Document ID: EPA-HQ-OAR-2010-0687-0001
Agency: epa
Document Type: Proposed Rule
Title: Control of Air Pollution From Aircraft and Aircraft Engines; Proposed Emission Standards and Test Procedures
Posted Date: 2011-07-27T04:00Z

[Federal Register Volume 76, Number 144 (Wednesday, July 27, 2011)]
[Proposed Rules]
[Pages 45012-45052]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-17660]

[[Page 45011]]

Vol. 76

Wednesday,

No. 144

July 27, 2011

Part II

Environmental Protection Agency

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40 CFR Parts 87 and 1068

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

  Federal Register / Vol. 76 , No. 144 / Wednesday, July 27, 2011 / 
Proposed Rules  

[[Page 45012]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 87 and 1068

[EPA-HQ-OAR-2010-0687; FRL-9437-2]
RIN 2060-AO70

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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: This action proposes several new NOX emission 
standards, compliance flexibilities, and other regulatory requirements 
for aircraft turbofan or turbojet engines with rated thrusts greater 
than 26.7 kilonewtons (kN). We also are proposing certain other 
requirements for gas turbine engines that are subject to exhaust 
emission standards. First, we are proposing to clarify 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 proposing 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 proposing amendments to aircraft engine test 
and emissions measurement procedures. EPA actively participated in the 
United Nation's International Civil Aviation Organization (ICAO) 
proceedings in which most of these proposed requirements were first 
developed. These proposed regulatory requirements have largely been 
adopted or are actively under consideration by its member states. By 
adopting such similar standards, therefore, the United States will 
maintain consistency with these international efforts.

DATES: Comments must be received on or before September 26, 2011.
    Hearing: The public hearing will be held on August 11, 2011 at the 
Sheraton Chicago O'Hare Airport Hotel, 6501 North Mannheim Road, 
Rosemont, IL 60018. Telephone (847)699-6300. See section VII for more 
information about public hearings.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-
OAR-2010-0687, by one of the following methods:
    http://www.regulations.gov: Follow the on-line instructions for 
submitting comments.
     E-mail: A-and-R-Docket@epamail.epa.gov.
     Fax: 202-566-9744.
    Mail: EPA Docket center, EPA West (Air Docket), Attention Docket ID 
No. EPA-HQ-OAR-2010-0687, Mailcode: Mail Code 2822T, 1200 Pennsylvania 
Ave., NW., Washington, DC 20460. Please include a total of two copies. 
In addition, please mail a copy of your comments to the contact person 
identified below (see FOR FURTHER INFORMATION CONTACT). Please mail a 
copy of your comments on the information collection provisions to the 
Office of Information and Regulatory Affairs, Office of Management and 
Budget (OMB), Attn: Desk Officer for EPA, 725 17th Street, NW., 
Washington, DC 20503.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2010-0687. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit information that you 
consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site 
is an ``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through http://www.regulations.gov your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at 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 
EPA Docket Center 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; e-
mail 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:

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                  Category                    NAICS \a\ Codes    SIC Codes \b\                  Examples of potentially affected entities
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Industry...................................            336412              3724  Manufacturers of new aircraft engines.
Industry...................................            336411              3721  Manufacturers of new aircraft.
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\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

[[Page 45013]]

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. Overview and Background
    A. Summary of the Proposal
    B. EPA's 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
II. Why is EPA taking this action?
    A. NOX Inventory Contribution
    1. Landing and Takeoff (LTO) Emissions
    2. Non-LTO Emissions
    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
III. Details of the Proposed 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. 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
    c. Voluntary Emission Offsets
    3. Potential Phase-In of New Tier 8 NOX Standards for 
Newly-Manufactured Engines
    C. Application of Standards for Derivative Engines for Emission 
Certification Purposes
    D. Annual Reporting Requirement
    E. Proposed 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
IV. 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
V. Technical Feasibility, Costs, and Emission Benefits
VI. Consultation With FAA
VII. Public Participation
VIII. Statutory Provisions and Legal Authority
IX. Statutory and Executive Orders Review
    A. Executive Order 12866: Regulatory Planning and 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

I. Overview and Background

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

    We are proposing 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 
proposing two new tiers of more stringent emission standards for oxides 
of nitrogen (NOX). The proposed standards would apply 
differently to two classes of these engines, i.e., ``newly-certified 
engines'' and ``newly-manufactured engines.'' The newly-certified 
engine standards would 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 would apply to aircraft engines that were 
previously certified and manufactured in compliance with preexisting 
standards, and would require manufacturers to either comply with the 
newer standards by a specified future date or cease production. Newly-
manufactured engine standards are also sometimes referred to as 
``production cutoff'' standards. Second, we are proposing 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 proposed 
NOX standards because of specific technical or economic 
reasons.
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    \1\ Turbofan and turbojet engines will be collectively referred 
to as turbofan engines hereafter for convenience.
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    We are also proposing a number of additional changes that would 
apply to a wider range of aircraft gas turbine engines \2\ than those 
that would be subject to the proposed new emission standards. First, we 
are proposing to define 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 proposing new reporting requirements for manufacturers 
that produce gas turbine engines subject to any exhaust emission 
standard. This would provide us with timely and consistent emission 
data and other information that is necessary to conduct emission 
analyses and develop appropriate public policy for the aviation sector. 
Specifically, reports would be 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. Third, we are proposing amendments to the test and 
measurement procedures for aircraft engines. Finally, as described in 
section IV., we are proposing minor amendments to provisions addressing 
definitions, acronyms and abbreviations, general applicability and

[[Page 45014]]

requirements, exemptions, and incorporation by reference.
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    \2\ 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).
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    Most of these proposed regulatory requirements have already been 
adopted or are actively under consideration by the United Nation's 
International Civil Aviation Organization (ICAO). The proposed 
requirements would 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 DC 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 (DC 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 insure 
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. 7573. 
Section VI. of today's proposal further discusses our coordination with 
DOT through the FAA.\3\ It also describes DOT's responsibility under 
the CAA to enforce the aircraft emission standards established by EPA.
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    \3\ 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).
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C. Interaction With the International Community

    We began regulating the 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 
``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.'' \4\ 
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 190 participating member States of ICAO.5 6
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    \4\ International Civil Aviation Organization (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 http://www.icao.int.
    \5\ Members of ICAO's Assembly are generally termed member 
States or contracting States. These terms are used interchangeably 
throughout this preamble.
    \6\ There are currently 190 Contracting States according to ICAO 
website located at http://www.icao.int.
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    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.\7\ 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.\8\ 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.\9\ However, 
if a nation sets tighter standards than ICAO, air carriers not based in 
that nation (foreign-flagged carriers) would only be required to comply 
with ICAO standards or more stringent standards imposed by their own 
nations, if applicable.
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    \7\ ICAO, ``Convention on International Civil Aviation,'' 
Article 87, Ninth Edition, Document 7300/9, 2006. Copies of this 
document can be obtained from the ICAO website located at http://www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
    \8\ 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 http://www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
    \9\ 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 http://www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
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    ICAO Council'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 contributing committees whose contributing 
members include atmospheric, economic, aviation, environmental, and 
other professionals. At CAEP meetings, the United States is represented 
by the FAA, which plays an active role at these meetings. 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).\10\
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    \10\ 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.

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[[Page 45015]]

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.\11\ 
Since that time, we have occasionally revised those regulations. Two of 
these revisions are most pertinent to today's proposal. 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.\12\ 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) \13\ 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.\14\ 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 (DC Cir. 2007).
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    \11\ U.S. EPA, ``Emission Standards and Test Procedures for 
Aircraft;'' Final Rule, 38 FR 19088, July 17, 1973.
    \12\ 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 today's notice, we are proposing to expand the 
scope of that finding and of our standards to include such emissions 
from both commercial and non-commercial aircraft engines, in order 
to bring our standards into full alignment with ICAO's.
    \13\ This does not mean that in 2005 we promulgated requirements 
for the re-certification or retrofit of existing in-use engines.
    \14\ 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.
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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 adopted by ICAO in 
1981.\15\ 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.\16\ 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 newly-
manufactured engines unlike the CAEP/2 standards). In 2004, CAEP/6 
recommended a 12 percent NOX reduction, which ICAO approved 
in 2005.17 18 The CAEP/6 standards applied to newly-
certified engine models beginning 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.19 20 The Committee also recommended that the CAEP/6 
standards be applied to newly-manufactured engines. ICAO is currently 
considering the CAEP/8 recommendations. We expect final ICAO action 
regarding the CAEP/8 recommendations in 2011.
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    \15\ ICAO, Foreword of ``Aircraft Engine Emissions,'' 
International Standards and Recommended Practices, Environmental 
Protection, Annex 16, Volume II, Third Edition, July 2008. A copy of 
this document is in docket number EPA-HQ-OAR-2010-0687.
    \16\ 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.
    \17\ CAEP/5 did not address new aircraft engine emission 
standards.
    \18\ 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 
http://www.icao.int.
    \19\ CAEP/7 did not address new aircraft engine emission 
standards.
    \20\ 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.
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II. 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. NOX is a precursor to the formation of 
tropospheric ozone.\21\ Many commercial airports are located in urban 
areas and many of these areas have ambient pollutant levels above the 
National Ambient Air Quality Standards (NAAQS) for ozone and fine 
particulate matter (PM 2.5) (i.e., they are in nonattainment 
for ozone and PM 2.5). 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 
nonattainment areas, the potential effect of NOX emissions 
in the upper atmosphere on ground level PM 2.5 in addition 
to the health and welfare impacts of NOX and PM emissions.
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    \21\ 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.
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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,

[[Page 45016]]

known as non-LTO emissions. Collectively, the emissions associated with 
all ground and flight operations are generally referred to as full 
flight emissions.
    The aircraft engine NOX emission inventories for the LTO 
and non-LTO flight regimes described above are discussed separately in 
the following sections.
 1. Landing and Takeoff Emissions
    In this section, we will discuss NOX emission 
inventories for commercial turbine-engine aircraft, both nationally and 
for selected ozone 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).\22\ 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 operations 
contributed about 97 thousand tons to the national NOX 
inventory. A summary of the national inventory of LTO NOX 
emissions is shown in Table 1.
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    \22\ ``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.
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    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.\23\
---------------------------------------------------------------------------

    \23\ 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.

    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 ozone NAAs with airports which had high 
commercial traffic volumes were identified. Second, the 25 ozone NAAs 
with the largest population were identified. These lists were combined. 
However, there was some overlap, and this led to a total of 41 NAAs 
being identified for the study. These 41 NAAs collectively include 200 
airports, accounting for about 70 percent of commercial air traffic 
operations. 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. Current (2008) and projected 
(2020) NOX emissions for these 40 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 2.24 25 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.
---------------------------------------------------------------------------

    \24\ 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.
    \25\ 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.

                      Table 2--Current NOX Emissions in Selected Ozone Nonattainment Areas
----------------------------------------------------------------------------------------------------------------
                                                                                2008 aircraft     2020 aircraft
                                                             2008 total NOX      percent of        percent of
                    Nonattainment area                           (tons)         mobile source     mobile source
                                                                                     NOX               NOX
----------------------------------------------------------------------------------------------------------------
Albuquerque, NM...........................................               380               1.6               4.3
Anchorage, AK.............................................             2,538              23.4              49.3
Aspen.....................................................                16               2.0               6.6
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
Cincinnati-Hamilton, OH-KY-IN.............................             1,287               1.5               3.3
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
El Paso, TX...............................................               223               0.9               1.1
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

[[Page 45017]]

 
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
Memphis, TN-AR............................................             2,988               6.3              16.8
Milwaukee-Racine, WI......................................               557               0.9               3.2
Minneapolis-St Paul, MN...................................             2,154               1.0               5.1
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
Raleigh-Durham-Chapel Hill, NC............................               565               1.0               3.2
Reno, NV..................................................               246               1.9               4.4
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
Syracuse, NY..............................................               139               0.8               1.9
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, as was seen in Table 2.

                          Table 3--Current and Projected Commercial Aircraft Operations
----------------------------------------------------------------------------------------------------------------
                                                                                                 Total increase
                                             Air carrier      Commuter/air    Total commercial    in 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.

2. Non-LTO Emissions
    Historically, emphasis has been placed on evaluating emissions 
during LTO operations given their obvious impact on local air quality. 
Less emphasis has been placed on evaluating emissions from non-LTO 
operations (emissions at altitudes greater than 3,000 feet above ground 
level) based on the assumption that such emissions have a lesser impact 
on local air quality. However, modeling by Barrett et al. (2010) finds 
that these upper atmosphere emissions may adversely affect public 
health more than was previously thought.\26\ Based on the data and 
methodology of the authors, this effect is caused primarily by two 
pathways:
---------------------------------------------------------------------------

    \26\ Barrett, S. R. H., R. E. Britter and I. A. Waitz, 2010. 
Global mortality attributable to aircraft cruise emissions. 
Environmental Science & Technology 44 (19), pp. 7736-7742. DOI: 
10.1021/es101325r.
---------------------------------------------------------------------------

    The formation of fine particulate matter, i.e., PM2.5, 
from emission of gaseous precursors of PM (NOX and 
SO2) in the upper atmosphere that are then transported to 
the lower atmosphere. (The formation of secondary PM2.5 from 
NOX is discussed further in section II.B.1.b).
    Aviation NOX emissions promote ozone formation 
throughout the troposphere and hence increase hydroxyl radical (OH) 
concentrations. This increases the oxidation of non-aviation 
SO2 (such as that emitted from power stations) in the gas 
phase relative to aqueous oxidation and dry deposition thereby 
increasing atmospheric sulfate (a type of PM2.5) 
concentrations.
    The authors of this work estimated that full flight emissions cause 
almost 10,000 premature mortalities (their central estimate) per year 
worldwide, with over 450 per year in the U.S. The pollutants emitted 
during cruise operations were estimated to be about 80 percent of the 
population-weighed PM2.5 from aviation, with the remainder 
being associated with LTO operations (although they note the LTO 
portion may be under-estimated). The study asserts that over 380 
premature mortalities per year in the U.S. can be attributed to 
secondary PM2.5 associated with non-LTO operations. We 
request comments on the results of these studies and the existence of 
other research into this area.

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

[[Page 45018]]

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 proposing to align will help reduce ambient 
ozone and secondary PM levels and thus will help areas with airports 
achieve or maintain compliance with the National Ambient Air Quality 
Standards (NAAQS).\27\
---------------------------------------------------------------------------

    \27\ The discussion of PM health and welfare effects throughout 
this notice relates exclusively to the effects of the proposed 
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 by the reaction of 
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.\28\ 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 can be transported hundreds of 
miles downwind from the sources of precursor emissions, resulting in 
elevated ozone levels even in areas with low local VOC or 
NOX emissions.
---------------------------------------------------------------------------

    \28\ 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). Current NAAQS 
use PM2.5 as the indicator for fine particles (with 
PM2.5 referring to particles with a nominal mean aerodynamic 
diameter less than or equal to 2.5 [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 aerodynamic 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 pollutants 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 can dissolve in water vapor and further 
oxidize to form nitric acid which reacts with ammonia to form nitrates, 
an important component of ambient PM. NOX along with non-
methane hydrocarbon (NMHC) 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 (ozone AQCD) and 
2007 Staff Paper.29 30 People who are more susceptible to 
effects associated with exposure to ozone can include children, 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 recent 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.\31\ Animal 
toxicological evidence indicates that with repeated exposure, ozone can

[[Page 45019]]

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

    \29\ 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.
    \30\ 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.
    \31\ 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).\32\ 
The ISA summarizes evidence associated with PM2.5, 
PM10-2.5, and ultrafine particles (UFPs), and concludes the 
following.
---------------------------------------------------------------------------

    \32\ 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 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 (COPD) and respiratory infections.\33\ The ISA notes 
that long-term exposure to PM2.5 (months to years) is 
associated with the development/progression of cardiovascular disease, 
premature mortality, and respiratory effects, including reduced lung 
function growth, increased respiratory symptoms, and asthma 
development.\34\ 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 
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 and cancer, 
mutagenicity, and genotoxicity and long-term exposure to 
PM2.5.\35\
---------------------------------------------------------------------------

    \33\ 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.
    \34\ 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.
    \35\ 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 cardiovascular effects, such as hospitalization for 
ischemic heart disease. There is also suggestive evidence of a causal 
relationship between short-term PM10-2.5 exposure and 
mortality and respiratory effects. Data are inadequate to draw 
conclusions regarding the health effects associated with long-term 
exposure to PM10-2.5.
    For ultrafine particulates (UFPs), the ISA further 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 UFPs 
and respiratory effects. Data are inadequate to draw conclusions 
regarding the health effects associated with long-term exposure to 
UFP's.
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.\36\ 
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. In addition, small but significant 
increases in non-specific airway hyper-responsiveness were reported 
following 1-hour exposures of asthmatics to 0.1 ppm NO2. 
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. 
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 a relationship between NO2 
exposures and an array of adverse health effects that range from the 
onset of respiratory symptoms to hospital admission.
---------------------------------------------------------------------------

    \36\ 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 U.S. 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

[[Page 45020]]

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 and damage to forest productivity. Across 
the U.S. there are many terrestrial and aquatic ecosystems that have 
been identified as particularly sensitive to nitrogen deposition. The 
most extreme effects resulting from nitrogen deposition on aquatic 
ecosystems are due to nitrogen enrichment which contributes to 
``hypoxic'' zones devoid of life. Three hypoxia zones of special 
concern in the U.S. are the zones located in the Gulf of Mexico, the 
Chesapeake Bay in the mid-Atlantic region, and Long Island Sound, in 
the northeast U.S.\37\
---------------------------------------------------------------------------

    \37\ U.S. EPA (2008). Nitrogen Dioxide/Sulfur Dioxide Secondary 
NAAQS Review: Integrated Science Assessment (ISA). Washington, DC: 
U.S. Environmental Protection Agency. Retrieved on March 18, 2009 
from http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=180903.
---------------------------------------------------------------------------

    The deposition of airborne particles 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.\38\ Particles 
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).
---------------------------------------------------------------------------

    \38\ 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.\39\ 
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.\40\
---------------------------------------------------------------------------

    \39\ 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.
    \40\ 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 proposing 
would impact ambient concentrations of air pollutants. Nationally, 
levels of PM2.5, ozone, and NOX are 
declining.\41\ However as of 2008, approximately 127 million people 
lived in counties that exceeded any NAAQS.\42\ These numbers do not 
include the people living in areas where there is a future risk of 
failing to maintain or attain the NAAQS.
---------------------------------------------------------------------------

    \41\ 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/.
    \42\ 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/.
---------------------------------------------------------------------------

    States with nonattainment areas are required to take action to 
bring those areas into compliance in the future. Based on the final 
rule designating and classifying 8-hour ozone nonattainment areas for 
the 1997 standard (69 FR 23951, April 30, 2004), most 8-hour ozone 
nonattainment areas will be required to attain the ozone NAAQS in the 
2007 to 2013 time frame and then maintain the NAAQS thereafter. EPA is 
reconsidering the 2008 ozone NAAQS. If EPA promulgates different ozone 
NAAQS as a result of the reconsideration, these standards would replace 
the 2008 ozone NAAQS and EPA would subsequently designate nonattainment 
areas for the revised primary ozone NAAQS. The attainment dates for 
areas designated nonattainment for a revised primary ozone NAAQS could 
range from 2015 to 2032, depending on the severity of the problem.\43\
---------------------------------------------------------------------------

    \43\ U.S. EPA (2010). Fact Sheet Revisions to Ozone Standards. 
This document can be accessed electronically at: http://www.epa.gov/groundlevelozone/pdfs/fs20100106std.pdf.
---------------------------------------------------------------------------

    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 them thereafter. The 2006 24-hour PM2.5

[[Page 45021]]

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.
    The aircraft engine emission standards being proposed today were 
approved by ICAO/CAEP and would have an implementation date of 2013. 
Therefore, the aircraft engine emission reductions that are being 
proposed today should be useful to states in attaining or maintaining 
the ozone and PM2.5 NAAQS.
    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 16 counties with a population of almost 35 million may not attain 
the 2008 ozone standard of 0.075 ppm (75 ppb).\44\ In addition, our air 
quality modeling projects that in 2030 at least 9 counties with a 
population of almost 28 million may not attain the 1997 annual 
PM2.5 standard of 15 [mu]g/m\3\ and 26 counties with a 
population of over 41 million may not attain the 2006 24-hour 
PM2.5 standard of 35 [mu]g/m\3\.\45\ 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.
---------------------------------------------------------------------------

    \44\ U.S. EPA (2010). Regulatory Impact Analysis: Final 
Rulemaking To Establish Light-Duty Vehicle Greenhouse Gas Emission 
Standards and Corporate Average Fuel Economy Standards. Chapter 7: 
Environmental and Health Impacts. EPA420-R-10-009.
    \45\ U.S. EPA (2010). Regulatory Impact Analysis: Final 
Rulemaking To Establish Light-Duty Vehicle Greenhouse Gas Emission 
Standards and Corporate Average Fuel Economy Standards. Chapter 7: 
Environmental and Health Impacts. EPA 420-R-10-009.
---------------------------------------------------------------------------

    There are currently no NO2 nonattainment areas. However, 
the NO2 standards were recently revised and a new 1-hour 
NO2 standard was promulgated.\46\ Nonattainment area 
designations for the 1-hour NO2 standard are expected to be 
finalized in 2012. These proposed aircraft NOX reductions 
would be useful to states in attaining or maintaining the 
NO2 standards.
---------------------------------------------------------------------------

    \46\ U.S. EPA, ``Primary National Ambient Air Quality Standards 
for Nitrogen Dioxide;'' Final Rule, 75 FR 6474, February 9, 2010.
---------------------------------------------------------------------------

III. Details of the Proposed Rule

    We are proposing 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).\47\ Each 
of the tiers would potentially 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.\48\
---------------------------------------------------------------------------

    \47\ The proposed standards would 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. See section IV.A.2. for more information regarding 
noncommercial applications.
    \48\ 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. A copy of this document is 
in docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    We are also proposing to apply the first tier of the two tiers of 
standards to newly-manufactured engines. 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 would need to comply with 
the same NOX limits as newly-certified engines, but at a 
later date or cease production.\49\ The end of this ``phase-in'' period 
for the newly-manufactured engine standards is sometimes referred to a 
``production cutoff,'' for obvious reasons. Again, we are proposing 
only the first of the two new tiers of NOX standards for 
newly-manufactured engines. These provisions are described in detail 
below.
---------------------------------------------------------------------------

    \49\ 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 http://www.icao.int.
---------------------------------------------------------------------------

    Five other regulatory features are being proposed in today's 
action. First, we are proposing to revise provisions addressing 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 proposed new NOX standards because of specific 
technical or economic reasons.\50\ Similarly, the proposal includes 
exception provisions for spare engines. Second, we are proposing to 
define 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 substantially from 
its existing parent engine design, and must show compliance with the 
emission standards for a newly-certificated engine. Third, we are 
proposing 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. The proposed standards would meet our 
treaty obligation under the Convention on International Civil Aviation 
as previously described in section I.B. Fourth, we are proposing 
several amendments 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 proposing amendments to 
current regulatory provisions addressing 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.
---------------------------------------------------------------------------

    \50\ These apply only to the Tier 6 NOX standards. We 
are not yet proposing a production cutoff for the Tier 8 
NOX standard.
---------------------------------------------------------------------------

    As discussed further below, with the exception of the annual 
reporting requirement described in section III.D., the proposed 
amendments reflect those changes that were previously adopted by ICAO 
or that CAEP has recommended for adoption by ICAO in the near future. 
In this latter case, we are proposing these standards and recommended 
practices at this time rather than wait until ICAO takes final action 
to help ensure that our standards, and the FAA's implementing 
regulations, are adopted in a timely manner once ICAO completes its 
process. We anticipate that our final standards would generally conform 
to ICAO's final standards, once adopted.

[[Page 45022]]

This would better enable the regulated industry to respond to new, 
globally harmonized requirements in an orderly manner, which is 
important given the international nature of the market for the aircraft 
engines that would be affected by today's proposed rule. It would also 
avoid continuing the significant lag time that has sometimes occurred 
between ICAO's adoption of international standards and our adoption of 
corresponding standards under U.S. law. To the extent ICAO adopts 
standards that differ from those recommended by CAEP before we issue 
our final rule, we would then consider whether to make conforming 
amendments in our final standards, or to issue a supplemental proposal 
reflecting the amended ICAO standards, if appropriate.
    This proposal 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 proposed 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 proposal would provide 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 proposed 
standards. Today's proposal is also consistent with U.S. treaty 
obligations under the Chicago Convention as described in section I.C., 
because the proposed requirements are consistent with current ICAO 
standards or those that we expect ICAO to adopt prior to the 
promulgation of any final rule.
    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 proposing revised exhaust emission 
standards for HC, CO, or smoke, which would remain in effect as 
currently promulgated. All engines subject to the proposed 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 proposing to include these existing HC, CO, and smoke 
standards in a new section 87.23, which would also contain the proposed 
Tier 6 and Tier 8 NOX standards, we are not actually 
proposing new standards, 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.
    We are proposing to adopt a new naming convention in this preamble 
and the regulatory text to more easily distinguish between the proposed 
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 proposed NOX 
standards, which are consistent with CAEP/6, will be referred to as 
Tier 6 in the remainder of today's notice. The second tier of proposed 
standards will be referred to as Tier 8, which is consistent with 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 upon the 
effectiveness of a final rule reflecting today's proposal 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 proposing 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.\51\ (See section III.B. for a discussion of how 
these standards would 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 a 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. Each of the 
proposed tiers is described separately below.
---------------------------------------------------------------------------

    \51\ 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.
---------------------------------------------------------------------------

1. Tier 6 NOX Standards for Newly-Certified Engines
    This first tier of proposed standards is equivalent to the CAEP/6 
NOX limits that were already adopted by ICAO and became 
internationally effective after December 31, 2007. Given that aircraft 
turbofan engines are international commodities, engine manufacturers 
have already 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, and on our 
evaluation of the necessary lead time, we are proposing that this tier 
of standards take effect immediately upon the effective date of our 
final regulations.
    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 proposed Tier 6 NOX 
standards for each of these power grouping are described separately 
below.
a. Numerical Emission Limits for Higher Thrust Engines
    The proposed Tier 6 NOX standards for newly-certified 
gas turbine engines with rated thrusts of 89 kN or more 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 corresponding CAEP/6 standards were derived by CAEP using the 
following methodology:
     Make the CAEP/6 standard 12 percent more stringent than 
the CAEP/4 requirement at a pressure ratio of 30;
     Retain the same percent reduction, i.e., 12 percent, for 
pressure ratios below 30;
     Retain the slope of the CAEP/4 standard for pressure 
ratios of 30 to 62.5 for the CAEP/6 pressure ratios of 30 to 82.6;
     Retain the slope of the CAEP/4 standard for pressure 
ratios equal to or

[[Page 45023]]

greater than 62.5 for the CAEP/6 pressure ratios at or above 82.6.\52\
---------------------------------------------------------------------------

    \52\ Reverting to the CAEP/4 slope at a pressure ratio of 82.6 
prevents the CAEP/6 standard from otherwise intersecting the older 
CAEP/2 standard at this point and thereby actually making CAEP/6 
less stringent than CAEP/2. It has no practical effect because 
current engines or anticipated engine designs do not utilize such 
high pressure ratios. Presently, there are no current engines with 
pressure ratios above approximately 42.
---------------------------------------------------------------------------

    The resulting proposed Tier 6 NOX standards for these 
higher thrust engines are presented in Figure 1 along with the most 
recently adopted existing EPA NOX standards, which were 
based on CAEP/4, for comparison.
[GRAPHIC] [TIFF OMITTED] TP27JY11.000

    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 proposed 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 proposed Tier 6 NOX standards for newly-certified 
gas turbine engines with rated thrusts between 26.7 and 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 = 46.1504 + (1.4285 * engine pressure ratio) - 
(0.5298 * kN rated thrust) + (0.00642 * engine pressure ratio * kN 
rated thrust).
    In developing the corresponding 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 
are well documented and increase progressively as size is reduced (from 
around 89 kN).\53\ For example, the relatively small combustor \54\ 
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.\55\ 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,

[[Page 45024]]

i.e., CAEP/6 relative to CAEP/4, as the rated output and physical size 
of the engines decrease. We agree with this approach.
---------------------------------------------------------------------------

    \53\ 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.
    \54\ 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.
    \55\ 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 proposed 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 proposed Tier 6 NOX standards for 
lower thrust engines based on the engine size versus technological 
challenge described in the previous paragraph.
    Comparing the proposed 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 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 proposed 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] TP27JY11.001

    At other thrust ratings the percent reduction between the proposed 
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 45025]]

[GRAPHIC] [TIFF OMITTED] TP27JY11.002

2. Tier 8 NOX Standards for Newly-Certified Engines
    The second tier of proposed 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.\56\ The CAEP/8 
recommended standards have a recommended effective 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. Therefore, we are proposing that this tier of proposed 
standards would take effect on January 1, 2014, provided ICAO adopts 
CAEP/8's recommended standards and effective date. If ICAO adopts 
different standards or a different effective date, we would evaluate 
whether to similarly adopt correspondingly different standards and 
effective dates, or seek further public comment before doing so.
---------------------------------------------------------------------------

    \56\ CAEP/7 did not adopt new aircraft engine NOX 
standards.
---------------------------------------------------------------------------

    As with the Tier 6 NOX standards, the basic form of the 
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.
a. Numerical Emission Limits for Higher Thrust Engines
    The proposed 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 corresponding CAEP/8 standards were derived by CAEP using the 
following methodology:
     Make the CAEP/8 standard 15 percent more stringent than 
the CAEP/6 requirement at a pressure ratio of 30;
     Retain the slope of the CAEP/6 standard for pressure 
ratios below 30;
     Retain the slope of the CAEP/6 standard for pressure 
ratios of 30 to 82.6 for the CAEP/8 pressure ratios of 30 to 104.7;
     Retain the slope of the CAEP/6 standard for pressure 
ratios above 82.6 for the CAEP/8 pressure ratios equal to or greater 
than 104.7.\57\
---------------------------------------------------------------------------

    \57\ Reverting to the CAEP/6 slope at a pressure ratio of 104.7 
prevents the CAEP/8 standard from otherwise intersecting the older 
CAEP/2 standard at this point and thereby actually making CAEP/8 
less stringent than CAEP/2. It has no practical value because 
current engines or anticipated engine designs do not utilize such 
high pressure ratios. Presently, there are no current engines with 
pressure ratios above approximately 42.
---------------------------------------------------------------------------

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

[[Page 45026]]

[GRAPHIC] [TIFF OMITTED] TP27JY11.003

    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 proposed 
Tier 8 standards (CAEP/8) are referred to as being 15 percent more 
stringent than the proposed 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 technology 
engines ranges from about 11 to 19 percent.
b. Numerical Emission Limits for Lower Thrust Engines
    The proposed Tier 8 NOX standards for newly-certified 
gas turbine engines with rated thrusts between 26.7 but 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 = 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 proposed 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 
proposed Tier 8 NOX standards for lower thrust engines based 
on the engine size versus technological challenge described in the 
previous paragraph. First, the proposed 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 proposed Tier 6 standards. Second, as shown below 
in Figure 5 for 89 kN engines, at this thrust rating the proposed Tier 
8 standards represents a 15 percent reduction from the proposed 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 45027]]

[GRAPHIC] [TIFF OMITTED] TP27JY11.004

    Third, at other thrust ratings the percent reduction between the 
proposed 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] TP27JY11.005

[[Page 45028]]

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

    This section describes our proposal to apply the proposed Tier 6 
NOX standards to newly-manufactured engines, and our 
proposed amended temporary flexibilities for newly-manufactured engines 
that may have significant problems complying with these requirements. 
Also, consistent with CAEP/8, we are not proposing to apply the 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 proposed Tier 6 NOX standards 
would apply to all engine types or models that receive a new type 
certificate after the effective date of the final rule. We are also 
proposing to phase-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.\58\ As a result, manufacturers would 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.\59\ 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 foundational to its basic design and 
purpose and helps to ensure that the full benefits of newer, more 
stringent requirements will be achieved in a reasonable time.\60\ We 
are, however, proposing certain limited flexibilities for engines that 
cannot be made compliant because of specific technical or economic 
reasons, as discussed later in this section.
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    \58\ 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.
    \59\ 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.
    \60\ 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.
---------------------------------------------------------------------------

    The proposed effective date of January 1, 2013 \61\ 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 62 63 64 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 2011 time frame, and (3) any noncompliant models 
will be phased out of production because of low market demand.
---------------------------------------------------------------------------

    \61\ The proposed 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 
proposed standards for newly-manufactured engines is effectively 
January 1, 2013.
    \62\ 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.
    \63\ 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.
    \64\ 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 proposed five-year phase-in period from ICAO's 
effective date of the CAEP/6 standards (corresponding to our proposed 
Tier 6 NOX standards) for newly-certified engines is 
adequate for manufacturers and their customers to respond to the new 
requirements without disrupting their future planning and purchasing 
decisions.65 66 This phase-in period for applying the Tier 6 
NOX standards to newly-manufactured engines is identical to 
the date for this same requirement that CAEP/8 has recommended to ICAO 
for adoption.\67\ Therefore, we are proposing that all engines newly-
manufactured after December 31, 2012 must comply with the Tier 6 
NOX standards. Again, if ICAO ultimately adopts a production 
cutoff date that differs from this proposed date, we would evaluate 
whether to adopt a correspondingly different date in the final rule or 
to seek further public comment on the change.
---------------------------------------------------------------------------

    \65\ The ICAO CAEP/6 NOX standards became effective 
after December 31, 2007.
    \66\ 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.
    \67\ We expect that ICAO will formally adopt the CAEP/8 
recommendations with an effective date in November 2011, which is 
well before the projected effective date of our final rule.
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2. Exemption and Exceptions From the Tier 6 Production Cutoff
    In conjunction with the implementation of the proposed Tier 6 
NOX standards, we are proposing provisions which would allow 
engine manufacturers to request an exemption exception from meeting the 
Tier 6 NOX standards for newly-manufactured engines. These 
proposed provisions would replace existing provisions addressing 
exemptions, currently promulgated in section 87.7 of our aircraft 
engine regulations. (Any exemptions previously issued under section 
87.7 would not be affected by the proposed revisions.) This section of 
the preamble describes these proposed 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. These provisions have largely been crafted to be consistent 
with exemption provisions in the ICAO Environmental Technical Manual 
(ETM).68 69 The provisions of the ETM guidance were 
developed in the context of the CAEP/6 NOX

[[Page 45029]]

production cutoff deliberations leading up to the CAEP/8 meeting in 
February 2010.
---------------------------------------------------------------------------

    \68\ 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.
    \69\ Note that EPA has submitted a paper to amend the exemption 
provisions included in this ETM to be consistent with this proposed 
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 proposing to revise 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.\70\ 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.
---------------------------------------------------------------------------

    \70\ 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.
---------------------------------------------------------------------------

    Under the existing regulations, the FAA, with EPA concurrence, may 
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.\71\ Therefore, we are 
proposing to delete these provisions to avoid confusion.
---------------------------------------------------------------------------

    \71\ 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 proposing to delete the existing provisions for 
temporary exemptions based on flights for short durations and 
infrequent intervals. These provisions are not necessary 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 
are of no utility.
    The current regulations also provide for permanent exemptions based 
on consideration of the certain factors specified in section 87.7(c). 
We are proposing to replace these provisions with new regulatory text 
consistent with the ETM that would provide for two separate types of 
permanent exemptions: Exceptions for spare engines and exemptions for 
engines on new aircraft. These are summarized below. (See Sec.  87.50 
of the proposed regulations for additional details on these 
exemptions.)
    Finally, we are deleting the time-limited exemption provisions for 
in-use engines that are contained in section 87.7(d). These provisions, 
which were intended for when the standards of sections 87.11(a), 
87.31(a), and 87.31(c) first took effect, are now obsolete.
a. New Provisions for Spare Engines
    This proposed allowance, which is an exception to the standards as 
described below, is intended to allow the production and sale of a 
newly-manufactured engine for installation on an in-service aircraft, 
i.e., a ``spare engine.'' It would 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. Also, under our proposed 
regulations, there would be no adverse environmental effect from 
allowing the use of a spare engine as a direct replacement for an 
existing engine, because a spare could be used only when the emissions 
of the spare engine are equal to or lower than those of the engine it 
is replacing, for all pollutants. Manufacturers would not be required 
to obtain FAA or EPA approval before producing spare engines. However, 
they would have to submit information about the production of spare 
engines in an annual report to the EPA. Because manufacturers would not 
be required to seek or obtain formal approval to produce spare engines, 
this allowance is being referred to as an ``exception'' rather than an 
``exemption''. This terminology would be consistent with current FAA 
regulations. 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.
    Exceptions for spare engines are 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, our proposal to apply a Tier 6 NOX production 
cutoff to all newly- manufactured engines means that if we did not also 
propose this exception process, manufacturers would be prohibited from 
producing Tier 4 spare engines under the existing type certificates. We 
see no reason to change our policy of allowing manufacturers to produce 
new engines for use as spares. The proposed regulatory provisions would 
allow this practice to continue.
    Under the proposed regulations, engines meeting the requirements 
for spare engines could be produced and enter into commerce without 
prior approval from EPA or FAA. (This allowance would also need to be 
promulgated by the FAA.) It is important to note that while spare 
engines would be excepted from the Tier 6 NOX standards 
being proposed today, they would 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 would expect little or no additional burden for 
manufacturers, since we are not proposing new restrictions, monitoring, 
recordkeeping, or reporting requirements other than the end of year 
report. When combined with the proposed prohibition against using spare 
engines to replace lower emitting engines, this program will ensure 
that using a spare engine would not increase emissions, but would at 
the same time allow the availability of spares for maintenance or 
replacement as needed.
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

[[Page 45030]]

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.'' Today's proposed amendments would replace this provision 
with a new set of provisions addressing exemptions for new engines. We 
invite public comment on any other ways to address the need for 
flexibilities in the above circumstances.
i. Time Frame and Scope
    The proposed regulations would allow manufacturers to request an 
exemption for engines not meeting the Tier 6 NOX standards 
so they may be installed in new aircraft. If granted, the exemption 
would allow manufacturers to produce a limited number of newly-
manufactured engines, in a time period beginning after December 31, 
2012 and going through December 31, 2016. The time period for any given 
approved exemption could be shorter depending on the specifics of the 
application but could not be longer. This exemption would be limited to 
NOX emissions from engines that are covered by a valid type 
certificate issued by FAA. The engines would be required to meet all 
other applicable requirements. More specifically, an engine exempted 
from the Tier 6 NOX standards would need to be covered by a 
previously issued type certificate showing compliance with the Tier 4 
NOX standards,\72\ as well as the current HC, CO, fuel 
venting, and smoke standards.
---------------------------------------------------------------------------

    \72\ Engines certified only for compliance with earlier 
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 proposed 
regulations.
---------------------------------------------------------------------------

ii. Production Limit
    In the proposed new regulatory language for exemptions, we are 
proposing to use the general exemption language for exhaust emission 
standards contained in part 87.7(c) of the current regulations. That 
language states that the Secretary of the Department of Transportation 
determines, with the EPA Administrator's concurrence, when the emission 
standards do not apply to engines based on a number of specific 
considerations such as adverse economic impact on the engine 
manufacturer, aircraft manufacturer, or airline industry; in addition 
to the effects on public health and welfare. We are also proposing to 
make this language applicable only to the Tier 6 production cutoff, 
which is consistent with the ETM guidance. No need has been identified 
to apply such exemption language to the other regulated exhaust 
pollutants, i.e., 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.\73\ 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.
---------------------------------------------------------------------------

    \73\ For example, the hydrocarbon exhaust emission standards 
were adopted on December 30, 1982. See 47 FR 58462.
---------------------------------------------------------------------------

    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 effects associated 
with the exemptions.
    We acknowledge that our proposal differs from the language 
contained in the current ICAO ETM guidance, which would nominally allow 
up to 75 engines per type certificate.\74\ To understand why we find 
that a deviation from the ETM is appropriate in this instance, the 
following explanation regarding the historical perspective on the 
development of the ETM provision is helpful.
---------------------------------------------------------------------------

    \74\ 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''.
---------------------------------------------------------------------------

    Prior to the CAEP/8 meeting in February 2010, ICAO had no specific 
provisions regarding exemptions. The only language regarding exemptions 
was contained in Annex 16 Volume II section 2.1.1 which rather 
generically stated that:

    In considering exemptions, certificating authorities should take 
into account the probable number of such engines that will be 
produced and their impact on the environment. When such an exemption 
is granted, the certificating authority should consider imposing a 
time limit on the production of such engines for installation on new 
aircraft or on existing aircraft as spares.

    When ICAO/CAEP began considering a production cut-off for the CAEP/
6 NOX standard, there was a consensus among the participants 
in the technical working group that more specific provisions were 
needed with respect to potential exemptions from that requirement.\75\ 
The provisions would help support an orderly transition in the 
implementation of the production cut-off. Toward that end, the group 
consulted periodically over several months to craft provisions 
addressing number, time limit, and emission levels (impact on the 
environment). The deliberations were complicated by the fact that the 
language in Annex 16 simultaneously addressed both engines for new 
production aircraft and spare engines for existing aircraft.\76\
---------------------------------------------------------------------------

    \75\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Report of the 6th Meeting,'' CAEP/8-WG3-WP7-03, Presented by 
the Rapporteurs, London, UK, April 1-3, 2009. A copy of this 
document is in docket number EPA-HQ-OAR-2010-0687.
    \76\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Draft Minutes of ETM/Annex 16 Ad-Hoc Group Telecon,'' May 
26, 2009. A copy of this document is in docket number EPA-HQ-OAR-
2010-0687.
---------------------------------------------------------------------------

    For new production engines, agreement was reached relatively 
quickly that exemptions should be available for up to four years after 
the production cut-off becomes effective, and that any engine model for 
which an exemption was requested should at a minimum comply with the 
emission standards for all other regulated pollutants, including the 
CAEP/4 NOX requirements. Similarly, it was readily agreed in 
the technical working group that there would be no limit on the number 
of spare engines because these units would essentially be installed in

[[Page 45031]]

place of in-use engines that are removed for maintenance or other 
reasons.\77\
---------------------------------------------------------------------------

    \77\ 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.
---------------------------------------------------------------------------

    However, discussions and deliberations were more difficult with 
regard to the number of potential exemptions for engines for new 
production aircraft. This difficulty stemmed from the fact that the 
ICAO Emissions Data Bank identified 20 unique engine models/sub models 
that could have been affected by the production cutoff. Those models 
had valid type certificates and, therefore, were considered to be ``in 
production.'' \78\ During further discussions the engine manufacturers 
clarified that most of these 20 were not in active production because 
the airlines normally purchase new aircraft with engines meeting the 
latest emission standards. Nonetheless, it was stated that if the 
demand existed, 14 of these 20 models could potentially be produced 
under the exemption provisions since they had valid type certificates 
and met the previously mentioned exemption emission 
requirements.79 80 81 82 After much deliberation, the 
technical working group settled on a value of 75 engines per type 
certificate over the four years for the ICAO ETM guidance based on the 
information available at the time.\83\
---------------------------------------------------------------------------

    \78\ U.S. EPA, ``Simplified Working Copy of ICAO EDB, Issue 
16A,'' memorandum from Glenn Passavant, Assessment and Standards 
Division, Office of Air Quality and Transportation, March 25, 2010. 
A copy of this document is in docket number EPA-HQ-OAR-2010-0687.
    \79\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Response to EPA Paper 14 and 16,'' WG-3 Flimsy 6-2, ICCAIA, 
London, UK, April 13, 2009. A copy of this document is in docket 
number EPA-HQ-OAR-2010-0687.
    \80\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Production Cut-Off for Engine NOX Standards,'' 
CAEP-SG/20082-WP/6, Presented by FESG, September 4, 2008. A copy of 
this document is in docket number EPA-HQ-OAR-2010-0687.
    \81\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), CAEP/6 NOX Productin Cut-Off Analysis,'' CAEP-SB/
20093-IP/19, Presented by FESG NOX Stringency Task Group, 
June 2, 2009. A copy of this document is in docket number EPA-HQ-
OAR-2010-0687.
    \82\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Production Cut-Off and Associated Flexibilities for ICAO 
Engine Emission Standards,'' CAEP-SG/20093-WP/39, U.S. EPA, June 8, 
2009. A copy of this document is in docket number EPA-HQ-OAR-2010-
0687.
    \83\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Report of the Eighth Meeting, Montreal, February 1-12, 
2010,'' CAEP/8-WP-80, Appendix B. A copy of this document is in 
docket number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    This value and the maximum number of engines it could represent 
were of immediate concern to EPA. First, in a hypothetical worst case, 
it represented the potential for over 1000 exempt engines (500 
aircraft) to enter the fleet over this time period based on the 
information above. Assuming two engines per aircraft, this is 
essentially equivalent to the number of civil aircraft shipped in a 
single year.\84\ Second, it was unclear to us if that number of 
potential exemptions, i.e., 75 per type certificate, was necessary. 
Third, from a broader perspective, while EPA regulations normally 
include hardship type provisions, it is not normal for EPA to include 
specific transitional exemptions of this magnitude in our regulations.
---------------------------------------------------------------------------

    \84\ See Table 5 of the most recent AIA statistical report 
available at http://www.aia-aerospace.org/assets/Table 5.pdf.
---------------------------------------------------------------------------

    As we continued efforts to identify how many exemptions might 
potentially be needed for the CAEP/6 production cutoff, three new 
pieces of information became available during the development of this 
proposed rule that were not considered during the deliberations leading 
up to the ICAO decision for the ETM guidance. First, a review of 
previously unavailable information on past exemption requests to FAA 
under the previous less specific ICAO language indicated that of the 
eight requests were granted since 1983, only three involved exemptions 
during standards transition (two related to smoke for turboprop engines 
and one related to NOX for a turbofan engine). These three 
exemption petitions in combination ultimately affected less than 50 
engines.\85\ Second, engine manufacturers indicated individually that 
the potential need for exemptions was not as large as EPA understood 
during the technical working group deliberations, and that absent 
unforeseen events, a much smaller value was workable on a per 
manufacturer basis as opposed to a per type certificate 
basis.86 87 88 Third, our most recent discussions with the 
engine manufacturers that are directly affected by the proposed Tier 6 
NOX standards, i.e., CAEP/6 standards, concluded that only 
one or two engine models may be candidates for exemptions. Those 
discussions also concluded that the likely potential number of 
justifiable exemptions would be less than 75 in total.\89\ Considering 
all of these factors and the basic intent of the CAEP ETM exemption 
provisions, we are proposing to adopt in our new regulatory text 
addressing exemptions, language that reflects the essence of the 
general exemption language for exhaust emission standards that is 
embodied in current section 87.7(c) of the regulations. That provision 
generally states 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. We are also proposing include in this new 
regulatory provision the key elements of the current 87.7(c) and 
additional facets of the ETM language not captured in existing 87.7(c). 
Like the ETM, we are proposing to apply this provision only to the Tier 
6 production cutoff for four years, but importantly we are not 
proposing a specific basis for the exemption, i.e., type certification 
or type certificate holder, or numerical limit. We believe the proposed 
approach addresses the intent of the ICAO guidance in addition to the 
potential needs of the engine manufacturers, while minimizing the 
potential for adverse environmental impacts from exemptions and 
aligning with EPA's general approach with regard to exemptions and 
hardship provisions.
---------------------------------------------------------------------------

    \85\ U.S. EPA, ``Historical Exemptions from Gas Turbine Aircraft 
Emission Standards,'' memorandum from Glenn Passavant, Assessment 
and Standards Division, Office of Air Quality and Transportation, 
March 28, 2011. A copy of this document is in docket number EPA-HQ-
OAR-2010-0687.
    \86\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Response to EPA Paper 14 and 16,'' WG-3 Flimsy 6-2, ICCAIA, 
London, UK, April 13, 2009. A copy of this document is in docket 
number EPA-HQ-OAR-2010-0687.
    \87\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Production Cut-Off for Engine NOX Standards,'' 
CAEP-SG/20082-WP/6, Presented by FESG, September 4, 2008. A copy of 
this document is in docket number EPA-HQ-OAR-2010-0687.
    \88\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), CAEP/6 NOX Production Cut-Off Analysis,'' CAEP-
SB/20093-IP/19, Presented by FESG NOX Stringency Task 
Group, June 2, 2009. A copy of this document is in docket number 
EPA-HQ-OAR-2010-0687.
    \89\ U.S. EPA, ``Results of Discussions with Aviation Gas 
Turbine Manufactures on the Potential Number of Exemptions from the 
Tier 6 Production Cutoff for the Proposed Rulemaking on Aircraft 
Engine Emission Standards,'' memorandum from Richard S. Wilcox, 
Assessment and Standards Division, Office of Air Quality and 
Transportation, May 19, 2011. A copy of this document is in docket 
number EPA-HQ-OAR-2010-0687.
---------------------------------------------------------------------------

    We acknowledge that our proposal in this respect differs from the 
ETM guidance and that this, on its face, may be of concern to some. To 
the extent this may occur, we point out that the ETM is guidance 
material; not an ICAO standard or regulation of any type. So as a 
general matter, consistency is not compelled when a deviation is 
justified, and we are comfortable with our proposed exemption provision 
for those reasons.

[[Page 45032]]

    Even if the ETM guidance were wrongly considered an ICAO standard 
of some kind, a justified deviation from such a provision is allowable 
under the Chicago Convention (the basis of ICAO) and the World Trade 
Organization's (WTO) Technical Barriers to Trade Agreement, Annex 
3.90, 91 The Chicago Convention allows nations to adopt 
their own unique standards that differ from the language in ICAO Annex 
16, Standards and Recommended Practices, as previously described in 
section I.C. The WTO Annex 3 also allows for exceptions `` * * * where 
such international standards or relevant parts would be ineffective or 
inappropriate, for instance, because of an insufficient level of 
protection * * *.'' We believe our proposed deviation from the ETM, 
assuming for argument's sake that it is a deviation from international 
standards as contemplated by ICAO and the WTO Annex 3, is justified for 
the reasons explained above.
---------------------------------------------------------------------------

    \90\ ICAO, ``Convention on International Civil Aviation,'' 
Article 38, Ninth Edition, Document 7300/9, 2006. Copies of this 
document can be obtained from the ICAO Web site located at http://www.icao.int/icaonet/arch/doc/7300/7300_9ed.pdf.
    \91\ WTO, ``Agreement on Technical Barriers to Trade,'' Uruguay 
Round of Multilateral Trade Negotiations, April 15, 1994, pp. 117-
137. Copies of this document can be obtained from the WTO Web site 
located at http://www.wto.org/english/docs_e/legal_e/17-tbt_e.htm.
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    We also note that the proposed exemption provision has no cost 
associated with it for the government or industry, and there is no 
difference in potential cost savings under either approach. Both are 
designed to provide manufacturers with an opportunity to reduce costs 
or other adverse effects should the need for exemptions arise.
    Finally, we believe the current ETM guidance provision should be 
revised to align with our proposed approach, and we will work through 
the ICAO/CAEP process to amend the ETM guidance as appropriate.
iii. Exemption Requests
    We are proposing a process for requesting exemptions (for engines 
used on new aircraft) that would be more formal and structured than the 
current process. We are proposing that manufacturers be required to 
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 would need to 
include the following details to describe the specific engine model for 
which the manufacturer is requesting the exemption. The proposed 
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 proposed 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 the manufacturer justifications would need 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 would need 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 proposed regulations 
would apply only for 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.
    In the past, some manufacturers have requested exemptions based on 
the largest number of engines they hoped to continue producing 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. At any time before approval, manufacturers 
could revise their requests to justify covering additional engines. We 
would then review the revised request. For exemptions that have already 
been approved, manufacturers could also request that additional engines 
be added after providing the justification for the increase. 
Manufacturers also would be 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.
    While we expect a manufacturer to have this specific information 
when they submit a request, the regulations would allow us to process 
exemption requests with somewhat less specific information. However, we 
would expect this to apply only for unusual circumstances.
    If, after consulting with FAA, we determine that the exemption 
request is fully documented and approval would be in the public 
interest, we would concur with approving the request if the FAA also 
concluded that the request should be granted. Note that we could 
approve the exemption for a smaller number of engines than the 
manufacturer requested, or we could include certain other conditions.
    In order to allow us to oversee these exempted engines, 
manufacturers would

[[Page 45033]]

also be required to provide an annual report to EPA on exempt engines 
similar to the information about spare exempt engines. The permanent 
record for each engine exempted under this provision would need to 
indicate that the engine is an exempted engine and the engine itself 
would need to be labeled as ``EXEMPT NEW'' in accordance with FAA 
marking requirements of 14 CFR.
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 collaboration and consultation among 
certificating authorities and member states whenever any authority 
receives an exemption request. Specifically, the ETM states:

    Exemptions for new engines should be processed and approved by 
the competent authorities for both the manufacture of the exempted 
engines and the initial operator of the aircraft to which they are 
to be fitted. Given the international nature of the aviation 
enterprise, civil aviation authorities of member states should 
attempt to collaborate and consult on the details of exemptions. In 
the case where engine type certification is done through a 
reciprocity agreement between or among member states, the states 
involved should coordinate on the processing of exemptions and 
concur before approval is granted.\92\
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    \92\ ICAO, ``Committee on Aviation Environmental Protection 
(CAEP), Eighth Meeting, Montreal, 1 to 12 February 2010,'' CAEP/8-
WP/80, Agenda Item 2: Review of Technical Proposals Relating to 
Aircraft Emissions, April 2, 2010. A copy of this document is in 
docket number EPA-HQ-OAR-2010-0687.

    Working with the FAA, we would expect to conduct such collaboration 
and consultation among the competent authorities whenever we receive an 
exemption request. This would include consultation with other 
certificating authorities as well as coordination with the competent 
civil aviation authority of any country where the aircraft with the 
exempted engines will be registered.
    To facilitate this consultation and coordination we are proposing 
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 collaboration, 
consultation and coordination called for in the ETM were 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. Nevertheless, because our proposed 
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.
    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 a type certificate is sought under a 
reciprocity agreement 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.
c. Voluntary Emission Offsets
    We are requesting 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 is summarized in a 
memorandum to the docket,\93\ and a basic overview of how credits might 
be generated is presented in the following paragraph. The types of 
programs being considered would be developed, promulgated, and 
administered solely by EPA.
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    \93\ 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.
---------------------------------------------------------------------------

    We would expect 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. For 
example, where we determine that an exemption would not be in the 
public interest because it would have an undue adverse effect on air 
quality, a manufacturer might use offsets so that the combination of 
the exemption and offsets would be more emission neutral. 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. We are asking 
for comment on this option, and could include it in the final rule 
based on the comments and our assessment of the inputs and issues. 
Third, provided a standard is 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. 
This would also require a change to the proposed regulations, as well 
as record support for such banking being appropriate under the relevant 
standard.
    Under this approach, generation of offsets would be voluntary and 
would be open to all certifying engine manufacturers. One concept would 
be 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). It is a separate question, however, how to calculate 
the credit. If we adopted 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. For example, an engine that was 15 percent below the standard 
would generate credits equivalent to 5 percent of the standard. This 
would ensure a net improvement in emissions. If we were to finalize 
such a program, 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

[[Page 45034]]

emission benefits from one aircraft model truly offset the higher 
emissions from another model. For example, emissions from regional 
aircraft may not be directly equivalent to emissions from aircraft 
designed for longer cross-country or international flights. Equivalency 
factors could be developed to account for differences in the number of 
LTOs per year, the lifetime of the aircraft, and the number of LTOs per 
mile. These factors could be developed based on the operation 
characteristics from existing sources of information and would not 
require the collection new operational data. Commenters are encouraged 
to review additional information contained in the memorandum to the 
public docket and provide input on the ideas, concepts, and options 
presented therein in addition to those discussed above.
3. Potential Phase-In of New Tier 8 NOX Standards for Newly-
Manufactured Engines
    We are not proposing to phase-in the proposed Tier 8 NOX 
standards for newly-manufactured engines at this time, since such a 
feature is not included in the CAEP/8 recommendation to ICAO. This 
means that engine manufacturers may continue to produce Tier 6 
compliant engines within already certified models after the proposed 
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 turbine 
engines. At the February 2010 meeting of CAEP, where the CAEP/8 
NOX standards were approved for recommendation to ICAO, the 
committee decided to continue considering a related newly-manufactured 
engine standard as a future work item at CAEP, pending new information 
on technology and market responses.
    We will continue our efforts to evaluate a newly-manufactured 
engine standard as a complement to the Tier 8 NOX standards 
as part of the future CAEP work programs. We believe that such a 
requirement is a necessary component of any effective NOX 
control strategy for aircraft turbine engines. It provides an orderly, 
stable transition between emission requirements that is helpful for 
product planning by engine and airframe manufacturers, and in making 
purchasing decisions by their customers. It also ensures compliance 
with any new emission standard in a reasonable period of time, thereby 
providing the public with all the environmental benefits that a new 
emission standard can provide. However, in order to maximize 
consistency with the CAEP/8 NOX standard as currently 
recommended to ICAO, our proposed Tier 8 standard does not contain a 
production cutoff.
    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 as 
part of future CAEP deliberations and 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 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 newer 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, that leaves open 
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 approved 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 proposing to include the ETM language in our regulations. 
This addresses a 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. Finally, it will 
make the decision criteria enforceable. To ensure that the numerical 
decision criteria can be administered to allow for the consideration of 
unusual circumstances or special information, we are also proposing 
that the FAA have 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 the proposed part 
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 will apply to 
modified engine models 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 regulations specify that to show emissions 
equivalency, the engine manufacturer must demonstrate 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.
    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.

[[Page 45035]]

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.\94\ 
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) \95\ 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.
---------------------------------------------------------------------------

    \94\ 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.
    \95\ United Kingdom, Civil Aviation Authority, ``ICAO Emissions 
Databank.'' Available at the Civil Aviation Authority Web site 
http://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.\96\ 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 EBD 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.\97\ 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 discharge our functions under the Act. (See 42 U.S.C. 
7414(a)(1).)
---------------------------------------------------------------------------

    \96\ Under the proposed regulations, a grouping of engines with 
an essentially identical emission-related design would be defined to 
be an ``engine sub-model''. Engines with slightly different designs 
would be defined to be an ``engine model''.
    \97\ The FAA already requires much of the information EPA is 
seeking through the certification process, but is unable to share it 
because of confidentiality agreements with engine manufacturers. 
Also, that information is part of a much larger submission, making 
it difficult to extract the specific reporting elements for EPA.
---------------------------------------------------------------------------

    Therefore, we are proposing to require that any engine manufacturer 
submit a production report directly to EPA \98\ 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 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 are also proposing 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.
---------------------------------------------------------------------------

    \98\ The proposed report would be submitted only to EPA. No 
separate submission or communication of any kind is required for the 
FAA.
---------------------------------------------------------------------------

    We are proposing to have each affected engine manufacturer report a 
reduced number of specific data elements to us as compared to those 
already reported voluntarily and periodically by most engine 
manufacturers to the EDB. We feel that this minimizes the reporting 
burden for each manufacturer while still providing us with sufficient 
information to perform our job. All of the specific reporting items we 
are proposing are 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.
    This information will be used in conjunction with the 
NOX and CO2 emission data already required to be 
submitted to us under part 87.64 for purposes of greenhouse gas (GHG) 
reporting to establish our own independent engine exhaust emissions 
database. We would expect most manufacturers generally to add the 
proposed information items to the annual GHG report. We want to 
clarify, however, that comments are invited only on the proposed 
incremental data reporting elements that comprise the production 
report. No changes are being proposed to the contents of the GHG 
report.
    The proposed incremental reporting elements for each affected gas 
turbine engine sub-model are listed below. The reporting elements of 
the existing GHG report are also identified for completeness.
     Company corporate name as listed on the engine type 
certificate (GHG);
     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, or if zero, state that the engine 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

[[Page 45036]]

intended for use as certified (non-exempt) spare engines on in-use 
aircraft;
     Reference pressure ratio (GHG);
     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; \99\
---------------------------------------------------------------------------

    \99\ See Regulation Part 87-Control of Air Pollution from 
Aircraft and Aircraft Engines, Subpart E, Sec.  87.42 Certification 
report to EPA for definitions.
---------------------------------------------------------------------------

     Unburned hydrocarbon (HC) characteristic level (i.e. mass 
of hydrocarbons over LTO cycle/Rated Thrust (Dp/Foo)); \100\
---------------------------------------------------------------------------

    \100\ Dp/Foo: total gross emissions of each gaseous pollutant 
(mass)/rated thrust (g/kN).
---------------------------------------------------------------------------

     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);
     Carbon monoxide (CO) characteristic level (i.e. mass of CO 
over LTO cycle/Rated Thrust (Dp/Foo));
     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);
     Nitrogen oxides (NOX) characteristic level 
(i.e. mass of NOX over LTO cycle/Rated Thrust (Dp/Foo)) 
(GHG);
     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);
     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));
     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); and
     Any additional remarks to the EPA.
    The proposed annual report would be submitted for each calendar 
year in which a manufacturer produces any turbofan engine subject to 
emission standards as previously described. These reports would be due 
by February 28 of each year, starting with the 2014 calendar year, and 
cover the previous calendar year. This report would 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 proposed reports to help inform any further public policy 
approaches regarding aircraft engine emissions that we consider, 
including possible future emissions standards, as well as help provide 
transparency to the general public. 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 would be updated 
annually. By collecting and publically posting this information on 
EPA's Web site, we will be able to calculate turbine exhaust emission 
rates and demonstrate to the public how the fleet meets the current 
emission requirements. We believe that this information will also be 
useful to the general public to help inform public knowledge regarding 
aircraft exhaust emissions. We ask for comment on our proposed plan to 
post this information on our Web site and whether any of it should be 
omitted as confidential business information. Such confidential 
information would be retained by EPA. For guidance on how to preserve a 
claim of confidentiality and on how EPA would treat submitted 
information covered by such a claim, please see our earlier discussion 
in section VII. of this notice regarding how a public commenter on the 
proposed rule should submit information that the submitter considers to 
be confidential business information. We have assessed the potential 
reporting burden associated with the proposed annual reporting 
requirement. That assessment is presented in sections V. and IX.B. of 
this notice.

E. Proposed Standards for Supersonic Aircraft Turbine Engines

    We are proposing 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 proposed 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. (See section III.G. for 
a brief discussion of potential revised emission standards for future 
engine designs that may be used on supersonic aircraft.) 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 propose these conforming standards. 
Therefore, the proposed standard simply aligns EPA standards with the 
rest of the world.

F. Amendments to Test and Measurement Procedures

    We are proposing to incorporate 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. These amendments to Annex 16, Volume II are mainly 
intended to ensure that the provisions reflect current certification 
practices. The amendments make clarifications or add flexibilities for 
engine manufacturers. They are described separately below for the 
amendments that have already been adopted by ICAO 101 102 
and those that have been recommended by CAEP for adoption by ICAO.\103\
---------------------------------------------------------------------------

    \101\ 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.
    \102\ 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.
    \103\ 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.
---------------------------------------------------------------------------

    The amendments that have already been adopted by ICAO are:
     Standardizing of the terminology relating to engine 
thrust/power;

[[Page 45037]]

     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; and
     Clarifying the appropriate value of fuel flow to be used 
at each LTO test point.
    The amendments that have been recommended for adoption by ICAO are:
     Clarifying exhaust nozzle terminology for exhaust 
emissions sampling; and
     Allowing an equivalent procedure for gaseous emission and 
smoke measurement if approved by the certificating authority.
    The test procedure amendments that ICAO has already adopted became 
applicable on November 20, 2008. The amendments that have been 
recommended to ICAO are expected to be adopted prior to the date of the 
final action on today's proposed rule. 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 are already undertaking to meet ICAO's adopted and recommended 
amendments.

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 kNs, 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.\104\ 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.
---------------------------------------------------------------------------

    \104\ 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.
---------------------------------------------------------------------------

    We request comments on the status and timing of open rotor and 
future engine designs for supersonic aircraft, and how the aircraft 
engine emission standards and test procedures may need to be modified 
to accommodate these types of engines.

IV. Description of Other Revisions to the Regulatory Text

    In addition to the proposed changes discussed above, we are 
proposing 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 the proposed rule relates to engines 
used in military and noncommercial civilian aircraft. We do not believe 
the proposed changes would 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 our proposal to have any impact on engines 
installed on military aircraft. 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 proposed new standards and 
requirements would continue to apply only to engines for which standard 
airworthiness certificates are issued, and 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, we 
are proposing to include a statement in the regulations to clarify that 
the proposed production

[[Page 45038]]

cutoff would not apply for previously certificated engines that are 
installed and used in military aircraft.
2. Noncommercial Engines
    The current section 87.21(d) specifies that gaseous emission 
standards apply 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, engines of equivalent thrust ratings that are 
used in aircraft certificated by the FAA that are used in non-revenue, 
general aviation service are not required to comply with our current 
HC, CO, and NOX exhaust emission standards in Sec.  
87.21(d). They are subject, however, to the current standards for smoke 
and fuel venting.
    We are proposing to apply the proposed 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 proposed action. First, the ICAO Annex 
16 standards and recommended practices apply equally to commercial and 
noncommercial engines, and our rules' current failure to reflect this 
means that our requirements do 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 proposal simply incorporates the status quo.
    In order to make EPA standards conform to ICAO's, we need 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.) Today, we are proposing 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.
    These noncommercial and commercial engines have a great deal in 
common. First, they each use the same thermodynamic engine cycle (i.e., 
a gas (air) compressor, fuel combustor, and expansion turbine), engine 
design, and technology. That means they emit the same pollutants, i.e., 
HC, CO, and NOX. Second, they are each used in the same 
manner, i.e., landing and takeoff operations from airports in the U.S., 
including commercial airports in ozone and CO nonattainment areas. That 
means their emissions are geographically, spatially, and temporally 
similar, and that they collectively contribute to ozone and CO air 
pollution in nonattainment areas and are projected to continue to do 
so. Third, noncommercial engines are usually the same engine model and 
sometimes sub-model as engines used in commercial operations, which 
makes distinguishing between commercial and noncommercial engines 
somewhat artificial. These attributes, taken together, demonstrate that 
engines used in noncommercial service have the same effect on the 
environment as their commercial counterparts. Therefore, the 
Administrator is proposing to find that commercial and noncommercial 
applications for turbofan and turbojet engines with rated thrusts 
greater than 26.7 kN collectively cause or contribute to the same air 
pollution as their commercial counterparts. Our emissions assessment 
supporting this conclusion is contained in the docket for this proposed 
rulemaking.\105\
---------------------------------------------------------------------------

    \105\ U.S. EPA, ``Proposed Finding for Commercial and 
Noncommercial Turbofan and Turbojet Aircraft Emissions,'' memorandum 
from John Mueller, Assessment and Standards Division, Office of 
Transportation and Air Quality, May 2011. 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 
proposing changes to 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 proposed changes to 
part 87 are not intended to significantly change the certification and 
compliance program. We are not reopening for comment the substance of 
any part of the program that remains unchanged substantively. 
Specifically, for those instances where we propose to move a provision 
to a different section or reword a provision in clearer language, we do 
not consider those changes to be substantive. It is also important to 
note that the changes to the regulation apply starting with the date 
that the final rule takes effect.
    In particular, it is worth emphasizing that while we are restating 
the HC, CO, and smoke standards, as they would apply to Tier 6 and 
later NOX standard-subject engines, in a new part 87.23, we 
are not proposing them as new standards or otherwise reopening them for 
comment. The HC, CO, and smoke standards in the proposed part 87.23 are 
identical to the existing standards of part 87.21 and are being copied 
into the new section merely for clarity to readers.
    The proposed 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 craft 
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 proposed 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

[[Page 45039]]

exempted engines because they are certified to prior-tier standards.
    ICAO Annex 16 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. 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, without requesting comment on those definitions:
     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 
proposed regulations would 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 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. 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 proposed definitions are intended to 
reflect the plain meaning of these terms.
    The proposed 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             These terms will no
                                 definitions for    longer be used in
                                 ``emission         part 87. There will
                                 measurement        be no more engines
                                 system'',          certified to the
                                 ``power            standards specified
                                 setting'',         in Sec.   87.21, so
                                 ``sample           removing these
                                 system'',          definitions will not
                                 ``shaft power'',   change the
                                 ``taxi/idle        requirements for
                                 (in)'', and        engines certified to
                                 ``taxi/idle        the Tier 4 or
                                 (out)''.           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
                                 defining ``new     turboprop engines
                                 aircraft turbine   and new engines used
                                 engine''.          for 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.

[[Page 45040]]

 
87.1..........................  Revise the         The editorial changes
                                 definition of      do not involve any
                                 ``standard day     substantive change
                                 condition'': (1)   in 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
                                 the list of        not involve a change
                                 acronyms in Sec.   in emission
                                   87.2 and add     standards or
                                 it to the set of   implementation.
                                 defined terms in
                                 Sec.   87.1.
87.3..........................  Add provisions     The broad statement
                                 describing the     in Sec.   87.3 is
                                 scope of           not intended to
                                 applicability of   conflict with the
                                 part 87.           applicability
                                                    statements in
                                                    individual subparts,
                                                    since those
                                                    additional
                                                    statements indicate
                                                    that certain
                                                    requirements in part
                                                    87 apply more
                                                    narrowly. All
                                                    applicability
                                                    statements in the
                                                    proposed rule are
                                                    intended to be
                                                    consistent with
                                                    current policy.
87.3..........................  Remove the         This change more
                                 provision          carefully tracks the
                                 related to         statutory provisions
                                 preemption of      related to
                                 state standards    preemption.
                                 for exempted
                                 aircraft and
                                 replace it with
                                 the preemption
                                 provision in the
                                 Clean Air Act.
87.5..........................  Move the           This provision, and
                                 provisions         the similar
                                 related to         provision from Sec.
                                 special test        87.3(a), should be
                                 procedures to      described together
                                 Sec.   87.60.      in the context of
                                                    the 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
                                 (f) to correctly   strictly editorial.
                                 reference the
                                 regulatory
                                 sections that
                                 describe the
                                 applicable test
                                 procedures.
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             87.21, so any
                                 procedures         changes to the test
                                 specified in       procedures will not
                                 ICAO Annex 16.     change the
                                 This includes a    requirements for
                                 variety of         engines certified to
                                 recent changes     the Tier 4 or
                                 to the Annex 16    earlier standards.
                                 procedures.        Moreover, 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 proposed 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 ``aircraft''.  This definition would revert to the
                                    normal FAA definition of aircraft,
                                    rather than the much narrower
                                    current definition in part 87. To
                                    understand this change, the
                                    proposed definition needs to be
                                    considered along with the proposed
                                    changes to applicability in
                                    87.3(a).
87.1, Definition of ``date of      This is generally the same
 manufacture''.                     definition as 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 ``derivative   It is important to consider this
 engine for emissions               definition in combination with the
 certification purposes''.          definition of ``engine type
                                    certificate family''.
87.1 Definition of ``engine        A manufacturer or FAA may further
 model''.                           divide 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 ``military     In Sec.   87.23(d) we clarify that
 aircraft'' and 87.23(d).           the production cutoff does not
                                    apply for military aircraft
                                    engines (even if they have been
                                    certificated). In Sec.   87.1, we
                                    define military aircraft to 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.
87.1, Definition of ``production   The production cutoff date for the
 cutoff date''.                     Tier 6 NOX standards is December
                                    31, 2012.
87.1, Definition of ``spare        Newly manufactured spare engines
 engine''.                          may be 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.

[[Page 45041]]

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

V. Technical Feasibility, Cost Impacts, Emission Benefits

    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.106 107 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 
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 will limit our discussion below of applying these 
technology levels to engines that need to comply with the CAEP/8 
NOX standard.
---------------------------------------------------------------------------

    \106\ 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.
    \107\ 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 than 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.
    Regarding the costs of this specific proposal, 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 
proposed here. Also, the proposed 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 a final rule. Therefore, EPA believes that today's 
proposed 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 proposed annual reporting requirement for emission 
related information. (See section III.D. for a description of the 
proposed 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). We expect the incremental 
reporting burden for these

[[Page 45042]]

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 proposing to require should be readily available, and these 
manufacturers have a very limited number of engine models.
    We have estimated the annual burden and cost to be 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.
    Turning to emission benefits, CAEP's assessments indicated that the 
CAEP/8 NOX standards would provide global NOX 
reductions, which would translate to emission reductions in the U.S. 
The global LTO NOX reductions were estimated to be about 5.5 
percent in 2026 and 7 percent in 2036 relative to the baseline.\108\ 
According to an analysis conducted for comparable percent 
NOX reductions in the U.S., it was estimated that this would 
translate to LTO NOX reductions in the U.S. of about 5,200 
tons in 2020 and 8,700 tons in 2030,\109\ and the cumulative LTO 
NOX reductions from 2014 to 2030 (2014 is the implementation 
date of the CAEP/8 NOX standards) were projected to be about 
100,000 NOX tons.
---------------------------------------------------------------------------

    \108\ CAEP Rapporteurs of Modeling Task Force and Forecasting 
and Economic Analysis Support Group, Environmental and Economic 
Assessment of the NOX Stringency Scenarios, CAEP/8-WP/15, 
December 2, 2009.
    \109\ ``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.
---------------------------------------------------------------------------

VI. Coordination With FAA

    The requirements contained in this action are being proposed after 
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 under section 
231.\110\ 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.
---------------------------------------------------------------------------

    \110\ 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.\111\ 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 
subsequently recommended to ICAO for adoption.
---------------------------------------------------------------------------

    \111\ 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.

VII. Public Participation

    We request comment on this proposal, however, we are not reopening 
for comment the substance of any part of the program that remains 
substantially unchanged as described in section IV.B. The remainder of 
this section describes how you can participate in this process.

How do I submit comments?

    We are opening a formal comment period by publishing this document. 
We will accept comments during the period indicated in the DATES 
section at the beginning of this document. If you have an interest in 
the proposed emission control program described in this document, we 
encourage you to comment on any aspect of this rulemaking.
    Your comments will be most useful if you include appropriate and 
detailed supporting rationale, data, and analysis. Commenters are 
especially encouraged to provide specific suggestions for any changes 
to any aspect of the regulations that they believe need to be modified 
or improved. You should send all comments, except those containing 
proprietary information, to our Air Docket (see ADDRESSES located at 
the beginning of this document) before the end of the comment period.
    You may submit comments electronically, by mail, or through hand 
delivery/courier. To ensure proper receipt by EPA, identify the 
appropriate docket identification number in the subject line on the 
first page of your comment. Please ensure that your comments are 
submitted within the specified comment period. Comments received after 
the close of the comment period will be marked ``late.'' EPA is not 
required to consider these late comments. If you wish to submit 
Confidential Business Information (CBI) or information that is 
otherwise protected by statute, please follow the instructions in 
section VIII.B.

How should I submit CBI to the agency?

    Do not submit information that you consider to be CBI 
electronically through the electronic public docket, http://www.regulations.gov, or by e-mail. Send or deliver information 
identified as CBI only to the following address: U.S. Environmental 
Protection Agency, Assessment and Standards Division, 2000 Traverwood 
Drive, Ann Arbor, MI 48105, Attention Docket ID EPA-HQ-OAR-2010-0687. 
You may claim information that you submit to EPA as CBI by marking any 
part or all of that information as CBI (if you submit CBI on disk or CD 
ROM, mark the outside of the disk or CD ROM as CBI

[[Page 45043]]

and then identify electronically within the disk or CD ROM the specific 
information that is CBI). Information so marked will not be disclosed 
except in accordance with procedures set forth in 40 CFR part 2.
    In addition to one complete version of the comment that includes 
any information claimed as CBI, a copy of the comment that does not 
contain the information claimed as CBI must be submitted for inclusion 
in the public docket. If you submit the copy that does not contain CBI 
on disk or CD ROM, mark the outside of the disk or CD ROM clearly that 
it does not contain CBI. Information not marked as CBI will be included 
in the public docket without prior notice. If you have any questions 
about CBI or the procedures for claiming CBI, please consult the person 
identified in the FOR FURTHER INFORMATION CONTACT section at the 
beginning of this document.

Will there be a public hearing?

    We will hold a public hearing on August 11, 2011. The hearing will 
start at 9:30 am local time and continue until everyone has had a 
chance to speak.
    If you would like to present testimony at the public hearing, we 
ask that you notify the contact person listed under FOR FURTHER 
INFORMATION CONTACT at least ten days before the hearing. You should 
estimate the time you will need for your presentation and identify any 
needed audio/visual equipment. We suggest that you bring copies of your 
statement or other material for the EPA panel and the audience. It 
would also be helpful if you send us a copy of your statement or other 
materials before the hearing.
    We will make a tentative schedule for the order of testimony based 
on the notifications we receive. This schedule will be available on the 
morning of the hearing. In addition, we will reserve a block of time 
for anyone else in the audience who wants to give testimony.
    We will conduct the hearing informally, and technical rules of 
evidence won't apply. We will arrange for a written transcript of the 
hearing and keep the official record of the hearing open for 30 days to 
allow you to submit supplementary information. You may make 
arrangements for copies of the transcript directly with the court 
reporter.

Comment Period

    The comment period for this rule will end on September 26, 2011.

What should I consider as I prepare my comments for EPA?

    You may find the following suggestions helpful for preparing your 
comments:
    Explain your views as clearly as possible.
    Describe any assumptions that you used.
    Provide any technical information and/or data you used that support 
your views.
    If you estimate potential burden or costs, explain how you arrived 
at your estimate.
    Provide specific examples to illustrate your concerns.
    Offer alternatives.
    Make sure to submit your comments by the comment period deadline 
identified.
    To ensure proper receipt by EPA, identify the appropriate docket 
identification number in the subject line on the first page of your 
response. It would also be helpful if you provided the name, date, and 
Federal Register citation related to your comments.

VIII. 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. 7414, 7571-7574 and 7601(a). See section II. of today's rule for 
discussion of how EPA meets the CAA's statutory requirements.

IX. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), 
this action is a ``significant regulatory action.'' This action 
proposes the adoption of 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 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 proposed regulations that conform with 
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 proposed here. Therefore, EPA 
believes that today's proposed 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 proposed 
reporting requirements, as discussed in section IX.B.

B. Paperwork Reduction Act

    The information collection requirements in this proposed 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 Request (ICR) document prepared by EPA has been 
assigned EPA ICR Number 2427.01.
    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. We are, 
therefore, proposing to require that engine manufacturers send this 
information to EPA on an annual basis. We also propose to require 
manufacturers to send us their annual production volumes, which is the 
only item 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 would expect most 
manufacturers generally to add the proposed information items to the 
annual report they are already required to submit with information 
about NOX

[[Page 45044]]

and CO2 emission levels. See section III.D. for a more 
complete description of the proposed annual reporting requirement.
    We have estimated the total annual burden of the proposed 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. To comment on the Agency's need for this information, 
the accuracy of the provided burden estimates, and any suggested 
methods for minimizing respondent burden, EPA has established a public 
docket for this rule, which includes this ICR, under Docket ID EPA-HQ-
OAR-2010-0687. Submit any comments related to the ICR to EPA and OMB. 
See the ADDRESSES section at the beginning of this notice for where to 
submit comments to EPA. Send comments to OMB at the Office of 
Information and Regulatory Affairs, Office of Management and Budget, 
725 17th Street, NW., Washington, DC 20503, Attention: Desk Office for 
EPA. Since OMB is required to make a decision concerning the ICR 
between 30 and 60 days after July 27, 2011, a comment to OMB is best 
assured of having its full effect if OMB receives it by August 26, 
2011. The final rule will respond to any OMB or public comments on the 
information collection requirements contained in this proposal.

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
----------------------------------------------------------------------------------------------------------------
                                                      NAICS \a\
                     Industry                           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 proposed 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 proposed 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 
impacted by the proposed regulations. An analysis of the impacts of the 
proposed rule on small businesses has been prepared and placed in the 
docket for this rulemaking.\112\
---------------------------------------------------------------------------

    \112\ ``Small Business Impact Memo, Proposed Aircraft Engine 
Emission Standards--Determination of No SISNOSE,'' EPA memo from 
Solveig Irvine to Alexander Cristofaro, November, 2010.
---------------------------------------------------------------------------

    We continue to be interested in the potential impacts of the 
proposed rule on small entities and welcome comments on issues related 
to such impacts.

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 IV, today's proposed 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 proposed 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 proposal 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 
proposes to revise 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.
    In the spirit of Executive Order 13132, and consistent with EPA 
policy to promote communications between EPA and State and local 
governments, EPA specifically solicits comment on this proposed action 
from State and local officials.

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

    These rules regulate aircraft manufacturers and aircraft engine

[[Page 45045]]

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.
    EPA specifically solicits additional comment on this proposed 
action from Tribal officials.

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

    This rule is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because 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.
    The public is invited to submit comments or identify peer-reviewed 
studies and data that assess effects of early life exposure to aircraft 
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 proposed 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 
Congress, through OMB, explanations when the Agency decides not to use 
available and applicable voluntary consensus standards.
    This proposed rulemaking involves technical standards for testing 
emissions for aircraft gas turbine engines. EPA proposes to use test 
procedures contained in ICAO's International Standards and Recommended 
Practices Environmental Protection, Annex 16, along with the 
modifications contained in this rulemaking.\113\ 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.
---------------------------------------------------------------------------

    \113\ 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 (http://www.icao.int).
---------------------------------------------------------------------------

    EPA welcomes comments on this aspect of the proposed rulemaking 
and, specifically, invites the public to identify potentially-
applicable voluntary consensus standards and to explain why such 
standards should be used in this regulation.

J. EO 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 proposed 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.

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, Incorporation by reference, 
Motor vehicle pollution, Penalties, Reporting and recordkeeping 
requirements, Warranties.

    Dated: July 6, 2011.
Lisa P. Jackson,
Administrator.

    For the reasons stated in the preamble title 40, chapter I of the 
Code of Federal Regulations is proposed to be amended as follows:

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

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

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

Subpart A--[Amended]

    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

[[Page 45046]]

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 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 than 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).
    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 means to round numbers according to NIST SP 811 (March 2008), 
unless otherwise specified.
    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 = 0.00 kg H2O/kg 
dry air, and pressure = 101.325 kPa.

[[Page 45047]]

    Subsonic means relating to aircraft that are not supersonic 
aircraft.
    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.
    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

    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)(4), ``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]  

    5. Remove Sec.  87.5.
    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]  

    7. Remove Sec.  87.7.
    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, http://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. [Update for CAEP8 changes]; IBR approved for 
Sec. Sec.  87.2, 87.40, 87.42(d) and (f), and 87.60(a) and (b).
    (2) [Reserved]
    (c) National Institute of Standards and Technology, 100 Bureau 
Drive, Stop 1070, Gaithersburg, MD 20899-1070, (301) 975-6478, http://www.nist.gov, or inquiries@nist.gov. Anyone may also purchase copies of 
these materials from the Government Printing Office, Washington, DC 
20402, (202) 512-0916, http://www.gpo.gov, or prntproc@gpo.gov.
    (1) NIST Special Publication 811, 1995 Edition, Guide for the Use 
of the International System of Units (SI), Barry N. Taylor, Physics 
Laboratory; IBR approved for Sec.  87.2.
    (2) [Reserved]

Subpart C--[Amended]

    9. Amend Sec.  87.21 as follows:
    a. By revising the section heading.
    b. By adding introductory text.
    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 
[INSERT EFFECTIVE DATE OF FINAL RULE] 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

[[Page 45048]]

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.
* * * * *
    (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.
    10. Add a new Sec.  87.23 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 [INSERT EFFECTIVE DATE OF FINAL RULE], 
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 the 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). 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 to Sec.   87.23(b)--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 > 26.7 kN........  83.6 [middot]    140 [middot] 0.92rPR...  36+2.42 [middot] rPR...  4550 [middot] rPR-1.03
                       rO-0.274 or
                       50, 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 to Sec.   87.23(c)(1)--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, whichever
                        is smaller.
rO >= 260.7 kN.......  83.6 [middot]    19.6...........  118.
                        rO-0.274 or
                        50, 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 to Sec.   87.23(c)(2)--Tier 6 NOX Standards for New Subsonic
      Turbofan or Turbojet Engines With Rated Output Above 26.7 kN
------------------------------------------------------------------------
                                                       The NOX emission
If the rated pressure ratio is .     and the rated     standard (in g/kN
               . .                 output (in kN) is  rated output) is .
                                         . . .                . .
------------------------------------------------------------------------
rPR <= 30.......................  26.7 < rO <= 89...  38.5486 + 1.6823
                                                       [middot] rPR -
                                                       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 45049]]

   Table to Sec.   87.23(c)(3)--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 is .     and the rated     standard (in g/kN
               . .                 output (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
                                                       [middot] rPR -
                                                       0.5823 [middot]
                                                       rO + 0.005562
                                                       [middot] rPR
                                                       [middot] rO
                                  rO > 89...........  -9.88 + 2.0
                                                       [middot] rPR
rPR >= 104.7....................  all...............  32 + 1.6 [middot]
                                                       rPR
------------------------------------------------------------------------

     (d) This paragraph 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 [INSERT EFFECTIVE DATE OF FINAL RULE] 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.
    11. Add a new subpart E containing Sec. Sec.  87.40, 87.42, 87.46, 
and 87.48 to part 87 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.

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. If you 
produce exempted engines, you may submit a single report with 
information on both exempted and non-exempted 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 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) The calendar-year production volume of engines from the sub-
model that are covered by an FAA type certificate, 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.
    (4) The number of engines tested and the number of test runs for 
the applicable type certificate.
    (5) 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. Include the 
percent of standard for the applicable standard, and for NOX 
include percent of standard for all the NOX standards 
specified in Sec. Sec.  87.21 and 87.23. 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) [Reserved]
    (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

[[Page 45050]]

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 model is considered a derivative engine 
for emissions certification purposes. This would mean that the engine 
model 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 model 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.
    (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.
    12. Add a new subpart F containing Sec.  87.50 to part 87 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 this section must be approved by the FAA, with 
the written concurrence of EPA, 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 before producing the 
engines to be exempted to the FAA who will provide a copy to the 
Designated EPA Program Officer. Exemption by an authority outside the 
United States does not satisfy this requirement. All requests must 
include the following:
    (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

[[Page 45051]]

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. The FAA may also require additional 
information pursuant to 14 CFR Parts 11 and 34, as applicable to 
exemption requests made to the FAA.
    (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) [Reserved]
    (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 equal to or lower 
than those of the engines they are replacing, for all 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).
    (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

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

[[Page 45052]]

                                                        Table to Sec.   87.60(f)--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.  87.61  [Removed]

    15. Remove Sec.  87.61

Sec.  87.62  [Removed]

    16. Remove Sec.  87.62.

Sec.  87.64  [Revised]

    17. Remove and reserve paragraph (a).

Sec.  87.71  [Removed]

    18. Remove Sec.  87.71.

Subpart H [Removed]

    19. Remove subpart H.

PART 1068--GENERAL COMPLIANCE PROVISIONS FOR ENGINE PROGRAMS

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

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

Subpart A--[Amended]

    21. 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. 2011-17660 Filed 7-26-11; 8:45 am]
BILLING CODE 6560-50-P