 
Division, Office of Transportation and Air Quality, to docket EPA-
HQ-OAR-2010-0687, May 10, 2011.

[[Page 36347]]



    Table 1--Current National NOX Emissions From Commercial Aircraft
------------------------------------------------------------------------
                                                         2008 Total NOX
                  Aircraft category                     (thousand tons)
------------------------------------------------------------------------
Air Carrier..........................................                 86
Commuter/Air Taxi....................................                 11
                                                      ------------------
    Total Commercial.................................                 97
------------------------------------------------------------------------

    In addition, it is important to assess the contribution of 
commercial aircraft LTO NOX emissions on a local level, 
especially in areas containing or adjacent to airports. The historical 
analysis conducted by ERG also included an assessment of selected ozone 
nonattainment areas (NAAs). The NAAs selected for study were chosen as 
follows. First, the 25 NAAs with airports which had high commercial 
traffic volumes were identified. Second, the 25 NAAs with the largest 
population were identified. These lists were combined. However, there 
was some overlap, and this led to a total of 40 NAAs being identified 
for the study.\34\ These NAAs collectively include 200 airports, 
accounting for about 70 percent of commercial air traffic operations.
---------------------------------------------------------------------------

    \34\ Although 41 NAAs were studied, the non-aircraft emissions 
data source that the aircraft emissions were compared to for this 
analysis did not distinguish between the Boston NAA in Massachusetts 
and the greater Boston NAA in New Hampshire. Thus, aircraft 
emissions from those two NAAs were combined into a single NAA for 
the purpose of this analysis, yielding 40 NAAs for study.
---------------------------------------------------------------------------

    Of the 40 NAAs originally studied by ERG as previously described, 
we identified the 30 areas that were in nonattainment for ozone or 
PM2.5 as of March 30, 2012.\35\ Current (2008) and projected 
(2020) NOX emissions for these 30 ozone and PM2.5 
NAAs, as well as the percent contribution of aircraft to total mobile 
source inventories (as compared to 2005 and 2020 mobile source 
inventories), are shown in Table 2.36 37 38 The relative 
contribution of aircraft in any given NAA varies based on activity in 
other transportation and industrial sectors. As can be seen from this 
table, expected growth in aircraft operations in many of these areas 
combined with anticipated reductions in NOX emissions from 
other mobile source categories results in the growth of the relative 
contribution of aircraft LTO emissions to mobile source NOX 
emissions in NAAs.
---------------------------------------------------------------------------

    \35\ For a current list of nonattainment areas see: http://www.epa.gov/oar/oaqps/greenbk/index.html.
    \36\ U.S. EPA, ``Relative Contribution of Aircraft to Total 
Mobile Source NOX Emissions in Selected Ozone 
Nonattainment Areas,'' memorandum from John Mueller, Assessment and 
Standards Division, Office of Transportation and Air Quality, to 
docket EPA-HQ-OAR-2010-0687, May 10, 2011.
    \37\ U.S. EPA, ``Addendum to `Relative Contribution of Aircraft 
to Total Mobile Source NOX Emissions in Selected Ozone 
Nonattainment Areas,' '' memorandum from John Mueller, Assessment 
and Standards Division, Office of Transportation and Air Quality, to 
docket EPA-HQ-OAR-2010-0687, May 17, 2011.
    \38\ U.S. EPA, ``Update to `Relative Contribution of Aircraft to 
Total Mobile Source NOX Emissions in Selected Ozone 
Nonattainment Areas,' '' memorandum from John Mueller, Assessment 
and Standards Division, Office of Transportation and Air Quality, to 
docket EPA-HQ-OAR-2010-0687, April 30, 2012.

                     Table 2--NOX Emissions in Selected Ozone and PM2.5 Nonattainment Areas
----------------------------------------------------------------------------------------------------------------
                                                                              2008 Aircraft      2020 Aircraft
                   Nonattainment area                      2008 Total NOX   percent of mobile  percent of mobile
                                                               (tons)           source NOX         source NOX
----------------------------------------------------------------------------------------------------------------
Atlanta, GA............................................              5,808                2.6                8.2
Baltimore, MD..........................................              1,148                1.3                4.4
Boston--including MA and NH NAAs.......................              2,032                1.0                2.7
Charlotte-Gastonia-Rock Hill, NC-SC....................              1,917                2.6               10.0
Chicago-Gary-Lake County, IL-IN........................              6,007                1.8                5.0
Cleveland-Akron-Lorain, OH.............................                680                0.5                1.3
Dallas-Fort Worth, TX..................................              3,880                1.7                6.9
Denver-Boulder-Greeley-Fort Collins-Loveland, CO.......              2,649                2.5                7.1
Detroit-Ann Arbor, MI..................................              2,312                1.1                3.0
Greater Connecticut, CT................................                405                0.8                2.4
Houston-Galveston-Brazoria, TX.........................              3,045                1.3                3.4
Indianapolis, IN.......................................              1,089                1.4                3.0
Las Vegas, NV..........................................              2,308                6.0               15.8
Los Angeles South Coast Air Basin, CA..................              6,479                1.5                4.5
Louisville, KY-IN......................................              1,211                1.9                6.2
Milwaukee-Racine, WI...................................                557                0.9                3.2
New York-N. New Jersey-Long Island, NY-NJ-CT...........             10,093                2.3                6.3
Philadelphia-Wilmington-Atlantic City, PA-NY-MD-DE.....              2,308                1.0                2.8
Phoenix-Mesa, AZ.......................................              2,298                1.4                3.3
Pittsburgh-Beaver Valley, PA...........................                480                0.5                1.1
Providence (entire State), RI..........................                232                1.0                2.3
Riverside County (Coachella Valley), CA................                 70                0.2                0.5
Sacramento Metro, CA...................................                603                1.0                2.0
Salt Lake City, UT.....................................              1,235                4.4               14.1
San Diego, CA..........................................              1,035                1.4                3.4
San Francisco Bay Area, CA.............................              4,405                2.7                6.7
San Joaquin Valley, CA.................................                 74                0.0                0.1
Seattle-Tacoma, WA.....................................              1,958                1.4                3.9
St. Louis, MO-IL.......................................                810                0.6                1.6
Washington, DC-MD-VA...................................              2,983                2.0                6.2
----------------------------------------------------------------------------------------------------------------

    Table 3 shows how commercial aircraft operations are projected to 
rise in the future on a nationwide basis. As operations increase, the 
inventory impact of these aircraft on national and local NOX 
inventories will also increase.

[[Page 36348]]



                          Table 3--Current and Projected Commercial Aircraft Operations
----------------------------------------------------------------------------------------------------------------
                                                                                               Total increase in
                                         Air carrier        Commuter/air     Total commercial      commercial
                Year                      operations      taxi operations       operations      operations over
                                          (millions)         (millions)         (millions)       2008 (percent)
----------------------------------------------------------------------------------------------------------------
2008................................               14.1               13.8               27.9
2020................................               16.5               14.1               30.5                  9
2030................................               20.6               16.0               36.6                 31
----------------------------------------------------------------------------------------------------------------
 Source: December 2010 FAA TAF, which is located at http://aspm.faa.gov/main/taf.asp.

B. Health, Environmental and Air Quality Impacts

    NOX emissions from aircraft and other mobile and 
stationary sources contribute to the formation of ozone. In addition, 
NOX emissions at low altitude also react in the atmosphere 
to form secondary fine particulate matter (PM2.5), 
particularly ammonium nitrate. In the following sections we discuss the 
adverse health and welfare effects associated with NOX 
emissions, in addition to the current and projected levels of ozone and 
PM across the country. The ICAO NOX standards with which we 
are aligning will help reduce ambient ozone and secondary PM levels and 
thus will help areas with airports achieve or maintain attainment with 
the National Ambient Air Quality Standards (NAAQS).\39\
---------------------------------------------------------------------------

    \39\ The discussion of PM health and welfare effects throughout 
this notice relates exclusively to the effects of the NOX 
emission standards on the formation of secondary PM from nitrate 
formation in the atmosphere. Presently, there are no emission 
standards for PM emitted directly from aircraft turbine engines. The 
current and planned future work programs for CAEP/ICAO are 
developing PM test procedures and information to characterize the 
amount and type of these emissions from aircraft engines that are in 
production. Ultimately, this information will be used to assess the 
need for an aircraft turbine engine PM standard (i.e., whether PM 
emissions from aircraft cause or contribute to air pollution which 
may reasonably be anticipated to endanger public health or welfare), 
with standard setting as appropriate.
---------------------------------------------------------------------------

1. Background on Ozone, PM and NOX
a. What is ozone?
    Ground-level ozone pollution is typically formed through reactions 
involving VOC and NOX in the lower atmosphere in the 
presence of sunlight. These pollutants, often referred to as ozone 
precursors, are emitted by many types of pollution sources, such as 
highway and nonroad motor vehicles and engines, power plants, chemical 
plants, refineries, makers of consumer and commercial products, 
industrial facilities, and smaller area sources.
    The science of ozone formation, transport, and accumulation is 
complex.\40\ Ground-level ozone is produced and destroyed in a cyclical 
set of chemical reactions, many of which are sensitive to temperature 
and sunlight. When ambient temperatures and sunlight levels remain high 
for several days and the air is relatively stagnant, ozone and its 
precursors can build up and result in more ozone than typically occurs 
on a single high-temperature day. Ozone and its precursors can be 
transported hundreds of miles downwind from precursor emissions, 
resulting in elevated ozone levels even in areas with low local VOC or 
NOX emissions.
---------------------------------------------------------------------------

    \40\ U.S. EPA Air Quality Criteria for Ozone and Related 
Photochemical Oxidants (Final). U.S. Environmental Protection 
Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document 
is available in Docket EPA-HQ-OAR-2010-0687. This document may be 
accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.
---------------------------------------------------------------------------

b. What is particulate matter?
    The discussion includes PM2.5 because the NOX 
emitted by aircraft engines can react in the atmosphere to form 
nitrate, a component of PM2.5. Particulate matter is a 
generic term for a broad class of chemically and physically diverse 
substances. It can be principally characterized as discrete particles 
that exist in the condensed (liquid or solid) phase spanning several 
orders of magnitude in size. Since 1987, EPA has delineated that subset 
of inhalable particles small enough to penetrate to the thoracic region 
(including the tracheobronchial and alveolar regions) of the 
respiratory tract (referred to as thoracic particles). The current PM 
NAAQS uses PM2.5 as the indicator for fine particles (with 
PM2.5 generally referring to particles with a nominal mean 
aerodynamic diameter less than or equal to 2.5 micrometers ([micro]m)), 
and use PM10 as the indicator for purposes of regulating the 
coarse fraction of PM10 (referred to as thoracic coarse 
particles or coarse-fraction particles; generally including particles 
with a nominal mean aerodynamic diameter greater than 2.5 [micro]m and 
less than or equal to 10 [micro]m, or PM10-2.5). Ultrafine 
particles are a subset of fine particles, generally less than 100 
nanometers (0.1 [mu]m) in diameter.
    Fine particles are produced primarily by combustion processes and 
by transformations of gaseous emissions (e.g., SOX, 
NOX and VOC) in the atmosphere. The chemical and physical 
properties of PM2.5 may vary greatly with time, region, 
meteorology, and source category. Thus, PM2.5 may include a 
complex mixture of different components including sulfates, nitrates, 
organic compounds, elemental carbon and metal compounds. These 
particles can remain in the atmosphere for days to weeks and travel 
hundreds to thousands of kilometers.
c. What is NOX?
    Nitrogen dioxide (NO2) is a member of the NOX 
family of gases. Most NO2 is formed in the air from the 
oxidation of nitric oxide (NO) emitted when fuel is burned at a high 
temperature. NO2 and its gas phase oxidation products can 
dissolve in water droplets and further oxidize to form nitric acid 
which reacts with ammonia to form nitrates, an important component of 
ambient PM. NOX and VOC are the two major precursors of 
ozone. The health effects of ozone, ambient PM and NOX are 
covered in section II.B.2.
2. Health Effects Associated With Exposure to Ozone, PM and 
NOX
a. What are the health effects of ozone?
    The health and welfare effects of ozone are well documented and are 
assessed in EPA's 2006 Air Quality Criteria Document and 2007 Staff 
Paper.41 42 People who are more susceptible to effects 
associated with exposure to ozone can include children,

[[Page 36349]]

the elderly, and individuals with respiratory disease such as asthma. 
Those with greater exposures to ozone, for instance due to time spent 
outdoors (e.g., children and outdoor workers), are of particular 
concern. Ozone can irritate the respiratory system, causing coughing, 
throat irritation, and breathing discomfort. Ozone can reduce lung 
function and cause pulmonary inflammation in healthy individuals. Ozone 
can also aggravate asthma, leading to more asthma attacks that require 
medical attention and/or the use of additional medication. Thus, 
ambient ozone may cause both healthy and asthmatic individuals to limit 
their outdoor activities. In addition, there is suggestive evidence of 
a contribution of ozone to cardiovascular-related morbidity and highly 
suggestive evidence that short-term ozone exposure directly or 
indirectly contributes to non-accidental and cardiopulmonary-related 
mortality, but additional research is needed to clarify the underlying 
mechanisms causing these effects. In a report on the estimation of 
ozone-related premature mortality published by the National Research 
Council (NRC), a panel of experts and reviewers concluded that short-
term exposure to ambient ozone is likely to contribute to premature 
deaths and that ozone-related mortality should be included in estimates 
of the health benefits of reducing ozone exposure.\43\ Animal 
toxicological evidence indicates that with repeated exposure, ozone can 
inflame and damage the lining of the lungs, which may lead to permanent 
changes in lung tissue and irreversible reductions in lung function. 
The respiratory effects observed in controlled human exposure studies 
and animal studies are coherent with the evidence from epidemiologic 
studies supporting a causal relationship between acute ambient ozone 
exposures and increased respiratory-related emergency room visits and 
hospitalizations in the warm season. In addition, there is suggestive 
evidence of a contribution of ozone to cardiovascular-related morbidity 
and non-accidental and cardiopulmonary mortality.
---------------------------------------------------------------------------

    \41\ U.S. EPA Air Quality Criteria for Ozone and Related 
Photochemical Oxidants (Final). U.S. Environmental Protection 
Agency, Washington, DC, EPA 600/R-05/004aF-cF, 2006. This document 
is available in Docket EPA-HQ-OAR-2010-0687. This document may be 
accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.
    \42\ U.S. EPA (2007) Review of the National Ambient Air Quality 
Standards for Ozone, Policy Assessment of Scientific and Technical 
Information. OAQPS Staff Paper.EPA-452/R-07-003. This document is 
available in Docket EPA-HQ-OAR-2010-0687. This document is available 
electronically at: http:www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_sp.html.
    \43\ National Research Council (NRC), 2008. Estimating Mortality 
Risk Reduction and Economic Benefits From Controlling Ozone Air 
Pollution. The National Academies Press: Washington, DC A copy of 
this document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

b. What are the health effects of PM?
    Scientific studies show ambient PM is associated with a series of 
adverse health effects. These health effects are discussed in detail in 
EPA's Integrated Science Assessment for Particulate Matter (ISA).\44\ 
The ISA summarizes health effects evidence associated with both short-
term and long-term exposures to PM2.5, PM10-2.5, 
and ultrafine particles.
---------------------------------------------------------------------------

    \44\ U.S. EPA (2009) Integrated Science Assessment for 
Particulate Matter, EPA 600/R-08/139F. A copy of this document is in 
docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    The ISA concludes that health effects associated with short-term 
exposures (hours to days) to ambient PM2.5 include 
mortality, cardiovascular effects, such as altered vasomotor function 
and myocardial ischemia, and hospital admissions and emergency 
department visits for ischemic heart disease and congestive heart 
failure, and respiratory effects, such as exacerbation of asthma 
symptoms in children and hospital admissions and emergency department 
visits for chronic obstructive pulmonary disease and respiratory 
infections.\45\ The ISA notes that long-term exposure (months to years) 
to PM2.5 is associated with the development/progression of 
cardiovascular disease, premature mortality, and respiratory effects, 
including reduced lung function growth in children, increased 
respiratory symptoms, and asthma development.\46\ The ISA concludes 
that the currently available scientific evidence from epidemiologic, 
controlled human exposure, and toxicological studies supports a causal 
association between short- and long-term exposures to PM2.5 
and cardiovascular effects and premature mortality. Furthermore, the 
ISA concludes that the collective evidence supports likely causal 
associations between short- and long-term PM2.5 exposures 
and respiratory effects. The ISA also concludes that the scientific 
evidence is suggestive of a causal association for reproductive and 
developmental effects including respiratory-related infant mortality 
and cancer, mutagenicity, and genotoxicity and long-term exposure to 
PM2.5.\47\
---------------------------------------------------------------------------

    \45\ U.S. EPA (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, 2009. Section 2.3.1.1.
    \46\ U.S. EPA (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, 2009. page 2-12, Sections 
7.3.1.1 and 7.3.2.1.
    \47\ U.S. EPA (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, 2009. Section 2.3.2.
---------------------------------------------------------------------------

    For PM10-2.5, the ISA concludes that the current 
evidence is suggestive of a causal relationship between short-term 
exposures and premature mortality, cardiovascular effects, and 
respiratory effects. Data are inadequate to draw conclusions regarding 
the health effects associated with long-term exposure to 
PM10-2.5.
    For ultrafine particles, the ISA concludes that there is suggestive 
evidence of a causal relationship between short-term exposures and 
cardiovascular effects, such as changes in heart rhythm and blood 
vessel function. It also concludes that there is suggestive evidence of 
association between short-term exposure to ultrafine particles and 
respiratory effects. Data are inadequate to draw conclusions regarding 
the health effects associated with long-term exposure to ultrafine 
particles.
c. What are the health effects of NOX?
    Information on the health effects of NO2 can be found in 
the EPA Integrated Science Assessment (ISA) for Nitrogen Oxides.\48\ 
The EPA has concluded that the findings of epidemiologic, controlled 
human exposure, and animal toxicological studies provide evidence that 
is sufficient to infer a likely causal relationship between respiratory 
effects and short-term NO2 exposure. The ISA concludes that 
the strongest evidence for such a relationship comes from epidemiologic 
studies of respiratory effects including symptoms, emergency department 
visits, and hospital admissions. The ISA also draws two broad 
conclusions regarding airway responsiveness following NO2 
exposure. First, the ISA concludes that NO2 exposure may 
enhance the sensitivity to allergen-induced decrements in lung function 
and increase the allergen-induced airway inflammatory response 
following 30-minute exposures of asthmatics to NO2 
concentrations as low as 0.26 ppm. Second, exposure to NO2 
has been found to enhance the inherent responsiveness of the airway to 
subsequent nonspecific challenges in controlled human exposure studies 
of asthmatic subjects. Small but significant increases in non-specific 
airway hyperresponsiveness were reported following 1-hour exposures of 
asthmatics to 0.1 ppm NO2. Enhanced airway responsiveness 
could have important clinical implications for asthmatics since 
transient increases in airway responsiveness following NO2 
exposure have the potential to increase symptoms and worsen asthma 
control. Together, the epidemiologic and experimental data sets form a 
plausible, consistent, and coherent description of

[[Page 36350]]

a relationship between NO2 exposures and an array of adverse 
health effects that range from the onset of respiratory symptoms to 
hospital admission.
---------------------------------------------------------------------------

    \48\ U.S. EPA (2008). Integrated Science Assessment for Oxides 
of Nitrogen--Health Criteria (Final Report). EPA/600/R-08/071. 
Washington, DC: U.S. EPA. A copy of this document is in docket 
number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    Although the weight of evidence supporting a causal relationship is 
somewhat less certain than that associated with respiratory morbidity, 
NO2 has also been linked to other health endpoints. These 
include all-cause (non-accidental) mortality, hospital admissions or 
emergency department visits for cardiovascular disease, and decrements 
in lung function growth associated with chronic exposure.
3. Environmental Effects Associated With Exposure to Ozone, PM and 
NOX
a. Deposition of Nitrogen
    Emissions of NOX from aircraft engines contribute to 
atmospheric deposition of nitrogen in the U.S. Atmospheric deposition 
of nitrogen contributes to acidification, altering biogeochemistry and 
affecting animal and plant life in terrestrial and aquatic ecosystems 
across the United States. The sensitivity of terrestrial and aquatic 
ecosystems to acidification from nitrogen deposition is predominantly 
governed by geology. Prolonged exposure to excess nitrogen deposition 
in sensitive areas acidifies lakes, rivers and soils. Increased acidity 
in surface waters creates inhospitable conditions for biota and affects 
the abundance and nutritional value of preferred prey species, 
threatening biodiversity and ecosystem function. Over time, acidifying 
deposition also removes essential nutrients from forest soils, 
depleting the capacity of soils to neutralize future acid loadings and 
negatively affecting forest sustainability. Major effects include a 
decline in sensitive forest tree species, such as red spruce (Picea 
rubens) and sugar maple (Acer saccharum); and a loss of biodiversity of 
fishes, zooplankton, and macro invertebrates.
    In addition to the role nitrogen deposition plays in acidification, 
nitrogen deposition also leads to nutrient enrichment and altered 
biogeochemical cycling. In aquatic systems increased nitrogen can alter 
species assemblages and cause eutrophication. In terrestrial systems 
nitrogen loading can lead to loss of nitrogen sensitive lichen species, 
decreased biodiversity of grasslands, meadows and other sensitive 
habitats, and increased potential for invasive species.
    Adverse impacts on soil chemistry and plant life have been observed 
for areas heavily influenced by atmospheric deposition of nutrients, 
metals and acid species, resulting in species shifts, loss of 
biodiversity, forest decline damage to forest productivity and 
reductions in ecosystem services. Potential impacts also include 
adverse effects to human health through ingestion of contaminated 
vegetation or livestock (as in the case for dioxin deposition), 
reduction in crop yield, and limited use of land due to contamination.
    Atmospheric deposition of pollutants can reduce the aesthetic 
appeal of buildings and culturally important articles through soiling, 
and can contribute directly (or in conjunction with other pollutants) 
to structural damage by means of corrosion or erosion.\49\ Atmospheric 
deposition may affect materials principally by promoting and 
accelerating the corrosion of metals, by degrading paints, and by 
deteriorating building materials such as concrete and limestone. 
Particles contribute to these effects because of their electrolytic, 
hygroscopic, and acidic properties, and their ability to adsorb 
corrosive gases (principally sulfur dioxide).
---------------------------------------------------------------------------

    \49\ U.S. EPA. (2005). Review of the National Ambient Air 
Quality Standards for Particulate Matter: Policy Assessment of 
Scientific and Technical Information, OAQPS Staff Paper. Retrieved 
on April 9, 2009 from http://www.epa.gov/ttn/naaqs/standards/pm/data/pmstaffpaper_20051221.pdf.
---------------------------------------------------------------------------

b. Visibility Effects
    NOX emissions contribute to visibility impairment in the 
U.S. through the formation of secondary PM2.5.\50\ 
Visibility impairment is caused by light scattering and absorption by 
suspended particles and gases. Visibility is important because it has 
direct significance to people's enjoyment of daily activities in all 
parts of the country. Individuals value good visibility for the well-
being it provides them directly, where they live and work, and in 
places where they enjoy recreational opportunities. Visibility is also 
highly valued in significant natural areas, such as national parks and 
wilderness areas, and special emphasis is given to protecting 
visibility in these areas. For more information on visibility see the 
final 2009 PM ISA.\51\
---------------------------------------------------------------------------

    \50\ U.S. EPA. (2004). Air Quality Criteria for Particulate 
Matter (AQCD). Volume I Document No. EPA600/P-99/002aF and Volume II 
Document No. EPA600/P-99/002bF. Washington, DC: U.S. Environmental 
Protection Agency. Retrieved on March 18, 2009 from http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=87903.
    \51\ U.S. EPA (2009). Integrated Science Assessment for 
Particulate Matter (Final Report). U.S. Environmental Protection 
Agency, Washington, DC, EPA/600/R-08/139F, 2009. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

c. Plant and Ecosystem Effects of Ozone
    Elevated ozone levels contribute to environmental effects, with 
impacts to plants and ecosystems being of most concern. Ozone can 
produce both acute and chronic injury in sensitive species depending on 
the concentration level and the duration of the exposure. Ozone effects 
also tend to accumulate over the growing season of the plant, so that 
even low concentrations experienced for a longer duration have the 
potential to create chronic stress on vegetation. Ozone damage to 
plants includes visible injury to leaves and impaired photosynthesis, 
both of which can lead to reduced plant growth and reproduction, 
resulting in reduced crop yields, forestry production, and use of 
sensitive ornamentals in landscaping. In addition, the impairment of 
photosynthesis, the process by which the plant makes carbohydrates (its 
source of energy and food), can lead to a subsequent reduction in root 
growth and carbohydrate storage below ground, resulting in other, more 
subtle plant and ecosystems impacts. These latter impacts include 
increased susceptibility of plants to insect attack, disease, harsh 
weather, interspecies competition and overall decreased plant vigor. 
The adverse effects of ozone on forest and other natural vegetation can 
potentially lead to species shifts and loss from the affected 
ecosystems, resulting in a loss or reduction in associated ecosystem 
goods and services. Lastly, visible ozone injury to leaves can result 
in a loss of aesthetic value in areas of special scenic significance 
like national parks and wilderness areas. The final 2006 Ozone Air 
Quality Criteria Document presents more detailed information on ozone 
effects on vegetation and ecosystems.
4. Impacts on Ambient Air Quality
    The aircraft NOX emission standards we are promulgating 
would affect ambient concentrations of air pollutants. Nationally, 
levels of PM2.5, ozone, and NOX are 
declining.\52\ However as of March 30, 2012, over 15 million people 
live in areas designated nonattainment for one or more of the current 
NAAQS.\53\ These numbers do not include the people living in areas 
where there is a future risk of failing to maintain or attain the 
NAAQS.
---------------------------------------------------------------------------

    \52\ U. S. EPA (2010) Our Nation's Air: Status and Trends 
through 2008. Office of Air Quality Planning and Standards, Research 
Triangle Park, NC. Publication No. EPA 454/R-09-002. This document 
can be accessed electronically at: http://www.epa.gov/airtrends/2010/.
    \53\ U.S. EPA, 2012. http://www.epa.gov/oar/oaqps/greenbk/index.html
---------------------------------------------------------------------------

    States with ozone nonattainment areas are required to take action 
to bring

[[Page 36351]]

those areas into attainment. The attainment date assigned to an ozone 
nonattainment area is based on the area's classification. Most ozone 
nonattainment areas are required to attain the 1997 8-hour ozone NAAQS 
in the 2007 to 2013 time frame and then to maintain it thereafter.\54\ 
We anticipate designating areas for the 2008 ozone standards in late 
spring 2012; thus, the attainment dates for areas designated 
nonattainment for the 2008 8-hour ozone NAAQS would likely be in the 
2015 to 2032 timeframe, depending on the severity of the problem in 
each area.\55\
---------------------------------------------------------------------------

    \54\ The Los Angeles South Coast Air Basin 8-hour ozone 
nonattainment area and the San Joaquin Valley Air Basin 8-hour ozone 
nonattainment area are designated as extreme and will have to attain 
before June 15, 2024. The Sacramento, Coachella Valley and Houston 
8-hour ozone nonattainment areas are designated as severe and will 
have to attain by June 15, 2019. In addition, the Western Mojave 8-
hour ozone nonattainment area has requested to be reclassified as 
severe. This request has not yet been acted on.
    \55\ U.S. EPA, 2012. Proposed Rule--Implementation of the 2008 
National Ambient Air Quality Standards for Ozone: Nonattainment Area 
Classifications Approach, Attainment Deadlines and Revocation of the 
1997 Ozone Standards for Transportation Conformity Purposes. (77 FR 
8107, February 14, 2012).
---------------------------------------------------------------------------

    Areas designated as not attaining the 1997 PM2.5 NAAQS 
will need to attain the 1997 standards in the 2010 to 2015 time frame, 
and then maintain compliance with them thereafter. The 2006 24-hour 
PM2.5 nonattainment areas will be required to attain the 
2006 24-hour PM2.5 NAAQS in the 2014 to 2019 time frame and 
then be required to maintain the 2006 24-hour PM2.5 NAAQS 
thereafter.
    EPA has already adopted many emission control programs that are 
expected to reduce ambient ozone and PM2.5 levels and which 
will assist in reducing the number of areas that fail to achieve the 
NAAQS. Even so, our air quality modeling projects that in 2030 as many 
as 10 counties with a population of over 30 million may not attain the 
2008 ozone standard of 0.075 ppm (75 ppb) without additional 
controls.\56\ In addition, our air quality modeling projects that in 
2030 at least four counties with a population of nearly 7 million may 
not attain the 1997 annual PM2.5 standard of 15 [mu]g/m\3\ 
and 22 counties with a population of over 33 million may not attain the 
2006 24-hour PM2.5 standard of 35 [mu]g/m\3\ without 
additional controls.57 58 These numbers do not account for 
those areas that are close to (e.g., within 10 percent of) the 
standards. These areas, although not violating the standards, would 
also benefit from any reductions in NOX ensuring long-term 
maintenance of the NAAQS.
---------------------------------------------------------------------------

    \56\ U.S. EPA (2010). Regulatory Impact Analysis: Final 
Rulemaking To Establish Greenhouse Gas Emission Standards and Fuel 
Efficiency Standards for Medium- and Heavy-Duty Engines and 
Vehicles. Chapter 8: Health and Environmental Impacts. EPA 420-R-11-
901.
    \57\ U.S. EPA (2010). Regulatory Impact Analysis: Final 
Rulemaking To Establish Greenhouse Gas Emission Standards and Fuel 
Efficiency Standards for Medium- and Heavy-Duty Engines and 
Vehicles. Chapter 8: Health and Environmental Impacts. EPA 420-R-11-
901.
    \58\ These figures are based on the results of EPA computer 
modeling, which is not affected by the upcoming 2008 ozone NAAQS 
nonattainment designations.
---------------------------------------------------------------------------

    In summary, the aircraft NOX reductions resulting from 
these new aircraft engine emission standards will be useful to states 
in attaining or maintaining the ozone, PM2.5, and 
NO2 NAAQS standards.

IV. Details of the Final Rule

    The following is a description of the regulations being adopted in 
this final rule, with any changes from the proposal also noted. The 
descriptions also include our response to the most significant comments 
received on the proposal. A full summary of the comments and our 
responses are contained in the response to comments document for the 
rule that is available in the public docket for this action.\59\
---------------------------------------------------------------------------

    \59\ U.S. Environmental Protection Agency, ``Summary and 
Analysis of Comments: Control of Air Pollution From Aircraft and 
Aircraft Engines,'' Office of Transportation and Air Quality, EPA-
420-R-12-011, May 2012. A copy of this document is in docket number 
EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    We are establishing two different levels or ``tiers'' of 
increasingly more stringent NOX emission standards for gas 
turbofan engines with maximum rated thrusts greater than 26.7 
kilonewtons (kN).\60\ Each of the tiers apply to newly-certified 
engines. Newly-certified aircraft engines are those that would receive 
a new type certificate after the effective date of the applicable 
standards. Such engine types or models would not have begun production 
prior to the effective date of the new requirement.\61\
---------------------------------------------------------------------------

    \60\ The standards will apply to engines used in commercial and 
noncommercial aviation for which the FAA issues airworthiness 
certificates, e.g., non-revenue, general aviation service. The vast 
majority of these engines are used in commercial applications.
    \61\ ICAO standards describe newly-certified engines as ``* * * 
engines of a type or model for which the date of manufacture of the 
first individual production model was after. * * *'' the effective 
date of the emission standards. See ICAO, ``Aircraft Engine 
Emissions,'' Annex 16, Volume II, Third Edition, July 2008, 
Amendment 4 effective on July 20, 2008. Copies of this document can 
be obtained from the ICAO Web site at www.icao.int. The term ``first 
individual production model'' means the first engine ever produced 
of a unique model or type.
---------------------------------------------------------------------------

    We are also requiring newly-manufactured engines to comply with the 
first tier of the two tiers of standards. Newly-manufactured aircraft 
engines are those that have been previously certified and manufactured 
in compliance with preexisting standards, and will continue to be 
produced after the effective date of a new applicable standard. 
Normally, these newly-manufactured engines must comply with the same 
NOX limits as newly-certified engines, but at a later date 
or cease production.\62\ The end of this ``phase-in'' period for the 
newly-manufactured engine standards is sometimes referred to as a 
``production cutoff.''. Again, we are adopting only the first of the 
two new tiers of NOX standards for newly-manufactured 
engines. These provisions are described in detail below.
---------------------------------------------------------------------------

    \62\ The standards for newly-manufactured engines are described 
in general regulatory terms as the date that the type or model was 
first certified and produced in conformance with specific emission 
standards, and the date beyond which an individual engine meeting 
those same requirements cannot be made. So ICAO standards describe 
newly-manufactured engines as ``* * * engines of a type or model for 
which the date of manufacture of the first individual production 
model was after. * * *'' the effective date of the applicable 
standards, and ``* * * for which the date of manufacture of the 
individual engine was on or before. * * *'' a specific date that is 
later than the first effective date of the standards. See ICAO, 
``Aircraft Engine Emissions,'' Annex 16, Volume II, Third Edition, 
July 2008, Amendment 4 effective on July 20, 2008. Copies of this 
document can be obtained from the ICAO Web site at www.icao.int.
---------------------------------------------------------------------------

    Five other regulatory features are being established in this final 
rule. First, we are revising provisions for certain time-limited 
flexibilities, i.e., potential exemptions, for newly-manufactured 
engines that may not be able to comply with the first tier of the new 
NOX standards because of specific technical or economic 
reasons.\63\ Second, we are defining ``derivative engine'' for 
emissions certification purposes. The intent of this definition is to 
distinguish when the emission characteristics of a new turbofan engine 
model vary substantially from its existing parent engine design, and 
must show compliance with the emission standards for a newly-
certificated engine. Third, we are establishing new CO and 
NOX standards for turbofan engines that are used to propel 
supersonic aircraft. These standards were adopted by ICAO in the 1980s, 
but were not previously added to our HC emission standard for these 
engines. Promulgating these standards meets our treaty obligation under 
the Convention on International Civil Aviation as previously described

[[Page 36352]]

in section I.C. Fourth, we are making several changes to the emission 
testing and measurement procedures in our regulations that are intended 
to implement ICAO's Annex 16 and to incorporate the entire annex in our 
regulations by reference. Finally, as described in section IV, we are 
amending the current regulatory provisions that address definitions, 
acronyms and abbreviations, general applicability and requirements, 
exemptions, and incorporation by reference. These amendments are 
intended to clarify requirements, make them more consistent with other 
parts of the program, update the text to be consistent with current 
standard language conventions, or remove obsolete provisions.
---------------------------------------------------------------------------

    \63\ These apply only to the first tier of NOX 
standards. We are not adopting a production cutoff for the second 
tier of standards.
---------------------------------------------------------------------------

    As discussed further below, with the exception of the annual 
reporting requirement described in section III.D, the amendments 
reflect those changes that were previously adopted by ICAO.
    This final rule also is consistent with our authority and 
obligations under the CAA as described in section I.B. More 
specifically, the technical feasibility and cost of the emission 
standards were well documented by our own analyses and CAEP as 
described later in this section and in section V, Technical 
Feasibility, Costs, and Emission Benefits. We think that the final rule 
provides adequate lead time for the development and application of the 
requisite technology with appropriate consideration to the cost of 
compliance. We have consulted with the Department of Transportation 
through the FAA regarding lead time, noise, safety, and the technical 
feasibility of the new standards. Today's final rule is also consistent 
with U.S. treaty obligations under the Chicago Convention as described 
in section I.C., because the requirements are consistent with current 
ICAO standards.
    Except to the extent needed to make our standards conform to ICAO's 
standards by making them applicable to both commercial and non-
commercial engines, we are not revising exhaust emission standards for 
HC, CO, or smoke. All engines subject to the new NOX 
standards would also continue to be subject to the existing HC, CO, and 
smoke standards. It is worth emphasizing that although we are including 
these existing HC, CO, and smoke standards in a new section 87.23, 
which would also contain the new Tier 6 and Tier 8 NOX 
standards, we are not actually adopting new standards for these three 
pollutants, since under the current form of part 87 these HC, CO and 
smoke standards would already continue to apply to new engine types 
subject to future revised NOX standards.
    As discussed above, we are adopting a new naming convention in this 
preamble and the regulatory text to more easily distinguish between the 
tiers of increasingly more stringent NOX emission standards. 
This convention is also consistent with the numeric identifier that 
CAEP uses to differentiate the CAEP work cycle that produces new 
NOX standards. (The CAEP naming convention is described in 
section I.E.) As a result, the first tier of NOX standards, 
which correspond to CAEP/6, are referred to as Tier 6 in the remainder 
of today's notice. The second tier of standards is referred to as Tier 
8, which correspond to CAEP/8. We are also incorporating the new naming 
convention in the regulations for the existing NOX emission 
standards, i.e., Tier 0, Tier 2, and Tier 4. There is no material 
change to the existing NOX standards themselves, except to 
the extent that when today's final rule becomes effective, the existing 
NOX standards would be superseded by Tier 6 standards.
    We acknowledge that this new naming convention is a change from the 
past practice of not describing aircraft engine emission standards as 
tiers. However, we believe the new naming scheme is a valuable tool 
that makes referring to individual NOX standards much 
easier. It is also similar to the terminology we use for other mobile 
source sectors that are subject to environmental regulation and for 
which standards have become more stringent or have otherwise been 
amended over time.

A. NOX Standards for Newly-Certified Engines

    We are adopting two different tiers of increasingly stringent 
NOX standards. These standards would apply for all for 
newly-certified turbofan aircraft engines with maximum rated thrusts 
greater than 26.7 kN.\64\ (See section III.B for a discussion of how 
these standards apply for newly-manufactured engines that are not 
considered to be newly certified.) The numerical value of the 
applicable standard for an individual engine model is defined by the 
engine's thrust level and pressure ratio. Simply stated, the pressure 
ratio is the numerical ratio of the air pressure entering the engine to 
the air pressure at the entrance to the combustor, i.e., after the air 
has passed through the compressor section of the engine.\65\ The new 
tiers are described separately below.
---------------------------------------------------------------------------

    \64\ There are no gaseous emission standards, e.g., 
NOX, for gas turbine engines with maximum rated thrusts 
equal to or less than 26.7 kN. These engines are, however, subject 
to smoke and fuel venting standards.
    \65\ The combustor is a chamber where a mixture of fuel and air 
is burned to form very hot, expanding gases. As these gases move 
through the combustion chamber, the walls of the combustor are 
cooled with dilution air to prevent thermal damage. Dilution air is 
also used to tailor the gas' temperature profile as it exits the 
combustor so that the final temperatures will not exceed the 
allowable limit at the turbine inlet.
---------------------------------------------------------------------------

1. Tier 6 NOX Standards for Newly-Certified Engines
    This first tier of new standards is equivalent to the CAEP/6 
NOX limits that were adopted by ICAO and became 
internationally applicable after December 31, 2007. Given that aircraft 
turbofan engines are international commodities, engine manufacturers 
introduced engine models after that date that demonstrate compliance 
with these international standards, or are already planning to do so 
for upcoming engine designs. Based on this, our evaluation of the 
necessary lead time, and the lack of any comments on this aspect of the 
proposal, this tier of standards takes effect immediately upon the 
effective date of this final rule.
    The basic form of the NOX standards for turbofan engines 
is different for higher- and lower-rated thrust engines. Higher output 
engines are defined as having rated thrusts equal to or greater than 89 
kN, while lower output engines are defined as having rated thrusts less 
than 89 kN but greater than 26.7 kN. The new Tier 6 NOX 
standards for each of these power groupings are described separately 
below.
a. Numerical Emission Limits for Higher Thrust Engines
    The Tier 6 NOX standards for newly-certified gas turbine 
engines with rated thrusts more than 89 kN are differentiated by 
pressure ratio as shown below.
     For engines with a pressure ratio of 30 or less:

g/kN rated output = 16.72 + (1.4080 * engine pressure ratio)
     For engines with a pressure ratio of more than 30 but less 
than 82.6:

g/kN rated output = -1.04 + (2.0 * engine pressure ratio)
     For engines with a pressure ratio of 82.6 or more:

g/kN rated output = 32 + (1.6 * engine pressure ratio)

    The new Tier 6 NOX standards for these higher thrust 
engines are presented in Figure 1 along with the previous EPA 
NOX standards, which were based on CAEP/4, for comparison.

[[Page 36353]]

[GRAPHIC] [TIFF OMITTED] TR18JN12.000

    As a matter of convention, the relative stringency from one CAEP 
standard to another is expressed relative to a pressure ratio of 30, 
because the percentage reduction is usually inconsistent across all of 
the possible pressure ratios, which otherwise makes a simple comparison 
difficult. Using that convention, the Tier 6 standards (CAEP/6) are 
referred to as being 12 percent more stringent than the existing EPA 
NOX Tier 4 standards (CAEP/4). The relative stringency can 
also be illustrated at other pressure ratios. At pressure ratios less 
than 30 the reductions are also 12 percent. At pressure ratios above 
30, however, the percent reduction decreases as the pressure ratio is 
increased. Based on the figure, the percent reduction for current 
technology engines ranges from about 8 to 12 percent.
b. Numerical Emission Limits for Lower Thrust Engines
    The new Tier 6 NOX standards for newly-certified gas 
turbine engines with rated thrusts between 26.7 and equal to or less 
than 89.0 kN are differentiated by both pressure ratio and rated thrust 
as shown below.
     For engines with a pressure ratio of 30 or less:

g/kN rated output = 38.5486 + (1.6823 * engine pressure ratio) - 
(0.2453 * kN rated thrust) - (0.00308 * engine pressure ratio * kN 
rated thrust)

     For engines with a pressure ratio of more than 30 but less 
than 82.6:

g/kN rated output = 46.1600 + (1.4286 * engine pressure ratio) - 
(0.5303 * kN rated thrust) + (0.00642 * engine pressure ratio * kN 
rated thrust)

    In developing the corresponding NOX standards for lower 
thrust engines, CAEP recognized the technical challenges that 
physically smaller-sized engines sometimes present relative to 
incorporating some of the lowest NOX technology approaches, 
which are otherwise available to their larger counterparts. These 
technical difficulties are well documented and increase progressively 
as size is reduced (from around 89 kN).\66\ For example, the relatively 
small combustor space and section height of these engines creates 
constraints on the use of low NOX fuel-staged combustor 
concepts which inherently require the availability of greater flow path 
cross-sectional area than conventional combustors. Also, fuel-staged 
combustors need more fuel injectors, and this need is not compatible 
with the relatively smaller total fuel flows of lower thrust engines. 
(Reductions in fuel flow per nozzle are difficult to attain without 
having clogging problems due to the small sizes of the fuel metering 
ports.) In addition, lower thrust engine combustors have an inherently 
greater liner surface-to-combustion volume ratio, and this requires 
increased wall cooling air flow. Thus, less air will be available to 
obtain acceptable turbine inlet temperature distribution and for 
emissions control.\67\ With these technological constraints in mind, 
CAEP fashioned the CAEP/6 NOX standards across the range of 
thrusts represented by low-thrust engines to become comparatively less 
stringent, i.e., CAEP/6 relative to CAEP/4, as the rated output and 
physical size of the engines decrease. We agree with this approach.
---------------------------------------------------------------------------

    \66\ ICAO/CAEP, ``Report of Third Meeting, Montreal, Quebec, 
December 5-15, 1995,'' Document 9675, CAEP/3. A copy of this paper 
can be found in Docket EPA-HQ-OAR-2010-0687.
    \67\ ICAO, ``Combined Report of the Certification and Technology 
Subgroups,'' section 2.3.6.1, CAEP Working Group 3 (Emissions). 
Presented by the Chairman of the Technology Subgroup, Third Meeting, 
Bonn, Germany, June 1995. A copy of this paper can be found in 
Docket EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    As mentioned, the new Tier 6 standards depend on an individual 
engine's rated thrust and pressure ratio. With two variables in the 
calculation, the standards cannot be represented in a simple figure, 
i.e., no single line graph showing the standards for all engines within 
the thrust range is possible as it was for higher thrust engines. 
Regardless of this complexity, however, some general observations are 
useful to characterize the Tier 6 NOX standards for lower 
thrust engines based on the engine size versus technological challenge 
described in the previous paragraph.
    Comparing the new lower and higher thrust standards at 89 kN, which 
is the demarcation point between the two sets of standards, shows that 
the standards for lower thrust engines are numerically equivalent to 
the limit for higher thrust

[[Page 36354]]

engines at each pressure ratio. This is as expected because the engine 
sizes and ability to incorporate low-NOX technologies are 
the same at 89.0 kN delineation point.
    Again focusing only on 89 kN engines, the new Tier 6 standards 
represent a 12 percent reduction from the existing EPA Tier 4 (CAEP/4 
based standards) for pressure ratios of 30 or less as shown below in 
Figure 2. This includes the region represented by almost all current 
engine designs. At higher pressure ratios, the relative numerical 
reduction is progressively less because the slope of the two standards 
is essentially the same.
[GRAPHIC] [TIFF OMITTED] TR18JN12.001

    At other thrust ratings the percent reduction between the new Tier 
6 and existing EPA NOX standards at any pressure ratio 
becomes progressively smaller as thrust decreases. This is illustrated 
in Figure 3 for a pressure ratio of 30. This pressure ratio was chosen 
for the example because, as before, the relative stringency of CAEP 
NOX standards is generally compared at this point as a 
matter of convention. As shown in the figure for current engines, the 
reduction ranges from 12 percent at the upper end of the thrust range 
to 0 percent at the lower end of the range. The pattern is similar for 
the other pressure ratios. Only the actual numerical value for 
percentage reduction at 89 kN, as shown on the far right of the figure, 
may vary by pressure ratio, as described at the beginning of this 
paragraph. However, in the region of pressure ratios represented by 
today's engines, the results are identical to those shown in the 
figure, i.e., a 12 percent reduction at 89 kN decreasing to 0 percent 
at 26.7 kN.

[[Page 36355]]

[GRAPHIC] [TIFF OMITTED] TR18JN12.002

2. Tier 8 NOX Standards for Newly-Certified Engines
    The second tier of new standards, i.e., Tier 8, are equivalent to 
the NOX limits that were most recently recommended at CAEP/8 
in February 2010 for adoption by ICAO.\68\ The CAEP/8 recommended 
standards have a recommended applicable date after December 31, 2013. 
As discussed further in section V of today's notice, we agree with CAEP 
that this provides engine manufacturers with adequate lead time to 
respond to these more stringent NOX standards considering 
the technical feasibility and cost associated with the 
requirements.\69\ Therefore, this tier of standards takes effect on 
January 1, 2014. As with the new Tier 6 NOX standards, the 
basic form of the new Tier 8 standards for turbofan engines is 
different for higher- and lower-rated thrust engines. Higher output 
engines are defined as having rated thrusts equal to or greater than 89 
kN, while lower output engines are defined as having rated thrusts less 
than 89 kN but greater than 26.7 kN. The longer-term standards for each 
of these power grouping are described separately below.
---------------------------------------------------------------------------

    \68\ CAEP/7 did not adopt new aircraft engine NOX 
standards.
    \69\ Leadtime in this context refers to the time between CAEP 
adoption of a new emission standard and the effective date of the 
requirement. ICAO emission standards are global in nature and 
designed to provide engine manufacturers with adequate time to 
develop and deploy the requisite technology. Manufacturers produce 
engines that comply with new ICAO standards to ensure their products 
can be sold and used worldwide even in the absence of specific U.S. 
regulations. Based on this response to the ICAO standard, we find 
that there is also adequate leadtime between EPA's promulgation of 
the new requirement and the associated effective date. No public 
comments pertaining to leadtime were received.
---------------------------------------------------------------------------

a. Numerical Emission Limits for Higher Thrust Engines
    The new Tier 8 NOX standards for newly-certified 
turbofan engines with rated thrusts of 89 N or more are differentiated 
by pressure ratio as shown below.
     For engines with a pressure ratio of 30 or less:

g/kN rated output = 7.88 + (1.4080 * engine pressure ratio)

     For engines with a pressure ratio of more than 30 but less 
than 104.7:

g/kN rated output = -9.88 + (2.0 * engine pressure ratio)

     For engines with a pressure ratio of 104.7 or more:

g/kN rated output = 32 + (1.6 * engine pressure ratio)

    The new Tier 8 NOX standards for these higher thrust 
engines are presented in Figure 4 along with the new Tier 6 standards 
for comparison.

[[Page 36356]]

[GRAPHIC] [TIFF OMITTED] TR18JN12.003

    As noted previously, as a matter of convention the relative 
stringency from one CAEP standard to another is generally expressed 
relative to a pressure ratio of 30. Using that convention, the new Tier 
8 standards (CAEP/8) are referred to as being 15 percent more stringent 
than the new Tier 6 NOX standards (CAEP/6). The relative 
stringency can also be illustrated at other pressure ratios. At 
pressure ratios less than 30 the reductions increase. At pressure 
ratios above 30, however, the percent reduction decreases. Based on the 
figure, the percent reduction for current engine designs range from 
about 11 to 19 percent.
b. Numerical Emission Limits for Lower Thrust Engines
    The new Tier 8 NOX standards for newly-certified gas 
turbine engines with rated thrusts between 26.7 but less than or equal 
to 89.0 kN are differentiated by both pressure ratio and rated thrust 
as shown below.
     For engines with a pressure ratio of 30 or less:

g/kN rated output = 40.052 + (1.5681 * engine pressure ratio) - (0.3615 
* kN rated thrust) - (0.0018 * engine pressure ratio * kN rated thrust)

     For engines with a pressure ratio of more than 30 but less 
than 104.7:

g/kN rated output = 41.9435 + (1.505 * engine pressure ratio) - 
(0.55823 * kN rated thrust) + (0.005562 * engine pressure ratio * kN 
rated thrust)

    In developing the corresponding CAEP/8 NOX standards for 
low thrust engines, CAEP recognized the technical challenges that 
physically smaller-sized engines represent relative to incorporating 
some of the lowest NOX technology, which is otherwise 
available to their larger counterparts. These technical difficulties 
were described in the previous section for the Tier 6 low-thrust engine 
standards.
    Also as previously described, no single line graph showing the 
standards for all engines within the thrust range is possible as it was 
for higher thrust engines, because the equations have two variables. 
However, some general observations are useful to characterize the new 
Tier 8 NOX standards for lower thrust engines based on the 
engine size versus technological challenge described in the previous 
paragraph. First, the new Tier 8 NOX standards for lower 
thrust engines are numerically equivalent to the limit for higher 
thrust engines across all pressure ratios at the highest rating of 89 
kN, where the engine sizes and ability to incorporated low-
NOX technologies are comparable. This same characteristic 
was observed for the Tier 6 standards. Second, as shown below in Figure 
5 for 89 kN engines, at this thrust rating the new Tier 8 standards 
represents a 15 percent reduction from the Tier 6 standards for a 
pressure ratio of 30. However, within the region of pressure ratios for 
all current engine designs, the reductions range from 19 to 23 percent.

[[Page 36357]]

[GRAPHIC] [TIFF OMITTED] TR18JN12.004

    Third, at other thrust ratings the percent reduction between the 
new Tier 6 and Tier 8 standards at any pressure ratio becomes 
progressively smaller as thrust decreases. This is illustrated in 
Figure 6 for a pressure ratio of 30, following the convention described 
above. Also as shown in the figure for current engines, the reduction 
ranges from 15 percent at the upper end of the thrust range to 5 
percent at the lower end of the range. While not depicted in a figure, 
the pattern is similar for the other pressure ratios. However, the 
actual numerical values for percentage reductions at both ends of the 
thrust range, i.e., 26.7 to 89 kN, may vary by pressure ratio. In the 
region of pressure ratios represented by today's engines, the results 
are identical to those shown in Figure 6 at 26.7 kN, i.e., a 5 percent 
reduction at all pressure ratios for that thrust rating. However, 
percent reductions increase linearly up to a maximum 23 percent 
reduction for 89 kN engines with pressure ratios of about 15.
[GRAPHIC] [TIFF OMITTED] TR18JN12.005


[[Page 36358]]



B. Application of the Tier 6 NOX Standards to Newly-
Manufactured Engines

    This section describes the application of the new Tier 6 
NOX standards to newly-manufactured engines, and our amended 
temporary flexibilities for newly-manufactured engines that show 
significant problems complying with these requirements. Also, 
consistent with CAEP/8, we are not applying the new Tier 8 
NOX standards to newly-manufactured engines at this time. 
This section concludes with a description of future efforts to examine 
such a possibility.
1. Phase-In of the Tier 6 NOX Standards for Newly-
Manufactured Engines
    As described above, the new Tier 6 NOX standards apply 
to all engine types or models that receive a new type certificate after 
the effective date of the final rule. We are also phasing in these same 
NOX limits for newly-manufactured engines for engine models 
(and their derivatives for emissions certification purposes) that were 
originally certified to less stringent requirements (i.e., Tier 2 or 
Tier 4) and were already being produced for installation on new 
aircraft prior to the effective date of the final rule.\70\ As a 
result, manufacturers need to bring newly-manufactured engines of these 
previously certified models into compliance with the applicable Tier 6 
standards by a future date or cease production of those engine 
models.\71\ As we discussed and described in our analysis of the need 
for a CAEP/6 production cutoff during the CAEP process, establishing a 
date certain for compliance with any emission standard is necessary to 
ensure that the full benefits of newer, more stringent requirements 
will be achieved in a reasonable time.\72\ We are, however, adopting 
certain limited flexibilities for engines that cannot be made compliant 
because of specific technical or economic reasons, as discussed later 
in this section.
---------------------------------------------------------------------------

    \70\ The requirement that newly-manufactured engines must meet 
the CAEP 6 NOX standard by a date certain applies only to 
engines that are intended to be installed on all new airframes. It 
would not apply to engines produced as ``spares,'' which are 
intended to be installed on existing airframes as replacements for 
maintenance or other reasons. See section III.B.2 for more 
information about new and spare engines.
    \71\ After this date the production of any noncompliant engines 
would cease because the FAA would discontinue issuing an 
airworthiness approval tag (FAA Form 8130-3) to these engines.
    \72\ ICAO, Committee on Aviation Environmental Protection 
(CAEP), Eight Meeting, Montreal, 1 to 12 February 2010, Agenda 2: 
Review of Technical Proposals Relating to Aircraft Engine Emissions, 
Adoption of Production Cutoff for Emission Standards, WP/56, 
Presented by the United States, December 12, 2009. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    As described in the proposal, the effective date of January 1, 2013 
\73\ for the newly-manufactured engine standards is consistent with the 
expected market demand for these previously certified engine types. 
Historically, engine manufacturers have often responded to the adoption 
of more stringent NOX standards by bringing older engine 
types into compliance with the newer requirements well before the 
required date in anticipation of the likely market demand, or planning 
for the orderly withdrawal of these engines from the marketplace. 
Information developed during the ICAO process in 2008 and 2009 
74 75 76 and our more recent discussions with manufacturers 
indicate that: (1) All but a few models are already compliant with 
CAEP/6 standards, (2) nearly without exception, all current production 
models will meet the CAEP/6 requirements by the 2012 time frame, and 
(3) any noncompliant models will be phased out of production because of 
low market demand.
---------------------------------------------------------------------------

    \73\ The regulatory text specifies that engine models certified 
at or below the Tier 4 NOX standards may be produced 
through December 31, 2012 without meeting the Tier 6 NOX 
standards. Therefore, the effective date of the standards for newly-
manufactured engines is effectively January 1, 2013.
    \74\ ICAO, Committee on Aviation Environmental Protection 
(CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 
2009, Agenda 6: Emissions Technical-WG3, Production Cutoffs and 
Associated Flexibilities for ICAO Engine Emission Standards, WP/39, 
Presented by U.S. Representative, August 6, 2009. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
    \75\ ICAO, Committee on Aviation Environmental Protection 
(CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 
2009, Agenda Item 3: Forecasting and Economic Analysis Support Group 
(FESG), CAEP/6 NOX Production Cutoff Cost Analysis, WP/
39, Presented by the FESG NOX Stringency Task Group, 
February 6, 2009. A copy of this document is in docket number EPA-
HQ-OAR-2010-0687.
    \76\ ICAO, Committee on Aviation Environmental Protection 
(CAEP), Steering Group Meeting, Seattle, 22 to 26 September 2008, 
Agenda Item 3: Forecasting and Economic Analysis Support Group 
(FESG), Production Cutoff for NOX Standards, WP/6, 
Presented by the FESG Rapporteurs, April 9, 2008. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    We think that the five-year phase-in period from ICAO's effective 
date of the CAEP/6 standards (corresponding to our new Tier 6 
NOX standards) for newly-manufactured engines is adequate 
for manufacturers and their customers to respond to the new 
requirements without disrupting their future planning and purchasing 
decisions.77 78 This phase-in period for applying the Tier 6 
NOX standards to newly-manufactured engines is also 
identical to the date for this same requirement that was adopted by 
ICAO. No comments were received expressing concern with this phase-in 
period for newly-manufactured engines.
---------------------------------------------------------------------------

    \77\ The ICAO CAEP/6 NOX standards became effective 
after December 31, 2007.
    \78\ This period of time is also consistent with the phase-in 
period associated with previous ICAO standards. CAEP's predecessor, 
the Committee on Aircraft Engines Emissions, established the first 
international emission standards with an effective date four years 
after adoption, i.e., effectively a four year phase-in. CAEP2 
included a phase-in period of 4 years for newly-manufactured 
engines.
---------------------------------------------------------------------------

    We did, however, receive two comments expressing the view that the 
time between the date of our final rule and the January 1, 2013 
effective date of the production cutoff would be too short if it is 
less than one year. General Electric Aviation (GE) was the most 
detailed and began by noting that most of the engine models currently 
in production were certified to the Tier 4 standards and had 
demonstrated NOX emissions below the Tier 6 at that time. 
They continued that if the original certification reports are 
sufficient for the FAA to formally certify these engines to the Tier 6 
standards, then none of these engines would be adversely affected by 
the production cutoff. However, GE expressed the concern that if 
additional interactions or formal action by the FAA were needed, or 
revisions to the FAA's FAR Part 34 were required, then having less than 
one year between EPA's final rule and the production cutoff could 
disrupt current engine production. As a result, GE asked that the date 
of the production cutoff be delayed to take effect 12 months after the 
final rule, i.e., 2013. The other joint comment from the Aerospace 
Industries Association (AIA) and the General Aviation Manufacturers 
Association (GAMA) was similar in nature, but without supporting 
details.
    The commenters' concerns do not relate to the technical or economic 
feasibility of newly-manufactured engines achieving emission levels in 
compliance with the new Tier 6 standards by the date of the production 
cutoff as proposed. The concerns expressed do not argue that additional 
time is necessary ``to permit the development and application of the 
requisite technology'' to comply with the standards under CAA section 
231(b). Therefore, the date of the Tier 6 production cutoff is 
appropriate and consistent with the Clean Air Act.
    Section 232(b) of the Act directly addresses our obligation 
relative to the effective date of the regulation. Specifically, it 
says: ``Any regulation prescribed under this section (and any revision 
thereof) shall take effect after such period as the Administrator finds 
necessary (after consultation with the

[[Page 36359]]

Secretary of Transportation) to permit the development and application 
of the requisite technology, giving appropriate consideration to the 
cost of compliance within such period.'' Based on the information 
provided above, the aircraft engine models described by GE are already 
capable of complying with the EPA Tier 6 NOX standards using 
already applied requisite technology, i.e., the cost of applying with 
has already been borne, as the effective date of the corresponding ICAO 
CAEP/6 NOX standard has already passed. We do not believe 
there are any technical feasibility or economic implications arising 
from the continued application of the requisite technology for those 
engines to meet the Tier 6 NOX standards. Also, consistent 
with our most recent previous amendment to the NOX 
standards, which similarly promulgated the standard at a level that was 
already being met by aircraft engine manufacturers who were already 
applying the requisite technology, the effective date does not need to 
include additional lead time for the development and application of 
additional technology that would be needed to comply with the 
standards. See, e.g., 70 FR 69604, 69674-76 (Nov. 17, 2005). As a 
result, the implementation dates provide more than adequate lead time 
under the statute. Therefore, because aircraft engine manufacturers are 
already able to comply with the Tier 6 NOX standard through 
the continued use of already applied requisite technology, and because 
the effective date of the corresponding ICAO CAEP/6 NOX 
standard has already passed (and also based on the assessment described 
in section V. Technical Feasibility, Cost, and Emission Benefits), we 
find that the dates provide more than adequate lead time under the 
statute for application of requisite technology.
    We also want to stress that the production cutoff is actually an 
ICAO standard and we think it is important to stay aligned with the 
CAEP production cutoff date. We note that this is also being adopted by 
the European Aviation Safety Agency (EASA) and perhaps other aviation 
certification authorities. Our adoption of the proposed date insures 
international consistency regarding the production cutoff date and 
avoids contradicting our international bilateral agreements with other 
governments, e.g., the European Union.
    Regarding the need for engine models to be formally recognized by 
the FAA as complying with the new Tier 6 standard, this is completely 
within the purview of the FAA. In our previous most recent amendment to 
the NOX standard, we provided just a one-month lead time 
period before the revised standard became effective, and FAA did not 
adopt corresponding implementing regulations until one year later, with 
no apparent disruption to the industry. (See 70 FR 69664, Nov. 17, 
2005.) The new Tier 6 standards are the same as the CAEP/6 standards 
that were approved by ICAO in 2005 with an effective date of beginning 
after December 31, 2007. Therefore, just as for the 2005 revised 
NOX standard that we similarly promulgated significantly 
later than the effective date of the corresponding ICAO CAEP standard, 
we do not believe that it is necessary to delay the effective date 
based on a need for the FAA to revise its own implementation and 
enforcement regulations.
    Finally, section 232(a) of the Act directs the FAA to ensure 
compliance with our standards. In this regard, the FAA has developed a 
streamlined process to recognize compliance with Tier 6 and or Tier 8 
as appropriate for currently type certified engine models which meet 
the emission standards and they have assured the regulated industry 
that they will dedicate the necessary resources to formally recognize 
conformance with the standards before the production cutoff date.
    For the reasons stated above, EPA is promulgating the Tier 6 
production cutoff with the originally proposed effective date of 
January 1, 2013.
2. Carryover of Previously Generated Emission Test Data
    Aircraft engine models normally receive type certificates, which 
include a determination that the model meets the emission standards in 
force at the time the type certificate is granted. EPA has not updated 
its aircraft emission standards or test procedure regulations since 
2005. In this action we are adopting Tier 6 and Tier 8 NOX 
emission standards and are adopting either in 40 CFR part 87 directly 
or through incorporation by reference of Annex 16, Volume II a number 
of minor changes to test procedures and related requirements. These 
changes will become effective on the date when the rule becomes 
effective.
    This leaves open a question regarding the future validity and 
acceptability for amended type certificates of emission tests and 
emission test data generated under previously specified test procedures 
and related requirements. For example, there may be an engine model 
tested in 2004 that demonstrated HC, CO, and NOX emission 
levels below the exhaust emission standards in effect at that time and 
also below the Tier 6 or perhaps even the Tier 8 standards that are 
being promulgated in this final rule. We want to be clear that we do 
not intend minor changes to test procedures or related provisions and 
requirements to trigger the need for additional testing. Thus, in cases 
where a manufacturer has a valid current type certificate based on 
emissions information generated under the test procedures in force at 
the time the type certificate was granted, we consider that data to be 
valid for any formal FAA recognition of compliance, e.g., an amended 
type certificate, with the Tier 6 or Tier 8 NOX emission 
requirements if the original test data demonstrate such compliance. The 
same is true for the HC and CO emission standards. This clarification 
should greatly facilitate compliance determinations by the FAA and 
eliminate any uncertainty regarding the potential for otherwise minor 
test procedure changes to trigger new emissions testing for previously 
certificated engines with emission levels below the new NOX 
standards.
3. Exemptions and Exceptions From the Tier 6 Production Cutoff
    In conjunction with the implementation of the new Tier 6 
NOX standards, we are establishing provisions which allow 
engine manufacturers to request an exemption or exception from meeting 
the Tier 6 NOX standards for newly-manufactured engines. 
These provisions replace existing provisions addressing exemptions that 
were promulgated in section 87.7 of our aircraft engine regulations. 
(Any exemptions previously issued under section 87.7 would not be 
affected by the revisions.) This section of the preamble describes 
these exemption and exception provisions, i.e., exemptions for engines 
installed in new aircraft and exceptions for spare engines used in 
existing aircraft for maintenance purposes. It also includes a 
description of a short-term exception program (termed the low-volume, 
time-limited transitional exemption program). These provisions have 
largely been crafted to be consistent with exemption provisions in the 
ICAO Environmental Technical Manual (ETM).79 80 The 
provisions of

[[Page 36360]]

the ETM guidance were developed in the context of the CAEP/6 
NOX production cutoff deliberations leading up to the CAEP/8 
meeting in February 2010.
---------------------------------------------------------------------------

    \79\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 
2010,'' CAEP/8-WP/80. A copy of this document is in docket number 
EPA-HQ-OAR-2010-0687.
    \80\ Note that EPA has submitted a paper to amend the exemption 
provisions included in this ETM to be consistent with this rule. See 
ICAO, ``Newly Produced Engine Exemptions for CAEP/6 NOX 
Production Cutoff,'' CAEP9--WG3-CTG-2--IP01, September 23, 2010. A 
copy of this document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    While we are revising our regulations, the process for evaluating 
any request for an exemption, i.e., petition, and any final decision on 
its disposition would be unchanged. In this regard, the FAA is the 
process owner under its enforcement authority contained in section 232 
of the Clean Air Act.\81\ The FAA must consult with EPA in evaluating 
the merits of the request, and the EPA must formally concur with any 
decision regarding the granting or denial of the request.
---------------------------------------------------------------------------

    \81\ EPA formally transferred the responsibility and authority 
for the evaluation of requests for exemptions from the emission 
standards to the Secretary of Transportation (DOT). See ``Control of 
Air Pollution from Aircraft and Aircraft Engines; Emission Standards 
and Test Procedures;'' Final Rule, 47 FR 58462, December 30, 1982.
---------------------------------------------------------------------------

    We are deleting from our regulations the requirement in Sec.  
87.7(e) that the FAA publish a notice of the exemption in the Federal 
Register. The FAA has an established process in place for publishing 
requests for exemption that are filed in accordance with 14 CFR part 
11. Under Sec.  87.7(b) of the existing regulations, the FAA, with EPA 
concurrence, may also exempt low-production volume engines from being 
fully compliant with the emission standards. Several such short-term 
exemptions were granted in the 1980s when emission standards were first 
applied. These exemptions have since expired, and requests for new 
exemptions under those provisions have not been submitted. We have 
determined that these provisions, which were adopted in conjunction 
with revised emission standards in 1982, are no longer of any 
utility.\82\ Therefore, we are deleting these provisions to avoid 
confusion.
---------------------------------------------------------------------------

    \82\ U.S.EPA, ``Control of Air Pollution from Aircraft and 
Aircraft Engines; Emission Standards and Test Procedures,'' Final 
Rule, 47 FR 58462, December 30, 1982.
---------------------------------------------------------------------------

    We are also deleting the time-limited exemption provision for in-
use engines that is contained in section 87.7(d) of the existing 
regulations. This provision applies to fuel venting and smoke emission 
standards, which were new when the exemption was adopted in 1973. The 
exemption allowance was limited to in-use engines that were unable to 
comply with the requirements when the regulation became effective in 
1974. The in-use fleet of engines was fully retrofitted to comply with 
the standards later in the 1970s. Therefore, this provision is now 
obsolete and we are deleting it to avoid confusion. We proposed to 
delete the existing provisions for temporary exemptions based on 
flights for short durations and infrequent intervals. This proposal was 
based on the EPA's and FAA's belief that the provisions were 
unnecessary because our standards apply to aircraft certificated by the 
FAA, and the FAA does not address in the certification process whether 
an aircraft will be used for short durations or infrequent intervals. 
Hence, the provisions appeared to have no utility.
    We received two comments from the Aerospace Industries Association 
(AIA) and the General Aviation Manufacturers Association (GAMA) 
requesting that the provision be retained. First, they argued that as 
in the past, a new aircraft may be produced at a commercial facility 
that is destined for immediate conversion to a military only 
application at a separate facility. These aircraft may require a small 
number of airworthiness flight tests before being delivered to the 
conversion facility and conceivably would be subject to EPA standards 
during flight testing. While these aircraft would generally utilize 
compliant engines, it may be possible that non-compliant engines could 
be used (our standards do not apply to engines used on military 
aircraft as discussed later) and temporary exemptions would be 
necessary. Second, AIA and GAMA commented that it would be helpful if 
the provision also allowed for granting a discrete number of exemptions 
over a specified time period, rather than having to request the 
exemption prior to each flight as currently required.
    In considering the commenters' suggestion to retain the exemption 
provision, we note that allowing such operations will not have any 
significant adverse affect on the environment because of the infrequent 
nature and short duration of such flights. Retaining the exemption is 
also consistent with exempting military aircraft from emission control 
requirements as discussed later. Therefore, we have retained the 
provision with one change, made in response to the comments, as 
described below.
    The current provision calls for the Secretary of Transportation to 
consult with the EPA Administrator when considering any exemption 
request for infrequent interval and short duration flights not 
explicitly allowed by the regulations. Given the inconsequential nature 
of such flights on the environment, we believe that the Secretary 
should be able to consider and act on these petitions unilaterally to 
streamline the process. Therefore, we are deleting that portion of the 
previous exemption provision. Of course, we will consult with the 
Secretary if asked to do so. As for requesting a discrete number of 
temporary exemptions, we believe this is an issue that the Secretary of 
Transportation may address under its enforcement role as described in 
section 232 of the CAA.
    The current regulations also provide for permanent exemptions for 
newly-manufactured engines based on consideration of the certain 
factors specified in section 87.7(c). We are replacing these provisions 
with new regulatory text generally consistent with the ETM that would 
provide for permanent exemptions or exceptions \83\ for newly 
manufactured engines used on new aircraft and spare engines used for 
maintenance or replacement purposes. These are summarized below. (See 
Sec.  87.50 of the regulations for additional details on these 
exemptions/exceptions.)
---------------------------------------------------------------------------

    \83\ As used in 40 CFR part 87, as a practical matter the 
meanings of ``exception'' and ``exemption'' are essentially 
equivalent. However, under FAA regulations, the meanings of these 
terms are distinct, especially with respect to the manner in which 
they are administered.
---------------------------------------------------------------------------

a. New Provisions for Spare Engines
    We are revising the regulations to allow the sale of a newly-
manufactured engine for installation on an in-service aircraft, i.e., a 
spare engine that does not conform to the applicable emissions 
standards at the time it was produced. It does not allow for installing 
such an engine on a new aircraft. Spare engines are produced from time 
to time in order to keep an aircraft in revenue service when the 
existing in-service engine must be removed for maintenance or 
replacement purposes as needed. Otherwise removing these aircraft from 
active service would be very expensive and logistically difficult.
    As we explained in the proposal, explicitly allowing for the 
production of spare engines is not addressed in the existing 
regulations because there is no production cutoff for the current Tier 
4 NOX standards. Thus manufacturers have been allowed to 
continue production of older engine designs under type certificates 
first issued before the Tier 4 standards took effect (e.g., Tier 2). 
However, final regulations now apply a Tier 6 NOX production 
cutoff to all newly- manufactured engines. This means that if we did 
not also adopt a provision for the continued production of spare 
engines, manufacturers would be prohibited from producing Tier 4 
engines under the existing type certificates for this purpose. We see 
no reason to change our policy of allowing manufacturers to

[[Page 36361]]

produce new engines for use as spares. Therefore, the final regulatory 
provisions allow this practice to continue.
    To ensure there would be no adverse environmental effect from 
allowing the use of a spare engine as a direct replacement for an 
existing engine, we proposed that the spare could be used only when the 
emissions for all pollutants of that engine were equal to or lower than 
those of the engine it replaced. This proposed requirement was 
consistent with the ETM, which also contains this allowance. We 
received a joint comment from AIA and GAMA stating that this is 
impractical because, while unlikely, a spare engine might have a 
different emissions profile for some pollutants than the engine it 
would replace. As an example, they stated that the two engines could 
have somewhat different combustion systems that might make one engine 
lower in NOX but higher in CO. They also suggested that EPA 
should consider the totality of the emissions in the decision, or 
delete the requirement in the final rule.
    These comments are surprising because this ETM provision, as well 
as the exception provisions, was subject to significant discussions 
within CAEP that included the engine manufacturers as well as a 
representative from AIA. Nonetheless, in this instance we believe the 
proposed provision should be modified to accommodate the potential for 
unusual circumstances as explained by the commenter.
    As noted above, AIA and GAMA suggested that EPA consider of the 
totality of emissions relative to their environmental effects as the 
basis for evaluating spare engine exemptions. This would entail 
understanding and comparing the environmental consequences of the 
different pollutants. We find that could be very complicated because 
different pollutants have different health and welfare end points and 
consequences. For example, in the illustration offered by the 
commenters, the effects of LTO NOX and CO are largely 
unrelated to one another.
    We think a preferred option to evaluating total environmental 
effects, or even dropping the provision entirely, is to incorporate an 
anti-backsliding requirement which ensures that at a minimum the 
excepted spare engine at least meets the same emission standards that 
are applicable to the engine it is replacing. For this reason, in 
response to the AIA and GAMA comment, we are modifying this provision 
in the final rule to allow an excepted spare engine to have different 
emission levels compared to the engine it replaces as long as it 
remains compliant with each of the applicable emission standards and 
any other requirements of its type certificate. Given the limited 
number of spare engines in the fleet, we expect allowing these engines 
to have somewhat different emissions profile from engines they are 
replacing will have no significant adverse environmental effect. This 
is especially true given that we expect the emissions of an excepted 
spare engine will be equal or better than the engine it is replacing in 
most cases in accordance with the basic tenant of the ETM.
    We are not requiring engine manufacturers to obtain FAA or EPA 
approval before producing spare engines. However, they must submit 
information about the production of spare engines in an annual report 
to EPA (see section III. D for more on the annual report). We proposed 
that because manufacturers are not required to seek or obtain formal 
approval to produce spare engines, this allowance was referred to as an 
``exception'' rather than an ``exemption''. This terminology would be 
consistent with current FAA regulations. Furthermore, we proposed that 
the permanent record for each engine excepted under this provision 
would need to indicate that the engine is an excepted spare engine and 
the engine itself would need to be labeled as ``EXCEPTED SPARE.'' in 
accordance with FAA marking requirements of 14 CFR.
    We received comments relating to allowing spare engines to be 
produced without requiring prior approval and the use of the terms 
``exceptions'' or ``excepted.'' The Air Transport Association (ATA) 
\84\ appreciated that there would be no case-by-case approval, noting 
that it simplifies administering the provision for FAA without 
compromising the structure of the exemptions program set forth in the 
ETM. Regarding the terminology, AIA and GAMA noted that the terminology 
was inconsistent with current engine name plate labeling practices. 
They stated that engines are currently either marked ``COMPLY'' or 
``EXEMPT'' for emissions. Both organizations generally felt the change 
in terminology for spare engines might be concerning to the operators 
holding an engine with a plate reading ``EXCEPTED.'' They concluded 
that the name plate for spare engines should continue to use 
``exempt.'' The ATA appeared to give at least tacit approval to the new 
terminology by acknowledging without objection that spare engines would 
be labeled accordingly.
---------------------------------------------------------------------------

    \84\ The Air Transport Association has changed its name to 
Airlines for America (A4A).
---------------------------------------------------------------------------

    First, we are puzzled that operators with a spare engine labeled as 
``excepted spare'' rather than ``exempt'' may have a concern, because 
AIA and GAMA did not elaborate on just what the concern might be. 
Without at least an example, we are unable to discern the nature of the 
concern and respond directly to it. We also find it puzzling that the 
two organizations that represent aerospace manufacturers expressed a 
concern regarding operators of aircraft and aircraft engines when the 
actual organization representing those companies, ATA, did not express 
such a concern.
    Second, regarding the terminology, the Tier 6 production cutoff 
does not apply to the continued production of engines that are 
designated spares. Spare engines are produced to replace a similar 
engine already in service that was removed from service for maintenance 
purposes. Accordingly, the production of a spare engine is not 
restricted by the production cutoff, and the regulation does not apply 
to these engines. The non-applicability of the cutoff eliminates the 
need to process an exemption for continued production of these engines 
beyond December 31, 2012.
    Conversely, engines that are intended to be produced for new 
installations (i.e. not replacing an engine already in service) are 
subject to the production cutoff regulation and the continued 
production of such engines beyond the cutoff date would require a grant 
of exemption. Since the production of spare engines is not subject to 
the new cutoff regulations, the FAA proposed and the EPA accepted the 
idea that referring to these engines as exceptions to the regulation 
was more appropriate than requiring case-by-case consideration of 
exemptions when the regulation did not apply.
    Moreover, the word ``exemption'' is a meaningful regulatory term. 
It is used by the FAA in 14 CFR Part 11 to mean that an applicant is 
subject to a particular regulation and is requesting time-limited 
relief under a specific set of criteria. It is a specialized form of 
rulemaking. When an entity or its product is specifically left out of a 
regulatory provision, it is considered ``excepted''. Any regulation 
adopted by the FAA would use these terms consistently.
    As already mentioned, assuming incorporation of these provisions by 
the FAA, engines meeting the requirements for spare engines could be 
produced and entered into commerce without prior approval from EPA or 
FAA. It is

[[Page 36362]]

important to note that while spare engines would be excepted from the 
Tier 6 NOX standards being promulgated today, they still 
need to be produced under an FAA type certificate. (This FAA oversight 
would serve the same role as the exemption approval step envisioned by 
ICAO in its ETM language for spare engines.) We also expect minimal 
additional burden for manufacturers, since we are not establishing new 
restrictions, monitoring, recordkeeping, or reporting requirements 
other than the end of year report.
b. New Provisions for Engines Installed in New Aircraft
    The primary purpose of allowing limited continued production of 
Tier 4 engines is to provide for an orderly implementation of the Tier 
6 NOX production cutoff. It addresses engines reaching the 
end of their production cycles in the time frame when new emission 
standards take effect. The typical production cycle would have annual 
production volumes ramp up quickly, remain at relatively large volumes 
for several or many years, and then fall off over a few more years. 
When new emission standards are adopted in the middle of a production 
cycle to take effect a few years later, manufacturers generally devote 
technical resources to bring into compliance those engine models 
expected to be produced in large numbers in the time frame when the new 
standards are in effect. In contrast, they may plan not to invest in 
upgrading the emissions of engine models that would be very near the 
end of their normal production cycles when compliance with the new 
standards becomes required. The actual length and shape of this tail of 
production volumes can be affected by factors not fully within the 
engine manufacturers' control, e.g., unexpected market demand. Thus, 
exemptions may be justified if a manufacturer does not complete the 
production cycle before the production cutoff date and projected 
production volumes are not adequate to justify investing the necessary 
resources to reduce emissions or there are other technological issues.
    Furthermore, in certain exceptional circumstances exemptions may 
also be appropriate. These are ``hardship'' situations that may arise 
as a result of unforeseen technical or economic circumstances or events 
beyond control of the manufacturer. For example, this could vary from 
unexpected problems with technology upgrade programs to labor 
disruptions or natural events disrupting production or parts 
availability.
    Our regulations currently address these kinds of situations in 
section 87.7(c), entitled, ``Exemptions for New Engines in Other 
Categories.'' We are replacing this provision with a new set of 
provisions addressing exemptions for new engines.
i. Time Frame and Scope
    The final regulations allow engine manufacturers to request an 
exemption for newly-manufactured engines not meeting the Tier 6 
NOX standards so they may be installed in new aircraft. If 
granted, manufacturers may produce a limited number of these newly-
manufactured engines in a four year time period beginning after 
December 31, 2012 and going through December 31, 2016. This four-year 
time period is consistent with the ETM. The period for any given 
approved exemption could be shorter depending on the specifics of the 
application, but it could not be longer. This exemption limits 
NOX emissions from engines that are covered by a valid type 
certificate issued by FAA. The engines must meet all other applicable 
requirements. More specifically, an engine exempted from the Tier 6 
NOX standards must be covered by a previously issued type 
certificate showing compliance with the Tier 4 NOX 
standards,\85\ as well as the current HC, CO, fuel venting, and smoke 
standards.
---------------------------------------------------------------------------

    \85\ Engines certified only for compliance with earlier Tier 2 
NOX standards would not be eligible for exemptions. This 
is also consistent with the exemption language in the ICAO ETM. Note 
that where such engines have emissions actually meeting the Tier 4 
NOX standard, they may be recertified to the Tier 4 
standards, but only before the effective date of the regulations.
---------------------------------------------------------------------------

    As explained above, the scope of the exemption provisions are 
limited to newly-manufactured engines that do not comply with the Tier 
6 NOX standards. No need has been identified to apply such 
exemption language to the other regulated exhaust pollutants, i.e., 
smoke, hydrocarbons and carbon monoxide. The emission standards for 
those pollutant species have remained unchanged for nearly three 
decades and present no technical issues for modern turbofan 
engines.\86\ If new emission standards for these pollutants are 
considered in the future, the potential need for exemption provisions 
will also be assessed at that time.
---------------------------------------------------------------------------

    \86\ For example, the hydrocarbon exhaust emission standards 
were adopted on December 30, 1982. See 47 FR 58462.
---------------------------------------------------------------------------

    We received comments requesting that exemptions be available for 
newly-certified engines in addition to newly-manufactured engines. 
General Electric Aviation (GE) stated that unforeseen circumstances may 
arise during the lengthy aircraft engine development process that 
necessitates a change in design, and that may affect the ability of 
that engine model to meet the prevailing Tier emission standard at 
certification. For that reason, GE concluded that exemptions for newly-
certified engine would be beneficial. The AIA and GAMA jointly stated 
that the existing 40 CFR 87.7(c) not only provides the flexibility to 
exempt newly-manufactured engines from a production cutoff, but also 
for newly-certificated engine models subject to any emission standards, 
e.g., the Tier 8 NOX standards. They requested that this 
flexibility should be retained.
    Regarding the availability of exemptions for newly-certified engine 
models, the proposed regulatory text made clear that the exemption 
provisions would only apply to newly-manufactured engines. 
Specifically, the intent was to establish provisions for newly-
manufactured engines to address the potential technology and economic 
adversities that may arise as part of adopting the Tier 6 production 
cutoff. The ICAO ETM provisions are clearly intended for that same 
purpose. Also, the original intent of EPA's current exemption 
provisions in Sec.  87.7(c), which we are modifying in this rulemaking, 
is clear from the proposed rulemaking and final rulemaking that 
resulted in those provisions. The March 24, 1978 proposal described the 
concern as ``* * * engines which are nearly [at] the end of their 
production life would be terminated prematurely because there would be 
insufficient future sales to justify incorporating emission controls.'' 
(See 43 FR 12619, March 24, 1978.) The December 30, 1982 final rule 
referenced ``* * * the removal of an engine model from the market 
because of its failure to comply.'' (See 47 FR 58468, December 30, 
1982.) Obviously, the intent of the existing exemption provision cited 
by AIA and GAMA was to make it apply only to newly-manufactured 
engines.
    As a general matter, we believe an exemption from the Tier 6 
standard, or any other standard, for newly-certified engine models is 
speculative at this time and would undermine the goal of regulatory 
compliance by new engine designs. In any event, neither the current 
ICAO Annex 16, Volume II provisions nor the ETM provide for newly-
certified engine exemptions. We believe that such would be a 
fundamental shift from Annex 16 and the ETM should be explored within 
the framework of ICAO/CAEP. Furthermore, engine manufacturers already 
have

[[Page 36363]]

significant leadtime between the date CAEP adopts a new emission 
standard and the standard's effective date, e.g., usually 3-5 years. 
Finally, engine manufacturers historically design new engine models to 
comply with the most stringent future standard that also provides for a 
longer development time horizon. Therefore, we are promulgating the 
exemption provisions for newly-manufactured engines as proposed.
ii. Production Limit
    As proposed, Sec.  87.5 of the final regulations reflect the 
essence of the general exemption language for exhaust emission 
standards regarding how to determine the number of allowable exemptions 
that is embodied in existing Sec.  87.7(c) of the regulations. That 
provision generally that the FAA, with EPA's concurrence, may grant 
exemptions to exhaust emission standards based on factors such as 
adverse economic impact on the engine manufacturer, aircraft 
manufacturer, or airline industry; in addition to the effects on public 
health and welfare.
    As a result, Sec.  87.5 does not specify a nominal number of 
exemptions. Rather, each request for exemption would be evaluated on a 
case-by-case basis, using the information provided by the applicant and 
any other relevant information that is available to FAA and EPA at the 
time. Any approved exemption would include a specific limit on the 
number of such engines based on that information and is not defined on 
a basis such as type certificate. (See section III.B.b.iii for a 
description of what the request must contain.) The intent, of course, 
would be to exempt the minimum number of engines that can be clearly 
justified, including a consideration of the public health and welfare 
effect associated with the exemptions.
    In the proposal, we acknowledged that our approach to determining 
limits on the number of exempt engines differs from the language 
contained in the current ICAO ETM guidance. The ETM states that ``[t]he 
number of engines exempted would normally not exceed 75 per engine type 
* * *.'' \87\ We chose not to propose adopting this language on the 
nominal number of engines based on a single type certificate. Our 
reasons for this deviation were detailed in the. The interested reader 
is referred to the proposed rule for more detail. (See 76 FR 45012. 
July 27. 2011.) We also want to emphasize that the exemption provisions 
as proposed and promulgated in this notice are not necessarily limited 
to the Tier 6 NOX production cut-off, but could in fact be 
applied to future aircraft engine emission standards if a similar 
production cut-off was adopted. Therefore, we believe our approach is 
preferable because it more clearly leaves the number of exemptions that 
might be granted open, not limited to either more or less than 75 per 
engine type, and subject to the justification supplied by the engine 
manufacturer, both for the Tier 6 production cut-off and the future.
---------------------------------------------------------------------------

    \87\ CAEP/8--WP/18, Environmental Technical Manual (ETM), Vol. 
II on the Use of Procedures in the Emission Certification of 
Aircraft Engines, Appendix ``ICAO Emissions Environmental Technical 
Manual''.
---------------------------------------------------------------------------

    We received several comments focusing primarily on the number of 
exemptions and the underlying process that is embodied in the ETM and 
our proposal. General Electric Aviation (GE) maintained that 
harmonization with the international community is not only required by 
the Chicago Convention, but also provides streamlined processes and 
procedures within the regulated industry. They contended that any 
purported benefits to EPA's unique exemption scheme were outweighed by 
setting up a conflict with the remainder of the world. They also 
suggested that if EPA wants a different approach for evaluating 
exemptions, it would be more appropriate to work inside the ICAO/CAEP 
process toward that end.
    The ATA commented that EPA's case-by-case approach to determining 
the number of engines is a rejection of the ICAO/ETM provisions that 
limit ``* * * the number of exemptions * * * to 75 engines per type 
certificate * * *.'' They argued that this would create a serious 
discontinuity between the U.S. and the rest of the world, undermining 
ICAO's objective of international uniformity. The ATA also argued that 
the ICAO exemption limits are intended to be coordinated among 
international aviation authorities, and that differing rules would make 
this impracticable. As evidence of this problem, ATA cited the European 
Aviation Safety Agency's (EASA) proposed rulemaking, which they noted 
was based on the assumption that the ICAO proposals will be adopted 
unaltered by other aviation authorities of the world. The ATA also 
stated that the ICAO ETM guidance document supplements the official 
standards of Annex 16, Vol. II and, therefore, the ETM provides 
technical elaboration on the implementation of Annex 16. From this ATA 
concluded that differing practices in this regard are counter to the 
Chicago Convention.
    Regarding consistency with the Chicago Convention, our proposal 
thoroughly explained that the ETM is guidance material; not an ICAO 
standard or regulation of any type. While consistency is desirable, it 
is not compelled when a deviation is justified. Therefore, we disagree 
with the commenters on this point, and specifically with ATA's comment 
that the ICAO guidance is effectively the equivalent of an ICAO Annex 
16 standard.
    Turning to ATA's comment regarding the ETM cap of 75 engines per 
type certificate, we first want to point out that this is not a maximum 
limit on the number of potential exemptions per type certificate nor is 
it an implied entitlement. Rather the ETM provision is an expectation 
that ``[T]he number of engines exempted would normally not exceed 75 
per engine type certificate * * *.'' as stated in the document. With 
this perspective both the ETM and our approach are similar in that the 
maximum number of exempted engines is based on a consideration of the 
petitioner's justification for such exemptions.
    Finally, we disagree with the comment that the differences with the 
ETM make international coordination unworkable. In fact, one of the 
proposed justification elements, i.e., how many affected aircraft will 
be registered in the U.S. and other countries (estimate allowed), was 
described in the preamble for the proposal as being aimed at helping to 
facilitate consultation and coordination. Also, as noted above, the 
ETM's expectation and our approach are similar in that the maximum 
number of exempted engines under both approaches is based on a 
consideration of the petitioner's justification for such exemptions. We 
do not think coordination with foreign aviation authorities, with these 
few differences, should pose any problems. After considering the above 
comments on the number of exemptions and the underlying process 
embodied in the ETM and our approach, we are promulgating the 
provisions relating to the comments as originally proposed.
iii. Exemption Requests
    We are establishing a process for requesting exemptions (for 
engines used on new aircraft) that would be more formal and structured 
than the current process. We are requiring manufacturers submit their 
request to the FAA, as currently required. The FAA will then share the 
submittal with EPA and execute the consultation process.
    To ensure that we have the information necessary to evaluate 
exemption requests in this specific manner, the requests need to 
include the following details to describe the specific engine model for 
which the manufacturer is requesting the

[[Page 36364]]

exemption. The final provisions contained in Sec.  87.50, which are 
summarized below, are consistent with and in some areas expand on the 
provisions in the ETM:
General Information
     Corporate name and an authorized representative's contact 
information (including a signed statement verifying the information);
     Description of the engines for which you are requesting 
the exemption, including the engine model and sub-model names;
     The number of engines that you would produce under the 
exemption and the period during which you would produce them;
     Identify the authorizing type certificate (type 
certificate number and date);
     Information about the aircraft in which the engines will 
be installed, including the airframe models and expected first 
purchasers/users of the aircraft, and the countries in which you expect 
the aircraft to be registered (including an estimate of how many will 
be registered in the U.S.); and
     List of other certificating authorities from which you 
have requested (or expect to request) exemptions, and a summary of each 
request.
Justification and Impacts Assessment
     A detailed description and assessment of the environmental 
impact of granting the exemption;
     Technical issues, from an environmental and airworthiness 
perspective, which may have caused a delay in compliance with a 
production cutoff, if any;
     Any economic impacts on the manufacturer, operator(s), and 
aviation industry at large; and
     Projected future production volumes and plans for 
producing a compliant version of the engine model in question.
Other Factors
     Hardship: Impact of unforeseen technical circumstances, 
business events, or other natural or manmade calamities beyond your 
control, and
     Equity issues in administering the production cutoff among 
economically competing parties.
    It is important that any action on a potential exemption request be 
in the public interest; the fairly comprehensive list of application 
information in the regulations is intended to gather the information 
needed for this assessment. We would expect to take a broad perspective 
in evaluating what is or is not in the public interest. This is why a 
manufacturer's justification needs to include a quantified description 
of the environmental effects of granting the exemption, as well as 
discussion of economic and technical issues related to bringing the 
engine into compliance. The analysis of environmental impacts needs to 
specify by how much the exempted engines would exceed the standards, 
the in-use effects in terms of lifetime tons of NOX, and 
estimate the emissions rates of engines/aircraft that could potentially 
be used if the exemption was not granted. Since exemptions granted 
under the regulations apply only to NOX emissions, the 
analysis could also include possible benefits regarding noise levels or 
reduced emissions of pollutants other than NOX. Relevant 
economic impacts could include effects on the engine manufacturer, 
airframe manufacturer, airline(s), and the general public.
    As we detailed in the proposal, some manufacturers have requested 
exemptions in the past based on the largest number of engines they 
hoped to continue manufacturing without knowing how many they would 
actually be able to produce or who would purchase them. The new 
exemption language calls for manufacturers to target their requests 
more specifically based on likely production needs and time periods. 
While we expect a manufacturer to have this specific information when 
they submit a request, the final regulations allow us to process 
exemption requests with somewhat less specific information. However, we 
expect this to apply only for unusual circumstances. Manufacturers also 
are being required to notify the FAA if they determine after submitting 
a request that the information is not accurate, either from an error or 
from changing circumstances.
    The final regulations also allow manufacturers to revise their 
requests to justify covering additional engines at any time before 
approval. We would then review the revised request. Similarly, for 
exemptions that are already approved, manufacturers could request that 
additional engines be added after providing the justification for the 
increase.
    We received comments on the level of detail required in a request 
for exemption and the time needed to add more engines to such a request 
or an already approved exemption. First, ATA was concerned that 
requesting an increased amount of engine exemptions can take a 
significant amount of time. They stated that there may be insufficient 
time for a manufacturer to receive approval for additional engine 
exemptions if necessary to meet previously unknown market demands.
    In response, we find it unfortunate that the comment does not 
provide a specific example or other information that may illustrate 
this concern. As a general response, given the long leadtime between 
the initiation of discussions among aircraft purchasers and aircraft 
manufacturers, and actual orders and final deliveries, we expect that 
manufacturers will have enough time to request additional engine 
exemptions, and if appropriate, for the FAA and EPA to approve such a 
request. We expect that amending an already approved exemption would 
take less time to act upon than the original petition. Also, engine 
manufacturers may request an expedited review from the FAA, and by 
association the EPA, if circumstances warrant. Finally, to the extent 
that an engine manufacturer has specific concerns in this area, they 
could be ameliorated by improving the lines of communication with air 
frame manufacturers to increase the manufacturer's awareness of market 
interest in potential new orders. Accordingly, we are promulgating the 
exemption provision relating to this comment as proposed.
    Second, ATA commented negatively that the exemption request for 
each individual engine be justified, ``* * * including the exact 
number, initial purchasers/users, countries of registry and plans for 
bringing the product into compliance.'' They claimed that this 
knowledge may not be known at the time of the exemption request because 
of market leadtime. As an example, ATA cited the 1998 Rolls Royce (RR) 
exemption request from the CAEP/2 cutoff for 150 engines that was not 
based on that type of certainty, but was a prospective exemption for 
two years as protection against the uncertainties of technical 
development. They stated that RR did not know when the development 
process would be completed, and hence did not know the exact number of 
non-compliant engines that airlines would purchase. The ATA also added 
that the three affected airlines worked with RR to provide 
documentation of the financial and operational hardship that they would 
suffer based on their aircraft delivery schedules.
    In response to ATA's second comment, we simply want to note that 
the information we would normally expect to be contained in the 
exemption application is actually not much different than the 
justification envisioned by the ETM. That guidance document explains 
that the petitioner should, to the extent possible, provide 
quantitative support to justify the

[[Page 36365]]

exemptions. Specifically, the ETM states that it ``* * * provides 
guidelines on the process and criteria for issuing exemptions * * *.'' 
These include some of the same elements as contained in our proposal 
and referenced above, i.e., the exact number of exemptions being 
requested, to whom the engines will be originally delivered, and plans 
for producing a compliant product. Therefore, the ETM envisions a 
consideration of specific information as part of the exemption request, 
in a similar fashion as EPA's approach, in order to decide on the exact 
number of exemptions to grant. We are simply being more explicit in 
some areas concerning the type of information that should be included 
in any exemption request. We also note ATA's comment that ``[T]he 
airlines worked with Rolls Royce to provide documentation of the 
financial and operational hardship that they would suffer if there were 
an interruption in the supply of ICAO-compliant engines during their 
aircraft delivery schedules.''
    Given the long lead times generally associated with new aircraft 
orders and deliveries, we expect aircraft operators will work closely 
with aircraft manufacturers as their new aircraft needs are identified. 
Engine manufacturers should in turn work with aircraft manufacturers to 
stay aware of market interest in potential new orders. This appears to 
be reflected in the commenter's example regarding the cooperation 
between airlines and RR in fashioning the exemption justification. 
Also, as explained in the proposed regulatory text, the petitioner 
should include information on the ``expected'' first purchasers/users 
of the aircraft. It also asked for information on the number of 
aircraft that will be registered in the U.S. versus other countries and 
that this may be estimated, if not known. Therefore, precise knowledge 
is not needed for certain elements of the justification. The preamble 
to the proposed requirements also stated that the regulations would 
allow us to process exemption requests with somewhat less specific 
information, although we expected that to apply only for unusual 
circumstances. We have made this clearer in the final regulations.
    In order to allow us to oversee these exempted engines, 
manufacturers are being required to also provide an annual report to 
EPA on exempt engines similar to the information about spare excepted 
engines. The permanent record for each engine exempted under this 
provision must indicate that the engine is an exempted engine and the 
engine itself must be labeled as ``EXEMPT NEW.''
iv. Coordination of Exemption Requests
    The limit on the number of potentially exempt engines as described 
in the ETM is intended to apply to overall worldwide production. Toward 
that end, the ETM envisions that certificating authorities and member 
states should coordinate whenever any authority receives an exemption 
request.
    Working with the FAA, we expect to consult with other aviation 
authorities whenever we receive an exemption request. This would 
include a consultation with other certificating authorities as well as 
coordination with the appropriate civil aviation authority of any 
country where the aircraft with the exempted engines will be 
registered.
    To facilitate this coordination, we are asking that manufacturers 
also include in their requests, a list of countries in which the 
aircraft are expected to be registered. While not specifically listed 
in the ETM, we believe that this information is consistent with the ETM 
as it would be necessary to ensure proper coordination. The ETM appears 
to presume that each member country will recognize exemptions granted 
by other countries. This presumption seems reasonable assuming that the 
exemption being granted is generally consistent with the guidelines of 
the ETM and that the consultation and coordination called for in the 
ETM was conducted in good faith. However, there should be no 
presumption that EPA would agree to an exemption for an engine model if 
the aforementioned collaboration, consultation, and coordination were 
not conducted. The Clean Air Act (which provides EPA with its authority 
to establish emission standards) includes no provisions that would 
allow any foreign country or other certificating authority to exempt 
subject aircraft engines, over the objection of FAA and EPA, from the 
applicable standards EPA promulgates.\88\ Nevertheless, because our 
final exemptions provisions are generally consistent with the 
procedures called for in the ETM, assuming appropriate consultation and 
coordination in accordance with the ETM and absent unforeseen 
complications, it is reasonable to believe that FAA and EPA would not 
object to exemptions for engines properly exempted by other countries 
under those procedures. The FAA would still need to take the 
certification action as called out in 14 CFR 91.203 and 14 CFR 21.183.
---------------------------------------------------------------------------

    \88\ It is possible that applications for exemptions by foreign 
entities may be filed with their national certificating authorities 
for engines manufactured after December 31, 2012 and could be 
operated in the United States. The FAA has several international 
bilateral agreements in place that include provisions and 
obligations for technical assistance on environmental certification 
matters. The FAA plans to continue to coordinate with those foreign 
certificating authorities in their considering and granting 
petitions for exemptions and, likewise, those that are filed with 
the FAA and in consultation with EPA.
---------------------------------------------------------------------------

    This, however, raises the question as to how we would respond to an 
exemption request when another certificating authority did not consult 
or coordinate on a previous request for the same engine model. A 
related concern arises if an FAA type certificate is sought under a 
reciprocity agreement for an engine which was previously certificated 
under an exemption by a foreign certificating authority, and the 
original exemption was not coordinated with the United States. Such 
requests would likely be viewed as new exemption requests if the 
anticipated collaboration, consultation, and coordination had not 
occurred.
    Thus to avoid these issues, in most cases, manufacturers may want 
to work with all relevant certificating authorities at the same time as 
well as the civil aviation authority of nation(s) where the aircraft 
will be initially registered or operated if that nation requires a type 
certificate issued under its own regulations to operate in its air 
space consistent with international agreements.
v. Low-Volume, Time-Limited Transitional Exemption Program
    We received a comment from one manufacturer expressing concern that 
once the final rule becomes effective additional time may be required 
for EPA and FAA to establish and undertake procedures to review and act 
upon exemption requests. They stated that the time needed for this 
process could be very disruptive for engine manufacturers that have 
already contracted to delivery engines during the period which FAA/EPA 
would need to consider exemption requests. They also claimed it would 
be harmful to airplane manufacturers and airlines. To avoid such an 
undesirable outcome, the commenter suggested that EPA should grant a 
one-time, interim block of perhaps 20 exemptions.
    Based on supplemental information we received from the 
commenter,\89\ we find the concerns center on six engines for which 
they have contract commitments to build and deliver within several 
months of this final rule. These six engines belong to two engine 
models, with four engines in one model

[[Page 36366]]

and two engines in the other. The first model consisting of four 
engines is scheduled to begin shipping in January 2013, shortly after 
the January 1, 2013 Tier 6 production cut off. These engines are 
currently certificated to the Tier 4 NOX standards. The 
commenter has stated, however, that the design of this engine model has 
been technically modified to achieve the Tier 6 standards. 
Unfortunately, compliance testing of this model to meet the Tier 6 
standards cannot be performed until December of 2012 when the first 
production version is built. Assuming that this testing is successful, 
inadequate time remains for the FAA to formally recognize Tier 6 
compliance based on those tests before the production cutoff becomes 
effective.\90\ The two new aircraft using these engines are being built 
and will be delivered to a foreign airline.
---------------------------------------------------------------------------

    \89\ Memoranda documenting this supplemental information are 
located in docket number EPA-HQ-OAR-2010-0687.
    \90\ The FAA has stated to EPA that inadequate time exists for 
the required formal compliance determination before the production 
cutoff takes effect.
---------------------------------------------------------------------------

    The second model is comprised of two engines with a contracted 
delivery date in May 2013. They are also certificated to the Tier 4 
NOX standards. These engines are at the end of their 
production life, i.e., no additional future deliveries for civilian 
uses are anticipated beyond these two contracted engines. For this 
reason, the commenter has stated that it is not economically feasible 
to redesign this model to conform with the Tier 6 NOX 
standards, even if it were technically feasible. The single new 
aircraft using these engines is also being built for delivery to a 
foreign airline.
    After assessing this concern, we are including an exception 
provision in the regulations that permits any aircraft engine 
manufacturer to produce and enter into commerce up to six newly-
manufactured engines with a date of manufacture, as defined in the 
regulations, prior to August 31, 2013 that are not certificated to meet 
Tier 6 emission requirements. We find that a considerable amount of 
time will indeed be required between the time this final rule becomes 
effective and completing any formal FAA action using the normal 
exemption process as previously described in this notice. Specifically, 
time is needed for: (1) The FAA to amend 14 CFR part 34 through 
rulemaking to incorporate the production cutoff and procedures for 
granting exemption from the new standards; (2) the manufacturer to 
develop the information needed to support a request; (3) submitting the 
request for review by FAA and EPA; (4) coordination with other 
certificating authorities; and (5) EPA and FAA review and final action 
on the request, i.e., approval or disapproval. Regarding this review 
and final action, we note that FAA staff involved in reviewing the 
manufacturers request may also be engaged in conducting the processes 
to adopt this rule in 14 CFR part 34 and to review emission information 
on current type certificates to confirm that they meet either Tier 6 or 
Tier 8 requirements, as previously described. Therefore, we conclude 
that inadequate time exists to act on an exemption request with 
certainty for these six engines before their contract deliver dates. 
Consequently, we conclude that a limited modification to the otherwise 
universal effective date of the final Tier 6 compliance deadline is 
appropriate to accommodate the commenter's situation and that for these 
six specific engines additional lead time is needed due to cost and 
technical feasibility factors.
    We also believe that disrupting the scheduled delivery dates of 
these engines could risk subjecting the commenter to possible financial 
penalties for late delivery, with possible follow-on effects for the 
aircraft manufacturer and airlines. We also find that there is no 
significant adverse effect on the environment in allowing these six 
engines to be produced and sold as compliant with Tier 4 standards, 
especially if four of the engines ultimately comply with the Tier 6 
standards.
    For the above reasons, and in response to the comments and under 
our authority under sections 231(a)(3) and (b) to issue final 
regulations with such modifications to the proposal as the 
Administrator deems appropriate and to make revised standards effective 
after such period as the Administrator finds necessary to permit the 
development and application or requisite technology, giving appropriate 
consideration to the cost of compliance within such period, we are 
including an exception provision in the regulations that permits any 
aircraft engine manufacturer to produce and enter into commerce up to 
six newly manufactured engines with a date of manufacture, as defined 
in the regulations, prior to August 31, 2013 that are not certificated 
to meet Tier 6 emission requirements. These engines must have a type 
certificate which indicates that they meet the 40 CFR part 87 
requirements last updated on October 30, 2009 (i.e., Tier 4). No formal 
exemption request or approval will be required for these six engines. 
These engines will be reported to EPA as part of the annual reporting 
requirement as described above for exempt engines.
    We know of no other engine manufacturer that is in this situation 
today, (i.e., contracted deliveries of engines not meeting the 
production cut-off within several months of the production cut-off 
date). However, as a matter of equity and to address situations which 
we may not be informed of at this time, we are extending this 
transitional flexibility to all manufacturers.
c. Voluntary Emission Offsets
    We requested comment on establishing a voluntary EPA program by 
which manufacturers could receive emission credits for producing 
cleaner engines, which they could use to offset higher emissions from 
exempted engines. An example of such a program was summarized in a 
memorandum to the docket.\91\ The types of programs we were considering 
would be developed, promulgated, and administered by EPA.
---------------------------------------------------------------------------

    \91\ U.S. EPA, ``Draft Regulatory Text for Voluntary Offset 
Program,'' Memorandum from Charles Moulis, Assessment and Standards 
Division, Office of Air Quality and Transportation, June 2011. A 
copy of this document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    As described in the proposal and summarized here, we expected 
manufacturers to be interested in generating offsets for one of three 
purposes. First, manufacturers might choose to generate offsets as part 
of their justifications for exemptions. Second, manufacturers might 
choose to generate offsets as part of a justification for being allowed 
to exceed the numerical limit that FAA and EPA are willing to approve 
in an exemption request. Third, provided a provision was promulgated to 
allow this, a manufacturer might also be interested in generating 
offsets to bank for use for exemptions of engines to be produced after 
the credit generating engines are produced, or possibly against a 
future production cutoff.
    Under the proposed approach, generation of offsets would be 
voluntary and would be open to all certifying engine manufacturers. One 
concept was to allow credits to be generated only from engine models 
that are introduced after this rule and that had characteristic levels 
significantly below the otherwise applicable standard (e.g., at least 
10 percent below). There was a separate question, however, regarding 
how to calculate the credit. If we adopted, for example, a 10 percent 
threshold for eligibility, we would probably also allow credits only to 
the degree which the NOX characteristic level was more than 
10 percent below the standard.

[[Page 36367]]

This would ensure a net improvement in emissions. Also, we could 
reserve the right to restrict the use of credits so that they were used 
in a manner that ensured there was no net adverse impact on air 
quality. Such a program would need to ensure that emission benefits 
from one aircraft model truly offset the higher emissions from another 
model. Equivalency factors could be developed to account for 
differences in the number of LTOs per year and the lifetime of the 
aircraft.
    We received a number of comments on the possibility of implementing 
a voluntary credit offset program. The ATA expressed significant doubt 
that EPA had the legal authority to adopt a voluntary emissions offset 
program. They argued that the standard setting authority under section 
231 of the CAA does not appear to provide such authority. ATA further 
stated that where offsets or emissions trading schemes exist for other 
source categories, the authority is express. Examples cited were the 
CAA authority for the trading program under the acid rain program, and 
the Energy Independence and Security Act authorization for the offset 
program used under the Corporate Average Fuel Efficiency Standards. 
Pratt & Whitney provided comments very similar to ATA relative to the 
lack of EPA's legal authority to create such a program.
    The ATA also commented that the voluntary offset program embodied 
in the proposal would be unworkable in the context of aviation. They 
noted that unlike cars or trucks, aircraft engine manufacturers have 
relatively low production volumes and few frequently updated models for 
generating credits. Also, some manufacturers have more models than 
others and this could possibly lead to competitive distortions in the 
market. The AIA and GAMA also raised concerns regarding potential 
market disruptions. Further, ATA argued that opportunities for 
generating offsets would be limited by the proposal's high thresholds 
for generating those credits. In the context of using emission credits 
for exemptions ATA added that each situation would be unique and it 
would not be possible to match exemptions to credits, or to assess the 
further complexities of the ``equivalency factors'' described in the 
proposal. Finally, they stated that an airline's delivery schedule 
would be held hostage to the manufacturer's ability to justify credits 
based on some other engine that the airline is not buying. For these 
reasons, ATA asked that no offset program be adopted.
    Pratt & Whitney stated that the EPA proposal assumes that an offset 
program would create an incentive for manufacturers to build lower-
emissions engines. On the contrary they argued, manufacturers already 
have that incentive because using the lowest-emitting technology that 
is available maximizes the life of the engine. Such a program would 
simply create a windfall to manufacturers whose product lines are 
already capable of generating credits. The AIA, GAMA, and GE jointly 
commented that the proposed emission offset program goes beyond the 
borders of CAEP, and any emissions offset program should be developed 
within ICAO. General Electric was interested in exploring a potential 
emission offset program, particularly if the program would be 
applicable to new engine designs and derivatives that are subject to 
the proposed Tier 8 standards, and if it created the incentive to adopt 
new technologies earlier than would otherwise be the case in the 
absence of such incentives.
    We appreciate the concerns raised by the commenters regarding the 
proposed voluntary offset emission program. We are also encouraged by 
GE's interest in further discussions about how this program may be 
useful in the context of the Tier 8 standards and a possible future 
Tier 8 production cutoff. EPA agrees that the proposal needs to be 
further developed to address certain aspects of the offset program. We 
have determined that the time it would take to sufficiently develop the 
program is incompatible with the need to promptly promulgate the Tier 6 
production cutoff standard with a near-term effective date of January 
1, 2013. Therefore we are not including the voluntary emission offset 
program in the final rule at this time. Nonetheless, we continue to see 
value in such a program for the aviation industry and recommend 
continuing to consider such a regulatory flexibility in the future.
    Although we are deferring action on the proposed voluntary emission 
offset program for the time being, we believe that such programs are 
envisioned within the ETM language related to exemptions. Furthermore, 
we do not agree with the commenters who questioned the EPA's legal 
authority for adopting a voluntary emissions offset program as part of 
the aircraft engine emission standards. We are somewhat surprised by 
the industry commenters who questioned the authority for averaging, 
banking, and trading (ABT) programs outside of the narrow examples 
cited in their comments, and we are not yet persuaded by their claims. 
Note that the U.S. Court of Appeals for the D.C. Circuit has clearly 
stated that EPA has substantial discretion under the CAA section 231 to 
adopt final aircraft emission standards as the agency deems appropriate 
(National Ass'n of Clean Air Agencies v. EPA 489 F.3d 1221 (D.C. Cir. 
2007)). We also wonder to what extent their view represents the 
industry as a whole, including any aircraft engine manufacturers who 
also manufacture engines that are subject to other EPA regulations that 
provide for ABT without the ``express'' statutory authority the 
commenters claim is necessary. If in future actions we seek additional 
comments on the legality of ABT programs under our aircraft standards, 
we will be interested in receiving comments from other stakeholders in 
the mobile source arena who might have views regarding the arguments 
presented by the industry commenters above.
    In the meantime, we note that several of our mobile source 
regulations, in addition to the rule cited by industry commenters, have 
long provided regulated industry with the flexibilities inherent in an 
ABT program, under the authority of, for example CAA section 213, and 
none of those subject industries have opposed the creation of such 
programs or questioned their legal basis. (See, e.g., 40 CFR part 89, 
subpart C (averaging, banking and trading provisions for nonroad 
compression-ignition engines); 40 CFR part 90, subpart C (certification 
averaging, banking and trading provisions for nonroad spark-ignition 
engines at or below 19 kilowatts); 40 CFR part 91, subpart C 
(averaging, banking and trading provisions for marine spark-ignition 
engines); 40 CFR part 92, subpart D (certification averaging, banking 
and trading provisions for locomotives and locomotive engines); 40 CFR 
part 94, subpart D (certification averaging, banking and trading 
provisions for marine compression-ignition engines).) EPA continues to 
believe that the legal basis of these ABT programs is sound.
4. Potential Phase-In of New Tier 8 NOX Standards for Newly-
Manufactured Engines
    We did not propose a production cutoff for the Tier 8 
NOX standards for newly-manufactured engines. This means 
that engine manufacturers may continue to produce Tier 6 compliant 
engines of previously certified models after the Tier 8 standards 
become effective for newly-certified engine models. As noted elsewhere, 
EPA is working within the ICAO/CAEP framework to develop harmonized 
international standards for aircraft

[[Page 36368]]

turbine engines. At the February 2010 meeting of CAEP, where the CAEP/8 
NOX standards were approved for recommendation to ICAO, the 
committee decided that further consideration could be given to a 
related newly-manufactured engine standard pending new information on 
technology and market responses, although no formal action was taken at 
the time to explicitly make this a future work item for CAEP.\92\
---------------------------------------------------------------------------

    \92\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 
2010,'' CAEP/8-WP-80. A copy of this document is in docket number 
EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    Assuming a CAEP/8 production cutoff is adopted at some time in the 
future, we will re-examine the permanent exemption provisions to ensure 
a timely and orderly phase-out of engine models that do not meet the 
CAEP/8 NOX standards. We would expect this to be done 
through a notice and comment rulemaking process to amend our own 
regulations.

C. Application of Standards for Derivative Engines

    It is very common for a manufacturer to make changes to an 
originally type certificated engine model that is in production while 
keeping the same basic engine core and combustor design. In some cases 
these modifications may affect emissions. As a result, the 
certificating authority (in our case the FAA) must decide whether the 
emission characteristics of the modified design were significant enough 
from the parent engine's certification basis that a demonstration of 
compliance with more recent emission standards is necessary, or if the 
changes were minor relative to the parent engine's emission 
certification basis so that it is considered a derivative version of 
the original model with no emissions changes. This may be further 
complicated because of the common practice of making iterative changes 
over time raises the question as to when the cumulative changes reach a 
point where a new demonstration of compliance is warranted.
    In the past, these determinations were made for turbofan engines by 
an engineering evaluation that was performed by the engine manufacturer 
and then reviewed by the FAA. As part of the ICAO/CAEP deliberations 
leading up to the February 2010 CAEP/8 meeting, a new standardized 
guidance was agreed upon as described in the ETM. The guidance, which 
the U.S. fully supported, includes specific criteria that can be used 
to determine when a design modification requires a new demonstration of 
compliance with newer emission standards, or when a modification was 
simple enough to be considered a no emissions change.
    We are including the ETM requirements in our regulations to address 
the longstanding need to provide consistent standards for the decision 
process regarding derivative engines and applicable emission standards. 
The definition of ``derivative engines for emissions certification 
purposes,'' along with the criteria for making this determination, will 
provide engine manufacturers and the regulators with more certainty 
regarding emission standard requirements for future modifications made 
to certificated models. To ensure that the numerical decision criteria 
can be administered to allow for the consideration of unusual 
circumstances or special information, we are also providing the FAA 
with some flexibility to make adjustments to the specific criteria 
based on good engineering judgment. In summary, if the FAA determines 
that an engine model is sufficiently similar to its parent engine so as 
to meet the criteria established in Sec.  87.48, the manufacturer may 
demonstrate certification compliance and continue production of the 
engine model to the same extent as allowed for the original engine 
model. However, if the FAA determines that an engine model is not a 
derivative for emission certification purposes, the manufacturer would 
be required to demonstrate compliance with the most recent emissions 
standards. This determination will be made using numerical criteria 
consistent with ICAO provisions, and a modified engine model can be 
considered a ``derivative'' only if it is: (1) Derived from an original 
engine that had received a U.S. certification, (2) the original engine 
was certified under title 14 of the CFR, and (3) one of the following 
conditions is met:
    (1) The FAA determined that a safety issue exists that requires an 
engine modification; or
    (2) Emissions from the derivative engines are equivalent to or 
lower than the original engine.
    The proposed rule provided that the engine manufacturer could show 
emissions equivalency by demonstrating that the difference between 
emission rates of a derivative engine and the original engine are 
within the following allowable ranges, unless otherwise adjusted using 
good engineering judgment as determined by the FAA:

3.0 g/kN for NOX
1.0 g/kN for HC
5.0 g/kN for CO
2.0 SN for smoke

    The proposed rule also provided that engine models represented by 
characteristic levels at least five percent below all applicable 
standards would be allowed to demonstrate equivalency by engineering 
analysis. In all other cases, the manufacturer would be required to 
test the new engine model to show that its emissions met the 
equivalency criteria.
    We received three significant comments on the proposed derivative 
provisions. First, ATA, PW, and Dassault-Aviation (DA) pointed out that 
the proposed criteria contained a substantial deviation from the 
expressed intent of the proposal and the ETM guidance. Specifically, 
they noted that the ETM provides that ``If a modified engine remains on 
the existing type certificate, it may retain the existing certification 
basis of the parent engine if the modification(s) * * * results in a 
decrease of the absolute emissions levels. * * * '' They pointed out, 
however, that the proposed rule provided that the certificate holder 
must demonstrate `` * * * the proposed derivative engine model's 
emissions meet the applicable standards and differ from the original 
model's emission rates only within * * * '' specified ranges for each 
pollutant. For example, the specified range is + or-3 g/kN for 
NOX. The commenters stated that this is more stringent than 
the ETM, and could discourage cleaner engines that are not clean enough 
to meet the next tier of standards. They asked that the final rule be 
consistent with the ETM to prevent this untoward effect.
    We agree that the regulations should allow for such engines to be 
considered derivatives, even if the difference was outside the ``no 
emission change'' range. This allowance is clearly consistent with the 
ETM and was inadvertently left out of our proposed language. Therefore, 
the final regulations contain this allowance.
    Second, AIA and GAMA jointly commented that the term ``new model'' 
was inappropriate when used to determine which engine models could 
demonstrate equivalency by engineering analysis, and when the 
manufacturer would be required to test the new engine model to 
demonstrate compliance with the equivalency criteria. They argued that 
because this provision applies to changes made to an existing engine, 
it could cause an engine manufacturer to conduct an additional 
emissions test in cases where a very small change was made to the 
engine

[[Page 36369]]

due to a performance or engine weight change. The commenters 
recommended that this be altered to allow a manufacturer to consider 
``* * * such emissions changes by analysis prior to this point, and 
only if such analysis revealed a deterioration that pushed the engine 
very close to the emission limits that the manufacturer be requested to 
complete an engine emissions test.''
    The AIA and GAMA also jointly commented on the proposed regulatory 
text that states if the characteristic level of the original 
certificated engine model before modification is at or above 95 percent 
of the applicable standard for any pollutant, you must measure the 
proposed derivative engine model's emissions for all pollutants to 
demonstrate the derivative engine's resulting characteristic levels 
will not exceed the applicable emission standards. They claimed that 
the use of the term ``you must measure'' also implies further engine 
testing when additional analysis may likely prove sufficient.
    We agree that the term ``new model'' should be modified and have 
instead used the term ``new engine configuration'' in the final 
regulations. We want to clarify, however, that the regulations do 
explicitly require engine testing when an original engine's emissions 
are within 5 percent of any emission standard. This text does not allow 
engineering analysis in such cases. We continue to believe this to be 
the appropriate policy. Given the greater uncertainty of engineering 
analysis relative to actual testing, we cannot rely on it for engines 
very close to the standard. This provision is also consistent with the 
ETM. Therefore, we are promulgating this requirement as proposed.
    Third, AIA, GAMA, and GE commented that as a general matter, EPA 
should not codify the ETM's derivative engine decision criteria because 
the ETM guidance will evolve over time and the Agency's rigid 
regulations will not, even allowing for the FAA flexibility to use good 
engineering judgment if necessary when deciding what is or is not a 
derivative engine. They concluded it was simply better to let the FAA 
rely on the ETM guidance in its decision making. As noted by the 
commenters, the ICAO ETM itself is a guidance document for use by 
aviation authorities. It does not represent a standard or any other 
enforceable regulatory requirement. In the particular case cited by the 
commenters, they appear to ask that FAA be given unlimited discretion 
to determine which engines are subject to each new tier of standards.
    In response to the comment, we also note that the Clean Air Act 
directs EPA to establish air pollution emission standards for aircraft 
engines. (See 42 U.S.C. 7551(a)(2)(A).) Implementation of this 
statutory directive mandates that we specify enforceable air pollution 
emission standards and control requirements for aircraft engines in 
regulatory form. We believe that it is reasonable for us to also 
establish other associated requirements in regulatory form. Our final 
rule achieves an appropriate balance between providing FAA discretion 
to implement the standards, and the need to establish aircraft engine 
emission regulations that ensure consistency in application.
    We also disagree with the suggestion that the ETM will evolve over 
time, but that our regulations will not. As a working member of ICAO's 
Committee on Aviation Environmental Protection, we will participate in 
developing any relevant revisions to the ETM and will make appropriate 
adjustments to our regulations as needed.
    We continue to believe that the ETM specifications for ``no 
emissions change'' are appropriate objective criteria for derivative 
engines. Thus, because we are codifying regulatory provisions to 
objectively specify when engines are considered to be ``derivative 
engines'', we are promulgating regulatory provisions consistent with 
the ICAO ETM guidance.

D. Annual Reporting Requirements

    In May of 1980, ICAO's Committee on Aircraft Engine Emissions 
(CAEE) recognized that certain information relating to environmental 
aspects of aviation should be organized into one document. This 
document became ICAO's ``Annex 16 to the Convention on International 
Civil Aviation, International Standards and Recommended Practices, 
Environmental Protection'' and was split into two volumes--Volume I 
addressing Aircraft Noise topics and Volume II addressing Aircraft 
Engine Emissions. Annex 16 has continued to grow and today Annex 16, 
Volume II includes a list of mandatory requirements to be satisfied in 
order for an aircraft engine to meet the ICAO emission standards.\93\ 
These requirements include information relating to engine 
identification and characteristics, fuel usage, data from engine 
testing, data analysis, and the results derived from the test data. 
Additionally, this list of aircraft engine requirements is supplemented 
with voluntarily reported information which has been assembled into an 
electronic spreadsheet entitled ``Emissions Databank'' (EDB) \94\ for 
turbofan engines with maximum thrust ratings greater than 26.7 kN in 
order to aid with emission calculations and analysis as well as help 
inform the general public.
---------------------------------------------------------------------------

    \93\ ICAO, ``Annex 16 to the Convention on International Civil 
Aviation, Environmental Protection, Volume II, Aircraft Engine 
Emissions,'' Part III, Chapter 2, Section 2.4. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
    \94\ United Kingdom, Civil Aviation Authority, ``ICAO Emissions 
Databank.'' Available at the Civil Aviation Authority Web site 
www.caa.co.uk/default.aspx?catid=702.
---------------------------------------------------------------------------

    In order to understand how current gaseous emission standards are 
affecting the current fleet, we need to have access to timely, 
representative emissions data of the engine fleet at the requisite 
model level. The EDB is a useful tool for providing a general overview 
of the aircraft fleet, as it contains information on engine exhaust 
emissions and performance tests. However, it is not updated on a 
consistent basis, it contains a varying amount of voluntarily reported 
data from each manufacturer, and it does not specifically list every 
engine sub-model.\95\ It also does not contain information on smaller 
thrust category turbofans or turboprops, and contains no information on 
past or recent engine production volumes. We need this data to conduct 
accurate emission inventories and develop appropriate policy. 
Accordingly, we do not consider the EDB to be a sufficient tool upon 
which to base policy decisions or adopt future standards. Furthermore, 
in the context of EPA's standards-setting role under the Clean Air Act 
with regard to aircraft engine emissions, it is consistent with our 
policy and practice to ask for timely and reasonable reporting of 
emission certification testing and other information that is relevant 
to our mission. Under the Clean Air Act, we are authorized to require 
manufacturers to establish and maintain necessary records, make 
reports, and provide such other information as we may reasonably 
require to discharge our functions under the Act. (See 42 U.S.C. 
7414(a)(1).)
---------------------------------------------------------------------------

    \95\ Under today's regulations, a grouping of engines with an 
essentially identical emission-related design are defined to be an 
``engine sub-model''. Engines with slightly different designs are 
defined to be an ``engine model''.
---------------------------------------------------------------------------

    Therefore, we proposed to require that each aircraft engine 
manufacturer submit a production report directly to EPA \96\ with 
specific information for each individual engine sub-model that: (1) Is 
designed to propel subsonic aircraft, (2) is subject to our exhaust 
emission standards, and (3) has received

[[Page 36370]]

a U.S. type certificate. More specifically, the scope of the proposed 
production report would include turbofan engines as described above 
with maximum rated thrusts greater than 26.7 kN, i.e., those subject to 
gaseous emission and smoke standards. In addition, it would include 
turbofans with maximum rated thrusts less than or equal to 26.7 kN and 
all turboprop engines, i.e., those only subject to smoke standards. We 
also proposed that this specific exhaust emission related information 
be reported to us in a timely manner, which will allow us to conduct 
proper emissions inventory analyses of the existing fleet and to ensure 
that any public policy we create based on this information will be well 
informed. All of the specific reporting items we proposed were the same 
as requested for the EDB, with the exception of total annual engine 
production volumes, information on type certificates, and the emission 
standards to which the engine sub-model was certified. We anticipated 
that the new emissions database would be a significant improvement over 
the current EDB because the data reporting is mandatory, it will be 
comprehensive in that it covers all engine models, and it must be 
updated annually.
---------------------------------------------------------------------------

    \96\ The report would be submitted only to EPA. No separate 
submission or communication of any kind is required for the FAA.
---------------------------------------------------------------------------

    In addition to some minor comments which are addressed in the 
analysis of comments document, we received comments from engine 
manufacturers addressing two specific areas of the proposed production 
reporting provision. First, the Aerospace Industries Association (AIA), 
General Aviation Manufacturers Association (GAMA) and Pratt & Whitney 
(PW) commented that annual production volume data is considered 
confidential business information (CBI) and as such, it should be 
exempt from Freedom of Information Act (FOIA) requests or other methods 
of public disclosure. Second, AIA, GAMA, PW and Williams International 
pointed out that for those engines which are only subject to smoke 
standards (turbofans with maximum thrust ratings less than or equal to 
26.7 kN, and turboprops), manufacturers are not required under current 
regulations to measure gaseous emissions (HC, CO, NOX, 
CO2). As such, data on these gaseous emissions, as well as 
information used to measure gaseous emissions (reference pressure ratio 
and fuel flow data) are not readily available for these engines. 
Further, smoke data by mode of the LTO cycle may not be available for 
these older engines. These manufacturers pointed out that new testing 
of such engines would be required to generate these data, and that 
appropriate test procedures for these engines do not currently exist.
    We understand and respect the needs of manufacturers to maintain 
the confidentiality of their legitimately proprietary data. However, we 
do not include in our regulations an up-front blanket CBI determination 
for any of the other mobile source sectors, and do not believe it is 
necessary here. As such, in response to the comments, we are including 
regulatory language patterned after existing regulations for several 
other mobile source categories which sets forth how we would treat--on 
a case by case basis--submitted data which is covered by a CBI claim 
from the manufacturer as provided by 40 CFR part 2. The addition of 
this provision will ensure that no information that is legitimately 
protected CBI gets inadvertently released to the public.
    We do not believe it is appropriate to require additional testing 
for turbofans with maximum thrust ratings less than or equal to 26.7 kN 
and turboprops specifically for production reporting purposes. Thus, 
for these engines, we will not be requiring the submission of HC, CO, 
NOX, CO2, reference pressure ratio or fuel rate 
data. Further, we will not require additional testing of older engines 
for which smoke data by specific LTO cycle segment is not currently 
available.
    We also noted in the proposal that the reported information would 
be used in conjunction with the NOX and CO2 
emission data already required to be submitted to us under section 
87.64 for purposes of greenhouse gas (GHG) reporting to establish. This 
would effectively provide us with a complete and comprehensive engine 
exhaust emissions database. We noted our expectation that most 
manufacturers would likely add the proposed information items to the 
annual GHG report. No comments were received on combining the two 
reports. After further deliberation, we have decided to require a 
single, integrated report in this final rule to eliminate any possible 
confusion regarding the two separate reports and make reporting more 
efficient.
    The incremental reporting elements for each affected gas turbine 
engine sub-model are listed below. Although not proposed, we have added 
engine type to the list for completeness. The reporting elements of the 
existing GHG report are also identified for completeness.
     Company corporate name as listed on the engine type 
certificate (GHG);
     Engine Type (turbofan, mixed turbofan, or turboprop);
     Calendar year for which reporting (GHG);
     Complete sub-model name (This will generally include the 
model name and the sub-model identifier, but may also include an engine 
type certificate family identifier) (GHG);
     The type certificate number, as issued by the FAA (Specify 
if the sub-model also has a type certificate issued by a certificating 
authority other than the FAA) (GHG);
     Date of issue of type certificate and/or exemption, i.e. 
month and year (GHG);
     Emission standards to which the engine is certified, i.e., 
the specific Annex 16, Volume II, edition number and publication date 
in which the numerical standards first appeared.
     If this is a derivative engine for emissions certification 
purposes, identify the original certificated engine model.
     Engine sub-model that received the original type 
certificate for the engine type certificate family;
     Production volume of the sub-model for the previous 
calendar year (even if zero). If an engine sub-model is no longer being 
produced, state that the engine sub-model is not in production and list 
the date of manufacture (month and year) of the last engine produced;
     Regarding the above production volume report, specify (if 
known) the number of engines that are intended for use on new aircraft 
and the number intended for use as certified (non-exempt) spare engines 
on in-use aircraft;
     Reference pressure ratio (GHG) (not applicable to 
turbofans with maximum thrust ratings less than or equal to 26.7 kN, 
and turboprops);
     Combustor description (type of combustor where more than 
one type available on an engine);
     Engine maximum rated thrust output, in kilonewtons (kN) or 
kilowatts (kW) (depending on engine type) (GHG);
     Unburned hydrocarbon (HC) mass (g) total (weighted) and 
over each segment of the Landing and Take-off Cycle (LTO), i.e. Take-
off, Climb, Approach, Taxi/Ground Idle (not applicable to turbofans 
with maximum thrust ratings less than or equal to 26.7 kN, and 
turboprops);\97\
---------------------------------------------------------------------------

    \97\ See Regulation Part 87--Control of Air Pollution from 
Aircraft and Aircraft Engines, Subpart E, Sec.  87.42 Production 
report to EPA for definitions.
---------------------------------------------------------------------------

     Unburned hydrocarbon (HC) characteristic level (i.e. mass 
of hydrocarbons over LTO cycle/Rated Thrust (Dp/Foo)) (not applicable 
to turbofans with maximum thrust ratings less than or equal to 26.7 kN, 
and turboprops);\98\
---------------------------------------------------------------------------

    \98\ Dp/Foo: total gross emissions of each gaseous pollutant 
(mass)/rated thrust (g/kN).

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

[[Page 36371]]

     Carbon monoxide (CO) mass (g) total (weighted) and over 
each segment of the entire Landing and Take-off Cycle (LTO) (i.e. Take-
off, Climb, Approach, Taxi/Ground Idle) (not applicable to turbofans 
with maximum thrust ratings less than or equal to 26.7 kN, and 
turboprops);
     Carbon monoxide (CO) characteristic level (i.e. mass of CO 
over LTO cycle/Rated Thrust (Dp/Foo)) (not applicable to turbofans with 
maximum thrust ratings less than or equal to 26.7 kN, and turboprops);
     Nitrogen oxides (NOX) mass (g) total (weighted) 
and over each segment of the entire Landing and Take-off Cycle (LTO) 
(i.e. Take-off, Climb, Approach, Taxi/Ground Idle) (GHG) (not 
applicable to turbofans with maximum thrust ratings less than or equal 
to 26.7 kN, and turboprops);
     Nitrogen oxides (NOX) characteristic level 
(i.e. mass of NOX over LTO cycle/Rated Thrust (Dp/Foo)) 
(GHG) (not applicable to turbofans with maximum thrust ratings less 
than or equal to 26.7 kN, and turboprops);
     Smoke number total and over each segment of the entire 
Landing and Take-off Cycle (LTO) (i.e. Take-off, Climb, Approach, Taxi/
Ground Idle), if available;
     Smoke number characteristic level;
     Carbon dioxide (CO2) mass (g) total (weighted) 
and over each segment of the entire Landing and Take-off Cycle (LTO), 
(i.e. Take-off, Climb, Approach, Taxi/Ground Idle (GHG)) (not 
applicable to turbofans with maximum thrust ratings less than or equal 
to 26.7 kN, and turboprops);
     Number of tests run per sub-model (GHG);
     Number of engines tested per sub-model (GHG);
     Fuel flow (grams/second) total (weighted) and over each 
segment of the Landing and Take-off Cycle (LTO) (i.e. Take-off, Climb, 
Approach, Taxi/Ground Idle) (GHG) (not applicable to turbofans with 
maximum thrust ratings less than or equal to 26.7 kN, and turboprops); 
and
     Any additional remarks to the EPA.
    The annual report is required to be submitted for each calendar 
year in which a manufacturer produces any engine subject to emission 
standards as previously described. These reports will be due by 
February 28 of each year, starting with the 2014 calendar year, and 
cover the previous calendar year. This report shall be sent to the 
Designated EPA Program Officer. Where information provided for any 
previous year remains valid and complete, the engine manufacturer may 
report the production figures and state that there are no changes 
instead of resubmitting the original information. To facilitate and 
standardize reporting, we expect to specify a particular format for 
this reporting in the form of a spreadsheet or database template that 
we provide to each manufacturer. As noted previously, we intend to use 
the reports to help inform any policy approaches regarding aircraft 
engine emissions that we consider, including possible future emissions 
standards. The information will also enhance the general public's 
understanding of the emission characteristics of aviation gas turbine 
engines and allow independent development of emission inventories and 
assessments of local environmental effects. Subject to the applicable 
requirements of 42 U.S.C. 7414(c), 18 U.S.C. 1905, and 40 CFR part 2, 
all data received by the Administrator that is not confidential 
business information may be posted on our Web site and will be updated 
annually. We have assessed the potential reporting burden associated 
with this annual reporting requirement. That assessment is presented in 
sections V. and IX.B of this notice.

E. Standards for Supersonic Aircraft Turbine Engines

    We proposed CO and NOX emission standards for turbine 
engines that are used to propel aircraft at sustained supersonic 
speeds, i.e., supersonic aircraft to complement our existing HC 
standard for these engines. These standards were originally adopted by 
ICAO in the 1980s, and our adoption of NOX and CO standards 
for commercial engines in 1997 omitted coverage of these pollutants for 
supersonic commercial engines that were then in use. The lack of EPA CO 
and NOX standards for engines used by supersonic aircraft 
has had no practical effect, because no such engines have been 
certified by the FAA. Also, none of the engines used on these aircraft 
are currently in production.
    The Aerospace Industries Association (AIA) and the General Aviation 
Manufacturers Association (GAMA) commented that within CAEP it was 
agreed that these standards are ``not appropriate for future products'' 
and should not be adopted by EPA.\99\ However, to meet U.S. treaty 
obligations under the Convention on International Civil Aviation as 
previously described in section I.C, we believe it is necessary and 
appropriate to adopt these conforming standards. Therefore, we are 
promulgating the standards for supersonic aircraft as proposed. As 
previously noted, this action has no practical effect, and simply 
aligns EPA standards with the rest of the world. (See section III.G for 
a brief discussion of potential revised emission standards for future 
engine designs that may be used on supersonic aircraft.)
---------------------------------------------------------------------------

    \99\ The CAEP position referred to by AIA and GAMA is based on 
the expectation that future designs for supersonic aircraft will be 
significantly different from past designs. The agreement was reached 
at CAEP/8 to evaluate emission standards for these engines as a 
future work item.
---------------------------------------------------------------------------

F. Amendments To Test and Measurement Procedures

    We are incorporating by reference into the 40 CFR 87.60 regulatory 
text, amendments to ICAO's International Standards and Recommended 
Practices for aircraft engine emissions testing and certification.\100\ 
\101\ \102\ These amendments to Annex 16, Volume II are primarily 
intended to ensure that the provisions reflect current certification 
practices. The amendments make clarifications or add flexibilities for 
engine manufacturers. They are described below.
---------------------------------------------------------------------------

    \100\ A strikeout and highlighted version of the amendments is 
contained in Attachment A to ICAO state letter AN 1/61.2, AN 1/62.2-
07/32 entitled, ``Proposed Amendment to International Standards and 
Recommended Practices, Environmental Protection, Annex 16 to the 
Convention on International Civil Aviation, Volume II Aircraft 
Engine Emissions, May 27, 2007. A copy of this document is in docket 
number EPA-HQ-OAR-2010-0687.
    \101\ ICAO, ``International Standards and Recommended Practices, 
Annex 16 to the Convention on International Civil Aviation, 
Environmental Protection, Volume II Aircraft Engine Emissions,'' 
Third Edition, July 2008, International Civil Aviation Organization. 
This document contains the full text of ICAO standards and practices 
and is in docket number EPA-HQ-OAR-2010-0687.
    \102\ ICAO, ``International Standards and Recommended Practices, 
Annex 16 to the Convention on International Civil Aviation, 
Environmental Protection, Volume II Aircraft Engine Emissions, 
Amendment 7, effective July 18, 2011'' Third. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

     Standardizing the terminology relating to engine thrust/
power
     Clarifying the need to correct measured results to 
standard reference day and reference engine conditions
     Allowing a certificating authority to approve the use of 
test fuels other than those specified during certification testing
     Allowing materials other than stainless steel in the 
sample collection equipment
     Clarifying the appropriate value of fuel flow to be used 
at each LTO test point
     Clarifying exhaust nozzle terminology for exhaust 
emissions sampling
     Allowing an equivalent procedure for gaseous emission and 
smoke

[[Page 36372]]

measurement if approved by the certificating authority
    Manufacturers are either already voluntarily complying with these 
changes or will be even in the absence of a final rule. Our adoption of 
these test procedure amendments is, therefore, unlikely to require new 
action by manufacturers beyond what they have already done to meet 
ICAO's adopted and recommended amendments.
    Our incorporation by reference of the ICAO test procedure makes 
most of the existing subpart G and all of subpart H of part 87 
obsolete. Therefore, we are removing these sections from the 
regulation, as proposed.

G. Possible Future Revisions to Emission Standards for New Technology 
Turbine Engines and Supersonic Aircraft Turbine Engines

    As a general matter, emission standards not only apply to all 
conventional turbofan aircraft engines greater than 26.7 kN, but also 
to all aircraft engines designed for applications that otherwise would 
have been fulfilled by turbofan aircraft engines. The high price of jet 
fuel, current emphasis on fuel economy, and need to reduce emissions 
have renewed interest in open rotor propulsion designs for future 
aircraft gas turbine engines. Essentially, the fan of an open rotor 
engine is not contained within an engine nacelle as it is with a 
conventional turbofan engine. This design has also been referred to as 
an unducted fan, propfan, or ultra-high bypass engine. At least two 
engine manufacturers are actively pursuing such designs for 
certification in the later part of this decade.
    It now appears that certain aspects of EPA's gas turbine engine 
emission standards may be incompatible with these new designs. For 
example, the current landing and takeoff cycle for emissions 
certification is based on conventional engine designs where a 
significant amount of thrust is generated by an idling engine. 
Specifically, idle emissions are measured and calculated at seven 
percent of the engine's rated thrust. However, the fan/prop blades of 
an open rotor engine may be variable in pitch and this may allow the 
blades to be ``feathered'' at idle. In that position, the blades are 
rotated so very little thrust is generated as the engine idles and 
generates emissions. Also, future aircraft using these engine designs 
may fly at somewhat slower speeds. This might affect the time these 
aircraft spend during the climbout mode of the landing and takeoff 
cycle. Therefore, the traditional landing and takeoff cycle used in 
turbofan engine emissions certification may need to be revised in the 
future to accommodate open rotor engines.
    We will be working within CAEP to evaluate the differences between 
conventional turbine engine and open rotor engine technologies, and to 
revise the emission standards and test procedures as appropriate for 
these latter engines. If any changes are required, EPA will undertake 
rulemaking to revise our regulations accordingly.
    There may also be changes in the emission standards and test 
procedures for engines used to power future supersonic transport 
aircraft designs. The emission standards for these engines were 
originally developed in the early 1970s in response to the 
Aerospatiale-BAC Concorde. Since that time, there have been varying 
levels of interest in developing a new generation of supersonic 
transport. As a result, the current CAEP work program is evaluating the 
status of supersonic aircraft engine development and the potential need 
for new emission standards and test procedures.\103\ Our recent 
discussions with engine manufacturers indicate that no substantive work 
is being undertaken at this time, however. We will continue to work 
within CAEP on this issue and undertake rulemaking to revise the 
regulations for supersonic aircraft engines as appropriate.
---------------------------------------------------------------------------

    \103\ The CAEP Working Group 3 has taken the position that 
engine development programs for future supersonic aircraft 
applications should be focused on achieving the emission standards 
that are applicable to subsonic aircraft engines. Past supersonic 
aircraft engines required the use of afterburner technology to 
achieve supersonic speeds. Future supersonic aircraft are expected 
to use engines without that technology, making them more similar to 
their subsonic counterparts.
---------------------------------------------------------------------------

V. Description of Other Revisions to the Regulatory Text

    In addition to the changes discussed above, we are including a 
number of other changes to the regulatory program. Most of these 
changes are designed to bring the program into conformity with current 
technology and current technical or policy practice. Each of these is 
discussed below.

A. Applicability Issues

    This section discusses how this final rule relates to engines used 
in military and noncommercial civilian aircraft. We do not believe 
these changes will have practical significance for current engine 
models because the changes align with manufacturers' current practice 
in certifying their engines.
1. Military Engines
    We do not intend today's action to have any impact on engines 
installed on military aircraft, or new aircraft that are destined to be 
converted for military use. Military aircraft are not required to have 
FAA standard airworthiness certificates, and our 1997 endangerment 
finding for NOX and CO emissions and resulting standards did 
not cover military aircraft (see 62 FR at 25359). As such, engines used 
in military aircraft are not required to meet EPA emission standards, 
since our current regulations define ``aircraft'' subject to our rules 
as any airplane for which a U.S. standard airworthiness certificate (or 
foreign equivalent) is issued. (See 40 CFR 87.1(a) of the existing 
regulations.) Currently, manufacturers certificate some engine models 
used in military aircraft with the FAA (with respect to emissions), 
because these engine models also have commercial applications and have 
to be certificated for such use. Our new standards and requirements 
will continue to apply only to engines used in aircraft for which 
standard airworthiness certificates are required, and thus are not 
applicable to engines used in military aircraft. It is not our intent 
to interfere with current practice with regard to engine models with 
joint commercial/military applications to the extent such engines are 
used in military aircraft. Although civilian aircraft applications of 
all such engines would be subject to the new standards and production 
cutoff, in the NPRM we proposed to include a statement in the 
regulations to clarify that the proposed production cutoff would not 
apply for previously certificated engines that are installed and used 
in military aircraft. One manufacturer commented that the definition of 
``military aircraft'' we proposed should extend to sales of military 
aircraft outside of the U.S. While we believe the regulations as 
written do not apply to foreign sales of military aircraft, we are 
nonetheless revising our proposed definition of ``military aircraft'' 
to clarify that foreign aircraft considered military under 
international laws and agreements are not covered by 40 CFR part 87.
2. Noncommercial Engines
    Prior to this action, section 87.21(d) specified that gaseous 
emission standards applied to engines used in commercial applications 
with rated thrusts greater than 26.7 kN. These are engines intended for 
use by an air carrier or a commercial operator as defined in the 
Chapter I, Title 49 of the United States Code and Title 14 of the Code 
of Federal Regulations. Therefore,

[[Page 36373]]

engines of equivalent thrust ratings that are used in aircraft 
certificated by the FAA that are used in non-revenue, general aviation 
service were not required to comply with our current HC, CO, and 
NOX exhaust emission standards in Sec.  87.21(d). They were 
and are subject, however, to the current standards for smoke and fuel 
venting.
    In today's action we are applying the gaseous emission standards 
for commercial engines to their noncommercial civilian counterparts 
that are required to obtain standard airworthiness certificates. There 
are a couple of reasons for this action. First, the ICAO Annex 16, 
Volume II standards and recommended practices apply equally to 
commercial and noncommercial engines, and our rules' previous failure 
to reflect this meant that our requirements did not fully conform to 
ICAO's standards. Second, manufacturers already emissions certify 
engines that are used in non-revenue, general aviation service to these 
standards. Therefore, this provision simply incorporates the status 
quo.
    In order to make EPA standards conform to ICAO's, we needed to, in 
addition to promulgating the necessary regulatory amendments, update 
the underlying finding regarding the need to limit gaseous emissions 
from commercial and non-commercial civilian aircraft, pursuant to CAA 
section 231(a)(2)(A). In 1997, our analysis and finding, and hence our 
regulations, were limited to commercial aircraft emissions. (See 62 FR 
at 25358.) In conjunction with the NPRM for this final rule, we 
proposed to expand that analysis and finding to include gaseous 
emissions from both commercial and non-commercial civilian aircraft 
engines with rated thrusts greater than 26.7 kN. We received no 
comments on that proposed finding, and are therefore finalizing our 
emissions assessment supporting this finding, which is contained in the 
docket for this rulemaking.\104\
---------------------------------------------------------------------------

    \104\ U.S. EPA, ``Final Finding for Commercial and Noncommercial 
Turbofan and Turbojet Aircraft Emissions,'' memorandum from John 
Mueller, Assessment and Standards Division, Office of Transportation 
and Air Quality, March 2012. A copy of this document is in docket 
EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

B. Non-Substantive Revisions

    We are also taking the opportunity to revisit the clarity of other 
regulatory provisions in part 87. Many of these provisions were first 
written 30 or 40 years ago with little or no change since then. We are 
revising the text related to some of these provisions to better 
organize, clarify, and update the regulations. Our goal is to revise 
the regulations in part 87 to properly organize the content of the 
regulation, use clearer language to describe the applicable 
requirements, clarify some definitions, and clear up a variety of terms 
and current practices that have not been adequately addressed.
    Except as discussed in previous sections, the changes to part 87 
are not intended to significantly change the certification and 
compliance program. We did not reopen for comment the substance of any 
part of the program that remains unchanged substantively.
    This rule includes the following definitions and other minor 
changes in addition to those changes described earlier in this section 
or in section III.
    The definition of the term ``aircraft'' is being revised to be 
consistent with its meaning under FAA regulations in 14 CFR 1.1. The 
existing part 87 definition limits ``aircraft'' to be only those 
aircraft issued an airworthiness certificate. This was done as a way to 
specify the applicability of the standards. However, this can cause 
confusion in a variety of ways. For example, this departs from the 
plain meaning of ``aircraft,'' as well as from the meaning given under 
the Clean Air Act and Title 49 of the United States Code. The revised 
definition aligns with these statutory definitions. The changed wording 
is intended to clarify the existing policy without changing it.
    Text specifying general applicability is being added to part 87.3 
to be consistent with the new definition of ``aircraft'' and maintain 
the effective applicability of the existing regulations, which uses 
narrow definitions to limit applicability. For example, the existing 
regulations limit the applicability of the standards by defining 
``aircraft'' to only include fixed-wing airplanes with airworthiness 
certificates. They exclude non-propulsion engines from the definition 
of ``aircraft engine'' and turboshaft engines from the definition of 
``aircraft gas turbine engine.'' We believe it is more appropriate to 
explicitly exclude these engines in an applicability section than to 
rely on readers finding these exclusions in the definitions section. We 
are also renaming part 87.3 as ``General applicability and 
requirements'' and reorganizing the content for clarity. Finally, we 
are replacing the existing regulatory text related to federal 
preemption for exempted engines in part 87.7(f) with a codification of 
the statutory preemption language in part 87.3 and an explanatory note 
that the statutory preemption applies to exempted engines because they 
are certified to prior-tier standards.
    ICAO Annex 16, Volume II is being incorporated by reference for 
test procedures. This involves a broader reference to Annex 16, with 
less content repeated in part 87. However, this does not substantively 
change the test procedures that apply since the existing procedures are 
based directly on Annex 16, Volume II. As part of this change, we are 
adding the ICAO definition of ``characteristic level'' to properly 
describe how manufacturers demonstrate that they meet applicable 
standards.
    Definitions are being added for ``date of introduction,'' ``date of 
manufacture,'' and ``derivative engine for emissions certification 
purposes,'' and the definition of ``engine model'' is being revised, to 
more carefully describe when new emission standards apply to specific 
aircraft engines. These definitions are generally consistent with the 
most common understandings of these terms by industry and FAA, and with 
the CAEP/8 recommendation for adoption by ICAO. Except for engines 
subject to exemptions, there will be no more engines required to be 
certified to the standards specified in part 87.21, so changing the 
definition of ``engine model'' will not change the requirements for 
engines certified to the Tier 4 or earlier standards. For the benefit 
of the reader, we are also reprinting the following definitions that 
remain unchanged:

 Aircraft engine
 Aircraft gas turbine engine
 Class TP
 Class TF
 Class T3
 Class T8
 Class TSS
 Commercial aircraft gas turbine engine
 Fuel venting emissions

    Specific provisions are being added to define and require the use 
of ``good engineering judgment.'' This applies for instances where the 
regulation cannot spell out every technical detail of how a 
manufacturer should comply with the regulation. For example, the 
regulations rely on good engineering judgment being used on the 
engineering analysis of emissions equivalency for derivative engines 
(part 87.48(b)(2)), and for applying the turbofan test procedures to 
turboprop engines (part 87.60(a)). The general approach for 
implementing good engineering judgment is to allow manufacturers to 
exercise well substantiated and explained technical judgment subject to 
potential EPA and FAA review (as appropriate). The consequences of 
disagreements with a manufacturer's decision would depend

[[Page 36374]]

on whether we believe the manufacturer made the decision in good faith. 
Where the manufacturer makes its decision in good faith, EPA or FAA 
could require a different approach for future work if we believe it 
would represent better engineering judgment. We believe these 
provisions reflect the spirit of the approach being used today to 
interpret the applicable regulations.
    Provisions are being added specifying rounding practices for rated 
output, rated pressure ratio, and calculated emission standards; 
generally specifying that they be expressed to at least three 
significant figures. The primary exception to this is the specification 
that smoke numbers be expressed to one decimal place. These 
specifications are consistent with how manufacturers are generally 
certifying engines today. Defining how to round these values would 
prevent manufacturers in the future from effecting small changes in the 
level of the emission standards to which they certify their engines. 
This is because standards are calculated using the numerical values of 
the rated output and rated pressure ratio. Without these 
specifications, manufacturers could subject themselves to a slightly 
less stringent standard by selectively rounding or truncating an engine 
model's rated output to be low and its rated pressure ratio to be high, 
or by strategically rounding the calculated standard itself. While this 
has not been an issue in the past, it is important to maintain a level 
playing field for all manufacturers as standards become more stringent. 
We do not expect any more engines type-certificated to the standards 
specified in part 87.21, so the specified procedures for rounding these 
values will not change the requirements for engines certified to the 
Tier 4 or earlier standards
    Definitions are being added for ``turbofan engine,'' ``turbojet 
engine,'' ``turboprop engine,'' ``turboshaft engine,'' ``supersonic,'' 
and ``subsonic'' to avoid any uncertainty about how the standards apply 
to different types of engines. The definitions are intended to reflect 
the plain meaning of these terms.
    The regulations include the following additional amendments:

------------------------------------------------------------------------
                               Description of
      Regulation cite             amendment               Notes
------------------------------------------------------------------------
87.1.......................  Add definition of   The characteristic
                              ``characteristic    level is established
                              level''.            by ICAO Annex 16 as a
                                                  means of calculating a
                                                  statistical adjustment
                                                  to measured emission
                                                  results to take into
                                                  account the level of
                                                  uncertainty
                                                  corresponding to the
                                                  number of tests run
                                                  for a given pollutant.
87.1.......................  Remove definitions  These terms will no
                              for ``emission      longer be used in part
                              measurement         87. There will be no
                              system'', ``power   more engines certified
                              setting'',          to the standards
                              ``sample            specified in Sec.
                              system'', ``shaft   87.21, so removing
                              power'', ``taxi/    these definitions will
                              idle (in)'', and    not change the
                              ``taxi/idle         requirements for
                              (out)''.            engines certified to
                                                  the Tier 4 or earlier
                                                  standards.
87.1.......................  Revise definition   The new language
                              of ``exhaust        references the
                              emissions'' and     emission testing
                              ``smoke''.          procedures, since that
                                                  is the practical
                                                  meaning of these terms
                                                  in part 87. This
                                                  clarifies, for
                                                  example, that
                                                  emissions from the
                                                  nozzle of an aircraft
                                                  or aircraft engine
                                                  count as exhaust
                                                  emissions only if they
                                                  are measured using the
                                                  specified test
                                                  procedures. There will
                                                  be no more engines
                                                  certified to the
                                                  standards specified in
                                                  Sec.   87.21, so
                                                  revising these
                                                  definitions will not
                                                  change the
                                                  requirements for
                                                  engines certified to
                                                  the Tier 4 or earlier
                                                  standards.
87.1.......................  Define ``new''      The regulations also
                              instead of          refer to new turboprop
                              defining ``new      engines and new
                              aircraft turbine    engines used for
                              engine''.           supersonic aircraft,
                                                  so it is appropriate
                                                  to define the
                                                  adjective as it
                                                  relates to these
                                                  different kinds of
                                                  engines. This approach
                                                  does not change the
                                                  meaning of the
                                                  applicable terms and
                                                  therefore has no
                                                  bearing on the
                                                  requirements that
                                                  applied under the
                                                  standards specified in
                                                  Sec.   87.21.
87.1.......................  Revise the          The editorial changes
                              definition of       do not involve any
                              ``standard day      substantive change in
                              condition'': (1)    the specified
                              Remove the          conditions.
                              reference to the
                              1976 U.S.
                              Standard
                              Atmosphere, (2)
                              correct a
                              typographical
                              error in the
                              humidity
                              specification,
                              and (3) change
                              the atmospheric
                              pressure units
                              from Pa to kPa.
87.2.......................  Remove FAA from     This is intended to not
                              the list of         involve a change in
                              acronyms in Sec.    emission standards or
                               87.2 and add it    implementation.
                              to the set of
                              defined terms in
                              Sec.   87.1.
87.3.......................  Add provisions      The broad statement in
                              describing the      Sec.   87.3 is not
                              scope of            intended to conflict
                              applicability of    with the applicability
                              part 87.            statements in
                                                  individual subparts,
                                                  since those additional
                                                  statements indicate
                                                  that certain
                                                  requirements in part
                                                  87 apply more
                                                  narrowly. All
                                                  applicability
                                                  statements in the rule
                                                  are intended to be
                                                  consistent with
                                                  current policy.
87.3.......................  Remove the          This change more
                              provision related   carefully tracks the
                              to preemption of    statutory provisions
                              state standards     related to preemption.
                              for exempted
                              aircraft and
                              replace it with
                              the preemption
                              provision in the
                              Clean Air Act.
87.5.......................  Move the            This provision, and the
                              provisions          similar provision from
                              related to          Sec.   87.3(a), should
                              special test        be described together
                              procedures to       in the context of the
                              Sec.   87.60.       testing requirements
                                                  in subpart G.
87.21......................  Identify the        This corrects a
                              specific date       typographical error
                              when the smoke      from the Federal
                              standard started    Register.
                              to apply for
                              turbofan engines
                              with rated output
                              less than 26.7
                              kilonewtons.
87.21......................  Revise paragraph    This change is strictly
                              (f) to correctly    editorial.
                              reference the
                              regulatory
                              sections that
                              describe the
                              applicable test
                              procedures.

[[Page 36375]]

 
87.60......................  Revise the          There will be no more
                              description of      engines certified to
                              test procedures     the standards
                              to rely broadly     specified in Sec.
                              on the procedures   87.21, so any changes
                              specified in ICAO   to the test procedures
                              Annex 16. This      will not change the
                              includes a          requirements for
                              variety of recent   engines certified to
                              changes to the      the Tier 4 or earlier
                              Annex 16            standards. Moreover,
                              procedures.         engine manufacturers
                                                  are expected to
                                                  perform all their
                                                  testing based on the
                                                  current test
                                                  procedures from ICAO
                                                  Annex 16, regardless
                                                  of the standards that
                                                  apply.
------------------------------------------------------------------------

C. Clarifying Language for Regulatory Text

    The regulations incorporate the changes described in this preamble. 
The following table highlights and clarifies several provisions that 
may not be obvious to the reader.

------------------------------------------------------------------------
       Regulation cite                            Note
------------------------------------------------------------------------
87.1, Definition of            This definition would revert to the
 ``aircraft''.                  normal FAA definition of aircraft,
                                rather than the much narrower current
                                definition in part 87. To understand
                                this change, the definition needs to be
                                considered along with the changes to
                                applicability in 87.3(a).
87.1, Definition of ``date of  This is generally the same definition as
 manufacture''.                 given in ICAO Annex 16. However, our
                                definition addresses certain specific
                                circumstances that could possibly occur,
                                but that are not addressed by the Annex.
                                For example, our definition would
                                provide a date of manufacture for an
                                engine not previously documented by a
                                manufacturer.
87.1, Definition of            It is important to consider this
 ``derivative engine for        definition in combination with the
 emissions certification        definition of ``engine type certificate
 purposes''.                    family''.
87.1, Definition of ``engine   A manufacturer or FAA may further divide
 model''.                       an engine model into sub-models. Engines
                                from an engine model must be contained
                                within a single engine type certificate
                                family. Where FAA determines that
                                engines are not sufficiently similar to
                                be included under a single type
                                certificate, they will not be considered
                                to be the same engine model for purposes
                                of part 87.
87.1, Definition of            In Sec.   87.23(d) we clarify that the
 ``military aircraft'' and      production cutoff does not apply for
 87.23(d).                      military aircraft engines (even if they
                                have been certificated). In Sec.   87.1,
                                we define military aircraft to primarily
                                mean ``aircraft owned by, operated by,
                                or produced for sale to the armed forces
                                or other agency of the federal
                                government responsible for national
                                security (including but not limited to
                                the Department of Defense).'' For
                                example, aircraft owned by the U.S.
                                Coast Guard would be military aircraft.
                                In response to comments, we added a
                                clarification that military aircraft
                                also include ``other aircraft considered
                                to be military aircraft under
                                international law and conventions.''
87.1, Definition of            The production cutoff date for the Tier 6
 ``production cutoff date''.    NOX standards is December 31, 2012.
87.1, Definition of ``spare    Newly manufactured spare engines may be
 engine''.                      excepted under Sec.   87.50.
87.1, Definitions of tiers...  As specified in the definitions of ``Tier
                                0'' through ``Tier 8'', tiers apply only
                                for NOX standards. Tiers do not apply
                                for HC, CO, and smoke standards because
                                these continue to apply, independent of
                                the NOX standards.
87.23(d)(2)..................  The allowance to continue production of
                                Tier 6 engines after the Tier 8
                                standards start to apply is not
                                necessary for engines with rated
                                pressure ratio at or above 104.7 because
                                the Tier 6 and Tier 8 standards are
                                numerically identical at these thrust
                                levels.
87.42(c)(1)..................  Sec.   87.42 requires that a manufacturer
                                report the engines it produces by sub-
                                model. The manufacturer must specify the
                                manufacturer's unique sub-model name,
                                which will generally include a model
                                name and a sub-model name. It may also
                                include a family name.
87.50........................  This provision specifies that EPA must
                                provide written concurrence for
                                exemptions.
87.50(a)(1)(iv)(F)...........  This provision states that manufacturers
                                requesting exemptions should describe
                                equity issues. As an example of equity
                                issues related to an exemption request,
                                a manufacturer might provide a rationale
                                for granting the exemption when another
                                manufacturer has a compliant engine and
                                does not need an exemption, taking into
                                account the implications for operator
                                fleet composition, commonality, and
                                related issues in the absence of the
                                engine model in question.
87.50(a)(6)..................  This provision requires manufacturers to
                                promptly notify the FAA if new or
                                changed information could have affected
                                approval of an exemption. For
                                corrections to an exemption request that
                                would not affect the approval of the
                                exemption, manufacturers may include the
                                updated information in the annual report
                                described in Sec.   87.50(e).
------------------------------------------------------------------------

VI. Technical Feasibility and Cost Impacts

    During the CAEP process, the technical feasibility and cost of 
compliance of the CAEP/6 and CAEP/8 NOX standards were 
thoroughly assessed and documented.105 106 EPA participated 
in these analyses and supported the results. Generally, CAEP considered 
certain factors as pertinent to the cost estimates of a technology 
level for engine changes, and these factors or technology levels are

[[Page 36376]]

described below. The first technology level was regarded as a minor 
change, and it could include modeling work, minor design changes, and 
additional testing and re-certification of emissions. The second 
technology level was considered a scaled proven technology. At this 
level an engine manufacturer applies its best-proven, combustion 
technology that was already certified in at least one other engine type 
to another engine type. This second technology level would include 
substantial modeling, design, combustion rig testing, modification and 
testing of development engines, and flight testing. The third 
technology level was regarded as new technology or current industry 
best practice, and it was considered where a manufacturer has no proven 
technology that can be scaled to provide a solution and some technology 
acquisition activity is required. (One or more manufacturers have 
demonstrated the necessary technology, while the remaining 
manufacturers would need to acquire the technology to catch up.) Since 
the effective date for the CAEP/6 NOX standard was January 
1, 2008 and nearly all in-production engines currently meet this 
standard, we believe this clearly demonstrates the technical 
feasibility of those standards. Therefore, we will limit our discussion 
below to applying these technology levels to engines that need to 
comply with the CAEP/8 NOX standard.
---------------------------------------------------------------------------

    \105\ CAEP/6 NOX standards: CAEP Forecasting and 
Economic Analysis Support Group, Economic Analysis of NOX Emissions 
Stringency Options, CAEP/6-IP/13 (Information Paper 13), January 15, 
2004. A copy of this document is in docket number EPA-HQ-OAR-2010-
0687.
    \106\ CAEP/8 NOX standards: CAEP Working Group 3, NOX 
Stringency Technology Response Assessment, CAEP-SG/20082-WP/18 
(Working Paper 18), September 25, 2008. CAEP Forecasting and 
Economic Analysis Support Group, Economic Assessment of the NOX 
Stringency Scenarios, CAEP/8-IP/14, November 30, 2009. Modeling Task 
Force, MODTF NOX .Stringency Assessment, CAEP/8-IP/13, December 11, 
2009. United States, Aviation Environmental Portfolio Management 
Tool for Economics (APMT-Economics) and Its Application in the CAEP/
8 NOX Stringency Analysis, CAEP/8-IP/29, January 6, 2010. A copy of 
these documents are in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    At the time of the CAEP reports, the CAEP/8 NOX standard 
for higher thrust engines, i.e., 89.0 kN or more would apply to a total 
of 15 engine types. For these types the following technology level 
response was anticipated: six types would require no change, one type 
would need the first technology level change, five would require the 
second technology level, and three would need the third technology 
level. For lower thrust engines, i.e., greater that 26.7 but less than 
89.0 kN, CAEP listed a total of 13 engine types in their analysis of 
the CAEP/8 NOX standard. The following technology level 
response was estimated for these types: 11 types would require no 
change, 1 type would need the first technology level change, and 1 type 
would require a second technology. Based on these analyses, CAEP 
concluded that the CAEP/8 NOX standards were technically 
feasible within the lead time and time frame identified in the action.
    Regarding the costs of this final rule, aircraft turbofan engines 
are designed and built for use on aircraft that are sold and operated 
throughout the world. As a result, engine manufacturers respond to this 
market reality by designing and building engines that conform to ICAO 
international standards and practices. This normal business practice 
means that engine manufacturers are compelled to make the necessary 
business decisions and investments to maximize their international 
markets even in the absence of U.S. regulations that would otherwise 
codify ICAO standards and practices. Indeed, engine manufacturers have 
developed or are already developing improved technology in response to 
ICAO standards that match the standards being promulgated in this final 
rule. Also, the recommended practices, e.g., test procedures, needed to 
demonstrate compliance are being adhered to by manufacturers during 
current engine certification tests, or will be even in the absence this 
final rule. Therefore, EPA believes that today's standards and 
practices that conform with ICAO standards and practices will impose no 
real additional burden on engine manufacturers. This finding regarding 
no incremental burden, is also consistent with past EPA rulemakings 
that adopted ICAO requirements. ((See 62 FR 25356 (May 8, 1997) and 70 
FR 69664 (November 11, 2005).
    In fact, engine manufacturers have suggested that certain benefits 
accrue for compliant products when the U.S. adopts ICAO standards and 
practices, but have not provided detailed information regarding these 
benefits. Primarily, such action makes FAA certification more 
straightforward and transparent. That in turn is advantageous when 
marketing their products to potential customers, because compliance 
with ICAO standards is an important consideration in purchasing 
decisions. It simply removes any question that their engines comply 
with international requirements. There will be some cost, however, 
associated with our annual reporting requirement for emission related 
information. (See section III.D for a description of the reports.) 
There are a total of 10 engine manufacturers that would be affected. 
Eight of these produce turbofan engines with rated thrusts greater than 
26.7 kN, which are already voluntarily reported to the ICAO-related 
Emissions Databank (EDB).\107\ We expect the incremental reporting 
burden for these manufacturers to be very small because we: (1) Have 
significantly reduced the number of reporting elements from those 
requested in the EDB, and (2) are adding only three basic reporting 
categories to those already requested by the EDB. Also, four of the 
eight manufacturers make smaller turbofan and turboprop engines that 
will be reporting for the first time. This will add a small incremental 
burden for these four manufacturers that otherwise already voluntarily 
report to the EDB. There are also two engine manufacturers that only 
produce turbofan engines with rated thrusts less than or equal to 26.7 
kN and they will be reporting for the first time. For these two 
manufacturers we believe that the reporting burden will be small 
because all of the information we are requiring should be readily 
available, and these manufacturers have a very limited number of engine 
models.
---------------------------------------------------------------------------

    \107\ As discussed in section III.D, we are requiring a single 
report that integrates the new reporting requirement contained in 
this final rule with the existing mandatory greenhouse gas (GHG) 
reporting of NOX and CO2 as already required 
under Sec.  87.64. Combining the existing GHG report with the new 
reporting requirement will not increase an engine manufacturer's 
reporting burden. A single, integrated report may actually reduce a 
manufacturer's total reporting burden somewhat because of the 
efficiency inherent in reporting to EPA once instead of twice.
---------------------------------------------------------------------------

    We have estimated the annual burden and cost to be about six hours 
and $365 per manufacturer. With 10 manufacturers submitting reports, 
the total burden of this reporting requirement is estimated to be 60 
hours, for a total cost of $3,646.

VII. Consultation With FAA

    The requirements contained in this action were developed in 
consultation with the Federal Aviation Administration (FAA). Section 
231(a)(2)(B)(i) of the CAA requires EPA to ``consult with the 
Administrator of the [FAA] on aircraft engine emission standards'' 42 
U.S.C. 7571(a)(2)(B)(i), and section 231(a)(2)(B)(ii) indicates that 
EPA ``shall not change the aircraft engine emission standards if such 
change would significantly increase noise. * * *'' 42 U.S.C. 
7571(a)(2)(B)(ii). Section 231(b) of the CAA states that ``[a]ny 
regulation prescribed under this section (and any revision thereof) 
shall take effect after such period as the Administrator finds 
necessary (after consultation with the Secretary of Transportation) to 
permit the development and application of the requisite technology, 
giving appropriate consideration to the cost of compliance within such 
period.'' 42 U.S.C. 7571(b). Section 231(c) provides that any 
regulation under section 231 ``shall not apply if disapproved by the 
President * * * 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). Under section 232 of the CAA, the 
Department of Transportation (DOT) has the responsibility to enforce 
the aircraft emission standards established by EPA

[[Page 36377]]

under section 231.\108\ As in past rulemakings and pursuant to the 
above referenced sections of the CAA, EPA has coordinated with the FAA, 
i.e., DOT, with respect to today's action.
---------------------------------------------------------------------------

    \108\ The functions of the Secretary of Transportation under 
part B of title II of the Clean Air Act (Sec. Sec.  231-234, 42 
U.S.C. 7571-7574) have been delegated to the Administrator of the 
FAA. 49 CFR 1.47(g).
---------------------------------------------------------------------------

    Moreover, FAA is the official U.S. delegate to ICAO. FAA agreed to 
the amendments at ICAO's Sixth and Eighth Meetings of the Committee on 
Aviation Environmental Protection (CAEP/6) after advisement from 
EPA.\109\ FAA and EPA were both members of the CAEP's Working Group 3 
(among others), whose objective was to evaluate emissions technical 
issues and develop recommendations on such issues for CAEP/6 and CAEP/
8. After assessing emissions test procedure amendments and new 
NOX standards, Working Group 3 made recommendations to CAEP 
on these elements. These recommendations were approved by CAEP/6 
meetings prior to their adoption by ICAO in 2004. Similarly, the more 
recent Working Group 3 recommendations were approved by CAEP/8 and have 
been adopted ICAO.
---------------------------------------------------------------------------

    \109\ The Sixth Meeting of CAEP (CAEP/6) occurred in Montreal, 
Quebec from February 2 through 12 in 2004.
---------------------------------------------------------------------------

    In addition, as discussed above, FAA will have the duty to enforce 
today's requirements. As a part of these duties, the FAA witnesses the 
emission tests or delegates aspects of that responsibility to the 
engine manufacturer, which is then monitored by the FAA.

VIII. Public Participation

    We proposed this regulation on July 27, 2011 (76 FR 45012). A 
public hearing was held on August 11, 2011 in Chicago, IL. The public 
was invited to submit written comments on the proposal during the 
formal comment period, which ended on September 26, 2011. We received 
eight public comments from aircraft and aircraft engine manufacturers, 
airline operators and an individual.
    The vast majority of commenters supported the central tenets of the 
proposed regulations. That is, there was broad support for the adoption 
of these standards and the alignment of U.S. and international 
emissions regulations. We received specific comments on several aspects 
of the proposal.
    Throughout this notice, we discussed the key issues arising from 
the public comment and our responses. In addition, we have addressed 
all of the public comments in the analysis of comments document 
associated with this final action and located in the docket (Docket ID 
EPA-HQ-OAR-2010-0687).

IX. Statutory Provisions and Legal Authority

    The statutory authority for today's proposal is provided by 
sections 114, 231-234 and 301(a) of the Clean Air Act, as amended, 42 
U.S.C. Sec. Sec.  7414, 7571-7574 and 7601(a). See section II of 
today's rule for discussion of how EPA meets the CAA's statutory 
requirements.

X. Statutory and Executive Order Reviews

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

    Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), 
this action is a ``significant regulatory action.'' This action 
promulgates new aircraft engine emissions regulations and as such, 
requires consultation and coordination with the Federal Aviation 
Administration (FAA). 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 the EO.'' 
Accordingly, EPA submitted this action to the Office of Management and 
Budget (OMB) for review under EO 12866 and 13563 (76 FR 3821, January 
21, 2011) and any changes made in response to OMB recommendations have 
been documented in the docket for this action.
    As discussed further in section V, we do not attribute any costs to 
the compliance with today's regulations that conform to ICAO standards 
and recommended practices. Aircraft turbofan engines are international 
commodities. As a result, engine manufacturers respond to this market 
reality by designing and building engines that conform to ICAO 
international standards and practices. Therefore, engine manufacturers 
are compelled to make the necessary business decisions and investments 
to maximize their international markets even in the absence of U.S. 
action. Indeed, engine manufacturers have or are already responding, or 
will in the future, to ICAO requirements that match the standards and 
practices adopted here. Therefore, EPA believes that today's 
requirements that conform with ICAO standards and practices will impose 
no real additional burden on engine manufacturers. This finding is also 
consistent with past EPA rulemakings that adopted ICAO requirements.
    There is, nonetheless, a small burden associated with the reporting 
requirements, as discussed in section IX.B.

B. Paperwork Reduction Act

    The information collection requirements in this rule have been 
submitted for approval to the Office of Management and Budget (OMB) 
under the Paperwork Reduction Act, 44 U.S.C. 3501 et seq. The 
information collection requirements are not enforceable until OMB 
approves them.
    Manufacturers keep substantial records to document their compliance 
with emission standards. We need to be able to access this data to 
conduct accurate emission inventories, understand how emission 
standards affect the current fleet, and develop appropriate policy in 
the form of future emission standards. Most manufacturers are already 
accustomed to reporting much of this information to ICAO. However, 
these reports are voluntary and aperiodic. As part of this action, we 
are requiring that engine manufacturers send this information to EPA on 
an annual basis. We are also requiring manufacturers to send us their 
annual production volumes, which we would treat as confidential 
business information. Under the Clean Air Act, we are authorized to 
require manufacturers to establish and maintain necessary records, make 
reports, and provide such other information as we may reasonably 
require to execute our functions under the Act. See 42 U.S.C. 
7414(a)(1). We will simply require manufacturers to add the required 
information items to the annual report they are already required to 
submit with information about NOX and CO2 
emission levels. See section III.D for a more complete description of 
the annual reporting requirement.
    We have estimated the total annual burden of the reporting 
requirement to be 60 hours, and the total cost to be $3,646. The annual 
burden and cost per respondent is estimated to be 6 hours and $365. 
Burden is defined at 5 CFR 1320.3(b).
    An agency may not conduct or sponsor, and a person is not required 
to respond to, a collection of information unless it displays a 
currently valid OMB control number. The OMB control numbers for EPA's 
regulations in 40 CFR are listed in 40 CFR part 9. When this ICR is 
approved by OMB, the Agency will publish a technical amendment to 40 
CFR part 9 in the Federal Register to display the OMB control number 
for the approved

[[Page 36378]]

information collection requirements contained in this final rule.

C. Regulatory Flexibility Analysis

    The Regulatory Flexibility Act (RFA) generally requires an agency 
to prepare a regulatory flexibility analysis of any rule subject to 
notice and comment rulemaking requirements under the Administrative 
Procedure Act or any other statute unless the agency certifies that the 
rule will not have a significant economic impact on a substantial 
number of small entities. Small entities include small businesses, 
small organizations, and small governmental jurisdictions.
    For purposes of assessing the impacts of today's rule on small 
entities, small entity is defined as: (1) A small business as defined 
by SBA size standards; (2) a small governmental jurisdiction that is a 
government of a city, county, town, school district or special district 
with a population of less than 50,000; and (3) a small organization 
that is any not-for-profit enterprise which is independently owned and 
operated and is not dominant in its field. The following Table 4 
provides an overview of the primary SBA small business categories 
potentially affected by this regulation.

                       Table 4--Primary Potentially Affected SBA Small Business Categories
----------------------------------------------------------------------------------------------------------------
                    Industry                       NAICS a Codes      Defined by SBA as a small business if: b
----------------------------------------------------------------------------------------------------------------
Manufacturers of new aircraft engines..........             336412  <1,000 employees.
Manufacturers of new aircraft..................             336411  <1,500 employees.
----------------------------------------------------------------------------------------------------------------
a North American Industry Classification System (NAICS).
b According to SBA's regulations (13 CFR part 121), businesses with no more than the listed number of employees
  or dollars in annual receipts are considered ``small entities'' for purposes of a regulatory flexibility
  analysis.

    After considering the economic impacts of today's rule on small 
entities, I certify that this action will not have a significant 
economic impact on a substantial number of small entities. Small 
governmental jurisdictions and small organizations as described above 
will not be impacted. We have determined that the estimated effect of 
the rule's reporting requirement is to affect one small entity turbofan 
engine manufacturer with costs less than one percent of revenues. This 
one company represents all of the small businesses affected by the 
regulations. An analysis of the impacts of the proposed rule on small 
businesses has been prepared and placed in the docket for this 
rulemaking.\110\ Since this final rule is largely unchanged from the 
proposal, that analysis remains valid for the final rule.
---------------------------------------------------------------------------

    \110\ ``Small Business Impact Memo, Proposed Aircraft Engine 
Emission Standards--Determination of No SISNOSE,'' EPA memo from 
Solveig Irvine to Alexander Cristofaro, November, 2010.
---------------------------------------------------------------------------

D. Unfunded Mandates Reform Act

    This rule does not contain a Federal mandate that may result in 
expenditures of $100 million or more for State, local, and tribal 
governments, in the aggregate, or the private sector in any one year. 
As discussed in section III, today's action will establish consistency 
between U.S. and existing international emission standards. The engine 
manufacturers are already developing the technology to meet the 
existing ICAO standards, and we do not believe it is appropriate to 
attribute the costs of that technology to this action. Thus, this rule 
is not subject to the requirements of sections 202 or 205 of UMRA.
    This rule is also not subject to the requirements of section 203 of 
UMRA because it contains no regulatory requirements that might 
significantly or uniquely affect small governments. The provisions of 
this rule apply to the manufacturers of aircraft and aircraft engines, 
and as such would not affect small governments.

E. 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, as 
specified in Executive Order 13132. As discussed earlier, section 233 
of the CAA preempts states from adopting or enforcing aircraft engine 
emission standards that are not identical to our standards. This rule 
revises the Code of Federal Regulations to more accurately reflect the 
statutory preemption established by the Clean Air Act. This rule does 
not impose any new preemption of State and local law. Thus, Executive 
Order 13132 does not apply to this action.

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

    These rules regulate aircraft manufacturers and aircraft engine 
manufacturers. We do not believe that Tribes own any of these 
businesses nor are there other implications for Tribes. Thus, Executive 
Order 13175 does not apply to this action.

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

    This rule is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it is not economically significant as defined 
in EO 12866 and the Agency does not believe the environmental health 
risks or safety risks addressed by this action present a 
disproportionate risk to children. See section II.B.2 for a discussion 
of the health impacts of NOX emissions.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution, or Use

    This action is not a ``significant energy action'' as defined in 
Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not 
likely to have a significant adverse effect on the supply, 
distribution, or use of energy. These aircraft engine emissions 
regulations are not expected to result in any changes to aircraft fuel 
consumption.

I. National Technology Transfer Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (``NTTAA''), Public Law 104-113 (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 EPA to provide

[[Page 36379]]

Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards.
    This rulemaking involves technical standards for testing emissions 
for aircraft gas turbine engines. EPA is using test procedures 
contained in ICAO's International Standards and Recommended Practices 
Environmental Protection, Annex 16, Volume II along with the 
modifications contained in this rulemaking.\111\ These procedures are 
currently used by all manufacturers of aircraft gas turbine engines 
(with thrust greater than 26.7 kN) to demonstrate compliance with ICAO 
emissions standards.
---------------------------------------------------------------------------

    \111\ ICAO International Standards and Recommended Practices 
Environmental Protection, Annex 16, Volume II, ``Aircraft Engine 
Emissions,'' Second Edition, July 1993--Amendment 3, March 20, 1997. 
Copies of this document can be obtained from ICAO (www.icao.int).
---------------------------------------------------------------------------

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

    Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes 
federal executive policy on environmental justice. Its main provision 
directs federal agencies, to the greatest extent practicable and 
permitted by law, to make environmental justice part of their mission 
by identifying and addressing, as appropriate, disproportionately high 
and adverse human health or environmental effects of their programs, 
policies, and activities on minority populations and low-income 
populations in the United States.
    EPA has determined that this rule will not have disproportionately 
high and adverse human health or environmental effects on minority or 
low-income populations because it increases the level 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.

K. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2). This rule will be effective July 18, 2012.

L. Executive Order 13609: Promoting International Regulatory 
Cooperation

    Executive Order (EO) 13609 (77 FR 26413, May 4, 2012) promotes 
international regulatory cooperation in order to identify approaches 
that are at least as protective as those that are or would be adopted 
in the absence of such cooperation in meeting shared challenges 
involving health, safety, labor, security, environmental, and other 
issues. International regulatory cooperation can also reduce, 
eliminate, or prevent unnecessary differences in regulatory 
requirements.
    These final standards are identical to the international standards 
developed through EPA's active participation in the United Nation's 
International Civil Aviation Organization (ICAO) activities. EPA has 
historically been a principal participant in the development of U.S. 
policy in various ICAO working groups and other international venues, 
assisting and advising the Federal Aviation Administration on aviation 
emissions, technology, and policy matters. These provisions provide a 
means by which the United States can meet its obligations under the 
Chicago Convention and ensure that engine manufacturers maintain 
worldwide acceptability of their products.

List of Subjects

40 CFR Part 87

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

40 CFR Part 1068

    Environmental protection, Administrative practice and procedure, 
Confidential business information, Imports, Motor vehicle pollution, 
Penalties, Reporting and recordkeeping requirements, Warranties.

     Dated: June 1, 2012.
Lisa P. Jackson,
Administrator.

    For the reasons described in the preamble, title 40, chapter I, of 
the Code of Federal Regulations is amended as set forth below.

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

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

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

Subpart A--[Amended]

0
2. Revise Sec.  87.1 to read as follows:


Sec.  87.1  Definitions.

    The definitions in this section apply to this part. The definitions 
apply to all subparts. Any terms not defined in this section have the 
meaning given in the Clean Air Act. The definitions follow:
    Act means the Clean Air Act, as amended (42 U.S.C. 7401 et seq).
    Administrator means the Administrator of the Environmental 
Protection Agency and any other officer or employee of the 
Environmental Protection Agency to whom authority involved may be 
delegated.
    Aircraft has the meaning given in 14 CFR 1.1, which defines 
aircraft to mean a device used or intended to be used for flight in the 
air. Note that under Sec.  87.3, the requirements of this part 
generally apply only to propulsion engines used on certain airplanes 
for which U.S. airworthiness certificates are required.
    Aircraft engine means a propulsion engine which is installed in or 
which is manufactured for installation in an aircraft.
    Aircraft gas turbine engine means a turboprop, turbofan, or 
turbojet aircraft engine.
    Characteristic level has the meaning given in Appendix 6 of ICAO 
Annex 16 (as of July 2008). The characteristic level is a calculated 
emission level for each pollutant based on a statistical assessment of 
measured emissions from multiple tests.
    Class TP means all aircraft turboprop engines.
    Class TF means all turbofan or turbojet aircraft engines or 
aircraft engines designed for applications that otherwise would have 
been fulfilled by turbojet and turbofan engines except engines of class 
T3, T8, and TSS.
    Class T3 means all aircraft gas turbine engines of the JT3D model 
family.
    Class T8 means all aircraft gas turbine engines of the JT8D model 
family.
    Class TSS means all aircraft gas turbine engines employed for 
propulsion of aircraft designed to operate at supersonic flight speeds.
    Commercial aircraft engine means any aircraft engine used or 
intended for use by an ``air carrier,'' (including those engaged in 
``intrastate air transportation'') or a ``commercial

[[Page 36380]]

operator'' (including those engaged in ``intrastate air 
transportation'') as these terms are defined in subtitle 7 of title 49 
of the United States Code and title 14 of the Code of Federal 
Regulations.
    Commercial aircraft gas turbine engine means a turboprop, turbofan, 
or turbojet commercial aircraft engine.
    Date of introduction or introduction date means the date of 
manufacture of the first individual production engine of a given engine 
model or engine type certificate family to be certificated. This does 
not include test engines or other engines not placed into service.
    Date of manufacture means the date on which a manufacturer is 
issued documentation by FAA (or other competent authority for engines 
certificated outside the United States) attesting that the given engine 
conforms to all applicable requirements. This date may not be earlier 
that the date on which assembly of the engine is complete. Where the 
manufacturer does not obtain such documentation from FAA (or other 
competent authority for engines certificated outside the United 
States), date of manufacture means the date of final assembly of the 
engine.
    Derivative engine for emissions certification purposes means an 
engine that has the same or similar emissions characteristics as an 
engine covered by a U.S. type certificate issued under 14 CFR part 33. 
These characteristics are specified in Sec.  87.48.
    Designated EPA Program Officer means the Director of the Assessment 
and Standards Division, 2000 Traverwood Drive, Ann Arbor, Michigan 
48105.
    DOT Secretary means the Secretary of the Transportation and any 
other officer or employee of the Department of Transportation to whom 
the authority involved may be delegated.
    Engine means an individual engine. A group of identical engines 
together make up an engine model or sub-model.
    Engine model means an engine manufacturer's designation for an 
engine grouping of engines and/or engine sub-models within a single 
engine type certificate family, where such engines have similar design, 
including being similar with respect to the core engine and combustor 
designs.
    Engine sub-model means a designation for a grouping of engines with 
essentially identical design, especially with respect to the core 
engine and combustor designs and other emission-related features. 
Engines from an engine sub-model must be contained within a single 
engine model. For purposes of this part, an original engine model 
configuration is considered a sub-model. For example, if a manufacturer 
initially produces an engine model designated ABC and later introduces 
a new sub-model ABC-1, the engine model consists of two sub-models: ABC 
and ABC-1.
    Engine type certificate family means a group of engines (comprising 
one or more engine models, including sub-models and derivative engines 
for emissions certification purposes of those engine models) determined 
by FAA to have a sufficiently common design to be grouped together 
under a type certificate.
    EPA means the U.S. Environmental Protection Agency.
    Except means to routinely allow engines to be produced and sold 
that do not meet (or do not fully meet) otherwise applicable standards. 
(Note that this definition applies only with respect to spare engines 
and that the term ``except'' has its plain meaning in other contexts.) 
Excepted engines must conform to regulatory conditions specified for an 
exception in this part and other applicable regulations. Excepted 
engines are deemed to be ``subject to'' the standards of this part even 
though they are not required to comply with the otherwise applicable 
requirements. Engines excepted with respect to certain standards must 
comply with other standards from which they are not excepted.
    Exempt means to allow (through a formal case-by-case process) 
engines to be produced and sold that do not meet (or do not fully meet) 
otherwise applicable standards. Exempted engines must conform to 
regulatory conditions specified for an exemption in this part and other 
applicable regulations. Exempted engines are deemed to be ``subject 
to'' the standards of this part even though they are not required to 
comply with the otherwise applicable requirements. Engines exempted 
with respect to certain standards must comply with other standards as a 
condition of the exemption.
    Exhaust emissions means substances emitted to the atmosphere from 
exhaust discharge nozzles, as measured by the test procedures specified 
in subpart G of this part.
    FAA means the U.S. Department of Transportation, Federal Aviation 
Administration.
    Fuel venting emissions means raw fuel, exclusive of hydrocarbons in 
the exhaust emissions, discharged from aircraft gas turbine engines 
during all normal ground and flight operations.
    Good engineering judgment involves making decisions consistent with 
generally accepted scientific and engineering principles and all 
relevant information, subject to the provisions of 40 CFR 1068.5.
    ICAO Annex 16 means Volume II of Annex 16 to the Convention on 
International Civil Aviation (incorporated by reference in Sec.  87.8).
    In-use aircraft gas turbine engine means an aircraft gas turbine 
engine which is in service.
    Military aircraft means aircraft owned by, operated by, or produced 
for sale to the armed forces or other agency of the federal government 
responsible for national security (including but not limited to the 
Department of Defense) and other aircraft considered to be military 
aircraft under international law and conventions.
    New means relating to an aircraft or aircraft engine that has never 
been placed into service.
    Operator means any person or company that owns or operates an 
aircraft.
    Production cutoff date or date of the production cutoff means the 
date on which interim phase-out allowances end.
    Rated output (rO) means the maximum power/thrust available for 
takeoff at standard day conditions as approved for the engine by FAA, 
including reheat contribution where applicable, but excluding any 
contribution due to water injection, expressed in kilowatts or 
kilonewtons (as applicable) and rounded to at least three significant 
figures.
    Rated pressure ratio (rPR) means the ratio between the combustor 
inlet pressure and the engine inlet pressure achieved by an engine 
operating at rated output, rounded to at least three significant 
figures.
    Round has the meaning given in 40 CFR 1065.1001.
    Smoke means the matter in exhaust emissions that obscures the 
transmission of light, as measured by the test procedures specified in 
subpart G of this part.
    Smoke number means a dimensionless value quantifying smoke 
emissions calculated in accordance with ICAO Annex 16.
    Spare engine means an engine installed (or intended to be 
installed) on an in-service aircraft to replace an existing engine and 
that is excepted as described in Sec.  87.50(c).
    Standard day conditions means the following ambient conditions: 
temperature = 15 [deg]C, specific humidity = 0.00634 kg H2O/
kg dry air, and pressure = 101.325 kPa.
    Subsonic means relating to aircraft that are not supersonic 
aircraft.

[[Page 36381]]

    Supersonic means relating to aircraft that are certificated to fly 
faster than the speed of sound.
    Tier 0 means relating to an engine that is subject to the Tier 0 
NOX standards specified in Sec.  87.21.
    Tier 2 means relating to an engine that is subject to the Tier 2 
NOX standards specified in Sec.  87.21.
    Tier 4 means relating to an engine that is subject to the Tier 4 
NOX standards specified in Sec.  87.21.
    Tier 6 means relating to an engine that is subject to the Tier 6 
NOX standards specified in Sec.  87.23.
    Tier 8 means relating to an engine that is subject to the Tier 8 
NOX standards specified in Sec.  87.23.
    Turbofan engine means a gas turbine engine designed to create its 
propulsion from exhaust gases and from air that bypasses the combustion 
process and is accelerated in a ducted space between the inner (core) 
engine case and the outer engine fan casing.
    Turbojet engine means a gas turbine engine that is designed to 
create all of its propulsion from exhaust gases.
    Turboprop engine means a gas turbine engine that is designed to 
create most of its propulsion from a propeller driven by a turbine, 
usually through a gearbox.
    Turboshaft engine means a gas turbine engine that is designed to 
drive a rotor transmission system or a gas turbine engine not used for 
propulsion.
    U.S.-registered aircraft means an aircraft that is on the U.S. 
Registry.
    We (us, our) means the Administrator of the Environmental 
Protection Agency and any authorized representatives.


0
3. Revise Sec.  87.2 to read as follows:


Sec.  87.2  Abbreviations.

    The abbreviations used in this part have the following meanings:

% percent
[deg] degree
CO carbon monoxide
CO2 carbon dioxide
g gram
HC hydrocarbon(s)
kN kilonewton
kW kilowatt
LTO landing and takeoff
NOX oxides of nitrogen
rO rated output
rPR rated pressure ratio
SN smoke number

0
4. Revise Sec.  87.3 to read as follows:


Sec.  87.3  General applicability and requirements.

    (a) The regulations of this part apply to engines on all aircraft 
that are required to be certificated by FAA under 14 CFR part 33 except 
as specified in this paragraph (a). These regulations do not apply to 
the following aircraft engines:
    (1) Reciprocating engines (including engines used in ultralight 
aircraft).
    (2) Turboshaft engines such as those used in helicopters.
    (3) Engines used only in aircraft that are not airplanes. For 
purposes of this paragraph (a)(3), ``airplane'' means a fixed-wing 
aircraft that is heavier than air.
    (4) Engines not used for propulsion.
    (b) Under section 232 of the Act, the Secretary of Transportation 
issues regulations to ensure compliance with the standards and related 
requirements of this part (42 U.S.C. 7572).
    (c) The Secretary of Transportation shall apply these regulations 
to aircraft of foreign registry in a manner consistent with obligations 
assumed by the United States in any treaty, convention or agreement 
between the United States and any foreign country or foreign countries.
    (d) No State or political subdivision of a State may adopt or 
attempt to enforce any aircraft or aircraft engine standard respecting 
emissions unless the standard is identical to a standard applicable to 
such aircraft under this part (including prior-tier standards 
applicable to exempt engines).


Sec.  87.5  [Removed]

0
5. Remove Sec.  87.5.


0
6. Revise Sec.  87.6 to read as follows:


Sec.  87.6  Aircraft safety.

    The provisions of this part will be revised if at any time the DOT 
Secretary determines that an emission standard cannot be met within the 
specified time without creating a hazard to aircraft safety.


Sec.  87.7  [Removed]

0
7. Remove Sec.  87.7.


0
8. Revise Sec.  87.8 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 notice of change 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 and Information 
Center, 1301 Constitution Ave. NW., Room B102, EPA West Building, 
Washington, DC 20460, (202) 202-1744, and is available from the sources 
listed below. It is also available for inspection at the National 
Archives and Records Administration (NARA). For information on the 
availability of this material at NARA, call 202-741-6030 or go to 
http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.
    (b) International Civil Aviation Organization, Document Sales Unit, 
999 University Street, Montreal, Quebec, Canada H3C 5H7, (514) 954-
8022, www.icao.int, or sales@icao.int.
    (1) Annex 16 to the Convention on International Civil Aviation, 
Environmental Protection, Volume II--Aircraft Engine Emissions, Third 
Edition, July 2008 (ICAO Annex 16). IBR approved for Sec. Sec.  87.1, 
87.42(c), and 87.60(a) and (b).
    (2) [Reserved]

Subpart C--[Amended]

0
9. Amend Sec.  87.21 as follows:
0
a. By revising the section heading.
0
b. By adding introductory text.
0
c. By revising paragraphs (d)(1)(iii), (d)(1)(iv), (d)(1)(vi) 
introductory text, (e)(1), and (f).


Sec.  87.21  Exhaust emission standards for Tier 4 and earlier engines.

    This section describes the emission standards that apply for Tier 4 
and earlier engines that apply for aircraft engines manufactured before 
July 18, 2012 and certain engines exempted under Sec.  87.50. Note that 
the tier of standards identified for an engine relates to 
NOX emissions and that the specified standards for HC, CO, 
and smoke emissions apply independent of the changes to the 
NOX emission standards.
    (d) * * *
    (1) * * *
    (iii) The following Tier 0 emission standard applies for engines of 
a type or model of which the date of manufacture of the first 
individual production model was on or before December 31, 1995 and for 
which the date of manufacture of the individual engine was on or before 
December 31, 1999.


Oxides of Nitrogen: (40 + 2(rPR)) grams/kilonewton rO.

    (iv) The following Tier 2 emission standard applies for engines of 
a type or model of which the date of manufacture of the first 
individual production model was after December 31, 1995 or for which 
the date of manufacture of the individual engine was after December 31, 
1999:

Oxides of Nitrogen: (32 + 1.6(rPR)) grams/kilonewton rO.
* * * * *

[[Page 36382]]

    (vi) The following Tier 4 emission standards apply for engines of a 
type or model of which the date of manufacture of the first individual 
production model was after December 31, 2003:
* * * * *
    (e) * * *
    (1) Class TF of rated output less than 26.7 kilonewtons 
manufactured on or after August 9, 1985:

SN = 83.6(rO)-\0.274\ (rO is in kilonewtons) not to exceed a 
maximum of SN = 50.
* * * * *
    (f) The standards in this section refer to a composite emission 
sample measured and calculated in accordance with the procedures 
described in subpart G of this part.


0
10. Add a new Sec.  87.23 to subpart C to read as follows:


Sec.  87.23  Exhaust emission standards for Tier 6 and Tier 8 engines.

    This section describes the emission standards that apply for Tier 6 
and Tier 8 engines. The standards of this section apply for aircraft 
engines manufactured on or after July 18, 2012, except where we specify 
that they apply differently by year, or where the engine is exempt from 
one or more standards of this section. Except as specified in paragraph 
(d) of this section, these standards apply based on the date the engine 
is manufactured. Where a gaseous emission standard is specified by a 
formula, calculate and round the standard to three significant figures 
or to the nearest 0.1 g/kN (for standards at or above 100 g/kN). Where 
a smoke standard is specified by a formula, calculate and round the 
standard to the nearest 0.1 SN. Engines comply with an applicable 
standard if the testing results show that the engine type certificate 
family's characteristic level does not exceed the numerical level of 
that standard, as described in Sec.  87.60. The tier of standards 
identified for an engine relates to NOX emissions and that 
the specified standards for HC, CO, and smoke emissions apply 
independent of the changes to the NOX emission standards.
    (a) New turboprop aircraft engines with rated output at or above 
1,000 kilowatts must comply with a smoke standard of 187 [middot] 
rO-0.168.
    (b) New supersonic engines must comply with the standards shown in 
the following table:

                                Table 1 to Sec.   87.23--Smoke and Gaseous Emission Standards for New Supersonic Engines
--------------------------------------------------------------------------------------------------------------------------------------------------------
          Rated output                  Smoke number            HC (g/kN rated  output)        NOX (g/kN rated  output)       CO (g/kN rated  output)
--------------------------------------------------------------------------------------------------------------------------------------------------------
rO < 26.7 kN....................  ........................  140 [middot] 0.92rPR            36 + 2.42 [middot] rPR         4550 [middot] rPR-1.03
rO [gteqt] 26.7 kN..............  83.6 [middot] rO-0.274    140 [middot] 0.92rPR            36+2.42 [middot] rPR           4550 [middot] rPR-1.03
                                   or 50.0, whichever is
                                   smaller.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    (c) New turbofan or turbojet aircraft engines that are installed in 
subsonic aircraft must comply with the following standards:
    (1) The applicable smoke, HC, and CO standards are shown in the 
following table:

       Table 2 to Sec.   87.23--Smoke, HC, and CO Standards for New Subsonic Turbofan or Turbojet Engines
----------------------------------------------------------------------------------------------------------------
                                                                               Gaseous emission standards (g/kN
                                                                                         rated output)
            Rated output (kN)                        Smoke standard          -----------------------------------
                                                                                     HC                CO
----------------------------------------------------------------------------------------------------------------
rO < 26.7 kN.............................  83.6 [middot] rO-0.274 or 50.0,    ................  ................
                                            whichever is smaller.
rO >= 26.7 kN............................  83.6 [middot] rO-0.274 or 50.0,                19.6               118
                                            whichever is smaller.
----------------------------------------------------------------------------------------------------------------

    (2) The Tier 6 NOX standards apply as described in this 
paragraph (c)(2). See paragraph (d) of this section for provisions 
related to models introduced before these standards started to apply 
and engines determined to be derivative engines for emissions 
certification purposes under the requirements of this part.

               Table 3 to Sec.   87.23--Tier 6 NOX Standards for New Subsonic Turbofan or Turbojet Engines With Rated Output Above 26.7 kN
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                           and the rated output (in kN)
   If the rated pressure ratio is . . .              is . . .                       The NOX emission standard (in g/kN rated output) is . . .
--------------------------------------------------------------------------------------------------------------------------------------------------------
rPR <= 30................................  26.7 < rO <= 89.............  38.5486 + 1.6823 [middot] PR-0.2453 [middot] rO-0.00308 [middot] rPR [middot]
                                                                          rO
                                           rO > 89.....................  16.72 + 1.4080 [middot] rPR
30 < rPR < 82.6..........................  26.7 < rO <= 89.............  46.1600 + 1.4286 [middot] rPR - 0.5303 [middot] rO + 0.00642 [middot] rPR
                                                                          [middot] rO
                                           rO > 89.....................  -1.04 + 2.0 [middot] rPR
rPR >= 82.6..............................  all.........................  32 + 1.6 [middot] rPR
--------------------------------------------------------------------------------------------------------------------------------------------------------

     (3) The Tier 8 NOX standards apply as described in this 
paragraph (c)(3) beginning January 1, 2014. See paragraph (d) of this 
section for provisions related to models introduced before January 1, 
2014 apply and engines determined to be derivative engines for 
emissions certification purposes under the requirements of this part.

[[Page 36383]]



 Table 4 to Sec.   87.23--Tier 8 NOX Standards for New Subsonic Turbofan
           or Turbojet Engines With Rated Output Above 26.7 kN
------------------------------------------------------------------------
                                                      The NOX emission
 If the rated pressure ratio  and the rated output    standard (in g/kN
          is . . .              (in kN) is . . .    rated output) is . .
                                                              .
------------------------------------------------------------------------
rPR <= 30...................  26.7 < rO <= 89.....  40.052 + 1.5681
                                                     [middot] rPR -
                                                     0.3615 [middot] rO
                                                      0.0018 [middot]
                                                     rPR [middot] rO
                              rO > 89.............  7.88 + 1.4080
                                                     [middot] rPR
30 < rPR < 104.7............  26.7 < rO <= 89.....  41.9435 + 1.505 rPR-
                                                     0.5823 [middot] rO
                                                     + 0.005562-rPR
                                                     [middot] rO
                              rO > 89.............  -9.88 + 2.0 [middot]
                                                     rPR
rPR >= 104.7................  all.................  32 + 1.6 [middot]
                                                     rPR
------------------------------------------------------------------------

     (d) This paragraph (d) specifies phase-in provisions that allow 
continued production of certain engines after the Tier 6 and Tier 8 
standards begin to apply.
    (1) Engine type certificate families certificated with 
characteristic levels at or below the Tier 4 NOX standards 
of Sec.  87.21 (as applicable based on rated output and rated pressure 
ratio) and introduced before July 18, 2012 may be produced through 
December 31, 2012 without meeting the Tier 6 NOX standards 
of paragraph (c)(2) of this section. This also applies for engines that 
are covered by the same type certificate and are determined to be 
derivative engines for emissions certification purposes under the 
requirements of this part. Note that after this production cutoff date 
for the Tier 6 NOX standards, such engines may be produced 
only if they are covered by an exemption under Sec.  87.50. This 
production cutoff does not apply to engines installed (or delivered for 
installation) on military aircraft.
    (2) Engine type certificate families certificated with 
characteristic levels at or below the Tier 6 NOX standards 
of paragraph (c)(2) of this section with an introduction date before 
January 1, 2014 may continue to be produced. This also applies for 
engines that are covered by the same type certificate and are 
determined to be derivative engines for emissions certification 
purposes under the requirements of this part.
    (3) An engine manufacturer may produce up to six newly manufactured 
Tier 4 engines on or after July 18, 2012, subject to the provisions of 
this paragraph (d)(3). Tier 4 engines meeting the criteria of this 
paragraph (d)(3) are excepted without request from the otherwise 
applicable Tier 6 NOX emission standard. To be eligible for 
this exception the engines must have a date of manufacture prior to 
August 31, 2013 and be fully compliant with all requirements applicable 
to Tier 4 engines. The manufacturer must include these engines in the 
report required by Sec.  87.50. This exception is void for any 
manufacturer that produces more than six excepted engines under this 
paragraph.

0
11. Add a new subpart E containing Sec. Sec.  87.40, 87.42, 87.46, and 
87.48 to read as follows:
Subpart E--Certification Provisions
Sec.
87.40 General certification requirement.
87.42 Production report to EPA.
87.46 Recordkeeping.
87.48 Derivative engines for emissions certification purposes.

Subpart E--Certification Provisions


Sec.  87.40  General certification requirement.

    Manufacturers of engines subject to this part must meet the 
requirements of title 14 of the Code of Federal Regulations as 
applicable.


Sec.  87.42  Production report to EPA.

    Engine manufacturers must submit an annual production report as 
specified in this section. This requirement applies for engines 
produced on or after January 1, 2013.
    (a) You must submit the report for each calendar year in which you 
produce any engines subject to emission standards under this part. The 
report is due by February 28 of the following calendar year. Note that 
Sec.  87.64 requires you to report CO2 emission rates to EPA 
in addition to NOX. Include these data in the report 
required by this section. If you produce exempted or excepted engines, 
you may submit a single report with information on exempted/excepted 
and normally certificated engines.
    (b) Send the report to the Designated EPA Program Officer.
    (c) In the report, specify your corporate name and the year for 
which you are reporting. Include information as described in this 
section for each engine sub-model subject to emission standards under 
this part. List each engine sub-model produced or certificated during 
the calendar year, including the following information for each sub-
model:
    (1) The type of engine (turbofan, turboprop, etc.) and complete 
sub-model name, including any applicable model name, sub-model 
identifier, and engine type certificate family identifier.
    (2) The certificate under which it was produced. Identify all the 
following:
    (i) The type certificate number. Specify if the sub-model also has 
a type certificate issued by a certificating authority other than FAA.
    (ii) Your corporate name as listed in the certificate.
    (iii) Emission standards to which the engine is certificated.
    (iv) Date of issue of type certificate (month and year).
    (v) Whether or not this is a derivative engine for emissions 
certification purposes. If so, identify the original certificated 
engine model.
    (vi) The engine sub-model that received the original type 
certificate for an engine type certificate family.
    (3) Identify the combustor of the sub-model, where more than one 
type of combustor is available.
    (4) The calendar-year production volume of engines from the sub-
model that are covered by an FAA type certificate. Record zero for sub-
models with no engines produced during the calendar year, or state that 
the engine model is no longer in production and list the date of 
manufacture (month and year) of the last engine produced. Specify the 
number of these engines that are intended for use on new aircraft and 
the number that are intended for use as non-exempt engines on in-use 
aircraft. For engines delivered without a final sub-model status and 
for which the manufacturer has not ascertained the engine's sub-model 
when installed before submitting its production report, the 
manufacturer may do any of the following in its initial report, and 
amend it later:
    (i) List the sub-model that was shipped or the most probable sub-
model.
    (ii) List all potential sub-models.
    (iii) State ``Unknown Sub-Model.''
    (5) The number of engines tested and the number of test runs for 
the applicable type certificate.

[[Page 36384]]

    (6) The applicable test data and related information specified in 
Part III, Section 2.4 of ICAO Annex 16 (incorporated by reference in 
Sec.  87.8), except as otherwise allowed by this paragraph. For 
purposes of this paragraph (c)(6), applicable test data means data 
required to certify the engine sub-model, which would typically include 
NOX, HC, CO and smoke number. However, applicable test data 
would not include NOX, HC, or CO emissions for engines 
subject to only smoke standards. Note that Sec.  87.64 also requires 
you to report CO2 emissions. Specify thrust in kW for 
turboprop engines. You may omit the following items specified in Part 
III, Section 2.4 of ICAO Annex 16:
    (i) Fuel specifications including fuel specification reference and 
hydrogen/carbon ratio.
    (ii) Methods used for data acquisition, correcting for ambient 
conditions, and data analysis.
    (iii) Intermediate emission indices and rates, however you may not 
omit the final characteristic level for each regulated pollutant in 
units of g/kN or g/kW.
    (d) Clearly show what information you consider confidential by 
marking, circling, bracketing, stamping, or some other method. We will 
store your confidential information as described in 40 CFR part 2. 
Also, we will disclose it only as specified in 40 CFR part 2. If you 
send us information without claiming it is confidential, we may make it 
available to the public without further notice to you, as described in 
40 CFR 2.204.
    (e) Include the following signed statement and endorsement by an 
authorized representative of your company: ``We submit this report 
under 40 CFR 87.42. All the information in this report is true and 
accurate to the best of my knowledge.''
    (f) Where information provided for the previous year remains valid 
and complete, you may report your production volumes and state that 
there are no changes, without resubmitting the other information 
specified in this section.


Sec.  87.46  Recordkeeping.

    (a) You must keep a copy of any reports or other information you 
submit to us for at least three years.
    (b) Store these records in any format and on any media, as long as 
you can promptly send us organized, written records in English if we 
ask for them. You must keep these records readily available. We may 
review them at any time.


Sec.  87.48  Derivative engines for emissions certification purposes.

    (a) General. A type certificate holder may request from the FAA a 
determination that an engine configuration is considered a derivative 
engine for emissions certification purposes. This would mean that the 
engine configuration is determined to be similar in design to a 
previously certificated engine (the ``original'' engine) for purposes 
of compliance with exhaust emission standards (gaseous and smoke). In 
order for the engine configuration to be considered a derivative engine 
for emission purposes under this part, it must have been derived from 
an original engine that was certificated to the requirements of 14 CFR 
part 33, and one of the following conditions must be met:
    (1) The FAA determined that a safety issue exists that requires an 
engine modification.
    (2) Emissions from the derivative engines are determined to be 
similar. In general, this means the emissions must meet the criteria 
specified in paragraph (b) of this section. FAA may adjust these 
criteria in unusual circumstances, consistent with good engineering 
judgment.
    (3) All of the regulated emissions from the derivative engine are 
lower than the original engine.
    (b) Emissions similarity. (1) The type certificate holder must 
demonstrate that the proposed derivative engine model's emissions meet 
the applicable standards and differ from the original model's emission 
rates only within the following ranges:
    (i) 3.0 g/kN for NOX.
    (ii) 1.0 g/kN for HC.
    (iii) 5.0 g/kN for CO.
    (iv) 2.0 SN for smoke.
    (2) If the characteristic level of the original certificated engine 
model (or any other sub-models within the emission type certificate 
family tested for certification) before modification is at or above 95% 
of the applicable standard for any pollutant, you must measure the 
proposed derivative engine model's emissions for all pollutants to 
demonstrate that the derivative engine's resulting characteristic 
levels will not exceed the applicable emission standards. If the 
characteristic levels of the originally certificated engine model (and 
all other sub-models within the emission type certificate family tested 
for certification) are below 95% of the applicable standard for each 
pollutant, then, you may use engineering analysis to demonstrate that 
the derivative engine will not exceed the applicable emission 
standards, consistent with good engineering judgment. The engineering 
analysis must address all modifications from the original engine, 
including those approved for previous derivative engines.
    (c) Continued production allowance. Where we allow continued 
production of an engine model after new standards begin to apply, you 
may also produce engine derivatives if they conform to the 
specifications of this section.
    (d) Non-derivative engines. If the FAA determines that an engine 
model does not meet the requirements for a derivative engine for 
emissions certification purposes, the type certificate holder is 
required to demonstrate that the engine complies with the emissions 
standards applicable to a new engine type.

0
12. Add a new subpart F containing Sec.  87.50 to read as follows:

Subpart F--Exemptions and Exceptions


Sec.  87.50  Exemptions and exceptions.

    This section specifies provisions related to exempting/excepting 
engines from some or all of the standards and requirements of this part 
87. Exempted/excepted engines must conform to regulatory conditions 
specified for an exemption in this section and other applicable 
regulations. Exempted/excepted engines are deemed to be ``subject to'' 
the standards of this part even though they are not required to comply 
with the otherwise applicable requirements. Engines exempted/excepted 
with respect to certain standards must comply with other standards. 
Exemption requests under paragraph (a) of this section must be approved 
by the FAA, with the written concurrence of EPA, to be effective. 
Exemption requests under paragraph (b) of this section must be approved 
only by the FAA to be effective. Exceptions do not require a case-by-
case FAA approval.
    (a) Engines installed in new aircraft. Type certificate holders may 
request an exemption to produce a limited number of newly manufactured 
engines through December 31, 2016, to be installed in new aircraft as 
specified in this paragraph (a). This exemption is limited to 
NOX emissions from engines that are covered by a valid type 
certificate issued by FAA.
    (1) Submit your request for an exemption to the FAA before 
producing the engines to be exempted, who will provide a copy to the 
Designated EPA Program Officer. Exemption by an authority outside the 
United States does not satisfy this requirement. Unless EPA and FAA 
allow otherwise, all requests must include the following:

[[Page 36385]]

    (i) Your corporate name and an authorized representative's contact 
information.
    (ii) A description of the engines for which you are requesting the 
exemption including the type certificate number and date it was issued 
by the FAA. Include in your description the engine model and sub-model 
names and the types of aircraft in which the engines are expected to be 
installed. Specify the number of engines that you would produce under 
the exemption and the period during which you would produce them.
    (iii) Information about the aircraft in which the engines will be 
installed. Specify the airframe models and expected first purchasers/
users of the aircraft. Identify all countries in which you expect the 
aircraft to be registered. Specify how many aircraft will be registered 
in the United States and how many will be registered in other 
countries; you may estimate this if it is not known.
    (iv) A justification of why the exemption is appropriate. 
Justifications must include a description of the environmental impact 
of granting the exemption. Include other relevant information such as 
the following:
    (A) Technical issues, from an environmental and airworthiness 
perspective, which may have caused a delay in compliance with a 
production cutoff.
    (B) Economic impacts on the manufacturer, operator(s), and aviation 
industry at large.
    (C) Environmental effects. This should consider the amount of 
additional air pollutant emissions that will result from the exemption. 
This could include consideration of items such as:
    (1) The amount that the engine model exceeds the standard, taking 
into account any other engine models in the engine type certificate 
family covered by the same type certificate and their relation to the 
standard.
    (2) The amount of the applicable air pollutant that would be 
emitted by an alternative engine for the same application.
    (3) The impact of changes to reduce the applicable air pollutant on 
other environmental factors, including emission rates of other air 
pollutants, community noise, and fuel consumption.
    (4) The degree to which the adverse impact would be offset by 
cleaner engines produced in the same time period (unless we decide to 
consider earlier engines).
    (D) Impact of unforeseen circumstances and hardship due to business 
circumstances beyond your control (such as an employee strike, supplier 
disruption, or calamitous events).
    (E) Projected future production volumes and plans for producing a 
compliant version of the engine model in question.
    (F) Equity issues in administering the production cutoff among 
economically competing parties.
    (G) List of other certificating authorities from which you have 
requested (or expect to request) exemptions, and a summary of the 
request.
    (H) Any other relevant factors.
    (v) A statement signed by your authorized representative attesting 
that all information included in the request is accurate.
    (2) In consultation with the EPA, the FAA may specify additional 
conditions for the exemption.
    (3) You must submit the annual report specified in paragraph (d) of 
this section.
    (4) The permanent record for each engine exempted under this 
paragraph (a) must indicate that the engine is an exempted new engine.
    (5) Engines exempted under this paragraph (a) must be labeled with 
the following statement: ``EXEMPT NEW''.
    (6) You must notify the FAA if you determine after submitting your 
request that the information is not accurate, either from an error or 
from changing circumstances. If you believe the new or changed 
information could have affected approval of your exemption (including 
information that could have affected the number of engines we exempt), 
you must notify the FAA promptly. The FAA will consult with EPA as 
needed to address any concerns related to this new or corrected 
information.
    (b) Temporary exemptions based on flights for short durations at 
infrequent intervals. The emission standards of this part do not apply 
to engines which power aircraft operated in the United States for short 
durations at infrequent intervals. Such operations are limited to:
    (1) Flights of an aircraft for the purpose of export to a foreign 
country, including any flights essential to demonstrate the integrity 
of an aircraft prior to its flight to a point outside the United 
States.
    (2) Flights to a base where repairs, alterations or maintenance are 
to be performed, or to a point of storage, and flights for the purpose 
of returning an aircraft to service.
    (3) Official visits by representatives of foreign governments.
    (4) Other flights the Secretary determines to be for short 
durations at infrequent intervals. A request for such a determination 
shall be made before the flight takes place.
    (c) Spare engines. Newly manufactured engines meeting the 
definition of ``spare engine'' are excepted as follows:
    (1) This exception allows production of a newly manufactured engine 
for installation on an in-service aircraft. It does not allow for 
installation of a spare engine on a new aircraft.
    (2) Each spare engine must be identical to a sub-model previously 
certificated to meet all requirements applicable to Tier 4 engines or 
later requirements.
    (3) Spare engines excepted under this paragraph (c) may be used 
only where the emissions of the spare engines are certificated to equal 
to or lower emission standards than those of the engines they are 
replacing, for all regulated pollutants.
    (4) No prior approval is required to produce spare engines. Engine 
manufacturers must include information about their production of spare 
engines in the annual report specified in paragraph (d) of this section
    (5) The permanent record for each engine excepted under this 
paragraph (c) must indicate that the engine was produced as an excepted 
spare engine.
    (6) Engines excepted under this paragraph (c) must be labeled with 
the following statement: ``EXCEPTED SPARE''.
    (d) Annual reports. If you produce engines with an exemption/
exception under this section, you must submit an annual report with 
respect to such engines.
    (1) You must send the Designated EPA Program Officer a report 
describing your production of exempted/excepted engines for each 
calendar year in which you produce such engines by February 28 of the 
following calendar year. You may include this information in the 
certification report described in Sec.  87.42. Confirm that the 
information in your initial request is still accurate, or describe any 
relevant changes.
    (2) Provide the information specified in this paragraph (d)(2). For 
purposes of this paragraph (d), treat spare engine exceptions separate 
from other new engine exemptions. Include the following for each 
exemption/exception and each engine model and sub-model:
    (i) Engine model and sub-model names.
    (ii) Serial number of each engine.
    (iii) Use of each engine (for example, spare or new installation).

[[Page 36386]]

    (iv) Types of aircraft in which the engines were installed (or are 
intended to be installed for spare engines).
    (v) Serial number of the new aircraft in which engines are 
installed (if known), or the name of the air carriers (or other 
operators) using spare engines.
    (3) Include information in the report only for engines having a 
date of manufacture within the specific calendar year.

Subpart G--Test Procedures

0
13. The heading for subpart G is revised as set forth above.

0
14. Revise Sec.  87.60 to read as follows:


Sec.  87.60  Testing engines.

    (a) Use the equipment and procedures specified in Appendix 3, 
Appendix 5, and Appendix 6 of ICAO Annex 16 (incorporated by reference 
in Sec.  87.8), as applicable, to demonstrate whether engines meet the 
gaseous emission standards specified in subpart C of this part. Measure 
the emissions of all regulated gaseous pollutants. Similarly, use the 
equipment and procedures specified in Appendix 2 and Appendix 6 of ICAO 
Annex 16 to determine whether engines meet the smoke standard specified 
in subpart C of this part. The compliance demonstration consists of 
establishing a mean value from testing some number of engines, then 
calculating a ``characteristic level'' by applying a set of statistical 
factors that take into account the number of engines tested. Round each 
characteristic level to the same number of decimal places as the 
corresponding emission standard. For turboprop engines, use the 
procedures specified for turbofan engines, consistent with good 
engineering judgment.
    (b) Use a test fuel meeting the specifications described in 
Appendix 4 of ICAO Annex 16 (incorporated by reference in Sec.  87.8). 
The test fuel must not have additives whose purpose is to suppress 
smoke, such as organometallic compounds.
    (c) Prepare test engines by including accessories that are 
available with production engines if they can reasonably be expected to 
influence emissions. The test engine may not extract shaft power or 
bleed service air to provide power to auxiliary gearbox-mounted 
components required to drive aircraft systems.
    (d) Test engines must reach a steady operating temperature before 
the start of emission measurements.
    (e) In consultation with the EPA, the FAA may approve alternate 
procedures for measuring emissions as specified in this paragraph (e). 
This might include testing and sampling methods, analytical techniques, 
and equipment specifications that differ from those specified in this 
part. Manufacturers and operators may request this approval by sending 
a written request with supporting justification to the FAA and to the 
Designated EPA Program Officer. Such a request may be approved only if 
one of the following conditions is met:
    (1) The engine cannot be tested using the specified procedures.
    (2) The alternate procedure is shown to be equivalent to or better 
(e.g., more accurate or precise) than the specified procedure.
    (f) The following landing and take-off (LTO) cycles apply for 
emission testing and calculating weighted LTO values:

                                                        Table 1 to Sec.   87.60--LTO Test Cycles
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                    Turboprop                   Subsonic turbofan              Supersonic turbofan
                                                        ------------------------------------------------------------------------------------------------
                          Mode                             Percent of     Time in mode     Percent of     Time in mode     Percent of      Time in mode
                                                          rated output      (minutes)     rated output      (minutes)     rated output      (minutes)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Take-off...............................................             100             0.5             100             0.7             100              1.2
Climb..................................................              90             2.5              85             2.2              65              2.0
Descent................................................  ..............  ..............  ..............  ..............              15              1.2
Approach...............................................              30             4.5              30             4.0              34              2.3
Taxi/ground idle.......................................               7            26.0               7            26.0             5.8             26.0
--------------------------------------------------------------------------------------------------------------------------------------------------------

     (g) Engines comply with an applicable standard if the testing 
results show that the engine type certificate family's characteristic 
level does not exceed the numerical level of that standard, as 
described in Sec.  87.60.


Sec. Sec.  87.61-87.63  [Removed]

0
15. Remove Sec. Sec.  87.61-87.63.


Sec.  87.64  [Amended]

0
16. In Sec.  87.64, remove and reserve paragraph (a).


Sec. Sec.  87.65-87.71  [Removed]

0
17. Remove Sec. Sec.  87.65-87.71.

Subpart H--[Removed]

0
18. Remove subpart H.

PART 1068--GENERAL COMPLIANCE PROVISIONS FOR HIGHWAY, STATIONARY, 
AND NONROAD PROGRAMS

0
19. The authority citation for part 1068 continues to read as follows:

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

Subpart A--[Amended]

0
20. Amend Sec.  1068.1 by revising paragraph (b) to read as follows:


Sec.  1068.1  Does this part apply to me?

* * * * *
    (b) This part does not apply to any of the following engine or 
vehicle categories:
    (1) Light-duty motor vehicles (see 40 CFR part 86).
    (2) Heavy-duty motor vehicles and motor vehicle engines, except as 
specified in 40 CFR part 86.
    (3) Aircraft engines, except as specified in 40 CFR part 87.
    (4) Land-based nonroad compression-ignition engines we regulate 
under 40 CFR part 89.
    (5) Small nonroad spark-ignition engines we regulate under 40 CFR 
part 90.
    (6) Marine spark-ignition engines we regulate under 40 CFR part 91.
    (7) Locomotive engines we regulate under 40 CFR part 92.
    (8) Marine compression-ignition engines we regulate under 40 CFR 
parts 89 or 94.
* * * * *
[FR Doc. 2012-13828 Filed 6-15-12; 8:45 am]
BILLING CODE 6560-50-P


