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Page 1 of 165 EO12866

_

Aircraft Engine Emission Standards 2060 - AO70 NPRM Rulemaking

Document

_2011/ 03 / 25 ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part s 87 and 1068 [EPA - HQ - OAR- 2010 - 0687 ; FRL - XXXX - X]

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 propos es 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 subje ct to exhaust emission standard s . 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 arePrivileged 

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Page 2 of 165 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 activel y participated in the United Nation’s International Civil Aviation Organization (I CAO) proceedings in which most of these proposed r equirements were first developed. T hese proposed regulatory

requirements have largely either been adopted or are actively under consideration b y ICAO . Therefore, adopting the proposed requirements would bring the United States into al ignment with international standards and recommended practices . DATES: Comments must be received on or before [insert date 6 0 days after publication in the Federal Register.] Hearing: The public hearing will be held [ i nsert d ate no fewer than 15 days after publication and at least 30 days b efore end of comment period ] at the Environmental Protection Agency , XXX Building, Room Number XXX, 1201 Constitution Avenue, NW, Washington, DC 20004, Telephone: (202) 564 - 1682. See section VIII 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: www.regulations.gov: Follow the on - line instructions for submitting comments.  Email: A - and - R - Docket@epamail.epa.gov.Privileged 

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Page 3 of 165  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 IN FORMAT ION CONTACT). Please mail a copy of your comments on the information collection provisions to the Office of Information and Regulato ry Affairs, Office of Management and Budget (OMB), Attn: Desk Officer for EPA, 725 17 th 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 include d in the public docket without change and may

be made available online at 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 b y statute. Do not submit information that you consider to be CBI or otherwise protected through www.regulations.gov or e - mail. The www.regulations.gov website is an “anon ym ous access” sy stem, which means EPA will not know yo ur identity or contact information unless you provide it in the body of your comment. If you send an e - mail comment directl y to EPA without going through www.regulations.gov your e - mail address will be automatically captured and included as part of the co mment that is placedPrivileged 

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Page 4 of 165 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, an y form of encry ption, and be free of any defects or viruses. Docket : All documents in the docket are listed in the 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 b y statute. Certain other material, such as cop yri ghted material, will be publicly available only

in hard copy . Publicly

available docket materials are available either electronically in www.regulations.gov or in hard copy at EPA Docket Center, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., N W, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday , excluding legal holiday s. 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 : Bryan Manning, Office of Transportation and Air Quality , Office of Air and Radiation, Environmental Protection Agency , 2000 Traverwood Drive, Ann Arbor, MI 48130 ; telephone number: ( 734) 214 - 4832 ; fax number: (73 4) 214 - 4816; email address: manning.bry an@epa.gov .Privileged 

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Page 5 of 165 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 NAI CS a Codes SI C 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 ty

pes of entities that EPA is now aware could potentially be regulated b y this action. Other types of entities not listed in the table could also be regulated. To determine whether your activities are regulated b y this action, you should carefully examine the applicability criteria in 40 CFR 87. 1 (part 87). If you have an y questions regarding the applicability of this action to a particular entity , c onsult 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 ActPrivileged 

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Page 6 of 165 C . Interaction w ith 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

Contributio n 1. L anding and Takeoff (L TO) 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 Ecos ys tem Effects of Ozone 4 . Impacts on Ambient Air QualityPrivileged 

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Page 7 of 165 III. Details of the Proposed Rule A. NOx Standards for Newly - Certified Engines 1. Tier 6 NOx Standards for Newl y - Certified Engines a. Numerical Emission Limits for Higher Thrust Engines b. Numerical Emission Limits for Lower Thrust Engines 2 . Tier 8 NOx Standards for Newl y - Certified Engines a. Numerical Emission Limits for Higher Thrust Engines b. Numerical Emission Limits for Lower Thrust Engines B . Application of NOx Standards for Newl y - Manufactured Engines 1. Phase - In of the Tier 6 NOx Standards for Newly Manufactured Engines 2. Exemption s 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 L imit iii . Exemption Requests iv . Foreign Aircraft c . Voluntary

Emission Offsets 3. Potential Phase - Inof New Tier 8 NOx Standards for Newl y Manufactured EnginesPrivileged 

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Page 8 of 165 C . Application of Standards for Derivative Engines D . Annual Report ing 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

En gines 2. Noncommercial Engines B. Non - Substantive Revisions C. Clarifying Language for Regulatory Text V. Technical Feasibility , Costs , and Emission Benefits V I. Consultation with FAA V I I. Public Participation VIII . Statutory

Provisions and Legal Authorit y IX . Statutory

and Executive Orders Review A. Executive Order 12866: Regulatory Planning and Review B. Paperwork Reduction Act C. Regulatory

Flexibility

Analy sis D. Unfunded Mandates Reform ActPrivileged 

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Page 9 of 165 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 & Safet y Risks H. Executive Order 13211: Actions that Significantly Affect Ene rgy Supply , Distribution, or Use I. National Technology

Transfer Advancement Act J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority Populations and L ow 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 stand ards and those of the international community , and a brief regulatory history for this source of emissions. A. Summary of the ProposalPrivileged 

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Page 10 of 165 We are proposing several new emission standards and other regulatory requirements for aircraft turbofan and turbojet engin es 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 (NO x ) . T he proposed standards would apply differentl y to two classes of these engines, i.e., “ newl y - certified engines ” and “ newly - manufactured engines. ” The newl y - certified engine standards would apply to aircraft engines that have received a new ty

pe certificate and have never been manufactured prior to the effective date o f the new emission stan dards. Requirements for n ewl y - manufactured engines would apply

to aircraft engines that were previously certified and manufactured in compliance with preexisting standards, and would require manufacturers to either compl y with the newer standards by a spe cified future date or cease production. Newly manufactured engine standards are also sometimes referred to as “production cutoff ” standards. Second, we are proposing certain time - limited flexibilities, i.e., the potential for exemptions as defined in the regulations for newly - manufactured engines that may not be able to compl y with the first tier of the proposed NOx standards because of specific technical or economic reasons.

1 Turbofan and turbojet engines will be collectively referred to as turbofan engines hereafter for convenience.Privileged 

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Page 11 of 165 We are also proposing a number of additional changes that would apply to a wider range of a ircraft gas turbine engines 2 than those that would be subject to the proposed new emission standards. First , we are proposing to clarify that when the emission characteristics of a new turbofan engine model have become different enough fro m its existing parent engine design, i.e., a derivative of an originally certified engine t ype, it must receive a new emissions approval showing conformance with the most current emission standard s . 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 analy ses and develop appropriate public pol icy 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 em ission 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 . Finall y, as described in section IV, we are proposing minor amendments to provisions addressing definitions,

2 The term gas turbine engine includes turbofan, turbojet, and turboprop engines designs. The rated output for turbofan and turbojet engines is norm ally expressed as kilonewtons (kN) thrust. The rated output for turboprop engines is normally expressed as shaft horsepower (hp) or shaft kilow att (kW).Privileged 

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Page 12 of 165 acron ym s and abbreviations, general applicability and requirements, exemptions, and incorporation b y reference . Most of these proposed regulatory requirements have already been adopted or are activel y under consideration by the United Nation ’ s International Civil Aviation Organization (I CAO) . T he proposed requirements would bring the United States into al ignment 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 Administr ation ( FAA ) on such standards, and prohibits EPA from changing aircraft emission standards if such a change would significantly increase noise and adversel y affect safet y. 42 U.S.C. § 7571(a)( 2)(B ) (i) - (ii) . Section 231(a)(3) provides that after we propos e standards, the Administrator shall issue such standards “with such modifications as he deems appropriat e.” 42 U.S.C. § 7571(a)(3). The U.S. Court of Appeals for the D.C. Circuit has held that this provision confers an unusuall y b r oad degree of discreti on on EPA toPrivileged 

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Page 13 of 165 adopt aircraft engine emission standards as the A gency determines are reasonable. NACAA v. EPA , 489 F.3d 1221 (D.C. Cir. 2007). In addition, under CAA section 231(b) EPA is required to ensure, in consultation with the U.S. Department of Transportation (DOT), that the effective date of any standard provide s the necessary

time to permit the development and application of the requisite technology , gi ving appropriate consideration to the cost of compl iance. 42 U.S.C . § 7571(b). Section 232 then directs the FAA to prescribe regulations to i nsure compliance with EPA’s standards. 42 U.S.C. § 7572. Finally, section 233 of the CAA vests the authority to promulgate e mission standards for aircraft or aircraft engines only in EPA. States are pree mpted 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 Italso describes DOT’s responsibility under the CAA to enforce the aircraft emission standards established by EPA. C. Interaction w ith the International Community

3 The 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).Privileged 

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Page 14 of 165 We began regulating the emissions from aircraft engines in 1973 . Since that time, we have worked with the FAA and the International Civil Aviation Organization (I CAO) to develop international standards and other recommended practices pertaining to aircr aft engine emissions. IC AO 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 orderl y manner and that international air transport services may be established on the basis of equality of opportuni ty

and operated soundly

and economically .” 4 IC AO’s responsibilities include developing aircraft technical and operating standards, recommending practices, and generall y fostering the growth of international civil aviation. The United States is currentl y one of 190 participating member States of I CAO. 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 I CAO.

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 website located at www.icao.int . 5 Mem bers of ICAO’s Assembly are generally termed member States or contracting States. These terms are used interchangeably throughout this preamble . 6 There are currently 190 Contracting States according to ICAO w ebsite located at www.icao.int .Privileged 

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Page 15 of 165 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 an y aircraft within their airspace that does not meet I CAO standards. 7 Second, States are required to recognize the airworthiness certificates of an y State whose standards are at least as stringent as ICAO ’s standards , thereb y assuring that aircraft of an y m ember State will be pe rmitted to operate in any other member State. Third, and finall y, t o ensure that international commer ce is not unreasonabl y constraine d , a participating nation which elects to adopt more stringent standards is obligated to notify I CAO of the differences between its standards and I CAO st andards. 8 , 9 However, if a nation sets tighter standards than ICAO, air carriers not based in that nation (foreign - flag ged 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 C ommittee is responsible for evaluating, resear ching, and recommending measures to the IC AO

7 Article 33 ICAO, “Convention on International Civil Aviation,” Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO we bsite located at www.icao.int . 8 ICAO, “Convention on International Civil Aviation,” Articles 87 and 88 , Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO website located at www.icao.int . 9 ICAO, “Convention on International Civil Aviation,” Article 38 , Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtained from the ICAO website located at www.icao.int . .Privileged 

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Page 16 of 165 Council that address the environmental impact of international civil aviation. CAEP is composed of various study groups, work groups, committees and other contributing memberships that include atmospheric, econ omic, aviation, environmental, and other professionals. At CAEP meetings, the United States is represented b y the FAA, which play s 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 adv ising 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 re commended practices (Annex 16 to the Chicago Convention). 10 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

10 ICAO, “Aircraft Engine Emissions,” International Standards and Recommended Practices, Environmental Protection, Annex 16, Volume II, Second Edition, July 2008 . A c op y of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 11 U.S. EPA, “ Emission Standards and Test Procedures for Aircraft; ” Final Rule, 38 FR 19088 , July 17, 1973 .Privileged 

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Page 17 of 165 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.) This included new NO x emission standards for newl y 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 newl y certified commercial turbofan en gines (those engine models that received their initial ty pe certificate after the effective date of the regulations). Italso included a CO emission standard for newl y - manufactured commercial turbofan engines. Second, in our most recent rulemaking in 200 5 , we promulgated more stringent NO x emission stand ards for newly - certi fied commercial turbofan engines . 14 That final rule brought the U.S. standards closer to alignment with IC AO CAEP/4 requirements that were effective in 2004 . Inruling 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

12 U.S. EPA, “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;” Final Rule, 62 FR 25356, May 8, 1997 . While ICAO’s standards w ere not limited to “commercial” aircraft engines, our 1997 standards w ere 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 at 25358. As explained later in today’s notice, w e are proposing to expand the scope of that finding and of our standards to include such emissi ons from both commercial and non - commercial aircraft engines, in order to bring our standards into full alignment with ICAO’s. 13 This does not mean that in 2005 w e promulgated requirements for the re - certification or retrofit of existing in - use engines. 14 U.S. EPA, “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;” Final Rule, 70 FR 2521, November 17, 2005.Privileged 

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Page 18 of 165 approach of tracking the ICAO standards was reasonable and permissible under the CAA. NACAA v. EPA , 489 F.3d 1221, 1230 - 32 (D.C. Cir. 2007). 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 b y ICAO in 1981 . 15 These standards limited aircraft engine emissions of HC, CO, and NO x . In 1994, ICAO adopted a CAEP /2 proposal to tighten the original NO x standard b y 20 percent and amend the te st 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 I CAO Council rejected this stringency

proposal and approved only the test pro cedure amendments. At the CAEP/4 meeting in 1998, the Committee adopted a similar 16 percent NO x reduction proposal, which ICAO approved on 1998. The CAEP/4 standard s applied only to new engine designs certified after December 31, 2003 (i.e., the require ments did not also apply to newly - manufactured engines unlike the CAEP/2 standards). In 200 4 , CAEP/6

15 ICAO, Foreword of “Aircraft Engine Emissions,” International Standards and Recommended Practices, Environmental Protection, Annex 16, Volume II, Third Edition, July 2008. Copies of this document can be obtained from the ICAO website at www.icao.int . 16 CAEP conducts its work over a period of years. Each work cycle is numbered sequentially and that identifier is used to differentiate the results from one CAEP to another by convention. The first technical meeting on aircraft emission standards w as CAEP’s successor, i.e., CAEE. The first meeting of CAEP, therefore, is referred to as CAEP/2.Privileged 

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Page 19 of 165 recommend ed a 12 percent NOx reduction , which ICAO approved in 200 5 . 17 , 18 The CAEP/6 standard s 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 newl y - certified engines. 19 , 20 The Committee also recommended that the CAEP/6 standards be applied to newl y - manufactured engines. ICAO is currently

considering the CAEP/8 recommendations. We expect final I CAO 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 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).

17 CAEP/5 did not address new aircraft engine emission standards. 18 ICAO, “Aircraft Engine Emissions,” Annex 16, Volume II, Third Edition, July 2008, Amendment 4 effective on July 20, 2008. Copies of this document can be obtained fro m the ICAO website at www.icao.int . 19 CAEP/7 did not address new aircraft engine emission standards. 20 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.Privileged 

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Page 20 of 165 One of the principal components of aircraft exhaust emissions is NO x . NO x is a precursor to the formation of ozone. 21 Many commercial airports are located in urban areas and man y 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 NO x emissions inventory and the health and welfare impacts of NOx and PM emissions . A. Inventory

Contribution In contrast to all other mobile sources, whose emissions occur completel y 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 lay e r of the atmosphere and directly affect local and regional ambient air quality . These emissions generall y 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 L TO cycl e are: engine idle at the terminal gate (and sometimes during ground delays while holding

21 Ground - level ozone, the main ingredient in smog, is formed by complex chemical reactions of volatile organic compounds (VOC) and NO x in the presence of heat and sunlight. Standards that reduce NO x emissions will help address ambient ozone levels. They can also help reduce particulate matter (PM) levels as NO x emissions can also be part of th e secondary formation of PM. See Section II.B below .Privileged 

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Page 21 of 165 for the active runway); taxiing between the terminal and the runway ; take - off; climb - out; and approach to the airport. The second regime includes emissions that occur above 3,000 feet above ground level, known as non - LTO emissions . Collectively , the emissions associated with all ground and flight operations are generally referred to as full flight emissions. The aircraft engine NOx emission inventories for the LTO and non - LTO flight regimes described above are discussed separatel y i n the following sections. 1. L anding and Takeoff Emissions In this section, we will discuss NO X emission inventories for commercial turbine engine aircraft, both nationally and for selected ozone nonattainment areas (NAAs). These inventories reflect emissions during the land and t akeoff cycle only . The most recent comprehensive analy sis of historical and current LTO emissions from aircraft engines comes from a study undertaken f

or us b y Eastern Research Group (ERG). 22 The study anal yz ed the national emissions of commercial aircraft operations in the United States, and showed that in the most recent ye ar studied (2008), such aircraft operations

22 “Historical Assessment of Aircraft Emissions (1986 - 2008),” Eastern Research Group, March XX, 2001. A copy of this document can be found in public docket EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 22 of 165 contributed about 97 thousand tons to the national NO X inventory . A summary of the national inventory

is shown in Table 1 . Table 1 : Current National NO X Emissions from Commercial Aircraft Aircraft Category 2008 Total NO X (thousand tons) Air Carrier 86 Commuter/Air Taxi 11 Total Commercial 97 This historical anal ys is also included an assessment of selected ozone nonattainment areas (NAAs). The top 25 ozone NAAs were identified based first in terms of NAAs with airports which had high commercial traffic volumes and then those with the largest population. There was some overlap, and this led to a total of 41 NAAs for the stud y. These 41 NAAs collectivel y include 200 airports, accounting for about 70 percent of commercial air traffic operations . Current (2008) NO X emissions fo r these 41 NAAs are shown in Table 2 . The relative contribution of aircraft in an y gi ven NAA would vary

based on activity

in other transportation and industrial sectors.Privileged 

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Page 23 of 165 Table 2 : Current NO X Emissions in Selected Ozone Nonattainment Areas Nonattainment Area 2008 Total NO X (tons) Albuquerque, NM 38 2 Anchorage, AK 256 2 Aspen 1 9 Atlanta, GA 5834 Baltimore, MD 1159 Boston - Lawrence - Worcester (eastern MA), MA 190 7 Boston - Manchester - Portsmouth (southeast NH), NH 224 Charlotte - Gastonia - Rock Hill, NC - SC 203 9 Chicago - Gary - Lake County, IL - IN 602 4 Cincinnati - Hamilton, OH - KY - IN 128 9 Cleveland - Akron - Lorain, OH 712 Dallas - Fort Worth, TX 3 900 Denver - Boulder - Greeley - Fort Collins - Loveland, CO 268 5 Detroit - Ann Arbor, MI 2328 El Paso, TX 22 4 Greater Connecticut, CT 413 Houston - Galveston - Brazoria, TX 3062 Indianapolis, IN 109 3 Las Vegas, NV 231 4 Los Angeles South Coast Air Basin, CA 6532 Louisville, KY - IN 121 1 Memphis, TN - AR 2996 Milwaukee - Racine, WI 558 Minneapolis - St Paul, MN 2170 New York - N. New Jersey - Long Island, NY - NJ - CT 10319 Phil a delphia - Wilmington - Atlantic City, PA - NY - MD - DE 2432 Phoenix - Mesa, AZ 230 7 Pittsburgh - Beaver Valley, PA 50 8 Providence (entire State), RI 240 Raleigh - Durham - Chapel Hill, NC 593 Reno, NV 249 Riverside County (Coachella Valley), CA 7 5 Sacramento Metro, CA 608 Salt Lake City, UT 12 50 San Diego, CA 1046 San Francisco Bay Area, CA 4447 San Joaquin Valley, CA 8 6 Seattle - Tacoma, WA 2242 St. Louis, MO - IL 81 3 Syracuse, NY 152 Washington, DC - MD - VA 302 8 Table 3 shows how commercial aircraft operations are projected to rise in the future. As operations increase, the inventory impact of these aircraft on national and local NO X inventories and on ozone and PM levels will also increase.Privileged 

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Page 24 of 165 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

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 - LT O 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 b y Barrett et al. (2010) finds that these upper atmosphere emissions may adversely

affect public health more than was previously

thought. 23 Based on the data and methodology of the authors, this effect is caused primarily

by two pathway s:

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

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Page 25 of 165 1. The formation of fine particulate matter, i.e., PM 2.5 , from emiss ion of gaseous precursors of PM (NO x and SO 2 ) in the upper atmosphere that are then transported to the lower atmosphere. (The formation of secondary PM 2.5 from NO x is discussed further in section II.B.1.b). 2. Aviation NO x emissions promote ozone formation throughout the troposphere and hence increase OH concentrations. This increases the oxidation of non - aviation SO 2 (such as that emitted from power stations) in the gas phase relative to aqueous oxidation and dry deposition thereb y increasing atmospheric su lfate (a ty pe of PM 2.5 ) 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 c ruise operations were estimated to be about 80 percent of the population - weighed PM 2.5 from aviation, with the remainder being associated with LTO operations (although they note the LTO portion may be under estimated). The stud y asserts that over 380 premature mortalities per ye ar in the U.S. can be attributed to secondary PM 2.5 associated with non - LT O operations. We request comments on the results of these studies, the existence of other research into this area, and the implications of these anal ys es on assessing the need for additional controls on aircraft engine emissions in the future.Privileged 

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Page 26 of 165 B. Heal th, Environmental and Air Quality Impacts NO x emissions from aircraft and other mobile and stationary sources contribute to the formation of ozone. In addition, NO x emissions at low altitude also react in the atmosphere to form secondary fine particulate matter (PM 2.5 ), particularl y ammonium nitrate. In the following sections we discuss the adverse health and welfare effects associated with NO x emissions, in addition to the current and projected levels of ozone and PM across the country . The IC AO NO x 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 and/or maintain compliance with the National Ambient Air Quality Standards (NAAQS). 24 1. Backgro und on Ozone, PM and NO X

24 The discussion of PM health and w elfare effects throughout this notice relates exclusively to the effects of the proposed NOx emission standards on the formation secondary PM from nitrate formation in the atmosphere. Presently, there are no emission stan dards 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 h ealth or welfare), with standard setting as appropriate.Privileged 

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Page 27 of 165 a. W hat is Ozone? Ground - level ozone pollution is ty pically formed by

the reaction of VOC and NO X in the lower atmosphere in the presence of sunlight. These pollutants, often referred to as ozone precursors, are emitted by man y typ es 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, tr ansport, and accumulation is complex. 25 Ground - level ozone is produced and destroy ed 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 relativel y stagnant, ozone and its precursors can build up and result in more ozone than ty picall y occurs on a single high - temperature day . Ozone can be transported hundreds of miles downwind from the sources of precursor emissions , resulting in elevated ozone levels even in areas with low local VOC or NO X emissions.

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

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Page 28 of 165 b . W hat is Particulate Matter? The discussion focuses on PM 2.5 because the NO X emitted by aircraft engines can react in the atmosphere to form nitrate, a component of PM 2.5 . Particulate matter is a generic term for a broad class of chemically and phy sicall y diverse substances. It can be principally

characterized as discrete particles that exist in the condensed (liquid or solid) phase spanning several orders of magn itude 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 PM 2.5 as the indicator for fine particles (with PM 2.5 referring to particles with a nominal mean aerodyn amic diameter less than or equal to 2.5 μm), and use PM 10 as the indicator for purposes of regulating the coarse fraction of PM 10 (referred to as thoracic coarse particles or coarse - fraction particles; generally including particles with a nominal mean aerodynamic diameter greater than 2.5 μm and less than or equal to 10 μm, or PM 10 - 2.5 ). Ultrafine particles are a subset of fine particles, genera lly less than 100 nanometers (0.1 μm) in aerodynamic diameter. Fine particles are produced primaril y b y combustion processes and b y transformations of gaseous emissions (e.g., SO X , NO X and VOC) in the atmosphere. The chemical and ph ys ical properties of PM 2.5 may vary greatl y with time, region, meteorology , and source category . Thus, PM 2.5 may include a complex mixture ofPrivileged 

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Page 29 of 165 different pollutants including sulfates, nitrates, organic compounds, elemental carbon and metal compounds. These particles can remai n in the atmosphere for day s to weeks and travel hundreds to thousands of kilometers.

c . What is NO

X? Nitrogen dioxide (NO 2 ) is a member of the NO X family of gases. Most NO 2 is formed in the air through the oxidation of nitric oxide (NO) emitted when fuel is burned at a high temperature. NO 2 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. NO X along with non - methane h ydrocarbon (NMHC) are the two major precursors of ozone. The health effects of ozone, ambient PM and NO X are covered in Section II.B.2. 2. Health Effects Associated with Exposure to Ozone, PM and NO X a. W hat are the Health Effects of Ozone?Privileged 

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Page 30 of 165 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. 26 , 27 People who are more susceptible to effects associated with exposure to ozone can include children, the elderl y, 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 s ys tem, 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 att acks 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 c ardiovascular - related morbidity and highl y suggestive evidence that short - term ozone exposure directl y or indirectly contributes to non - accidental and cardiopulmonary - related mortality , but additional research is needed to clarify the underlying mechanisms causing these effects. In a recent report on the

26 U.S. EPA Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental Protection Agency, Washington, D.C., 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 . 27 U.S. EPA (2007) Review of the National Ambient Air Quality Standards for Ozone, Policy Assessment of Scientific and Technical Information. OAQPS Staff Paper.EPA - 452/R - 07 - 003. This document is available in Docket EPA - HQ - OAR - 2010 - 0687 . This document is available electronically at: http:www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_sp. html.Privileged 

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Page 31 of 165 estimation of ozone - related premature mortality published by

the National Research Council (NRC), a panel of experts and reviewers concluded that short - term exposure to ambient ozone is likely

to contribut e to premature deaths and that ozone - related mortality should be included in estimates of the health benefits of reducing ozone exposure. 28 Animal toxicological evidence indicates that with repeated exposure, ozone can inflame and damage the lining of the lungs, which may lead to permanent changes in lung tissue and irreversible reductions in lung function. The respiratory effects observed in controlled human exposure studies and animal studies are coherent with the evidence from epidemiologic studies sup porting 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 - rel ated morbidity and non - accidental and cardiopulmonary mortality . b. W hat 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

28 National Research Council (NRC), 2008. Estimating Mortality Risk Reduction and Economic Benefits from Controlling Ozone Air Pollution . The National Academies Press: Washington, D.C. A copy of this document is in d ocket num ber EPA - HQ - OAR - 2010 - 068 7Privileged 

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Page 32 of 165 Assessment for Particulate Matter (I SA) . 29 The I SA summarizes evidence associated with PM 2.5 , PM 10 - 2.5 , and ultrafine particles (UFPs) , and concludes the following. The I SA concludes that health effects associated with short - term exposur es (hours to day s) to ambient PM 2.5 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 . 30 The ISA notes that l ong - term exposure to PM 2.5 (months to y ears) is assoc iated with the development/progression of cardiovascular disease, premature mortality , and respiratory effects, including reduced lung function growth, increased respiratory

s ymptoms, and asthma development. 31 The I SA 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 PM 2.5 and cardiovascular effects and mortality . Furthermore, the I SA

29 U.S. EPA (2009) Integrated Science Assessment for Particulate Matter, EPA 600/R - 08/139F. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687 30 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Env ironmental Protection Agency, Washington, DC, EPA/600/R - 08/139F, 2009 . Section 2.3.1.1. 31 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R - 08/139F, 2009 . p age 2 - 12, Sections 7.3.1.1 and 7.3.2.1.Privileged 

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Page 33 of 165 concludes that the collective evidence supports likely causal associations between short and long - term PM 2.5 exposures and respiratory effects. The ISA also concludes that the scientific evidence is suggestive of a causal association for reproductive and developmental effe cts and cancer, mutagenicit y, and genotoxicity and long - term exposure to PM 2. 5 . 32 For PM 10 - 2.5 , the I SA concludes that the current evidence is suggestive of a causal relationship between short - term exposures and cardiovascular effects, such as hospitalizat ion for ischemic heart disease. There is also suggestive evidence of a causal relationship between short - term PM 10 - 2.5 exposure and mortality and respiratory effects. Data are inadequate to draw conclusions regarding the health effects associated with lo ng - term exposure to PM 10 - 2.5 . For UFPs, the I SA further concludes that there is suggestive evidence of a causal relationship between short - term exposures and cardiovascular effects, such as changes in heart rh ythm and blood vessel function. It also concl udes 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.

32 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R - 08/139F, 2009 . Section 2.3.2.Privileged 

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Page 34 of 165 c. What are the Health Ef fects of NO

X? In formation on the health effects of NO 2 can be found in the EPA Integrated Science Assessment (I SA) for Nitrogen Oxides. 33 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 NO 2 exposure. The I SA concludes that the strongest evidence for such a relationship comes from epidemiolo gic studies of respiratory effects including sy mptoms, emergency

department visits, and hospital admissions. The I SA also draws two broad conclusions regarding airway responsiveness following NO 2 exposure. First, the I SA concludes that NO 2 exposure may e nhance the sensitivity

to allergen - induced decrements in lung function and increase the allergen - induced airway inflammatory response following 30 - minute exposures of asthmatics to NO 2 concentrations as low as 0.26 ppm . In addition, small but significant increases in non - specific airway hy per responsiveness were reported following 1 - hour exposures of asthmatics to 0.1 ppm NO 2 . Second, exposure to NO 2 has been found to enhance the inherent responsiveness of the airway to subsequent nonspecific challenges i n controlled human exposure studies of asthmatic subjects. Enhanced airway responsiveness could have important clinical

33 U.S. EPA (2008). Integrated Scie nce 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 .Privileged 

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Page 35 of 165 implications for asthmatics since transient increases in airway responsiveness following NO 2 exposure have the potential to increase s ymptoms and worsen asthma control. Together, the epidemiologic and experimental data sets form a plausible, consistent, and coherent description of a relationship between NO 2 exposures and an array of adverse health effects that range from the onset of re spiratory s ymptoms to hospital admission. Although the weight of evidence supporting a causal relationship is somewhat less certain than that associated with respiratory morbidity , NO 2 has also been linked to other health endpoints. These include all - ca use (non - accidental) mortalit y, 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 NO X

a. Deposition of Nitrogen Emissions of NO X 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 ecos ys tems across the U.S. The sensitivity of terrestrial and aquatic ecos ys tems to acidification fr om nitrogen deposition is predominantly governed b y geology . ProlongedPrivileged 

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Page 36 of 165 exposure to excess nitrogen deposition in sensitive areas acidifies lakes, rivers and soils. In creased acidity

in surface waters creates inhospitable conditions for biota and affects the abundance and nutritional value of preferred prey species, threatening biodiversity and ecos ys tem function. Over time, acidifying deposition also removes essential nutrients from forest soils, depleting the capacity of soils to neutralize future acid loadings and negativel y 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 inv ertebrates . In addition to the role nitrogen deposition play s in acidification, nitrogen deposition also leads to nutrient enrichment and altered biogeochemical cycling. In aquatic s ys tems increased nitrogen can alter species assemblages and cause eutrophication. In terrestrial sy stems nitrogen loading can lead to loss of nitrogen sensitive lichen species, decreased biodiversit y of grasslands, meadows and other sensitive habitats, and increased potential for invasive species. Adverse impacts on soi l 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 man y terrestrial and aquatic ecos ys tems that have been identified as particularly sensitive to nitrogen deposition. The most extreme effects resulting from nitrogen deposition on aquatic ecosy stems are due to nitrogen enrichmentPrivileged 

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Page 37 of 165 which contributes to “h ypoxic” zones devoid of life. Three h ypoxia 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 L ong Island Sound, in the northeast U.S. 34 The deposition of airborne particles can reduce the aesthetic appeal of buildings and culturall y important articles through soiling, and can contribute directly (or in conjunction with other pollutants) to structural damage b y means of corrosion or erosion. 35 Particles affect materials principall y b y promoting and accelerating the corrosion of metals, b y degrading paints, and b y deteriorating building materials such as concrete and limestone. Particles contribute to these effects because of their electrol yt ic, hygroscopic, and acid ic properties, and their ability to adsorb corrosive gases (principall y sulfur dioxide). b. Visibility Effects

34 U.S. EPA. (2008). Nitrogen Dioxide/Sulfur Dioxide Secondary NAAQS Review: Integrated Science Assessment (ISA). Washington, DC : U.S. Environmental Protection Agency. Retrieved on March 18, 2009 from http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=180903 . 35 U.S. EPA. (2005). Review of the National Ambient Air Quality Standard s 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.pdfPrivileged 

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Page 38 of 165 NOx e missions contribute to visibility impairment in the U.S. through the formation of secondary

PM 2.5 . 36 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 enjoy ment of dail y 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 highl y valued in significant natural areas , such as national parks and wilderness areas , and s pecial emphasis is given to protecting visibility in these areas. For more information on visibility

see the final 200 9 PM ISA. 37

c . Plant and Ecosystem Effects of Ozone Elevated ozone levels contribute to environmental effects, with impacts to plants and ecos ys tems 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

36 U.S. EPA. (2004). Air Quality Criteria for Particulate Matter (AQCD). Volume I Document No. EPA600/P - 99/002aF and Volume II Document No. EPA600/P - 99/002bF. Washington, DC: U.S. Environmental Protection Agency. Retrieved on March 18, 2009 from http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=87903 . 37 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R - 08/139F, 2009 . A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 39 of 165 create chronic stress on vegetation. Ozone damage to plants includes visible injury to leaves and impaired photosy nthesis, both of which can lead to reduced plant growth and reproduction, resulting in reduced crop yi elds, forestry production, and use of sensitive ornamentals in landscaping. In addition, the impairment of photosy nthesis, the process by which the plant makes carbohydrates (its source of energy and food), can lead to a subsequent reduction in root growth and carboh ydrate storage below ground, resulting in other, more subtle plant and ecos ys tems 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 ecos ys tems, resulting in a loss or reduction in associated ec osy stem goods and services. Lastl y, 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 ecos ys tems. 4. Impacts on Ambient Air Quality Th e aircraft NOx emission standards we are proposing would impact ambient concentrations of air pollutants. Nationally , levels of PM 2.5 , ozone, and NO X arePrivileged 

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Page 40 of 165 declining. 38 However as of 2008, approximately 127 million people lived in counties that exceeded an y NAAQS. 39 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 ozo ne 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 ozo ne NAAQS. The attainment dates for areas designated nonattainment for a revised primary ozone NAAQS could range from 2015 to 2032 , depending on the severit y of the problem. 40

38 U. S. EPA (20 10 ) 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 - 0 9 - 00 2 . This document can be accessed electronically at: http://www.epa.gov/airtrends/2010/ . 39 U. S. EPA (20 10 ) 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 - 0 9 - 00 2 . This document can be accessed electronically at http://www.epa.gov/airtrends/2010/ . 40 U .S. EPA ( 2010 ) , Fact Sheet Revisions to Ozone Standards. This document can be accessed electronically at: http://www.epa.gov/groundlevelozone/pdfs/fs20100106std.pdfPrivileged 

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Page 41 of 165 Areas designated as not attaining the 1997 PM 2.5 NAAQS will need to attain the 19 97 standards in the 2010 to 2015 time frame, and then maintain them thereafter. The 2006 24 - hour PM 2.5 nonattainment areas will be required to attain the 2006 24 - hour PM 2.5 NAAQS in the 2014 to 2019 time frame and then be required to maintain the 2006 24 - hour PM 2.5 NAAQS thereafter. The aircraft engine emission standards being proposed today were a pproved by

ICAO /CAEP and would have an implementation date of 201 3 . Therefore, the aircraft engine emission reductions that are being proposed today should be useful to states in attaining or maintaining the PM 2.5 NAAQS. EPA has alread y adopted many emission control programs that are expected to reduce ambient ozone and PM 2.5 levels and which will assist in reducing the number of areas that fail to achieve the NAAQS . Even so, our air qualit y modeling projects that in 2030 as man y as 16 counties with a population of almost 35 million may not attain the 2008 ozone standard of 0.075 ppm (75 ppb). 41 In addition, our air quality modeling projects that in 2030 at le ast 9 counties with a population of almost 28 million may not attain the 1997 annual PM 2.5 standard of 15 μg/m 3 and 26 counties with a population of

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

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Page 42 of 165 over 41 million may

not attain the 2006 24 - hour PM 2.5 standard of 35 μg/m 3

. 42 Th ese 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 an y reductions in NO X ensuring long - term maintenance of the NAAQS. There ar e currently

no NO2 nonattainment areas. However, the NO2 standards were recently

revised and a new 1 - hour NO2 standard was promulgated . 43 Nonattainment area designations for the 1 - hour NO2 standard are expected to be finalized in 2012 . These proposed air craft 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 increasingl y more stringent NOx emission standards for gas turb ofan engines with maximum rated thrusts greater than 26.7 kilonewtons (kN). 44 Each of the tiers would potentially appl y to newl y - certified

42 U.S. EPA (2010). Regulatory Impact Analysis: Final Rulemaking to Establish Light - Duty Vehicle Greenhou se Gas Emission Standards and Corporate Average Fuel Economy Standards. Chapter 7: Environmental and Health Impacts. EPA 420 - R - 10 - 009. 43 U.S. EPA, "Primary National Ambient Air Quality Standards for Nitrogen Dioxide;" Final Rule, 75 FR 6474, February 9, 2010. 44 The proposed standards would apply to engines used in commercial and noncommercial aviation for which the FAA issues airworthiness cert ificates, e.g., non - revenue, general aviation service. The vast majority of these engines are used in commercial applications. See section V.A.2. for more information regarding noncommercial applications.Privileged 

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Page 43 of 165 engines. Newl y - certified aircraft engines are those that would receive a new ty pe certificate after the effective date o f the applicable standards . Such engine ty pes or models would not have begun production prior to the effective date of the new requirement. 45 We are also proposing to apply the first tier of the two tiers of standards to n ewly manufactured engine s. Newl y - manufactured aircraft engine s 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 newl y - manu factured engines would need to comply with the same NOx limits as newly - certified engines , but at a later date or cease production. 46 The end of this “phase in” period for the newl y - manufactured engine standards is sometimes referred to a

“production cutof

f , ” for obvious reasons. Again, w e are proposing onl y the first of the

45 ICAO standards describe newly - certified engines as “...engines of a type or model for which the date of manufacture of the first individual production model was after....” the effective date of the emission standards. See ICAO, “Aircraft Engine Emissions,” Annex 16, Volume II, Third Edition, July 2008, Amendment 4 effective on July 20, 2008. Copies of this document can be obtained from the ICAO website at www.icao.int . 46 The standards for newly - manufactured engines are described in general regulatory terms as the date that the type or model was first certified and produced in conformance with specific emission standards, and the date beyond which an individual engine meeting those same requirements cannot be made. So ICAO standards describe newly - manufactured engines as “...engines of a type or model for which the date of manufacture of the first individual production model was after....” the effective date of the applicable standards, and “...for which the date of manufacture of the individual engine was on or before....” a spe cific 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 we bsite at www.icao.int .Privileged 

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Page 44 of 165 two new tiers of NOx standards for newl y - 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 propose d new NOx standards because of specific technical or economic reasons 47 . Second, we are proposing to clarify when the emission characteristics of a new engine model have become different enough from its existing parent engine design, i.e., a “derivative” o f an originally certified engine ty

pe, that it must receive an emissions approval demonstrating conformance with the latest emission standard. Third, we are proposing new CO and NOx standards for turbofan engines that are used to propel supersonic aircraf

t. These standards were adopted by I CAO 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 IC AO’s Annex 16 and to incorporate the entire annex in our regulations b y

47 These apply only to the Tier 6 NOx standards as discussed below . We are not yet proposing a production cutoff for the Tier 8 NOx standard.Privileged 

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Page 45 of 165 reference . Finally , as described in Section IV, we are proposing amendments to current regulatory

provisions addressing definitions, acrony ms and abbreviations, general applicability

and requirements, exemptions, and incorporation b y 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 discussed in section III.D., the proposed amendments reflect those changes that were previously

adopted by

I CAO 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 I CAO takes final action to help ensure that our standards, and the FAA’s implementing regulations, are adopted in a timely manner once I CAO completes its process . We anticipate that our final standards would generall y conform to I CAO’s final standards, once adopted. This would b etter e nable the regulated industry to respond to new, globally harmonized requirements in an orderl y manner, which is important given the international nature of the market for the aircraft engines that would be affected b y 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 recommend ed byPrivileged 

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Page 46 of 165 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 s ection I. B . More specifically , the technical feasibility and cost of the proposed emission standards were well documented by our own anal ys es and CAEP as described later in this section and in s ection V . , Regulatory Impacts. 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. W e have consulted with the Department o f Transportation through the FAA regarding leadtime, noise, safet y, and the technical feasibility of the proposed standards. Today ’s proposal is also consistent with U.S. treat y obligations under the Chicago Convention as described in section I. C ., becaus e the proposed requirements are consistent with current ICAO standards or those that we expect I CAO 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, w e 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.Privileged 

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Page 47 of 165 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 Tie r 8 NOx standards , we are not actuall y 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 t ypes subject to future revised NOx standards . W e are proposing to adopt a new naming convention in this preamble and the regulatory

text to more easily

distinguish between the proposed tiers of increasingl y more stringent NOx emission standards. This convention is also consistent with the numeric identifier that CAEP us es 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., Ti er 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 NOxPrivileged 

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Page 48 of 165 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 Standar ds for Newly - Certified Engines W e are proposing two different tiers of increasingly stringent NOx standards. These standards would apply for all for newly - certified turb ofan aircraft engines with maximum rated thrusts greater than 26.7 kN . 48 (See section III.B for a discussion of how these standards would apply for newl y - manufactured engines that are not con sidered to be newl y 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 propo sed tiers is described separately below. 1. Tier 6 NOx Standards for Newl y - Certified Engines This first tier of proposed standards is equivalent to the CAEP/6 NOx limits that were alread y adopted b y ICAO and became internationally effective after December 31,

48 There are no gaseous emission standards, e.g., NOx, for gas turbine engines with maximum rated thrusts equal to or less than 26.7kN. These engines are, however, subject to smoke and fuel venting standards.Privileged 

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Page 49 of 165 2007. Given that aircraft turb ofan engines are international commodities, engine manufacturers have already introduced engine models after that date that demonstrate compliance with these international standar ds , or are alread y planning to do so for upcoming engine designs. Based on this, and on our evaluation of the necessary leadtime, 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 newl y - 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)Privileged 

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Page 50 of 1 65 • 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 stand ards 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 greater than 62.5 for the CAEP/6 pressure ratios at or above 82.6. 49

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

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Page 51 of 165 The resulting proposed Tier 6 NOx standards for these higher thrust engines are presented in Figure 1 along with the most recentl y 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 Fi gure 1: P ro posed Ti er 6 N OxS ta ndards fo r Hi gher T hr ust E ngi nes

0 20 40 60 80 100 120 140 160 180

10 30 50 70 90 Pre ssu re Rat io ( PR)g/kN Thrust Ex is ting Standar d Pr opos ed Tie r 6

8% Reducti on Current En gine PR s

12% Reducti onPrivileged 

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Page 52 of 165 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 techno logy engines ranges from about 8 to 12 percent. b. Numerical Emission Limits for Lower Thrust Engines The proposed Tier 6 NOx standards for newl y - certified gas turbine engines with rated thrusts between 26.7 and less than 89.0 kN are differentiated b y bo th 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 corres ponding NOx standards for low thrust engines, CAEP recognized the technical challenges that ph ys ically smaller - sized engines represent relative to incorporating some of the lowest NOx technology , which is otherwisePrivileged 

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Page 53 of 165 available to their larger counterparts. These technical difficulties are well documented and increase progressively as size is reduced (from around 89 kN ). 50 For example, the relativel y small combustor 51 space and section height of these engines creates constraints on the use of low NO x fuel - stag ed combustor concepts which inherentl y 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 relativel y smaller tota l 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 inherentl y greater liner surface - to - combustion volume ratio, and this requires increased wall cooling air flow. Thus, less air will be available to obtain acceptable turbine inlet temperature distribution and for emissions control. 52 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 comparativel y less stringent, i.e., CAEP/6 relative to

50 ICAO/CAEP, “Report of Third Meeting, Montreal, Quebec, December 5 - 15, 1995,” Docum ent 9675, CAEP/3. 51 The combustor is a chamber where a mixture of fuel and air is burned to form very hot, expanding gases. As these gases move through the combustion chamber, the walls of the combustor are cooled with dilution air to prevent thermal damage. Dilution air is also used to tailor the gas’ temperature profile as it exits the combustor so that the final temperatures will not exceed the allowable limit at the turbine inlet. 52 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 .Privileged 

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Page 54 of 165 CAEP/4, as the rated output and phy sical size of the engines decrease. We agree wi th 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 showi ng 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 engin es based on the engine size versus technological challenge described in the previous paragraph. C omparing 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 delineati on point. Again focusing onl y on 89 kN engines, the proposed Tier 6 standards represent a 12 percent reduction from the existing EPA CAEP/4 - based standards (Tier 4) for pressure ratios of 30 or less as shown below in Figure 2. This includes the region r epresented b y almost all current engine designs. At higher pressure ratios, the relative numericalPrivileged 

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Page 55 of 165 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 an y pressure ratio becomes progressivel y s maller 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, th e 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

Fi gure 2: P ro posed Ti er 6 N OxS ta ndards fo r Lower T hr ust E ngi nes Rat ed at

8 9. 0 kN

0 20 40 60 80 100 120 140 160 180

10 20 30 40 50 60 Pres su re Rat io ( PR)g/kN Thrust Ex is ti ng Standar d

Pr opos ed T ier6

12% R educ ti on Current E ngine PR sPrivileged 

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Page 56 of 165 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 b y 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 .

2. Tier 8 NOx Standards for Newl y - Certified Engi nes 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 b y Figur e 3: Pr opose d T ie r 6 N Ox Standar ds for Low erT hr ust Engine s A

t Pre ssur e Ra tio 30

40 50 60 70 80 90 100

20 40 60 80 100 Thrus t (kN)g/kN Thrust Ex is ting Standar d

Pr opos ed Tier6

0% R educ tion at 26.7k N 12% R educ tion at 89kN Cu rre nt Engi ne Thr us tsPrivileged 

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Page 57 of 165 ICAO. 53 The CAEP/8 recommended standards have a recommended effective date after December 31, 2013. As discussed further in section V . o f today ’s notice, we agree with CAEP that this provides engine manufacturers with adequate leadtime to respond to these more stringent NOx standards considering the technical feasibility and cost asso ciated 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 correspondingl y 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 turb ofan engines is different for higher - and lower - rated thrust engines. Higher output engines are defined as having rated thrusts equal to or greater than 89 kN , while lower output engines are defined as having rated thrusts less than 89 kN but greater than 26.7 kN . The longer - term standards for each of these power grouping are described separatel y below. a. Numerical Emission Limits for Higher Thrust Engines

53 CAEP/7 did not adopt new aircraft eng ine NOx standards.Privileged 

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Page 58 of 165 The proposed Tier 8 NOx standards for newl y - certified turb ofan 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 les s 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 fol lowing 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 press ure ratios of 30 to 82.6 for the CAEP/8 pressure ratios of 30 to 104.7;Privileged 

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Page 59 of 165 • 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. 54 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.

54 Reverting to the CAEP/6 slope at a pressure ratio of 104.7 prevents the CAEP/8 standard from otherwise intersecting the older CAEP/2 standard at this point and thereby actually making CAEP/8 less stringent than CAEP/2. It has no pract ical 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. Fi gure 4: P ro posed Ti er 8 NOx St andards fo r Hi gher T hrust Engi nes

0 20 40 60 80 100 120 140 160 180

10 30 50 70 90 Pres su re Rat io ( PR)g/kN Thrust Pr opos ed Tier6 Pr opos ed Tier8 Cur rent En gine PRs

19% Reducti on

15% Reduct ion 11% Reducti onPrivileged 

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Page 60 of 165 As noted previousl y, as a matter of convention the relative stringency from one CAEP standard to another is generall y 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 stringen cy

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 engine s ranges from about 11 to 19 percent. b. Numerical Emission Limits for Lower Thrust Engines The proposed Tier 8 NOx standards for newl y - certified gas turbine engines with rated thrusts between 26.7 but less than 89.0 kN are differentiated b y both pressur e 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 eng ines 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)Privileged 

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Page 61 of 165 In developing the corresponding CAEP/8 NOx standards for low thrust engines, CAEP recognized the technical challenges that physicall y smaller - sized engines represent relative to incorporating some of the lowest NOx technology , which is otherwise available to their larger counterparts. These te chnical 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 high er 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 numericall y 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 incorp orated 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 reducti on 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.Privileged 

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Page 62 of 165 Third, at other thrust ratings the percent reduction between the proposed Tier 6 and Tier 8 standards at any pressure ratio becomes progressivel y smaller as thrust decreases. This is illustrated in Figure 6 for a pressure ratio of 30, following the convention described above. A lso a s shown in the figure for curre nt 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 . H owever, the actual numerical values f or 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 Fi gure 5: P roposed Ti er 8 N OxS ta ndards fo r Lower T hr ust E ngi nes Ra te d at 89. 0 kN

0 20 40 60 80 100 120 140 160 180

10 20 30 40 50 60 Pres su re Rat iog/kN Thrust Pr opos ed Tier6

Pr opos ed Tier8

Cur re nt En gine PRs 15% Reducti on 23% Reducti on 19% Reduct ionPrivileged 

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Page 63 of 165 F igure 6 at 26.7 kN , i.e., a 5 percent reduction at all pressure ratios for that thrust rating . However , percent reductions increase linearl y up to a maximum 23 percent reduction for 89 kN engines with pressure ratios of about 15.

B. Application of the Tier 6 NOx Standards to N ewly - Manufactured Engines This section describes our proposal to appl y the proposed Tier 6 NOx standards to newly - manufactured engines, and our proposed amended temporary flexibilities for newly - manufactured engines that may have significant problems compl yi ng with these requirements. Also , consistent with CAEP/8, we are not proposing to apply the Tier 8

Fi gur e 6: P ro posed Ti er

8 N Ox S tandards fo r Lower Thr ust

E ngi nes at

P ressure Ra tio 3 0

40 50 60 70 80 90

20 40 60 80 100 Thrus t (kN)g/kN Thrust Pr opos ed Tier6

Pr opos ed Tier8

Cur re nt E ngine Th ru sts 15% Reduct ion at 89 kN 5% Reduct ion at 2 6. 7 kNPrivileged 

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Page 64 of 165 NOx standards to newly - manufactured engines at this time . T his section concludes with a description of future efforts to examine such a pos sibility . 1. Phase - In of the Tier 6 NOx Standards for Newly - Manufactured Engines As described above, the proposed Tier 6 NOx standards would appl y to all engine ty pes or models that receive a new ty pe certificate after the effective date of the final r ule. We are also proposing to phase - in these same NOx limits for newly - manufactured engines for engine models (and their derivatives) that were originally certified to less stringent requirements ( i.e ., Tier 2 or Tier 4) and were already being produced fo r installation on new aircraft prior to the effective date of the final rule . 55 As a result, manufacturers would need to bring newly - manufactured engines of these previously certified models into compliance with the applicable Tier 6 standards b y a future date or cease production of those engine models. 56 As we discussed and describe d in our anal ys is 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

55 The requirement that newly - manufactured engines must meet the CAEP 6 NOx standard by a date certain applies only to engines that are intended to be installed on all new airframes. It would not apply to engines produced as “spares,” which are intended to be installed on existing airframes as replacements for maintenance or other reasons. See section III.B.2.b. for more information about new and spare engines. 56 After this date the production of any noncompliant engines would cease because the FAA w ould d iscontinue issuing an airworthiness approval tag (FAA Form 8130 - 3) to these engines.Privileged 

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Page 65 of 165 will be achieved in a reasonable time. 57 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, 201 3 58 for the newl y - manufactured engine s tandards is consistent with the expected market demand for these previously certified engine ty

pes. Historically , engine manufacturers have often responded to the adoption of more stringent NOx standards by bringing older engine t ypes 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 59 , 60 , 61

57 ICAO, Committee on Aviation Environmental Protection (CAEP), Eight Meeting, Montreal, 1 to 12 February 2010, Agenda 2: Review of Technical Proposals Relating to Airc raft 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. 58 The proposed regulatory text specifies that engine m odels 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 new - manufactured engines is effectively January 1, 2013. 59 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, Prese nted by U.S. Representative, August 6, 2009. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 60 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 2009, Agenda Item 3: F orecasting 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. 61 ICAO, Committ ee 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.Privileged 

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Page 66 of 165 and our mo re recent discussions with manufacturers indicate that : 1) all but a few models are alread y compliant with CAEP 6 standards , 2) nearl y without exception, all current production models will meet the CAEP 6 requirements by the 2011 time frame, and 3) any no ncompliant models will be phased out of production because of low market demand. W e think that the proposed five - ye ar phase - in p eriod from IC AO’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 significantl y d isrupting their future planning and purchasing decisions. 62 , 63 T his phase - in period for applying the Tier 6 NOx standard s to newly - manufactured engines is identical to the date for this same requirement that CAEP /8 has recommended to I CAO for adoption. 64 Therefore, we are proposing that all engines newl y - manufactured after December 31, 2012 must comply with the Tier 6 NOx s tandards. Again, if IC AO ultimately adopts a production cutoff date that differs from

62 The ICAO CAEP/6 NOx standards became effective after December 31, 2007. 63 This period of time is also consistent with the phase - in period associated with previous ICAO sta ndards. 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. 64 We expect that ICAO will formally adopt the CAEP/8 recommendations in early 2011, which is well before the projected effective date of our final rule.Privileged 

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Page 67 of 165 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 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 exemption from meeting the Tier 6 NOx standards. 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 b y the proposed revisions.) This section of the preamble describes these proposed exemption provisions which have largel y been crafted to be consistent with exemption provisions in the I CAO Environmental Technical Manual (ETM). 65 , 66 The provisions of th e ETM guidance were crafted in the context of the CAEP/6 NOx production cutoff deliberations leading up to the CAEP /8 meeting in February 2010.

65 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 num ber EPA - HQ - OAR - 2010 - 0687. 66 Note that EPA has submitted a paper to amend the exemption provisions included in this ETM to be consistent with this proposed rule. See ICAO, “Newly Produced Engine Exemptions for CAEP/6 NOx Production Cutoff

, ” CAEP9_WG3 - CTG - 2_IP01, September 23, 2010. A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 68 of 165 While we are proposing to revise our regulations, the process for evaluating any request for an exemption and an y final decisi on 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 . T he FAA must consult with EPA in evaluating the merits of the request, and the EPA must formally concur with an y 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 full y compliant with the emission st andards. 67 Several such short - term exemptions were granted in the 1980s when emission standards were first applied. These exemptions have since expired, and requests for new exemptions under those provisions have not been submitted ; therefore, we believe that the provisions allowing for such exemptions are no longer of any utility , and are proposing to delete these provisions. We are also proposing to delete the existing provision s for temporary

exemptions based on flights for short durations and infrequent intervals. Th ese provision s are not necessary because our standards appl y to aircraft certificated b y the FAA , and the FAA does not address in the certification process

67 An exemption allows an engine manufacturer to produce an engine that does not meet current NOx emission standards, even though the current NOx standard would otherwise apply. Such engines w ould need to meet the curr ent emission standards for other pollutants. Exempted engines must also meet a less stringent NOx emission standard. Exempted engines must therefore still get FAA certification.Privileged 

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Page 69 of 165 whether an aircraft will be used for short durations or infrequent interval s . Hence, the provisions are of no utility. The current regulations also provide for permanent exemptions based on consideration of the certain factors specified in §87.7(c) . We are proposing to replace these provisions with new regulatory text consistent with the ETM that would provide for two separate ty

pes of permanent exemptions: exemptions 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 exemption provisions in §87.7(d). These provisions , which were intended for when the standards of §§87.11(a), 87.31(a), and 87.31(c) took effect, are now obsolete.

a . New Provisions for Spare Engi nes This proposed exemption is intended to allow production and sale of a newly manufactured engine for installation on an in - service aircraft (i.e., a “spare engine”). It would not allow for installing such an engine on a new aircraft. Spare engines are produced from time to time in order to keep an aircraft in revenue service when the existing in - service engine must be removed for maintenance purposes. Otherwise removing these aircraft from active service would be very expensive and lo gisticall y difficult. Also, under our proposed regulations, there would be no adverse environmentalPrivileged 

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Page 70 of 165 effect from allowing the use of a spare engine as a direct replacement for an existing engine, because a spare could be used only whe n the emissions of the spare engine are equal to or lower than those of the engine it is replacing, for all pollutants. While manufacturers would not be required to obtain FAA or EPA approval before producing or shipping spare engines, they would have to submit an annual report to the EP A with information about spare engines. The permanent record for each engine exempted under this provision would need to indicate that the engine is an exempted spare engine and the engine itself would need to be labeled as “EXEMPT SPARE . ” in a ccordance with FAA marking requirements of 14 CFR . Exemptions for spare engines are not addressed in the existing regulations because there is not a production cutoff for the current Tier 4 NOx standards. Thus manufacturers have been allowed to continue production of older engine designs under ty pe 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 newl y manufactured engines means that if we did not also propose this exemption process, manufacturers would be prohibited from producing Tier 4 spare engines under the existing ty

pe certificates. W e see no reason to change our policy of al lowing manufacturers to produce new engines for use as spares . The proposed regulatory provisions would allow this practice to continue.Privileged 

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Page 71 of 165 Under the proposed regu lations, engines meeting the requirements for spare engines could be produced and enter into co mmerce without prior approval from EPA. ( The FAA intends to adopt its own separate provisions for overseeing production of spare engines.) It is important to note that while engines would be exempt from the Tier 6 NOx standards being proposed today , they would still need to be produced under an FAA t yp e certificate . ( This FAA oversight w ould essentially serve as the same role as the exemption approval step envisioned by IC AO in its ETM language for spare engines.) We would expect little or no additional burden for manufacturer s, since we are not proposing new restrictions , monitoring, recordkeeping, or reporting requirements other than the end of ye ar 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 cyc les in the time frame when new emission standards take effect. The ty pical production cycle would have annual production volumes ramp up quickly , remain at relatively large volumes for several or many y ears, and then fall off over a few more y ears. When new emission standards arePrivileged 

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Page 72 of 165 adopted in the middle of a production cycle to take effect a few y ears later, manufacturers generall y devote technical resources to bringing 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. T he actual length and shape of this tail of production volumes can be affected b y factors not full y within the engine manufacturers’ control , e.g., unexpected market demand . Thus , exemptions may be needed if a manufacturer does not complete the production cycle before the production cutoff date and projected production volumes are not adequate to justify resource investment to reduce emissions or there are other technological issues . 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 availab ility . Our regulations currentl y address these kinds of situations in sections 87.7(c) and (d), entitled, respectivel y, “Exemptions for New Engines in Other Categories,” and “Time L imited Exemptions for In Use Engines.” Today ’s proposed amendments would replace these provisions with a new set of provisions addressing exemptions for newPrivileged 

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Page 73 of 165 engines. We invite public comment on any other way s to address the need for flexibilities in the above circumstances. i . Time Frame and Scope T he proposed regulations would allow manufacturers to request an exemption for engines not meet ing the Tier 6 NOx standards to be installed in new aircraft . If granted, the exemption would allow manufacturers to produce a limited number of newly manufactured engines, in a time period beginning after December 31, 2012 and going through December 31, 2016. The time period for any given approved exemption could be shorter depending on the specifics of the application but could not be longer. This exemption would be limited to NOx emissions from engines that are covered by a valid ty pe certificate issued by

FAA. The engines would be required to meet all other applicable requirements. More specificall y, an engine exempted from the Tier 6 NOx s tandards would need to be covered b y a previously issued ty pe certificate showing compliance with the Tier 4 NOx standards, 68 as well as the current HC, CO, fuel venting, and smoke standards. ii . Production L imit

68 Engines certified only for compliance with earlier NOx standards w ould 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 NOx they may be recertified to the Tier 4 standards, but only before the effective date of the proposed regulations.Privileged 

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Page 74 of 165 We are proposing that the number of engin es eligible for exempt ions would generall y not be allowed to exceed 75 engines per manufacturer

– or more precisel y per ty pe certificate holder. 69 , 70 Any specific approved exemption would include a specific limit based in part on the information presented in the manufacturer’s exe mption request. We acknowledge that this proposed limit differs from the current ICAO ETM exemption guidance , which would generall y allow up to 75 engines per type certificate. 71 While our proposal is different than the current ETM guidance (assuming under the ETM guidance an y m anufacturer might seek multiple exempti o ns for more than a total of 75) , it would have practical significance onl y to the extent that an y manufacturer seeks exemptions for more than one engine ty pe and cou ld separatel y justify exempting sufficient numbers of each ty pe to exceed the 75 total. We do not expect this situation to occur for the Tier 6 NOx standards for the reasons discussed below .

69 Under norm al circumstances, the number may not exceed 75 engines per type certificate holder. How ever, in unusual circumstances, a type certificate holder may ask that this limit be waived . 70 While in most cases the type certificate holder and the production organization are the same, there are cases where more than one production organization exists for a given type certificate. This is especially likely to be the case in joint ventures. In such cases, we would exp ect that the type certificate holder and its production organizations would need to coordinate in the development of exemption application requests, and that the type certificate holder would ultimately need to take responsibility for coordinating requests -- in order to avoid a situation where the cumulative exemption requests exceeded 75 for a given type certificate holder. Note that this preamble discussion generally uses the term manufacturer for simplicity. 71 CAEP/8

– WP/18, Environmental Technical Ma nual (ETM), Vol II on the Use of Procedures in the Emission Certification of Aircraft Engines, Appendix ”ICAO Emissions Environmental Technical Manual”.Privileged 

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Page 75 of 165 Prior to the CAEP/8 meeting in February 2010 , I CAO 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: Inconsidering exemptions, certificating authorities should take into account the pro bable 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 I CAO/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 po tential exemptions from that requirement. 72 The provisions would help support an orderl y transition in the implementation of the production cut - off. Toward that end, the group consulted periodicall y over several months to craft provisions addressing number, time limit, and emission levels (impact on the environment). The deliberations were complicated b y the

72 ICAO, “Committee on Aviation Environmental Protection (CAEP), Report of the 6 th 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.Privileged 

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Page 76 of 165 fact that the language in Annex 16 simultaneously addressed both engines for new production aircraft and spare engines for existing aircraft. 73 For both new production and spare engines agreement was reached relatively quickly that the time period for exemptions to be available should be four years after the production cut - off becomes effective and that any engine model for which an exemption was requested should meet at least the emission standards being affected by the cut - off. In this case engines would have to meet at least 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 during the four - ye ar period since these would essentially be replacing in use engines removed for maintenance or other reasons. 74 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 I CAO Emissions Data Bank identified 20 unique engine models/sub models that could have been affected by the production cutoff. Those models

73 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. 74 ICAO, “Committee on Aviation Environmental Protection (CAEP), Eighth Meeting, Montreal, 1 to 12 February 2010,” CAEP/8 - WP/80, Appendix B, April 2, 2010. A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 77 of 165 had valid ty

pe certificates and therefore were consid er ed to be “in production.” 75 During further discussions the engine manufacturers clarified that most of these 20 were not in active production because the airlines normall y purchase new aircraft with engines meeting the latest emission standards. However, it was stated that if the demand existed, 14 of these 20 models could be produced under the exemption provisions since they had valid ty pe certificates and met the previously mentioned exemption emission requirements . 76 , 77 , 78 , 79 After much deliberation, the technical working group settled on a value of 75 engines per ty pe certificate over the four years for the ICAO ETM guidance. 80

75 U.S. EPA, “Simplified Working Cop y of ICAO EDB, Issue 16A,” Glenn Passavant, Assessment and Standards Division, March 25, 2010. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 76 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 num ber EPA - HQ - OAR - 2010 - 0687. 77 ICAO, “Committee on Aviation Environmental Protection (CAEP), Production Cut - Off for Engine NOx Standards,” CAEP - SG/20082 - WP/6, P resented by FESG, September 4, 2008. A copy of this document is in docket num

ber EPA - HQ - OAR - 2010 - 0687. 78 ICAO, “Committee on Aviation Environmental Protection (CAEP), CAEP/6 NOx Productin Cut - Off Analysis,” CAEP - SB/20093 - IP/19, Presented by FESG NOx Strin gency Task Group, June 2, 2009. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 79 ICAO, “Committee on Aviation Environmental Protection (CAEP), Production Cut - Off and Associated Flexibilities for ICAO Engine Emission Standards,” CAEP - SB/20093 - WP/39, U.S.EPA, June 8, 2009. A copy of this document is in docket num ber EPA - HQ - OAR - 2010 - 0687. 80 ICAO, “Committee on Aviation Environmental Protection (CAEP), Eighth Meeting, Montreal, 1 to 12 February 2010,” CAEP/8 - WP/80, Appendix B, April 2, 2010 . A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 78 of 165 This value was of concern to EPA. First, in the worst case, it represented the potentia l 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 shipp ed in a single ye ar. 81 Second, from a broader perspective, while EPA regulations normally include hardship ty

pe provisions, it is not normal for EPA to include transitional exemptions of this magnitude in our regulations. Instead , we provide for other means such as emission credit programs to provide the flexibility necessary to transition into or out of emission control requirements. Such an emission credit - related provision was recognized in the ETM guidance as being a potentially useful adjunct that may

be required “...in vew of the number of engines for which exemptions are sought (e.g., greater than 30), duration and/or exceedance described in an application . ” However, such provisions are helpful when considerati n g exemptions from the CAEP/6 production cutoff because the re are no NOx credits available today . We began our assessment of a reasonable limit for potential exemptions from the CAEP/6 standards by

noting the underlying conditions that may support the need for such provisions. In this regard, it is often the case that the engine modifications needed to

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

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Page 79 of 165 meet more stringent standards and subsequent recertification are often an expensive undertaking. When future sales are projected to be larger in number, manufacturers have argued that economics favor a return on investment and that market forces dictate that they make the investment to so that they have fully

compliant engines to meet customer demands. 82 , 83 Inthese cases exemptions would probably not be necessary . However, when an engine model has low expected future sales, i.e., near the end of its production life, th e n the economics involved in transitioning to a new emission standard are less attractive and the market forces argument is less compelling. In such cases, li mited exemptions may

be appropriate. To help inform us regarding situations such as those described above, w e looked at past production histories and projected future orders of engine models, focusing on the ye ars associated with the production cutoff wh erever possible. 84 We utilized the ASCEND Database 85 to conduct this analy sis. ASCEND contains information on past

82 ICAO, “Committee on Aviation Environmental Protection (CAEP), Response to U.S. EPA Papers 14 and 16” WP3 Flimsy 6 - 2, ICCAIA, April 1 - 3, 2009. A copy of this document is in docket number EPA - HQ OAR - 2010 - 0687. 83 ICAO, “Committee on Aviation Environmental Protection ( CAEP), NOx Production Cut - Off Considerations,” ICCAIA, January 9, 2009. A copy of this document is in docket number EPA - HQ - OAR 2010 - 0687. 84 U.S. EPA, “E ngine E xemption A llowable L imit A ssessment, ” Memorandum from Brad Nordman to Glenn Passavant, Assessment and Standards Division, Office of Transportation and Air Quality, April 2011. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 85 ASCEND Online ( www.ascendworldwide.com) is a database that includes comprehensive transaction data, orders and deliveries, and airline fleet historiesPrivileged 

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Page 80 of 165 production volumes and projected production volumes for future y ears based on either actual orders for aircraft or potential new orders. The results of this anal ys is were supportive of a limit for potential exemptions from the CAEP/6 standards that was much less than the ETM guidance of 75 engines per t yp e certificate. Rather it appeared a number of approximately 100 engines per t ype certific ate holder was more likely to be adequate . In addition , two new pieces of information became available during the development of this proposed rule that were un available during the deliberations leading up to the I CAO decision for the ETM guidance . Fi rst , 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 granted since 1983, onl y three involved exemptions during standards transition ( two related to smoke for turboprop engines and one related to NOx for a turbo fan engine). These three exemption petitions in combination ultimately

affected less than 50 engines. 86 Second , engine manufacturers indicated individually

that the potential need fo r exemptions was not as large as EPA understood during the technical working group deliberations, and that absent unforeseen

86 U.S. FAA, "Historical Exemptions from Gas Turbine Aircraft Engine Emission Standards," Electronic spreadsheet from Edward McQueen, Office of Environment and Energy, September 22, 2010. An extract from this spreadsheet addressing the pertinent issue is in docket num ber EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 81 of 165 events, a much smaller value was workable on a per manufacturer basis as opposed to a per ty pe certificate basis. 87 , 88 , 89 Our subsequent discussions with engine manufacturers affected by the proposed Tier 6 NOx standards, i.e., CAEP/6 standards, resulted in a consensus that a numerical limit of 75 exempt engines per manufacturer, or more specifically t yp e certificate holder, with some flexibility

for additional exemptions to allow for very unusual circumstances, was reasonable for the proposed Tier 6 NOx standards. It was also agreed that if a newly - manufactured engine requirement is considered in the future for the proposed Tier 8 NOx standards i.e., CAEP/8 standards, than an y numerical limit associated with those standards would need to be evaluated based on information available at the time. Therefore, based on the above and after consultation with FAA, EPA is proposing to keep th e 75 engines from the ETM guidance, but apply it on a per ty

pe certifi cate holder basis with some flexibility to increase the limit in very unusual circumstances .

87 ICAO, “Committee on Aviation Environmental Protection (CAEP), Response to EPA Paper 14 and 16,” WG - 3 Flimsy 6 - 2, ICCAI A, London, UK, April 13, 2009. A copy of this document is in docket num ber EPA - HQ - OAR - 2010 - 0687. 88 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 num

ber EPA - HQ - OAR - 2010 - 0687. 89 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.Privileged 

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Page 82 of 165 W e believe this approach addresses the intent of the I CAO guidance and the potential need of the 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. W e have also submitted a paper through the ICAO/CAEP process seeking to align the ETM guidance with the provisions in this proposal. 90 While it is not possible to know precisel y how many engines (if any

at all) might qualify for exempt ions during the four - ye ar period , we can estimate a worst - case scenario. For example, previous CAEP anal ys is indicated that there are four engine manufacturers with product that d id not yet meet the proposed Tier 6 NOx standard. If each of these t ype certificate holders applie d for and were granted the maximum allowable 75 exemptions over the four - ye ar period, the total of 300 exempted engines worldwide would onl y be 2 - 3 percent of the newly produced fleet. 91 More recent information from engine manufacturers suggests, however, that onl y one or two manufacturers may

each request an exemption for a single engine model (i.e., a total two exemptions for two ty

pe certificate holders). In this case, and assuming each ty pe

90 ICAO, “Ne wly 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 n umber EPA - HQ - OAR - 2010 - 06 87. 91 ICAO, “Committee on Aviation Environmental Protection (CAEP), Production Cut - Off and Associated Flexibilities for ICAO Engine Emission Standards,” CAEP - SB/20093 - WP/39, U.S.EPA, June 8, 2009. A copy of this document is in docket num ber EPA - HQ - OAR - 201 0 - 0687.Privileged 

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Page 83 of 165 certificate holder requested 75 exemptions, then the exempted engines w ould represent only 1 - 2 percent of sales over the four - ye ar exemption period. iii . Ex emption 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 currentl y required. The FAA will then inform and share the submittal with EPA . 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 i s 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 repre sentative’s contact information (including a signed statement verifying the information) ;

• Description of the engines for which you are requesting the exemption, including the e ngine model and sub - model names;Privileged 

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Page 84 of 165 • The number of engines that you would produce under the exemption and the period duri ng which you would produce them;

• Id entify the authorizing t ype certificate (t y pe certificate number and date);

• In formation 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

• Li st 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 i mpact of granting the exemption;

• Technical issues, from an environmental and airworthiness perspective, which may have caused a delay

in compliance w ith a production cutoff , if an y;

• Any economic impacts on the manufacturer, operator(s), and aviation industry at large; and

• Projecte d future production volumes and plans for producing a compliant version of the engine model in question.Privileged 

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Page 85 of 165 Other Factors

• Hardship: Impact of unforeseen technical circumstances , business events. Or other natural or manmade ca lami ties beyond your control, and

• Equity issues in administering the production cutoff among economically competing parties . It is important that an y action on a potential exemption request be in the public interest; the fairl y comprehensive list of application information in the proposed regulations is intended to gather the information needed for this assessment. We would exp ect 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 discussio n of economic and technical issues related to bringing the engine into compliance. The analy sis 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 onl y for NOx emissions, the analy sis could also include possible be nefits regarding noise levels or reduced emissions of pollutants other than NOx. Relevant economic impacts couldPrivileged 

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Page 86 of 165 include effects on the engine manufacturer, airframe manufacturer, airline(s), and the general public. In the past, some manufacturers have re quested exemptions based on the largest number of engines they

hoped to continue producing without knowing how many they would actuall y be able to produce or who would purchase them. The new exemption language calls for manufacturers to target their reque sts more specifically based on likely production needs and time periods. At an y time before approval, manufacturers could revise their requests to justify covering additional engines up to the allowable limit . We would then review the revised request. F or e xemptions that have alread y been approved , manufacturers could also ask for additional engines , again subject to the limit . If the y were able to justify

it, we would then amend the exemption. For example, in the past, a manufacturer with a potential customer interested in purchasing 10 engines might have requested an exemption to cover up to 100 engines in case they subsequently

find additional customers. Under the proposed regulations, the manufacturer would request an exemption for the first 10 eng ines. If additional engines are needed after approval of the exemption , including cases where they are needed by a different customer, the manufacturer could ask to amend their approved exemption to cover a higher number of engines. Manufacturers also wo uld 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.Privileged 

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Page 87 of 165 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 onl y for unusual circumstances. If, after consult ing with FAA, we determine that the exemption request i s fully documented and approval would be in the public interest, we would concur with approv ing 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 also be required to provide an annual report to EPA on exempt engines similar to the information about spare exe mpt 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 C FR . iv . Foreign Aircraft We are proposing that manufacturers also include in their requests a list of countries in which the aircraft are expected to be registered ( i.e., “ flagged ”) , as previously

noted . While not specificall y listed in the ETM, we believe that thisPrivileged 

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Page 88 of 165 information is consistent with the ETM as it would be necessary to ensure proper coordination with other countries in which these aircraft are expected to be registered. This coordination i s necessary because man y countries require FAA certification even for aircraft that will never operate in the U.S. Normally , we would not expect that we would approve an exemption for engines used on aircraft that would be registered in countries opposing the exemption. It is worth emphasizing that the proposed requirement for EPA concurrence with any FAA approval would apply equall y for engines that were exempted by foreign authorities if an y of them would be used on aircraft subject to U.S. regulations. The ETM appears to presum e that each member country will recognize exemptions granted by other countries. However, this presumption is conditioned upon the exemption being granted consistent with the guidelines of the ETM. Significantl y, the ETM requir es thorough coordination when exempted engines will be used in multiple countries. It states: Exemptions for new engines should be processed and approved b y the competent authorities for both the manufacture of the exempted engines and the initial operato r 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 ty pe c ertification is done through a reciprocity agreement between orPrivileged 

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Page 89 of 165 among member states, the states involved should coordinate on the processing of exemptions and concur before approval is granted. 92 Thus in most cases, manufacturers should be getting approval from all relevant authorities at the same time , e.g. , FAA, European Aviation Safety Agency ( EASA ) , and Foreign Civil Aviation Authority ( FCAA ) . However, whether they seek approval at the same time or in sequence , requiring EPA concurrence with an y FAA ap proval of exemptions for foreign aircraft subject to U.S. regulations is consistent with our international agreements. T he Clean Air Act (which provides EPA with its authority to establish emission standards) includes no provisions that would allow any fo reign country to exempt aircraft engines from the applicable standards promulgated thereunder. Nevertheless, since our proposed exemptions provisions are consistent with the procedures called for in the ETM, assuming appropriate coordination, we would not expect to object to exemptions to engines properly exempted b y other countries under those procedures. Finally , the proposed production limit would apply to worldwide sales of the exempted engines. More specificall y, w e would not grant an exemption that would

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 num ber EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 90 of 165 violate the ETM specifications with respect to worldwide sales. For example, where a manufacturer requesting an exemption already has an exemption for that same engine model that was issued by a foreign competent authority for 20 engines not subject to EPA emission standards , the maximum number of engines that we would exempt would be an additional 55. We believe that to approve more than 55 would be inconsistent with the ETM. We would also likely include as a co ndition of our exemption approvals that manufacturers could not obtain exemptions for more than 75 engines worldwide.

c . Voluntary

Emission Offsets We are requesting comment on establishing a voluntary EPA program b y which manufacturers could receive em ission 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 prese nted in the following paragraph. The t yp es of programs being considered would be administered solely by EPA. Therefore, the FAA would have no direct responsibility for a voluntary

emission offset program, although such a program would be considered b y bo th agencies when evaluating the merits of any exemption request. We would expect manufacturers to be interested in generating offsets

93 U.S. EPA, “Draft Regulatory Text for Voluntary Offset Program,” Memorandum from Charles Moulis, Assessment and Standards Division, to Docket EPA - HQ - OAR - 2010 - 0687, November XX, 2010.Privileged 

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Page 91 of 165 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 a n 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 limit of 75 exempted engines per manufacturer. Note that since this is not specificall y allowed in the proposed regul ations, we would need to amend the proposed regulations as part of the f inal r ule to allow this option. 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. Th ird , 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. Under this approach, generation of offsets would be voluntary and would be open to all certifying engine manufacturers. One concept would be to allow c redits to be generated only

from engine models that are introduced after this rule and that had characteristic level s significantly below the otherwise applicable standard (e.g., at least 10 percent below) . It is a separate question, however, how to calculate the c redit. If we adopted a 10 percent threshold for eligibility , we would probabl y also allow credits onl yPrivileged 

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Page 92 of 165 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 stan dard 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 emission benefits from one aircraft model truly offset the higher emissions from another model. For example, emissions from regional aircraft may not be di rectl y equivalent to emissions from aircraft designed for longer cross - country or international flights. Equivalency factors could be developed to account for differences in the number of LTOs per ye ars, the lifetime of the aircraft , and the number of LTO s 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. 3. Potential Phase - Inof New Tier 8 NOx Standards for Newl y - Manufactured Engines We are not proposing to phase - in the proposed Tier 8 NOx standard s 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 toPrivileged 

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Page 93 of 165 produce Tier 6 compliant engines within alread y certified models after the propo sed Tier 8 standards become effective for newl y - certified engine models. As noted elsewhere, EPA is working within the I CAO/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 I CAO , the committee decided to continue considering a related newly - manufactured engine standard as a future work item at CAEP , pending new information on technology and market responses . We will continue our efforts to evaluate a newl y - manufactured engine standard as a complement to the Tier 8 NOx standards as part of the future CAEP work program s . We believe that such a requirement is a necessary component of any

effective NOx control strategy

for aircraft turbine engines. It provides an orderl y , stable transition between emission requirements that is helpful for product planning b y 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, thereb y 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 currentl y recommended to I CAO, 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 timel y and orderl yPrivileged 

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Page 94 of 165 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 Engine s It is very common for a manufacturer to make changes to an originall y t yp e 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 if 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 “no emissions change” derivative version of the original model . 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 b y the engine manufacturer and then approved by the FAA’s certificating office. 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 , includ e s specificPrivileged 

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Page 95 of 165 criteria that can be used to determine when a design modification required a new demonstration of compliance with newer emission standards , or when a modification was simple enough to be considered a no emissions change . W e are proposing to include the ETM language in our regulations . This addresses a longstanding need to make the decision process regarding derivative engines and applicable emission standards more transparent and consistent. It will provide engine manufacturers with more certaint y regarding emission standard requirement s as they contempt future engine modificat ions . Finally , it will make the decision criteria enforceable. To ensure that the numerical decision criteria described below can be administered in a way

that allows for the consideration of unusual circumstances or special information, w e are also pro posing that the FAA have some flexibility to make adjustments to the specific criteria based on good engineering judgment . In summary , if the FAA determine s an engine model to be sufficiently similar to be considered a derivative engine, then the manufacturer could continue production of engine model to the same extent as allowed for the original engine model. However, if the FAA determines that an engine model is not an emissions - related derivative of a previously certifi cat ed engine model, the n the manufacturer would be required to demonstrate conformance with the most recent emissions standards. Consistent with I CAO provisions, we would consider a modified engine to be a derivative engine for emissions purposes ifPrivileged 

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Page 96 of 165 the modified engine model had been derived from an original engine that was certified to the requirements of this part, and one of the following conditions is met: (1) All modifications from the original engine were necessary for improved safet y and continued airworthiness, as determined b y FAA ; and (2) Emissions from the derivative engines must be 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 b y the FAA using good engineering judgment :

± 3.0 g/kN for NOx. ± 1.0 g/kN for HC. ± 5.0 g/kN for CO. ± 2.0 SN for smoke. E ngine models represented by characteristic levels at least five percent below all applicable standards would be allowed to demonstrate equivalency by engineeringPrivileged 

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Page 97 of 165 anal ys is. In all other cases, the manufacturer would be required to test the new engine model to sh ow that its emissions met the equivalency criteria. 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 IC AO’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 Airc raft 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 I CAO emission standards . 94 These requirements include information relating to engine identification and characteristics, fuel usage, data from engine testing, data anal ys is, and the results derived from the test data. Additionally, this list of aircraft engine requirements is s upplemented with voluntarily reported information which has been

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 n umber EPA - HQ - OAR - 2010 - 0687Privileged 

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Page 98 of 165 assembled into an electronic spreadsheet entitled “Emissions Databank” (EDB) 95 for turbofan engines with maximum thrust rating s greater than 26.7 kN in order to aid with emission calculations and anal ys is 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 timel y , representative emissions data of the engine fleet at the requisite mod el 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 . H owever, it is not updated on a consistent basis, it contains a varying amount of vol untarily

reported data from each manufacturer, and it does not specificall y list every engine sub - model . 96 It also does not contain information on smaller thrust category turbofans or turboprops, and contains no information on past or recent e ngine production volumes. We need this data to conduct accurate emission inventories and develop appropriate policy . Accordingl y, we do not consider the EBD to be a sufficient tool up on which to base policy decisions or adopt future standards. Furthermore, in the context of EPA ’ s standards - setting role under the C lean Air Act with regard to aircraft engine emission s , it is consistent with our policy and practice to ask for timely and

95 United Kingdom, Civil Aviation Authority, “I CAO Emissions Databank.” Available at the Civil Aviation Authority website www.caa.co.uk/default.aspx?catid=702 . 96 Under the proposed regulations, a grouping of engines with an essentially identical emission - related design wo uld defined to be an “e ngine sub - model ”. Engi nes with slightly different designs would be defined to be an “engine model”.Privileged 

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Page 99 of 165 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 reasonabl y require discharge our functions under the Act. ( See 42 U.S.C. § 7414 (a)(1). ) T herefore, we are proposing to require that an y 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. ty pe 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

97 The FAA already requires much of the information EPA is seeking through the certification process, but is unable to share it because of confidentiality agreements with engine manufacturers. Also, that information is part of a much larger submission, making it difficult to extract the specific reporting elements for EPA. 98 The proposed report would be submitted only to EPA. No separate submission or communication of any kind i s required for the FAA.Privileged 

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Page 100 of 165 proper emissions inventory anal ys es 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 alread y reported voluntarily and periodicall y by

most engine manufacturers t o the EDB . We feel that this minimizes the reporting burden for each manufacturer while still providing us with sufficient information to perform our job. A ll of the specific reporting items we are proposing are same as requested for the EDB , with the exception of total annual engine production volumes, information on ty pe certificates, and the emission standards to which the engine sub - model was certified . This information will be used in conjunction with the NOx and CO 2 emission data alread y required to be submitted to us under p art 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 infor mation 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.Privileged 

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Page 10 1 of 165 The proposed incremental reporting elements for each affected gas turbine engine sub - model are listed below . T he reporting elements of the existing GHG report are also identified for completeness.

• Company corporate name as listed on the engine ty pe certificate (GHG) ;

• Calendar y ear 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 t ype certificate family identifier) (GHG) ;

• The ty pe certificate number, as issued by the FAA ( Specify if the sub - model also has a ty pe certificate issued by

a certifi cating authorit y other than the FAA) (GHG) ;

• Date of issue of t yp e certificate and / or exemption, i.e. month and y ear (GHG) ;

• Emission standards to which the engine is certified, i.e. , the specific Annex 16, Volume II, edit ion number and publication date in which the numerical standards first appeared .

• If this is a derivative engine, identify the original certifi cat ed engine model .

• Engine sub - model that received the original t ype certificate for the engine type certificate famil y ;

• P roduction volume of the sub - model for the previous calendar ye ar , or if zero, state that the engine model is not in production and list the date of manufacture (month and y ear) of the last engine produced ;Privileged 

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Page 102 of 165 • Regarding the above production volume report, specify ( if known ) the number of engines that are intended for use on new aircraft and the number intended for us e as certified (non - exempt) spare engines on in - use aircraft ;

• Reference pressure r atio (GHG) ;

• Combustor d escription (ty pe of combustor where more than one t yp e available on an engine) ;

• Engine maximum rated thrust output, in kilo n ewtons (kN) ) or k ilo w atts ( kW) (depending on engine t yp e) (GHG) ;

• Unburned h ydrocarbon (HC) mass (g) total (weighted) and over each segment of the Landing and Take - off C ycle (LTO), i.e. Take - off, Climb, Approach, Taxi / Ground Idle ; 99

• Unburned h ydrocarbon characteristic level (i.e. mass of hydrocarbons over LTO cycle / Rated Thrus t (Dp/Foo) ; 100

• Carbon m onoxide (CO) mass (g) total (weighted) and over each segment of the entire Landing and Take - off C ycle (LTO) (i.e. Take - off, Climb, Approach, Taxi / Ground Idle) ;

• Carbon m onoxide (CO) characteristic level (i.e. mass of CO over LTO cycle / Rated Thrust (Dp/Foo)) ;

99 See 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 emission of each gaseous pollutant (mass) / rated thrust (g/kN).Privileged 

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Page 103 of 165 • Nitrogen o xides (NOx) mass (g) total (weighted) and o ver each segment of the entire Landing and T ake - off C ycle (LTO) (i.e. Take - off, Climb, Approach, Taxi / Ground Idle) (GHG) ;

• Nitrogen o xides (NOx) characteristic level (i.e. mass of NOx over LTO cycle / Rated Thrust (Dp/Foo)) (GHG) ;

• Smoke number total and over each segment of the entire Landing and Take - off C ycl e (L TO) (i.e. Take - off, C limb, Approach, Taxi / Ground I dle) ;

• Smoke number characteristic level ;

• Carbon d ioxide (CO 2 ) mass (g) total (weighted) and over each segment of the entire L anding and Take - off C ycle (LTO), i.e. Take - off, Climb, Approach, Taxi / Ground Idle (GHG) ;

• Number of tests run per sub - model (GHG) ;

• Number of engines tested per sub - model (GHG) ;

• Fuel flow (grams / second) total (weighted) and over each segment of the Landing and Take - off Cycle (LTO) (i.e. Take - off, Climb, Approach, Taxi / Ground Idle) (GHG ) ; and

• Any a dditional r emarks to the EPA . The proposed annual report would be submitted for each calendar ye ar in which a manufacturer produces any turbofan engine subject to emission standards as previousl y described . These reports would be due by February 28 of each y ear , starting with the 2014 calendar year , and cover the previous calendar y ear . This report w ould be sent toPrivileged 

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Page 104 of 165 the Designated EPA Program Officer. Where information provided for any previous y ear remains valid and complete, the en gine 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 inten d to use the proposed report s to help inform any further public policy approaches regardin g 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 CF R part 2, all dat a received b y the Administrator that is not confidential business information may be posted on our website and would be updated annuall y. By

collecting and publically posting this information on EPA’s website, we will be able to calculate turbine exhaust e mission 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 emission s . We ask for comment on our proposed plan to post this information on our website and whether an y of it should be omitted as confidential business information. Such confidential information would be retained b y EPA. For guidance on how to preserve a claim of confidentiality and on how EPA would treat submitted information covered b y such a claim, please see our earlier discus sion inPrivileged 

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Page 105 of 165 s ection 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 section s V. and IX.A. 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 originall y adopted b y IC AO in the 1980s , and our adoption of NOx and CO standards for commercial engines in 1997 omitted coverage of the se pollutants for supersonic commercial engines that were then in use . The lack of EPA CO and N Ox standards for engines used b y supersonic aircraft has had no practical effect, because no such engines have been certified b y the FAA. Also, none of the engines used on these aircraft are currentl y 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. treat y obligation s under the Convention on International Civil Aviation as previou sly

described in section I. C . , we believe it is necessary andPrivileged 

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Page 106 of 165 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 b y reference into the 40 CFR § 87.6 0 regulatory text , amendments to I CAO’s International Standards and Recommended Practices for aircraft engine emissions testing and certification. These amendments to Annex 16, Volume II are mainl y intended to ensure that the provisions reflect current certification practices. T he amendments make clarifications or add flexibilities for engine manufacturers. They are described separatel y below for the amendments that have alread y been adopted b y ICAO 101 , 102 and those that have been recommended b y CAEP for adoption b y ICAO. 103 The amendments that have already been adopted by ICAO are:

101 A strikeout and highlighted version of the amendments is contained in Attachment A to ICAO state letter AN 1/61.2, AN 1/62.2 - 07/32 entitled, “Proposed Amendment to International Standards and Recommended Practices, Environmental Protection, Ann ex 16 to the Convention on International Civil Aviation, Volume II Aircraft Engine Emissions, May 27, 2007. A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687. 102 ICAO, “International Standards and Recommended Practices, Annex 16 to the Conve ntion 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 docke t num ber EPA - HQ - OAR - 2010 - 0687. 103 ICAO, “Agenda Item 2,” Committee on Aviation Environmental Protection (CAEP), Montreal, 1 to February 2010, CAEP/8 - WP/80. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 107 of 165 • Standardizing of the terminology relating to engine thrust/power; • Clarifying the need to correct measure d results to standard reference day and reference engine conditions; • Allowing a certificating authorit y 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 I CAO are:

• Clarifying exhaust nozzle termi nology for exhaust emissions sampling; and • Allowing an equivalent procedure for gaseous emission and smoke measurement if approved b y the certificating authorit y. The test procedure amendments that I CAO 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 . M anufacturers are either alread y voluntaril y complying with these changes or will be even in the absen ce of a final rule . Our adoption of these test procedure amendments are, therefore , un likel y require new action by manufacturers beyond what they are alread y undertaking to mee t ICAO’s adopted and recommended amendments .Privileged 

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Page 108 of 165 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 econom y , 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 by pass engine . At least two engine manufacturers are actively pursuing such designs for certification in the 2018 timeframe. It now appears that certain aspects of EPA’s gas turbine engine emission standards may

be incompatible with these new designs. Fo r 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 idli ng engine. Specifically , idle emissions are measured and calculated at seven p ercent 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 v e ry little thrust is generated as the engine idles and generates emissions. Also, future aircraft using these engine designs may fl y at somewhat slower speeds. This might affectPrivileged 

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Page 109 of 165 the time these aircraft spend during the climbout mode of the landing and takeoff cy cle. Therefore, the traditio nal landing and takeoff cycle used in turb ofan 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 revis e the emission standards and test procedures as appropriate for these latter engines. If an y changes are required, EPA will undertake rulemaking to revise our regulations accordingl y. There may

also be changes in the emission standards and test procedures for engines used to power future supersonic transport aircraf t designs . The emission standards for these engines were originally developed in the earl y 1970s in response to the Aerosp atiale - 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

104 The CAEP Working Group 3 has taken the position that engine development programs for future supersonic aircraft applications should be focused on achieving the emission standards that are applicable to subsonic aircraft engines. Past supersonic aircraft e ngines 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.Privileged 

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Page 110 of 165 discussions with engine manufacturers indicate that no substantive work is being undertake n 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 ai rcraft , and how the aircraft engine emission standards and test procedures may

need to be modified to accommodate these ty pes of engines .

I V. Description of Other Revisions to the Regulatory Text In addition to the proposed changes discussed above, we ar e 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 w ould have practical significance for current engine models because the chang es align with manufacturers’ current practice in certifying their engines.Privileged 

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Page 111 of 165 1. Military

Engines We do not intend our proposal to have an y impact on engines installed on military aircraft. Military

aircraft are not required to have FAA standard airworth iness 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 C.F.R. § 87.1(a) of the existing regulations.) Currentl y, manufacturers certific ate 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 t o apply onl y 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 mi litary 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 cutoff would not a ppl y for previously

certificated engines that are installed and used in military aircraft. cutoff 2. Noncommercial EnginesPrivileged 

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Page 112 of 165 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 Federal Aviation Act and title 14 of the Code of Federal Regulations . Therefore, e ngines of equivalent thrust ratings that are use d in aircraft certifi cat ed by the FAA that are use d 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 air

worthiness certificates. There are a couple of reasons for doing this. First, the ICAO Annex 16 standards and recommended practices appl y equally to commercial and noncommercial engines, and our rules’ current failure to reflect this means that our requi rements do not fully conform to I CAO’s standards. Second, manufacturers alread y emissions certify engines that are used in non - revenue, general aviation service to these standards .. . Therefore, this proposal simply incorpo rates the status quo . In order to make EPA standards conform to I CAO’s, we need to , in addition to promulgating the necessary regulatory

amendments, update the underl yi ng finding regarding the need to limit gaseous emissions from commercial and non - commercialPrivileged 

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Page 113 of 165 civilian aircraft , pursuant to CAA section 231(a)(2)(A) . In 1997, our analy sis and finding, and hence our regulations, were limited to commercial aircraft emissions. (See 62 FR at 25358.) Today , we are proposing to expand that anal ys is and finding to include gaseous emissions fr om 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 temporall y similar, and that they collectively contribute to ozone and CO nonattainment concentrations and are projected to continue to do so. Third, noncommercial engines are usuall y 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 commercial and noncommercial service have the same effect on the environment as their commercial counterparts. Therefore, the Administrator is proposing to find that commercial and noncommercial ap plications for turbofan and turbojet engines with rated thrusts greater than 26.7 kN collectively cause orPrivileged 

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Page 114 of 165 contribute to the same air pollution as their commercial counterparts . Our emissions assessment supporting this conclusion is contained in the docke t 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 y ears ago with little or no change sin ce 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 properl y 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 an y part of the program that remains unchanged substantively . Spec ifically , 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

105 U.S. EPA, “ Assessment of Turbofan and Turbojet Aircraft Emissions,” memorandum from John Mueller , Assessment and Standards Division, to docket EPA - HQ - OAR - 2010 - 0687, Decem ber XX , 2010.Privileged 

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Page 115 of 165 changes to be substantive. It is also important to note that the changes to the regulation apply starting with the date that the final rule takes effect. In particular, it is worth emphasizing that while we are restating the HC, CO, and smoke standards , as they

would apply

to Tier 6 and later NOx standard - subject engines, in a new part 87.23, we are not proposing them as new standards or otherwise reopening them for comment. The HC, CO, and smoke standards in the proposed part 87.23 are identical to the existing standards of part 87.21 and are being copied into the new section merel y for clarit y to r eaders. The proposed rule includes the following definitions and other minor changes in addition to those changes described earlier in this section or in s ection 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 variet y of way s. For example, this departs from the plain meaning of “aircraft , ” as well as from the meaning given under the Clean Air Act and the Federal Aviation Act. The proposed definition aligns with these statutory definitions. The changed word ing is intended to clarify

the existing policy

without changing it .Privileged 

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Page 116 of 165 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 regulation s, which uses narrow definitions to limit applicability . For example, the existing regulation s limit the applicability of the standards by

defining “aircraft” to only include fixed - wing airplanes with airworthiness certificates. They exclude non propulsi on 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 rel y on readers find ing these exclusions in the definitions section. We are also renaming part 87.3 as “General applicability

and requirements” and reorganizing the content for clarity. Finally, we are replacing the existing regulatory text related to federal preemption for exempted engines in part 87.7(f) with a codification of the statutory preemption language in part 87.3 and an explanatory

note that the statutory

preemption applies to exempted engines because they are certified to prior - tier standards . ICAO Annex 16 is b eing incorporated b y 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 appl y since the existing procedures are based d irectly on Annex 16. As part of this change, we are adding the IC AO definition of “characteristic level” to properl y describe how manufacturers demonstrate that they meet applicable standards.Privileged 

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Page 117 of 165 Definitions are being added for “date of introduction , ” “date of manufacture , ” and “derivative engine” , 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 generall y consistent with the most common understandings of these terms by industry and FAA, and with the CAEP / 8 recommendation for adoption by I CAO. 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 c hanging 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 c omment 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 emissionsPrivileged 

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Page 118 of 165 Specific provisions are being added to define an d 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 rel y on a good engineering judgment standard for showing emissions equivalence of derivative engines b y engineering analy sis (part 87.48(b)(2)), and for applying the turbofan test procedures to turboprop engines (part 87.60(a)) . The good engineering judgment standard is somewhat analogous to the common law concept of a “reasonable person” standard. The general approach for implementing the good - engineering - judgment standard is allow manufacturers to exercise some judgment subje ct to potential EPA and FAA review (as appropriate) . The consequences of d isagree ments with a manufacturer’s decision would depend o n 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 approach being used today to interpret the applicable regulations. Provis ions are being added specifying rounding practices for rated output, rated pressure ratio, and calculated emission standards; generall y specifying that they be expressed to at least three significant figures. These specifications are consistent with how m anufacturers are generall y certifying engines today . Defining how to round thesePrivileged 

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Page 119 of 165 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 b y selectivel y rounding or truncating an engine model ’s rated output to be low and its rated pressure ratio to be high, or b y strategicall y 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 standar ds become more stringent. We do not expect any more engines ty pe - certifi cat ed 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 s tandards Definitions are being added for “turbofan engine , ” “turbojet engine , ” “turboprop engine , ” “turboshaft engine , ” “supersonic , ” and “subsonic” to avoid any uncertaint y about how the standards apply to different t ypes of engines. The proposed definit ions 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 The characteristic level is established by ICAOPrivileged 

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Page 120 of 165 “characteristic level”. 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. 87.1 Revise the definition of

“standard day condition”: (1) remove the refer ence to the 1976 U.S. Standard Atmosphere, (2) correct a typographical error in the The editorial changes do not involve any substantive change in the specified condition s.Privileged 

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Page 121 of 165 humidity specification, and (3) change the atmospheric pressure units from Pa to kPa. 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 subp art 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 This change is strictly editorial.Privileged 

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Page 122 of 165 procedures. 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 Tie r 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. F or example, our definition would provide a date of manufacture for an engine not previously documented by a manufacturer. 87.1, Definition of “ d erivative engine” Itis important to consider this definition in combination with the definition of “engine typ e certificate family”. 87.1 Definition of “ e ngine A manufacturer or FAA may further divide an engine modelPrivileged 

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Page 123 of 165 model” into sub - models. Engines from an engine model must be contained within a single engine type certificate family. Where FAA determines that e ngines 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 pro duction 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 b y, operated b y, or produced for sale to the armed forces or other agency of the federal gover nment responsible for national securit y ( including but not limited to the Department of Defense ) . ” For example, a ircraft owned by the U.S. Coast Guard would be military aircraft. 87.1, Definition of “ p roduction cutoff date” The production cutoff date for the Tier 6 NOx standards is December 31, 2012. 87.1, Definition of “ s pare engine” Newly manufactured spare engines may be exempt 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 continu e production of Tier 6 engines after the Tier 8 standards start to apply is not necessary for engines with rated pressure ratio at or above 104.7 because the Tier 6 and Tier 8 standards are numerically identical at these thrust levels . 87.42(c)(1) § 87.42 requires that manufacturer report the engines it produces b y sub - model. The manufacturer must specify the manufacturer’s unique sub - model name, which will generall y 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 r equest , 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,Privileged 

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Page 124 of 165 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 c ould have affected approval of an exemption . For corrections to an exemption request that w ould 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 , Em ission Benefits During the CAEP process , the technical feasibility and cost of compliance of the CAEP/6 and CAEP/8 NOx standards were thoroughl y assessed and documented . 106 , 107 EPA participated in these anal ys es and supported the results. Generall y, 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 modeli ng work, minor design changes, and additional testing and re - certification of emissions. The

106 CAEP/6 NOx standards: CAEP Forecasting and Economic Analysis Support Group , Economic Analysis of NOx Emi

ssions Stringency Options , CAEP/6 - IP/13 (Information Paper 13), January 15, 2004. A copy of this document is in docket num ber EPA - HQ - OAR - 2010 - 0687. 107 CAEP/8 NOx standards: CAEP Working Group 3, NOx Stringency Technology Response Assessment , CAEP - SG/20082 - WP/18 (Working Paper 18), September 25, 2008. CAEP Forecasting and Economic Analysis Support Group, Economic Assessment of the NOx Stringency Scenarios , CAEP/8 - IP/14, November 30, 2009. Modeling Task Force, MODTF NOx Stringency Assessment , CAEP/8 - IP/13 , December 11, 2009. United States, Aviation Environmental Portfolio Management Tool for Economics (APMT -Economics) and Its Application in the CAEP/8 NOx Stringency Analysis , CAEP/8 - IP/29 , January 6, 2010. A copy of these documents are in docket num ber EP A - HQ - OAR - 2010 - 0687.Privileged 

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Page 125 of 165 second technology

level was considered a scaled proven technology . At this level an engine manufacturer applies its best - proven, combustion technology that was a lready certified in at least one other engine ty pe to another engine t ype. This second technology level would include substantial modeling, design, combustion rig testing, modification and testing of development engines, and flight testing. The third te chnology 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 mor e 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 nearl y al l in - production engines currently meet this standard, we will limit our discussion below of applying these technology levels to engines that needed to comply with the CAEP/8 NOx standard. At the time of the C AEP reports, the CAEP/8 NOx standard f or higher thrust engines, i.e., 89.0 kN or more would appl y to a total of 15 engine ty pes . For these ty

pes the following technology level response was anticipated: 6 ty pes would require no change, 1 ty

pe would need the first technology level change, 5 would require the second technology level, and 3 would need the third technology level. For lower thrust engines, i.e., greater that 26.7 but less than 89.0 kN , CAEP listed a total of 13 engine ty pes in their anal ys is of the CAEP/8 NOx standard. The following technology level response wasPrivileged 

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Page 126 of 165 estimated for these ty

pes : 11 ty pes would require no change, 1 ty pe would need the first technology

level change, and 1 ty

pe would require a second technology . Regarding the costs of this specific proposal, a ircraft turbofan engines are designed and build 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 I CAO 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 a

bsence of U.S. regulations that would otherwise codify I CAO standards and practices. Indeed, engine manufacturers have developed or are alread y developing improved technology

in response to I CAO 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 pro posed 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 requi rements. ( (See 62 FR 25356 (May 8, 1997) and 70 FR 69664 (November 11, 2005 ) ) .Privileged 

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Page 127 of 165 In fact, engine manufacturers have suggested that certain benefits accrue for compliant products when the U.S. adoption s ICAO standards and practices , but have not provide d 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 I CAO standards is an important consideration in purchasing decisions. It simply removes any question that their engines comply with international requirements . T here 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. E ight of these produce turbofan engines with rated thrusts great er than 26.7 kN , which are alread y voluntarily report ed to the ICAO - related Emissions Databank (EDB). We expect the incremental reporting burden for these manufacturers to be very small because we : 1) have significantl y reduced the number of reporting ele ments from those requested in the EDB, and 2) are adding onl y three basic reporting categories to those alread y 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 voluntaril y report to the EDB. There are also two engine manufacturers that onl y 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 twoPrivileged 

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Page 128 of 165 manufacturers we believe that the reporting burden will be small because all of the information we are proposing to require should be readil y 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 a 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. According to an anal ys is we had conducted for the U.S., it was estimated that this would tran slate to LTO NOx reductions in the U.S. of about 0.7 percent in 2020 and 1.1 percent in 2030, 108 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 17,000 NOx tons. V I . Coordination with FAA

108 U.S. EPA, Historical Assessment of Aircraft Emissions , Prepared by Eastern Research Group under Contract to E.H. Pechan and Associates, Inc., November XX, 2010. A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687.Privileged 

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Page 129 of 165 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 significantl y 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 (an d an y 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 considerati on 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 safet y.” 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. 109 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.

109 The 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).Privileged 

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Page 130 of 165 Moreover, FAA is the official U.S. delegate to IC AO. FAA agreed to the amendments at ICAO's Sixth and Fourth Meetings of the Committee on Aviation Environmental Protection (CAEP/6) after advisement from EPA. 110 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 NO x standards, Working Group 3 made recommendations to CAEP on these elements. These recommendations were approved b y CAEP/6 meetings prior t o their adoption by ICAO in 2004. Similarl y , the more recent Working Group 3 recommendations were approved b y CAEP/8 and subsequently recommended to I CAO for adoption. In addition, as discussed above, FAA will have the duty to enforce today 's requirement s . As a part of these duties , FAA conducts the emission tests or delegates that responsibility

to the engine manufacturer, which is then monitored by the FAA. Since the FAA does not have the resources or the funding to test engines, FAA generally selects engineers at each plant to serve as representatives (called designated engineering representatives (DERs)) for the FAA while the manufacturer performs the test procedures. DERs' responsibilities include evaluating the test plan, the test engine, the

110 The Sixth Meeting of CAEP (CAEP/6) occurred in Montreal, Q uebec from February 2 through 12 in 2004.Privileged 

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Page 131 of 165 test equipment, and the final testing report sent to FAA. DERs' responsibilities are determined b y the FAA and today's rulemaking will not affect their duties. Finally , the FAA takes the lead in processing a manufacturer’s petition for exemptions to the aircraft emission standards. As part of that process, the FAA consults with EPA, and both Agenc ie s must concur on an y decision regarding such requests. VII. Public Participation We request comment on this proposal , however, we are not reopening for c omment the substance of an y part of the program that remains substantially unchanged as described in section IV.B . T he remainder of this section describes how you can participate in this process. How Do I Submit Comments? We are opening a formal comment p eriod b y publishing this document. We will accept comments during the period indicated in the DATES section at the beginning of this document. I f you have an interest in the proposed emission control program described in this document, we encourage you t o comment on any aspect of this rulemaking. Your comments will be most useful if you include appropriate and detailed supporting rationale, data, and anal ys is. Commenters are especiall y encouraged toPrivileged 

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Page 132 of 165 provide specific suggestions for an y changes to any a spect 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 electronicall y, b y 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 In form ation (CBI) or information that is otherwise protected b y statute, please follow the instructions in section VIII.B. How Should ISubmit CBI to the Agency? Do not submit information that you consider to be CBI electronicall y through the electronic publi c docket, www.regulations.gov , or by e - mail. Send or deliver information identified as CBI onl y to the following address: U.S. Environmental Protection Agency , Assessment and Standards Division, 2000 Traverwood Dri ve, Ann Arbor, MI , 48105, Attention Docket ID EPA - HQ - OAR- 2010 - 0687 . You may claim information that you submit to EPA as CBIby marking any part or all of that information as CBI (if youPrivileged 

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Page 133 of 165 submit CBIon disk or CD ROM, mark the outside of the disk or CD ROM as CBI 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 th e comment that includes any information claimed as CBI, a cop y 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 cop y that does not contain CBI on disk or CD ROM, mark the outside of the disk or CD ROM clearl y 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 th e 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 [Insert date no fewer than 15 days before and at least 30 days before end of comment period ] at the Environmental Protection Agency , XXX Building, Room Number XXX, 1201 Constitution Avenue, NW., Washington, DC 20004, Telephone: (202) 564 - 1682. The hearing will start at XX:XX local time and continue until everyone has had a chance to speak .Privileged 

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Page 134 of 165 If you would like to present testimony at the public hearing, we ask that yo u notify the contact person listed under FOR FURTHER INFORMATION CONTACT at least ten day s 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 cop y of your statement or other materials before the hearin g. 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 testimon y. We will conduct the hearing informall y, 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 day s to allow you to submit suppleme ntary information. You may make arrangements for copies of the transcript directly with the court reporter.

Comment PeriodPrivileged 

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Page 135 of 165 The comment period for this rule will end on [Insert date 60 days after date publication ] . What Should IConsider as I Prepare M y C omments for EPA? You may find the following suggestions helpful for preparing your comments: Explain your views as clearl y as possible. Describe an y assumptions that you used. Provide an y 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. Itwould also be helpful if yo u provided the name, date, and Federal Register citation related to your comments. VIII. Statutory Provisions and Legal AuthorityPrivileged 

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Page 136 of 165 The statutory

authorit y 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, require s consultation and coordination with the Federal Aviation Administration (FAA). OMB has determined that this action raises “... novel legal or policy

issu es arising out of legal mandates, the President’s priorities, or the principles set forth in the EO. ” Accordingl y, EPA submitted this action to the Office of Management and Budget (OMB) for review under EO 12866 and an y changes made in response to OMB rec ommendations have been documented in the docket for this action. As discussed further in section V, we do not attribute an y costs to the compliance with today ’s proposed regulations that conform with I CAO standards and recommended practices. A ircraft turbofan engines are international commodities . As a result, engine manufacturers respond to this market realit y b y designing and building engines that conform to ICAO international standards and practices. Therefore, e ngine manufacturersPrivileged 

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Page 137 of 165 are compelled to make the necessary business decisions and investments to maximize their international markets even in the absence of U.S. Indeed, engine manufacturers have or are alread y responding, or will in the future, to I CAO requirements that match the standards and practices proposed here. Therefore, EPA believes that today ’s proposed requirements that conform with I CAO standards and practices will impose no real additional burden on engine manufacturers. This finding is also consistent with past EPA rulemakings that adopted I CAO requirements. T here 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 r ule 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 (I CR) document prepared by EPA has been assigned EPA I CR Number 2427.01 . Manufac turers 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 c urrent fleet, and develop appropriate poli cy

in the form of future emission standards. M ost m anufacturers are alread y accustomed to reporting much of this information to I CAO. We are , therefore ,Privileged 

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Page 138 of 165 proposing to require that engine manufacturers send this information to EPA on an annual basis. We a lso 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 nece ssary 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 generall y to add the proposed information items to the annual report they are alread y required to submit with information about NOx and CO 2 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 th e propose d 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 require d to respond to, a collection of information unless it display s a currentl y 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 I CR, under Docket ID EPA

–HQ

– OAR

–2010 - 0687 . Submit any comments related to the ICR to EPA and OMB.Privileged 

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Page 139 of 165 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 IC R between 30 and 60 day s after [Insert date of publication in the Federal Register] , a comment to OMB is best assured of having its full effect if OMB receives it by [Insert date 30 days after publication in the Federal Register] . The final rule will respond to any OMB or public comments on the information collection requirements contained in this proposal. C. Regulatory

Flexibility

Analy sis The Regulatory

Flexib ility Act (RFA) generall y requires an agency to prepare a regulatory

flexibility

analy sis of any

rule subject to notice and comment rulemaking requirements under the Administrative Procedure Act or an y other statute unless the agency certifies that the rul e 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 smallPrivileged 

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Page 140 of 165 governmental jurisdiction that is a government of a city , count y, town, school district or special district with a population of less than 50,000; and (3) a small organization that is any not - for - profit enterprise which is independently owned and operated and is not dominant in its field. The following Table 4 provides an overview of the primary SBA small business categories potentially affected by

thi s regulation. Table 4 : Primary

SBA Small Business Categories Potentially Affected by

This Regulation Industry NAI CS a Codes Defined b y SBA as a small

business if: b Manufacturers of new aircraft engines 336412 < 1,000 employ ees Manufacturers of new aircraft 336411 < 1,500 employ ees a North American Industry Classification System (NAICS) b According to SBA's regulations (13 CFR part 121), businesses with no more than the listed number of em ploy ees 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, Icertify

that this action will not have a significant economic impact on a substantial number of small entitie s. 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 compan y represents all of the small businesses impacted b y the proposed regulations. AnPrivileged 

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Page 141 of 165 anal ys is of the impacts of the proposed rule on small businesses has been prepared and placed in the docket for thi s rulemaking. 111 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 an y one year. As discussed in Section IV, today ’s proposed action wil l establish consistency

between U.S. and existing international emission standards. The engine manufacturers are already developing the technology to meet the existing I CAO 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 signi ficantl y or uniquely affect small

111 “ Small Business Impact Memo, Proposed Aircraft Engine Emission Standards

– Determination of No SISNOSE ,” EPA memo from Solveig Irvine to Alexander Cristofaro, November, 2010.Privileged 

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Page 142 of 165 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 fed eralism 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 accuratel y 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 a c tion. 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 Ind ian Tribal GovernmentsPrivileged 

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Page 143 of 165 These rules regulate aircraft manufacturers and aircraft engine manufacturers. We do not believe that Tribes own an y of these businesses nor are there other implications for Tribes. Thus, Executive Order 13175 does not apply to this action. EPA specifi call y 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 because it is not a significant re gulatory

action under E.O. 12866. Furthermore, the Agency does not have reason to believe the environmental health risks or safety risks addressed b y this action present a disproportionate risk to children. EPA believes that the NO x emission reductions (NO x is a precursor to the formation of ozone and PM) from this rulemaking will further improve air quality

and will further improve children’s health. See Section II.B.2. f or a discussion of the health impacts of NO X emissions. The public is invited to submit comments or identify peer - reviewed studies and data that assess effects of earl y life exposure to aircraft emissions . H. Executive Order 13211: Actions that Significantly Affect Energy

Supply , Distribution, or UsePrivileged 

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Page 144 of 165 This acti on 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 . The se 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 No. 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 specificatio ns, test methods, sampling procedures, and business practices) that are developed or adopted b y voluntary consensus standards bodies. NTTAA directs EPA to provide Congress, through OMB, explanations when the Agency decides not to use available and applica ble 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 IC AO’s International Standards and Recommended Practices Environmental Protection, AnnexPrivileged 

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Page 145 of 165 16, along with the modifications contained in this rulemaking. 112 These procedures are currentl y used b y 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, specificall y, 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 L ow - Income Populations Executive Order (EO) 12898 (59 FR 7629 (Feb. 16, 1994)) establishes federal executive policy

on environmental justice. Its main provisio n directs federal agencies, to the greatest extent practicable and permitted b y law, to make environmental justice part of their mission by

identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effect s 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 disproportionatel y high and adverse human health or environmental effects on m inority or low - income

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

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Page 146 of 165 populations because it increases the level of environmental protection for all affected populations without having an y disproportionately high and adverse human health or environmental effects on any population, including any minorit y or l ow - 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: Lisa P. Jackson , Administrator.Privileged 

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Page 147 of 165 PART 87 - CONTROL OF AIR POLLUTION FROM AIRCRAFT AND AIRCRAFT ENGINES 1. The authorit y 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 employ ee 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 §87.1, the requirements of this part generall y appl y onl y 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 mean ing given in Appendix 6 of IC AO 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 engi nes. Class TF means all turbofan or turbojet aircraft engines or aircraft engines designed for applications that otherwise would have been fulfilled by turbojet and turbofan engines except engines of class T3, T8, and TSS. Class T3 means all aircraft gas turbine engines of the JT3D model family . Class T8 means all aircraft gas turbine engines of the JT8D model family . Class TSS means all aircraft gas turbine engines employed for propulsion of aircraft designed to operate at superson ic flight speeds. Commercial aircraft engine means an y aircraft engine used or intended for use by an “air carrier,” (including those engaged in “intrastate air transportation”) or a “commercialPrivileged 

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Page 148 of 165 operator” (including those engaged in “intrastate air transpo rtation”) as these terms are defined in the Federal Aviation Act 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 introducti on date means the date of manufacture of the first individual production engine of a given engine model or engine t ype certificate famil y to be certifi cat ed. 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 certifi cat ed outside the United States) attesting that the given engine conforms to all applicable requirements . This date may not be earlier that the date on which assembl y of the engine is complete. . Where the manufacturer does not obtain such documentation from FAA (or other competent authority for engines certifi cat ed outside the United States), date of manufacture means the date of final assembly of the engine. Derivative engine means an engine of the same generic family as an engine model alread y covered b y a t yp e certificate issued b y FAA under 14 CFR part 33 as 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 S ecretary means the Secretary of the Transportation and an y other officer or employ ee 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 en gine ty pe certificate family , where such engines have similar design , including being similar with respect to the core engine and combustor designs . Engine sub - model means a designation for a grouping of engines with essentially identical design , especially with respect to the core engine and combustor designs and other emission - related features . Engines from an engine sub - model must be contained within a single engine model . For purposes of this part, an original engine model configuration is considered a sub - model. For example, if a manufacturer initially produces an engine model designated ABC and later introduces a new sub - model ABC - 1, the engine model consists of two sub - models: ABC and ABC - 1. Engine ty pe certificate family means a group of engines ( comprising one or more engine models , including sub - models and derivatives of those engine models ) determined by FAA to have a sufficiently common design to be grouped together under a ty pe certificate . EPA means the U.S. E nvironmental Protectio n Agency .Privileged 

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Page 149 of 165 Exempt means to allow engines to be produced and sold that do not m eet (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 regu lations. Exempted engines are deemed to be “subject to” the standards of this part even though they

are not required to compl y with the otherwise applicable requirements. Engines exempted with respect to certain standards must comply with other standards a s a condition of the exemption. E xhaust emissions means substances emitted to the atmosphere from exhaust discharge nozzles, as measured b y 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 h ydrocarbons in the exhaust emissions, discharged from aircraft gas turbine engines during all normal ground and flight operations. Good engineering judgment means judgments made 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 b y 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 , o r produced for sale to the armed forces or other agency of the federal government responsible for national securit y ( 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. Productio n 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 b y 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 b y 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 b y the test procedures specified in subpart G of this part. Smoke number means a dimensionless value quantifying smoke emissions calculated in accordance with I CAO Annex 16.Privileged 

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Page 150 of 165 Spare engine means an engine installed (or intended to be installed) on a used (in service) aircraft to replace an existing engine for maintenance purposes. Standard day

conditions means the following ambient conditions: temperature =15 °C, specific humidity

= 0.00 kg H 2 O/kg dry

air, and pressure =101.325 kPa. Subsonic means relating to aircraft that are not supersonic aircraft. Supersonic m eans relating to aircraft that are certif icated to fl y 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 by passes the combustion process and is accelerated in a ducted space between the inner (core) engine cas e 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 propel ler driven b y a turbine, usually through a gearbox. Turboshaft engine means a gas turbine engine that is designed to drive a rotor transmission sy stem or a gas turbine engine not used for propulsion . U.S. - registered aircraft means an aircraft that is on th e 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: % p ercent ° d egree CO c arbon monoxide CO 2 carbon dioxide g gram HC hydrocarbon(s)Privileged 

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Page 151 of 165 kN kilonewton kW kilow att LTO l anding and takeoff NO x o xides of nitrogen rO r ated output rPR r ated pressure ratio SN s moke number 4. Revise §87.3 to read as follows: §87. 3 General a pplicability and requirements. (a) The regulations of this part appl y to engines on all aircraft that are required to be certificated b y FAA under 14 CFR part 3 3 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 ) T urboshaft engines such as those used in helicopters . (3) Engines used o nl y 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 e nsure 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 b y the United States in any treat y, convention or agreement between the United States and an y 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 safet y. §87.7— [Removed]Privileged 

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Page 152 of 165 7. Remove §87.7. 8. Revise §87.8 to read as follows: §87.8 Incorporation by reference. Documents listed in this section have been incorporated b y reference into this part. The Director of the Federal Register approved the incorporation by reference as prescribed in 5 U.S.C. 552(a) and 1 CFR part 51. Anyone may inspect copies at the U.S. EPA, Air and Radiation Docket and Information Center, 1301 Constitution Ave., NW., Room B102, EPA West Building, Washington, DC 20460 or 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. (a) ICAO material . This paragraph (a) lists material from the International Civil Aviation Organization that is incorporated b y reference. Anyone may purchase copies of these materials from the International Civil Aviation Organization, Document Sales Unit, 999 Univ ersity

Street, Montreal, Quebec, Canada H3C 5H7. Table 1 follows: (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] (b) NI ST material . This paragraph (b) lists material from the National Institute of Standards and Technology that we have incorporated by reference. An yo ne may purchase copi es of these materials from the Government Printing Office, Washington, DC 20402 or download them free from the Internet at www.nist.gov. (1) NI ST Special Publication 811, 1995 Edition, Guide for the Use of the International S ys tem of Units (SI ), Barry N. Taylor, Phy sics 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.Privileged 

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Page 153 of 165 This section describes the emission standard s that apply for Tier 4 and earlier engines that apply for air craft engines manufactured before [I NSERT EFFE CTIVE DATE OF FINAL RUL E] 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 e ngines of a t ype or model of which the date of manufacture of the first individual production model was on or before December 31, 1995 and for which the date of manufacture of the individual engine was on or before December 31, 1999. Oxides of Nitrogen: (40 + 2(rPR)) grams/kilonewton rO. (iv) The following Tier 2 emission standard applies for e ngines of a t ype 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 e ngines of a t ype 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 aft er 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 [I NSERT EFFECTIVE DATE OF FINAL RULE], except where we specify that they apply differ ently

by y ear , 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 appl y based on the date the engine is manufactured. Where the standard is specified by a formul a, 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 standardPrivileged 

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Page 154 of 165 if the testing results show that the engine t ype certificate family ’s characterist ic 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 change s 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 : Ta ble 1 to §87.23

– Smoke and Gaseous Emission Standards for New Supersonic Engines Rated Output Smoke

Number HC

(g/kN rated output) NOx

(g/kN rated output) CO

(g/kN rated output) rO < 26.7 kN

— 140•0.92 rPR 36+2.42•rPR 4550•rPR- 1.03 rO > 26.7 kN 83.6•rO - 0.274 or 50,

whichever is smaller 140•0.92 rPR 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 2 to §87.23

– 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 > 26.7 kN 83.6•rO - 0.274 or 50,

whichever is smaller 19.6 118Privileged 

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Page 155 of 165 (2) The Tier 6 NOx standards appl y as described in this paragraph (c)(2). See paragraph (d) of this section for provisions related to models introduced before these standards started to appl y (and the associated derivative engines).

Table 3 to §87.23

– Tier 6 NOx Standards for New Subsonic Turbofan or Turbojet Engines with Rated Output Above 26.7 kN I f the rated pressure ratio is... and the rated output

(in k N ) is... T he NO x emission standard (in g/k N 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 appl y 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 (and the associated derivative engines).

Table 4 to §87.23

– Tier 8 NOx Standards for New Subsonic Turbofan or Turbojet Engines with Rated Output Above 26.7 kN I f the rated pressure ratio is... and the rated output

(in k N ) is... T he NO x emission standard (in g/k N 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•rPRPrivileged 

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Page 156 of 165 (d) This paragraph specifies phase - in provisions that allow continued production of certain engines after the Tier 6 and Tier 8 standards begin to appl y. (1) Engine ty

pe certificate families certifi cat ed 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 RUL E] 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 derivative engines covered b y the same ty pe certificate. Note that a fter this production cutoff date for the Ti er 6 NOx standards, such engines may be produced onl y if they are covered b y an exemption under §87.50. This production cutoff does not apply to engines in stalled (or delivered for installation) on military aircraft. (2 ) Engine ty

pe certificate families certifi cat ed 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 derivative engines covered b y the same ty pe certificate. 11. Add a new subpart E containing §§87.40, 87.42, 87.44, 87.46, and 87.48 to part 87 to read as follows: Subpart E — Certification Provisions Sec. 87.40 General certification requirement. 87.42 Certification report to EPA. 87.4 4 Reporting CO 2 emissions. 87.46 Recordkeeping. 87.4 8 Derivative engines. §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 an y 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 singl e report with information on both certificated and exempted engines.Privileged 

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Page 157 of 165 (b) Send the report to the Designated EPA Program Officer. ( c ) In the report, specify

your corporate name and the y ear for which you are reporting. In clude information as described in this section for each engine sub - model subject to emission standards under this part. L ist each engine sub - model produced or certificated during the calendar ye ar, including the following information for each sub - model: (1) The complete sub - model name, including any applicable model name , sub - model identifier, and engine ty

pe certificate family

identifier. (2) The certificate under which it was produced. Identify all the following: (i) The t ype certificate number. Specify i f the sub - model also has a t ype certificate issued b y a certificating authority other than FAA. (ii) Your corporate name as listed in the certificate. (i ii ) Emission s tandards to which the engine is certifi cat ed. (iv ) Date of issue of t ype certificate (month and ye ar) . (v ) Whether or not this is a derivative engine. If so, identify the original certifi cat ed engine model. ( v i ) The engine sub - model that received the original ty pe certificate for an engine ty pe certificate family . (3) The calendar - ye ar pro duction volume of engines from the sub - model that are covered b y an FAA t ype certificate, or state that the engine model is no longer in production and list the date of manufacture (month and y ear) 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 certificated (non - exempt) spare engines on in - use aircraft. (4) The number of engines tested and the number of test runs for the applicable ty pe certificate. (5 ) T he applicable test data and related information specified in Part III, Section 2.4 of I CAO 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 fo r 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 I CAO Annex 16 : (i) Fuel specifications includin g fuel specification reference and h ydrogen/carbon ratio. (ii) Methods used for data acquisition, correcting for ambient conditions, and data anal ys is. (iii) Intermediate emission indices and rates, however you may not omit the final characteristic level f

or each regulated pollutant in units of g/kN or g/kW. (d) [Reserved]Privileged 

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Page 158 of 165 ( 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 m y 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. §87.4 6 Recordkeeping . (a) You must keep a copy of any reports or other information you submit t o us for at least three ye ars. (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 readil y available. We may review them at an y time. § 87.48 Derivative engine s. [The FAA to provide appropriate terminology regarding the established rules for describing the certification process relative to distinguishing derivative from non derivat iv e engines and how this distinction is made in the engine t ype certificate. Both here and in the definitions as needed ] (a) General . A manufacturer may ask for a determination that an engine model is a derivative of a previously certifi cat ed engine having substantiall y the same engine core design. To be considered a derivati ve engine under this part, it must have been derived from an original engine that was certifi cat ed to the requirements of this part, and one of the following conditions must be met: (1) All modifications from the original engine were necessary for improved safet y and continued airworthiness, as determined b y FAA. (2) Emissions from the derivative engines are determined to be equivalent. 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 equivalency . The engine manufacturer must demonstrate that the modified engine’s emission rates meet the applicable standards and are sufficientl y similar to the emission rates of the original model in the engine type certificate family , as follows: (1) The difference between emission rates of a derivative engine and the original engine should be within the following allowable ranges:Privileged 

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Page 159 of 165 (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 parent engine before modification is at or above 95% of the applicable standard for an y pollutant, you generall y must measure emissions for al l pollutants to demonstrate that the derivative engine’s resulting characteristic levels will not exceed the applicable emission standards. You may otherwise use an engineering anal ys is to demonstrate that the derivative engine will not exceed the applica

ble emission standards, consistent with good engineering judgment. (c) Continued production allowance . Where we allow continued production of an engine model after new standards begin to appl y, you may also produce engine derivatives if they conform to the specifications of this section. (d) Non - derivative engines . Where FAA determines that an engine model is not a derivative of a previously certifi cat ed engine model, you must have an emission approval from the FAA . 12. Add a new subpart F containing §87. 50 to part 87 to read as follows: Subpart F —Exemptions §87.50 Exemptions. This section specifies provisions related to exempting engines from some or all of the standards and requirements of this part 87. Exempted engines must conform to regulatory conditions specified for an exemption in this section 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. Engi nes exempted with respect to certain standards must comply with other standards as a condition of the exemption. Exemption requests under this section must be approved b y FAA under 14 CFR part 34. EPA will participate in this approval process by engaging in consultations with FAA and providing written concurrence for engines that qualify for an exemption under the provisions of this section. (a) Engines installed in new aircraft. Engine manufacturers may request an exemption to produce and sell a limited number of newl y 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 fr om engines that are covered b y a valid type certificate issuedPrivileged 

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Page 160 of 165 by FAA. Under normal circumstances, this number may not exceed 75 engines per t ype certificate holder. However, in unusual circumstances , you may ask us to waive this limit . ( 1 ) Submit yo ur 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. This requirement applies equally for engine models that have already been exempted by

a competent authority

o utside the United States. 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. In clude in your description the engine model and sub - model names and the ty pes of aircraft in which the engines will be installed. Specify the number of engines that you would produce under the exemption and the period during which you would produce them. Also identify the authorizing t ype certificate (t ype certificate number and date). (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 yo u 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. In clude other relevant information such as the f ollowing. (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) Environme ntal 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 an y o ther engine models in the engine t yp e certificate family covered b y the same t ype 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 ) Th e 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 .Privileged 

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Page 161 of 165 ( 4 ) The degree to which the adverse impact would be offset by cleaner engine s 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 employ ee strike, supplier disruption, or calamitous events) . (E) Projected future production volumes and plans for producing a compliant version of the engine model in question. (F) Equit y issues in administering the production cutoff among economically competing parties. (G) List of other certificating authoritie s from which you have requested (or expect to request) exemptions, and a summary of the request. (H) An y other relevant factors. (v) A statement signed by yo ur authorized representative attesting that all information included in the request is accurate. ( 2 ) In consultation with the EPA, the FAA may specify additional conditions for the exemption. ( 3 ) You must submit the annual report specified in paragraph ( d) of this section. ( 4 ) The permanent record for each engine exempted under this paragraph (a) mu st 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 yo u believe the new or changed information c ould 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 an y concerns related to this new or corrected information. (b) [Reserved] ( c ) S pare engines . Newly manufactured engines meeting the definition of “spare engine” are exempt as fo llows: (1) This exemption allow s production and sale of a newl y manufactured engine for installation on an in - service aircraft. It does not allow for installing a new 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 exempt ed under this paragraph ( c ) may be used only

where the emissions of the spare engines are equal to or lower than those of the engin es they are replacing, for all pollutants.Privileged 

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Page 162 of 165 ( 4 ) Manufacturers are not required to obtain approval before producing or shipping spare engines. However, engine manufacturers must submit the annual report specified in paragraph ( d ) of this section with inform ation about spare engines. ( 5 ) The permanent record for each engine exempted under this paragraph (c) must indicate that the engine is an exempted spare engine. ( 6 ) Engines exempted under this paragraph (c) must be labeled with the following statement: “EX EMPT SPARE”. ( d) Annual reports. If you produce engines with an exemption 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 p roduction of exempted engines for each calendar y ear in which you produce such engines b y 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 reques t is still accurate, or describe an y relevant changes. (2) Provide the information specified in this paragraph ( d)(2). For purposes of this paragraph ( d), treat spare engine exemptions separate from other new engine exemptions. Include the following for each exemption 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) Ty pes 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 onl y for engi nes 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 I CAO Annex 16 (incorporated b y reference in §87.8), as applicable, to determine whether engines meet the gaseous emission standards specified in subpart C of this p art . Measure the emissions of all regulated gaseous pollutants. Similarly , use the equipment and procedures specified in Appendix 2 and Appendix 6 of I CAO 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 somePrivileged 

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Page 163 of 165 number of engines, then calculating a “characteristic level” b y appl yi ng 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 specificati ons described in Appendix 4 of I CAO Annex 16 (incorporated b y 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 avail able with production engines if they

can reasonably

be expected to influence emissions. The test engine may not extract shaft power or bleed service air to provide power to auxiliary gearbox - mounted components required to drive aircraft sy stems. (d) Test engines must reach a stead y 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, anal ytical 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 onl y 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 than the s pecified procedure.Privileged 

### EPA INTERNAL USE ONLY Do Not Quote or Cite ***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 164 of 165 (f) The following landing and take - off (LTO) cycles apply for emission testing and calculating weighted LTO values : Table 1 to § 87.60

– LTO Test Cycles Mode Turboprop Subsonic Turbofan Supersonic Turbofan

Percent of Rated Output Tim e in

Mode (minutes) Percent of

Rated Output Tim e in

Mode (minutes) Percent of

Rated Output Tim e 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 compl y with an applicable standard if the testing results show that the engine ty pe certificate family ’s characteristic level does not exceed the numerical level of that standard, as described in §87.60. §§87.61 - 87.63 — [Removed] 15. Remove §§87.61 - 87.63. 16. Amend §87.64 by

revising paragraph (a) to read as follows: §87.64 Sampling and analytical procedures for measuring gaseous exhaust emissions. (a) [Reserved.] * * * * * §§8 7.6 5 - 87.71 — [Removed] 17. Remove §§87.6 5 - 87.71. Subpart H— [Removed] 18. Remove subpart H. PART 1068 -- GENERAL COMPLIANCE PROVISIONS FOR ENGINE PROGRAMSPrivileged 

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Page 16 5 of 165 19. The authorit y citation for part 1068 continues to read as follows: Authority : 42 U.S.C. 7 401 - 7671q . Subpart A— [Amended] 20. 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 an y of the following engine or vehicle categories: (1) L ight - duty

motor vehicles (see 40 CFR part 86). (2) Heav y - dut y motor vehicles and motor vehicle engines, except as specified in 40 CFR part 86. (3) Aircraft engines, except as specified in 40 CFR part 87. (4) Land - based nonroad compression - ignition engines we regulate under 40 CFR part 89. (5) Small nonroad spark - ignition engines we regulate under 40 CFR part 90. (6) Marine spark - ignition engines we regulate under 40 CFR part 91. (7) Locomotive engines we regulate under 40 CFR part 92. (8) Marine compression - ignition engines we regulate under 4 0 CFR parts 89 or 94. * * * * *