45012 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

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. 

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: 

Category NAICSa Codes SIC Codes b Examples of potentially affected entities 

Industry ............................................................................ 336412 3724 Manufacturers of new aircraft engines. 

Industry ............................................................................ 336411 3721 Manufacturers of new aircraft. 

a North American Industry Classification System (NAICS) b Standard Industrial Classification (SIC) system code 

This table lists the types of entities 

that EPA is now aware could potentially 

be regulated by this action. Other types 

of entities not listed in the table could 

also be regulated. To determine whether 

your activities are regulated by this 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 45013 

1Turbofan and turbojet engines will be 

collectively referred to as turbofan engines hereafter 

for convenience. 

2The 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). 

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 NewlyCertified Engines 

a. Numerical Emission Limits for Higher 

Thrust Engines 

b. Numerical Emission Limits for Lower 

Thrust Engines 

2. Tier 8 NOX Standards for NewlyCertified 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 ‘‘newlymanufactured engines.’’ The newlycertified 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. Newlymanufactured 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. 

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 newlycertificated 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 

mstockstill on DSK4VPTVN1PROD with PROPOSALS2

45014 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

3The functions of the Secretary of Transportation 

under part B of title II of the Clean Air Act (§§ 231– 

234, 42 U.S.C. 7571–7574) have been delegated to 

the Administrator of the FAA. 49 CFR 1.47(g). 

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. 

5Members of ICAO’s Assembly are generally 

termed member States or contracting States. These 

terms are used interchangeably throughout this 

preamble. 

6There are currently 190 Contracting States 

according to ICAO website located at http:// 

www.icao.int. 

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. 

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. 

requirements, exemptions, and 

incorporation by reference. 

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. 

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

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. 

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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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 45015 

11U.S. EPA, ‘‘Emission Standards and Test 

Procedures for Aircraft;’’ Final Rule, 38 FR 19088, 

July 17, 1973. 

12U.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 noncommercial aircraft engines, in order to bring our 

standards into full alignment with ICAO’s. 

13This does not mean that in 2005 we 

promulgated requirements for the re-certification or 

retrofit of existing in-use engines. 

14U.S. EPA, ‘‘Control of Air Pollution from 

Aircraft and Aircraft Engines; Emission Standards 

and Test Procedures;’’ Final Rule, 70 FR 2521, 

November 17, 2005. 

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. 

16CAEP 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. 

17CAEP/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. 

19CAEP/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. 

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. 

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 newlymanufactured 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). 

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 newlycertified engines.19 20 The Committee 

also recommended that the CAEP/6 

standards be applied to newlymanufactured engines. ICAO is 

currently considering the CAEP/8 

recommendations. We expect final 

ICAO action regarding the CAEP/8 

recommendations in 2011. 

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. 

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, 

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45016 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

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. 23U.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. 24U.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. 

25U.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. 

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. 

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

TABLE 1—CURRENT NATIONAL NOX

EMISSIONS FROM COMMERCIAL AIRCRAFT

Aircraft category 2008 total NOX

(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. 

TABLE 2—CURRENT NOX EMISSIONS IN SELECTED OZONE NONATTAINMENT AREAS

Nonattainment area 2008 total NOX

(tons) 

2008 aircraft 

percent of mobile 

source NOX

2020 aircraft 

percent of mobile 

source 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 

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26Barrett, 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. 

TABLE 2—CURRENT NOX EMISSIONS IN SELECTED OZONE NONATTAINMENT AREAS—Continued 

Nonattainment area 2008 total NOX

(tons) 

2008 aircraft 

percent of mobile 

source NOX

2020 aircraft 

percent of mobile 

source NOX

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

Year 

Air carrier 

operations 

(millions) 

Commuter/air 

taxi operations 

(millions) 

Total commercial 

operations 

(millions) 

Total increase in 

commercial 

operations over 

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: 

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 nonaviation 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 

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27The 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. 

28U.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. 

29U.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. 

30U.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. 

31National 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. 

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

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 hightemperature 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. 

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 μm), and use PM10 as the 

indicator for purposes of regulating the 

coarse fraction of PM10 (referred to as 

thoracic coarse particles or coarsefraction particles; generally including 

particles with a nominal mean 

aerodynamic diameter greater than 2.5 

μm and less than or equal to 10 μm, or 

PM10–2.5). Ultrafine particles are a subset 

of fine particles, generally less than 100 

nanometers (0.1 μm) 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 nonaccidental 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 ozonerelated 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 

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32U.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. 

33U.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. 

34U.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. 

35U.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. 36U.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. 

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. 

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. 

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 longterm 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

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 allergeninduced 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. 

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 

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37U.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. 

38U.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. 

39U.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. 

40U.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. 

41U.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/. 

42U.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/. 

43U.S. EPA (2010). Fact Sheet Revisions to Ozone 

Standards. This document can be accessed 

electronically at: http://www.epa.gov/ 

groundlevelozone/pdfs/fs20100106std.pdf. 

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

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). 

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

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. 

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

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

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44U.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. 

45U.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. 

46U.S. EPA, ‘‘Primary National Ambient Air 

Quality Standards for Nitrogen Dioxide;’’ Final 

Rule, 75 FR 6474, February 9, 2010. 

47The 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. 

49The 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 newlymanufactured 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. 

50These apply only to the Tier 6 NOX standards. 

We are not yet proposing a production cutoff for the 

Tier 8 NOX standard. 

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 μg/m3

and 26 counties with a population of 

over 41 million may not attain the 2006 

24-hour PM2.5 standard of 35 μg/m3.45

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. 

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. 

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

We are also proposing to apply the 

first tier of the two tiers of standards to 

newly-manufactured engines. Newlymanufactured 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. 

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. 

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. 

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45022 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

51There 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. 

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. 

1. Tier 6 NOX Standards for NewlyCertified 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 

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52Reverting 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. 

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. 

54The 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. 

greater than 62.5 for the CAEP/6 

pressure ratios at or above 82.6.52

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. 

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 fuelstaged 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-tocombustion 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, 


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45024 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

i.e., CAEP/6 relative to CAEP/4, as the 

rated output and physical size of the 

engines decrease. We agree with this 

approach. 

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. 

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. 


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56CAEP/7 did not adopt new aircraft engine NOX

standards. 

57Reverting 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. 

2. Tier 8 NOX Standards for NewlyCertified 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. 

As with the Tier 6 NOX standards, the 

basic form of the Tier 8 standards for 

turbofan engines is different for higherand 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

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. 


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45026 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

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. 


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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. 


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45028 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

58The 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. 

59After 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. 

61The 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. 

65The ICAO CAEP/6 NOX standards became 

effective after December 31, 2007. 66This 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. 

67We 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. 

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. 

69Note 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. 

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 newlymanufactured 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. 

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. 

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. 

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

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70EPA 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. 

71U.S.EPA, ‘‘Control of Air Pollution from 

Aircraft and Aircraft Engines; Emission Standards 

and Test Procedures,’’ Final Rule, 47 FR 58462, 

December 30, 1982. 

production cutoff deliberations leading 

up to the CAEP/8 meeting in February 

2010. 

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. 

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 shortterm 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. 

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 § 87.50 of the proposed 

regulations for additional details on 

these exemptions.) 

Finally, we are deleting the timelimited 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 newlymanufactured 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 newlymanufactured 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 

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72Engines 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. 

73For example, the hydrocarbon exhaust 

emission standards were adopted on December 30, 

1982. See 47 FR 58462. 

74CAEP/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’’. 

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. 

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 newlymanufactured 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. 

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. 

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. 

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 cutoff. 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

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 

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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. 

78U.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. 

84See Table 5 of the most recent AIA statistical 

report available at http://www.aia-aerospace.org/ 

assets/Table 5.pdf. 

85U.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. 89U.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. 

place of in-use engines that are removed 

for maintenance or other reasons.77

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

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. 

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. 

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. 

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45032 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

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. 

91WTO, ‘‘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. 

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. 

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 § 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 

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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. 

93U.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. 

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

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. 

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 

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45034 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

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 crosscountry 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 newlymanufactured 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. 

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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. 

95United Kingdom, Civil Aviation Authority, 

‘‘ICAO Emissions Databank.’’ Available at the Civil 

Aviation Authority Web site http://www.caa.co.uk/ 

default.aspx?catid=702. 

96Under the proposed regulations, a grouping of 

engines with an essentially identical emissionrelated design would be defined to be an ‘‘engine 

sub-model’’. Engines with slightly different designs 

would be defined to be an ‘‘engine model’’. 

97The 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. 

98The proposed report would be submitted only 

to EPA. No separate submission or communication 

of any kind is required for the FAA. 

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. 

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 submodel.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).) 

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. 

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 submodel 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 submodel 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 submodel 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 

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45036 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

99See Regulation Part 87-Control of Air Pollution 

from Aircraft and Aircraft Engines, Subpart E, 

§ 87.42 Certification report to EPA for definitions. 

100 Dp/Foo: total gross emissions of each gaseous 

pollutant (mass)/rated thrust (g/kN). 

101A 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. 

intended for use as certified (nonexempt) 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

• Unburned hydrocarbon (HC) 

characteristic level (i.e. mass of 

hydrocarbons over LTO cycle/Rated 

Thrust (Dp/Foo)); 100

• 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 Takeoff 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 submodel (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

The amendments that have already 

been adopted by ICAO are: 

• Standardizing of the terminology 

relating to engine thrust/power; 

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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 45037 

104The 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. 

• 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. 

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 

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45038 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

105U.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. 

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 § 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

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 standardsubject 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 

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

Regulation 

cite Description of amendment Notes 

87.1 ......................... Add definition of ‘‘characteristic level’’. The characteristic level is established by ICAO Annex 16 as a means of calculating a statistical adjustment to measured emission results to take into account the level of uncertainty corresponding to the number of tests run for a 

given pollutant. 

87.1 ......................... Remove definitions for ‘‘emission measurement system’’, ‘‘power setting’’, 

‘‘sample system’’, ‘‘shaft power’’, 

‘‘taxi/idle (in)’’, and ‘‘taxi/idle (out)’’.

These terms will no longer be used in part 87. There will be no more engines 

certified to the standards specified in § 87.21, so removing these definitions 

will not change the requirements for engines certified to the Tier 4 or earlier 

standards. 

87.1 ......................... Revise definition of ‘‘exhaust emissions’’ and ‘‘smoke’’.The new language references the emission testing 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 § 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’’ instead of defining ‘‘new 

aircraft turbine engine’’.

The regulations also refer to new turboprop engines and new engines used 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 § 87.21. 

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45040 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

Regulation 

cite Description of amendment Notes 

87.1 ......................... Revise the definition of ‘‘standard day 

condition’’: (1) remove the 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.

The editorial changes do not involve any substantive change in the specified 

conditions. 

87.2 ......................... Remove FAA from the list of acronyms 

in § 87.2 and add it to the set of defined terms in § 87.1.

This is intended to not involve a change in emission standards or implementation. 

87.3 ......................... Add provisions describing the scope of 

applicability of part 87.

The broad statement in § 87.3 is not intended to conflict with the 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 provision related to preemption of state standards for exempted aircraft and replace it with 

the preemption provision in the Clean 

Air Act.

This change more carefully tracks the statutory provisions related to preemption. 

87.5 ......................... Move the provisions related to special 

test procedures to § 87.60.

This provision, and the similar provision from § 87.3(a), should be described together in the context of the testing requirements in subpart G. 

87.21 ....................... Identify the specific date when the 

smoke standard started to apply for 

turbofan engines with rated output 

less than 26.7 kilonewtons.

This corrects a typographical error from the FEDERAL REGISTER. 

87.21 ....................... Revise paragraph (f) to correctly reference the regulatory sections that 

describe the applicable test procedures.

This change is strictly editorial. 

87.60 ....................... Revise the description of test procedures to rely broadly on the procedures specified in ICAO Annex 16. 

This includes a variety of recent 

changes to the Annex 16 procedures.

There will be no more engines certified to the standards specified in § 87.21, so 

any changes to the test procedures will not change the requirements for engines certified to the Tier 4 or earlier standards. 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 manufacture’’ ......... This is generally the same 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 engine for emissions certification purposes’’.It is important to consider this definition in combination with the definition of ‘‘engine type certificate family’’.

87.1 Definition of ‘‘engine model’’ ..................... A manufacturer or FAA may further 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 aircraft’’ and 

87.23(d).

In § 87.23(d) we clarify that the production cutoff does not apply for military aircraft engines 

(even if they have been certificated). In § 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 cutoff date’’ ...... The production cutoff date for the Tier 6 NOX standards is December 31, 2012.

87.1, Definition of ‘‘spare engine’’ .................... Newly manufactured spare engines may be excepted under § 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.

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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 45041 

106CAEP/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. 

107CAEP/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. 

Regulation cite Note 

87.42(c)(1) ......................................................... § 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 § 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. 

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 

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108CAEP 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. 

110The functions of the Secretary of 

Transportation under part B of title II of the Clean 

Air Act (§§ 231–234, 42 U.S.C. 7571–7574) have 

been delegated to the Administrator of the FAA. 49 

CFR 1.47(g). 

111The Sixth Meeting of CAEP (CAEP/6) occurred 

in Montreal, Quebec from February 2 through 12 in 

2004. 

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. 

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. 

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. 

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 email. 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 

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

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45044 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

112 ‘‘Small Business Impact Memo, Proposed 

Aircraft Engine Emission Standards—Determination 

of No SISNOSE,’’ EPA memo from Solveig Irvine to 

Alexander Cristofaro, November, 2010. 

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-forprofit enterprise which is independently 

owned and operated and is not 

dominant in its field. The following 

Table 4 provides an overview of the 

primary SBA small business categories 

potentially affected by this regulation. 

TABLE 4—PRIMARY POTENTIALLY AFFECTED SBA SMALL BUSINESS CATEGORIES

Industry NAICSa 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). 

bAccording 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

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 

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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 45045 

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). 

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. 

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 § 87.1 to read as follows: 

§ 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 § 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 

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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 § 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 submodels: ABC and ABC–1. 

Engine type certificate family means a 

group of engines (comprising one or 

more engine models, including submodels 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 § 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 § 87.50(c). 

Standard day conditions means the 

following ambient conditions: 

temperature = 15 °C, specific humidity 

= 0.00 kg H2O/kg dry air, and pressure 

= 101.325 kPa. 

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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 § 87.21. 

Tier 2 means relating to an engine that 

is subject to the Tier 2 NOX standards 

specified in § 87.21. 

Tier 4 means relating to an engine that 

is subject to the Tier 4 NOX standards 

specified in § 87.21. 

Tier 6 means relating to an engine that 

is subject to the Tier 6 NOX standards 

specified in § 87.23. 

Tier 8 means relating to an engine that 

is subject to the Tier 8 NOX standards 

specified in § 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 § 87.2 to read as follows: 

§ 87.2 Abbreviations. 

The abbreviations used in this part 

have the following meanings: 

% percent 

° 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 § 87.3 to read as follows: 

§ 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). 

§ 87.5—[Removed]

5. Remove § 87.5. 

6. Revise § 87.6 to read as follows: 

§ 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. 

§ 87.7—[Removed]

7. Remove § 87.7. 

8. Revise § 87.8 to read as follows: 

§ 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 §§ 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 § 87.2. 

(2) [Reserved] 

Subpart C—[Amended] 

9. Amend § 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). 

§ 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 

§ 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 

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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 § 87.23 to read as 

follows: 

§ 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 § 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 · rO¥0.168. 

(b) New supersonic engines must 

comply with the standards shown in the 

following table: 

TABLE TO § 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 · 0.92rPR ......... 36+2.42 · rPR ....... 4550 · rPR¥1.03

rO > 26.7 kN .... 83.6 · rO¥0.274 or 50, whichever is smaller ............................ 140 · 0.92rPR ......... 36+2.42 · rPR ....... 4550 · rPR¥1.03

(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 § 87.23(c)(1)—SMOKE, HC, AND CO STANDARDS FOR NEW SUBSONIC TURBOFAN OR TURBOJET ENGINES

Rated output 

(kN) Smoke standard 

Gaseous emission standards (g/kN rated output) 

HC CO 

rO < 26.7 kN ..... 83.6 · rO¥0.274 or 50, whichever is smaller. 

rO ≥ 260.7 kN ... 83.6 · rO¥0.274 or 50, whichever is smaller ............................ 19.6 ........................................ 118. 

(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 § 87.23(c)(2)—TIER 6 NOX STANDARDS FOR NEW SUBSONIC TURBOFAN OR TURBOJET ENGINES WITH RATED

OUTPUT ABOVE 26.7 KN 

If the rated pressure ratio is . . . and the rated output (in kN) is . . . The NOX emission standard (in g/kN rated output) is . . . 

rPR ≤ 30 ........................................... 26.7 < rO ≤ 89 ................................. 38.5486 + 1.6823 · rPR ¥ 0.2453 · rO¥0.00308 · rPR · rO 

rO > 89 ............................................ 16.72 + 1.4080 · rPR 

30 < rPR < 82.6 ............................... 26.7 < rO ≤ 89 ................................. 46.1600 + 1.4286 · rPR ¥ 0.5303 · rO + 0.00642 · rPR · rO 

rO > 89 ............................................ ¥1.04 + 2.0 · rPR 

rPR ≥ 82.6 ........................................ all ..................................................... 32 + 1.6 · 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. 

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TABLE TO § 87.23(C)(3)—TIER 8 NOX STANDARDS FOR NEW SUBSONIC TURBOFAN OR TURBOJET ENGINES WITH RATED

OUTPUT ABOVE 26.7 KN 

If the rated pressure ratio is . . . and the rated output (in kN) is . . . The NOX emission standard (in g/kN rated output) is . . . 

rPR ≤ 30 ........................................... 26.7 < rO ≤ 89 ................................. 40.052 + 1.5681 · rPR ¥ 0.3615 · rO¥0.0018 · rPR · rO 

rO > 89 ............................................ 7.88 + 1.4080 · rPR 

30 < rPR < 104.7 ............................. 26.7 < rO ≤ 89 ................................. 41.9435 + 1.505 · rPR ¥ 0.5823 · rO + 0.005562 · rPR · rO 

rO > 89 ............................................ ¥9.88 + 2.0 · rPR 

rPR ≥ 104.7 ...................................... all ..................................................... 32 + 1.6 · 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 

§ 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 § 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 

§§ 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. 

§ 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. 

§ 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 § 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 

§§ 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. 

§ 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 

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available. We may review them at any 

time. 

§ 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 

§ 87.50 to part 87 to read as follows: 

Subpart F—Exemptions and 

Exceptions 

§ 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 

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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 § 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 § 87.60 to read as follows: 

§ 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 § 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 § 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 gearboxmounted 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: 

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45052 Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Proposed Rules 

TABLE TO § 87.60(f)—LTO TEST CYCLES

Mode 

Turboprop Subsonic Turbofan Supersonic Turbofan 

Percent of 

rated output 

Time in mode 

(minutes) 

Percent of 

rated output 

Time in mode 

(minutes) 

Percent of 

rated output 

Time in mode 

(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 § 87.60. 

§ 87.61 [Removed] 

15. Remove § 87.61 

§ 87.62 [Removed] 

16. Remove § 87.62. 

§ 87.64 [Revised] 

17. Remove and reserve paragraph (a). 

§ 87.71 [Removed] 

18. Remove § 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 § 1068.1 by revising 

paragraph (b) to read as follows: 

§ 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 compressionignition 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 

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