***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 1 of 153 EO12866

_

Aircraft Engine Emission Standard s 2060 - AO70 NPRM Rulemaking

Document

_2011/01/20 ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 87 and Part 1068 [EPA - HQ - OAR- 2010 - 0687 ; FRL - XXXX - X]

RIN 2060 - AO70 Control of Air Pollut ion 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 subject to exhaust emission standard s . Firs t, 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 be separatel y certified to the most current emission standards. Se cond , we are proposing a new reporting requirement for manufacturers of gas turbine engines that are subject to any

exhaust emission standard to provide us with timely and consistent emission - related information . Third, and finally , we are proposing amendments to***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 2 of 153 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 requirements were first developed. T hese pro posed 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 the international requirements . DATES: Comments mu st be received on or before [insert date 6 0 days after publication in the Federal Register.] H earing: 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 Environm ental 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.

 Fax: 202 - 566 - 9744***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 3 of 153 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 Regulatory 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 included in the public docket without change and may

be made available online at www.regulations.gov, including an y 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 otherwis e 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 your identity or contact information unless you provide it in the body of your comment. If you send an e - mai l 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 comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 4 of 153 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, EP A 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 an y 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., NW, 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 Transport ation 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: (734) 214 - 4816; email address: manning.bry an@epa.gov . SUPPLEMENTARY INFORMATION:***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 5 of 153 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 potentiall y 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 tabl e 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 care fully 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 , consult the person listed in the preceding FOR FURTHER INFORMATION CONTACT section. Table of Contents I. Overview and Background A. Summary

of the Proposal B . EPA’s Responsibilities under the Clean Air Act***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 6 of 153 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

Contribution 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 Hea lth Effects of PM? c. What are the Health Effects of NOx ?***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 7 of 153 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 Quality 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 L ower 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 8 of 153 2. Exemption s from the Tier 6 Production Cutoff

a . Spare Engines b . New Provisions for Engines Installed in New Aircraft i . Time - Frame and Scope ii . Produc tion 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 Engines C . Application of Standards for Derivative Engines D . Annual Rep ort ing Requirement E. Proposed Standards for Supersonic Aircraft Turbine Engines F . Amendments to Test and Measurement Procedures G. Future Standards for New Technology Turbine Engines and Supersonic Aircraft Turbine Engines***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 9 of 153 IV. Description of Othe r Revisions to the Regulatory Text A. Applicability Issues 1. Military

Engines 2. Noncommercial Engines B. Non - Substantive Revisions C. Clarifying Language for Regulatory Text V. Technical Feasibility , Costs , and Emission Benefits V I. Consu ltation 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

An aly sis D. Unfunded Mandates Reform Act E. Executive Order 13132: Federalism***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 10 of 153 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 Energy Supply , Distribution, or Use I. National Technology

Transfer Advancement Act J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minori ty 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 responsibi lities under the Clean Air Act, the connection between our emission standards and those of the international community , and a brief regulatory history for this source of emissions. A. Summary of the Proposal***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 11 of 153 We are proposing several new emission standards and other regulatory requirements for aircraft turbofan and turbojet engines 1 with rated thrusts greater than 26.7 kilonewtons (kN). First, we are proposing two new tiers of more stringent emission standards for oxides of nitrogen (NO x ) . T he proposed stan dards 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 standards. 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 re quire manufacturers to either compl y with the newer standards by a specified future date or cease production. Newly manufactured engine standards are also sometimes referred to as “ production cutoff ” standards. Second, we are proposing certain time - limit ed 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. 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

1 Turbofan and turbojet engines will be collectively referred to as turbofan engines hereafter for convenience. 2 The term gas turbine engine includes turbofan, turbojet, and turboprop engines designs. The rated outp ut for turbofan and turbojet engines is normally expressed as kilonewtons (kN) thrust. The rated output for turboprop engines is normally expressed as shaft horsepower (hp) or shaft kilow att (kW).***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 12 of 153 new emission standards. First , we are proposing to clarify that when the emission characteris tics of a new turbofan engine model have become different enough from its existing parent engine design, i.e., a derivative of an originally certified engine t ype, that it must be separatel y certified to 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 anal ys es and develop appropriate public policy for this aviation sector . Specificall y, reports would 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 , which are onl y subject to smoke standards. Third, we are proposing amendments to the test and measurement procedures for aircraft engines . Finally , as described in section IV, we are proposing min or amendments to provisions addressing definitions, 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 requirements . B. EPA’s Authority and Responsibilities Under the Clean Air Act***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 13 of 153 Section 231 (a)(2)(A) of the Clean Air Act (CAA) directs EPA, from time to time, to propose aircraft engine emission standards applicable to the emission of any air pollutant from classes of aircraft engines which in its judgment causes, or contributes to, air pollution which may

reasonabl y be anticipated to endanger public health or welfare. (See 42 U.S.C . § 7571(a)(2)(A).) Section 231(a)(2)(B) directs EPA to consult with the Administrator of the Federal Aviation Administration ( FAA ) on such standards, and prohibits EPA from changing aircraft emission standards if such a change would significantl y increase noise and adversel y affect safety. 42 U.S.C. § 7571(a)( 2)(B ) (i) - (ii) . Section 231(a)(3) provides that after we propose standards, the Admini strator 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 discretion on EPA to adopt airc raft engine emission standards as the agency

determines are reasonable. NACAA v. EPA , 489 F.3d 1221 (D.C. Cir. 2007). In addition, under CAA section 231(b) EPA is required to ensure, in consultation with the U.S. Department of Transportation (DOT), that the effective date of an y 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 pr escribe 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 14 of 153 States are preempted from adopting or enf orcing 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 respons ibility under the CAA to enforce the aircraft emission standards established by EPA. C. Interaction w ith the International Community We began regulating the emissions from aircraft engines in 1973 . Since that time, we have worked with the FAA and the Inter national Civil Aviation Organization (I CAO) to develop international standards and other requirements pertaining to aircr aft engine emissions. IC AO was established in 1944 by the United Nations (by

the Convention on International Civil Aviation, the “Chic ago Convention”) “... in order that international civil aviation may

be developed in a safe and orderly manner and that international air transport services may

be established on the basis of equality of opportunity

and operated soundly and economically .” 4 IC AO’s responsibilities include developing aircraft technical and operating standards, recommending practices, and generall y fostering the

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). 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 w ebsite located at www.icao.int .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 15 of 153 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 ai rworthiness standards and that some may adopt standards that are more stringent than those agreed upon by I CAO. The Convention has a number of other features that govern international commerce. First, States that wish to use aircraft in international tr ansportation must adopt emission standards and other requirements that are at least as stringent as IC AO ’s standards . States may ban the use an y aircraft within their airspace that does not meet ICAO standards. 7 Second, States are required to recognize the airworthiness certificates of an y State whose standards are at least as stringent as IC AO ’s standards , thereby assuring that its aircraft of an y member State will be pe rmitted to operate in any other member State. Third, and finally , t o ensure that international commer ce is not unreasonabl y constraint ed , 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

5 Mem bers of ICAO’s Assembly are generally termed member States or contracting States. These terms are used i nterchangeably throughout this preamble. 6 There are currently 190 Contracting States according to ICAO w ebsite located at www.icao.int . 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 website located at www.icao.int .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 16 of 153 standards. 8 , 9 However, if a nation sets tighter st andards 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 Environme ntal Protection (CAEP) undertakes ICAO’s technical work in the environmental field. The C ommittee is responsible for evaluating, researching, and recommending measures to the IC AO Council that address the environmental impact of international civil aviati on. CAEP is composed of various study groups, work groups, committees and other contributing memberships that include atmospheric, economic, 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, technol ogy , and policy matters. If ICAO adopts a CAEP proposal for a new environmental standard, it then becomes part of ICAO standards and recommended practices (Annex 16 to the Chicago Convention). 10

8 ICAO, “Convention on International Civil Aviation,” Articles 87 and 88 , Ninth Edition, Document 7300/9, 2006. Copies of this document can be obtai ned 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 loc ated at www.icao.int . . 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 dock et number EPA - HQ - OAR - 2010 - 0687.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 17 of 153 D. Brief History of EPA’s Regulation of Aircraft Engine Emissio ns As mentioned above , we initially regulated gaseous exhaust emissions, smoke , and fuel venting from aircraft engines in 1973. 11 Since that time, we have occasionall y revised those regulations. Two of these revisions are most pertinent to today’s propos al. First , in a 1997 rulemaking, we made our emission standards and test procedures more consistent with those of ICAO for turbofan and turbojet engines used in commercial aviation with rated thrusts greater than 26.7kN . 12 These ICAO requirements are ge nerally 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 effec tive date of the regulations that were already certified to pre - existing standards) 13 and for newly - certified commercial turbofan engines (those engine models that received their initial ty

pe certificate after the effective date of the regulations). Ital so included a CO emission standard for newl y - manufactured commercial turbofan engines. Second, in our most recent rulemaking in 2005 , we promulgated more stringent NO x

11 U.S. EPA, “ Emission Standards and Test Procedures for Aircraft; ” Final Rule, 38 FR 19088 , July 17, 1973 . 12 U.S. EPA, “Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;” Fi nal 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 contrib ute 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 s uch emissions from both commercial and non - commercial aircraft engines, in order to bring our standards into full alignment with ICAO’s. 13 This does not mean that in 2005 w e promulgated requirements for the re - certification or retrofit of existing in - use engines.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 18 of 153 emission stand ards for newly - certi fied commercial turbofan engines . 14 That final rule b rought the U.S. standards closer to alignment with IC AO CAEP/4 requirements that were effective in 2004 . In ruling on a petition for judicial review of the 2005 rule filed by the National Association of Clean Air Agencies (NACAA), the U.S. Court of Appeal s held that EPA’s approach of tracking the IC AO 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 stand ards 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 test procedures. 16 At the next CAEP meeting (CAEP/3) in 1995, the Committee recommended a further tightening of 16 percent and additional test procedure amendments, but in 1997 the I CAO Council rejected this stringency

proposal and approved only the test procedure amendments. At the CAEP/4 meeting in 1998, the Committee adopted a similar 16 percent NO x reduction

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. 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, ther efore, is referred to as CAEP/2.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 19 of 153 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 requirements did not also apply to newly - manufactured engines unlike the CAEP/2 standards). In 200 4 , CAEP/6 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 earl y 2011. II. Why Is EPA Taking This Action? As mentioned above, section 231(a)(2)(A) of the CAA authorizes the 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 engi nes 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 ob tained from the ICAO website at www.icao.int . 19 CAEP/7 did not address new aircraft engine emission standards.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 20 of 153 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 ozone levels above the National Ambient Air Quality Standards (NAAQS) for ozone (i.e., they are in nonattainment for ozone) and fine particulate matter ( 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 er of the atmosphere and affect local and regional ambient air qualit y. These emissions generall y occur at or below 3,000 feet above ground level and during the landing and takeoff (LTO) cycle. The aircraft operations that comprise an L TO cycle are: engine idle at the terminal gate (and sometimes during ground delays while holding for the active runway); taxiing between the terminal and the runway ; take - off; climb - out;

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. 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 the secondary formation of PM. See Section II.B below .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 21 of 153 and approach to the airport. The second regime includes emis sions that occur above 3,000 feet above ground level, known as non - LTO emissions . Collectively these emissions associated with all ground and flight operations are generall y referred to as full flight emissions. The aircraft engine NOx emission inventorie s 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 present NOx emission inventories for commercial turbine engine aircraft . The most rece nt comprehensive analy sis of historical, current and future LTO emissions from aircraft engines comes from a study undertaken for us by

Eastern Research Group (ERG). 22 The study anal yz ed the national emissions of commercial aircraft operations in the United States from 1986 through 2008, and then projected emissions in 2020 and 2030 . The study

showed that total LTO NOx emissions from this sector have increased approximately

28 percent from 78 thousand tons in 1986 to 97 thousand tons in 2008. Table 1 shows the contribution of aircraft NOx to the current total mobile source NOx

22 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 i n docket n umber EPA - HQ - OAR - 2010 - 0687.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 22 of 153 inventory . It should be noted that the aircraft baseline emissions y ear in this table is 2008, whereas the baseline y ear for all other mobile sources is 2009 . Clearly aircraft are a meaningful portion of the current national NOx inventory whose contribution has grown despite 20 ye ars of NOx emission standards of increasing stringency . Table 1: Annual NOx Baseline Levels for Commercial Aircraft (LTO onl y) and

Other Mobile Sources 23 Cat egory NOx (Thous and Tons) Aircraft 97 0.8% All Other Nonroad 4,392 37.6% Highway 7,195 61.6% Total Mobile Source 11,684 --

As previously

mentioned, the operation of other mobile source categories occurs completely

at ground level, and when we compare emissions of aircraft to other sources, we tend to focus on the LTO emissions that occur close to the ground. However, as will be discussed in more detail in the next section, non - LT O emissions are almost an order of***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 23 of 153 magnitude larger than LTO emissions. If we take full flight emissions into account, the NOx emissions of aircraft are much more comparable to those from more substantial categories such as locomotives or ocean - going vessels. As shown in Table 2, when considering full flight emissions, aircr aft account for 8.5 percent of total mobile source NOx emissions.

Table 2: Current Annual NOx Baseline Levels for C ommercial Aircraft (full

flight) and Other Mobile Sources Category NOx (Thousand Tons) Aircraft 1,078 8.5% All Other Nonroad 4,392 34.7% H ighway 7,195 58.8% Total Mobile Source 12,665 --

While aircraft traffic volumes have been down somewhat during the recent economic downturn, air traffic has historicall y shown itself to be a resilient sector, demonstrating consistent growth over time. Thus, aircraft traffic is expected to increase

23 U.S. EPA, “Summary of Mobile Source Emissions in Comparison to Aircraft Emissions,” memorandum from John Mueller , Assessment and Standards Division, to docket EPA - HQ - OAR - 2010 - 0687, Decem ber XX , 2010.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 24 of 153 in the future. Indeed, the FAA projects domestic revenue passenger - miles will rise at an annual rate of 3.1 percent per year from 2009 to 2030 . 24 Expected improvements in aircraft size, load factor and trip l ength over that time period result in expected take - off increases from FAA air traffic facilities to be somewhat lower than expected increases in passenger - miles, at 1.9 percent per ye ar. Table 3 shows the projected 2020 and 2030 baseline NOx emissions of aircraft relative to highway

and nonroad mobile sources in the absence of today ’s proposed action. As can be seen from Table 3, in the absence of further emission controls, national aircraft LTO emissions are projected to grow b y 64 percent from 2008 to 2 030, and triple from 0.8 percent to 2.5 percent of the national mobile source NOx inventory over that same period. This latter increase can be attributed to both the fact that NOx emissions from most of the other source categories are projected to decreas e , and aircraft emissions are projected to increas e due to growth.

Table 3: Projected Future L evels of LTO NOx for Commercial Aircraft 25

Year Aircraft NOx

( T hous and Tons) Percent of Total Mobile Source NOx

24 FAA Aerospace Forecast Fiscal Year 2010 - 2030, http://www.faa.gov/data_research/aviation/aerospace_forecasts/2010 - 2030/media/2010%20Forecast%20Doc.p df , retrieved August 4, 2010 . 25 U.S. EPA, “Summary of Mobile Source Emissions in Comparison to Aircraft Emissions,” memorandum from John Mueller , Assessment and Standards Division, to docket EPA - HQ - OAR - 2010 - 0687, November XX , 2010.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 25 of 153 2020 119.1 1.8% 2030 147.4 2.5%

As previously

m entioned, many

airports are located in areas that are in nonattainment for the ozone NAAQS. Table 4 shows the current and projected commercial aircraft NOx emissions inventories in several extreme, severe and moderate ozone nonattainment areas . As can be seen from the table, aircraft emissions are also projected to more than double in some areas most in need of ozone control.

Table 4: Commercial Aircraft LTO NOx Emissions in Various Ozone

Nonattainment Areas 26

Ozone Nonattainment Area Nonattainment Status Aircraft NOx (Tons) Percent increase 2008 - 2030 2008 2020 2030 -- Atlanta, GA Moderate 5,808 9,172 11,185 92.6%

26 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 26 of 153 Baltimore, MD Moderate 1,148 1,696 2,167 88.8% Charolotte - Gastonia - Rock Hill, NC - SC Moderate 1,917 3,118 4,189 118.5% Chicago - Gary - Lake Co unty , IL - IN Moderate 6,007 9,089 11,449 90.6% Houston - Galveston - Brazoria, TX Severe 3,045 4,571 6,173 102.7% Los Angeles South Coast Air Basin, CA Extreme 6,479 8,357 9,753 50.3% Milwaukee - Racine, WI Moderate 557 909 1,089 95.5% Philadelphia - Wilmin gton Atlantic City , PA - NY - MD DE Moderate 2,308 3,166 4,047 75.3% San Joaquin Valley , CA Extreme 74 161 180 143.2% Riverside County , CA Severe 70 136 165 136.7% Sacramento, CA Severe 603 783 941 56.1% Washington, DC - MD - VA Moderate 2,983 4,142 5,217 74.9 %

2. Non - LTO Emissions***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 27 of 153 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 (3,000 feet above ground level) based on the assumption that such emissio ns have a lesser impact on local air quality . However, a recent presentation at the American Meteorological Societ y and a follow - up paper by the same authors suggest these upper atmosphere emissions may also adversel y affect public health at ground level more than was previously thought . 27 , 28 Based on the data and methodology

of the authors, this effect is caused primarily by the formation of fine partic u l at e matter, i.e., PM 2.5 from gaseous emission p recursors in the upper atmosphere that are then transported to the lower atmosphere. (The formation of secondary PM 2.5 from NOx is discussed further in section II.B. 1.b). More specificall y, the authors of th ese works estimated that full flight emissions c ause almost 10,000 premature mortalities per ye ar worldwide , with over 450 per y ear in the U.S. The pollutants emitted during cruise operations we re estimated to be about 89 percent of the population - weighed PM 2.5 from aviation, with the remainder being a ssociated with LTO operations. Thus, these studies assert that over 350 premature mortalities per year in the U.S. can be attributed to secondary PM 2.5 emissions originating

27 Barrett, S., Rex Britten, Ian Waltz, “Assess ing the Air Quality Impacts of Aviation,” presentation at the American Meteorological Society Annual Meeting, Joint Session 20, Air Quality in Cities

— Criteria Pollutants, January 15, 2009. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 28 Barrett, S., Rex Britten, Ian Waltz, “Global Mortality Attributable to Aircraft Emissions,” [DRAFT PAPER, Peer review ed waiting publication - need final cite] . A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 28 of 153 from non - LTO operations. We request comments on the results of th ese stud ies , th e existence of other research into this area, and the implications of these analy ses on assessing the need for additional controls on aircraft engi ne emissions in the future. B. Heal th, Environmental and Air Quality Impacts NO x emiss ions 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 ICAO NO x standards that we are proposing to align with 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). 29 1. Background on Ozone, PM and NO X

29 The discussion of PM hea lth 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 standards for PM emitted dire ctly 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. Ultimate ly , this information will be used to assess the need for an aircraft turbine engine PM standard (i.e., whether PM emissions from aircraft cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare), with s tandard setting as appropriate.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 29 of 153 a. W hat is Ozone? Ground - level oz one 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 many ty pes of pollution sources, such as highway and nonroad moto r vehicles and engines, power plants, chemical plants, refineries, makers of consumer and commercial products, industrial facilities, and smaller area sources. The science of ozone formation, transport, and accumulation is complex. 30 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 day s and the air is relativel y stagnant, ozone and its precursor s 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 VO C or NO X emissions. b . W hat is Particulate Matter?

30 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 - 2 010 - 0687. This document may be accessed electronically at: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_cd.html.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 30 of 153 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 magnitude in size. Since 1987, EPA has delineated that subset of inhala

ble 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 refer ring to particles with a nominal mean aerody namic 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, generall y less than 100 nanometers (0.1 μm) in aerodynamic diameter. Fin e 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 of different pollutants including sulfates, nitrates, organic compounds, elemental carbon and metal compounds. These particles can remain in the atmosphere for day s to weeks and travel hundreds to thousan ds of kilometers.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 31 of 153 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 wate r 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? 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. 31 , 32

31 U.S. EPA Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental Protection Agency, Washingto n, 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 . 32 U.S. EPA (2007) Review of the National Ambie nt 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 32 of 153 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 attacks that require medical attention and/or the use of additional medication. Thus, ambient ozone may cause both healthy

and asthmatic individu als to limit their outdoor activities. In addition, there is suggestive evidence of a contribution of ozone to cardiovascular - 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 estimation of ozone - related premature mortality published by

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

to contribute to premature deaths and that ozone - related mortality should be included in estimates of the health benefits of reducing ozone exposure. 33 An imal 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

33 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 33 of 153 c ontrolled human exposure studies and animal studies are coherent with the evidence from epidemiologic studies supporting a causal relationship between acute ambient ozone exposures and increased respiratory - related emergency room visits and hospitalization s in the warm season. In addition, there is suggestive evidence of a contribution of ozone to cardiovascular - related morbidity and non - accidental and cardiopulmonary mortality . b. 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 Assessment for Particulate Matter (I SA) . 34 The I SA summarizes evidence associated with PM 2.5 , PM 10 - 2.5 , and ultrafine particles (U FPs) , and concludes the following. The I SA concludes that health effects associated with short - term exposures (hours to day s) to ambient PM 2.5 include mortality , cardiovascular effects, such as altered vasomotor function and hospital admissions and emerge ncy 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 (C OPD) and respiratory

document is in d ocket num ber EPA - HQ - OAR - 2010 - 0687 34 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 34 of 153 infections . 35 The ISA notes that l ong - term exposure to PM 2.5 (months to y ears) is associated with the development/progression of cardiovascular disease, premature mortality , and respiratory effects, including reduced lung function growth, increased respiratory

s ymptoms, and asthma development. 36 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 concludes that the collective evidence supports likely causal associations between short and long - term PM 2.5 exposures and respiratory effects. The ISA also conclude s that the scientific evidence is suggestive of a causal association for reproductive and developmental effects and cancer, mutagenicity , and genotoxicity and long - term exposure to PM 2. 5 . 37 For PM 10 - 2.5 , the I SA concludes that the current evidence is sugge stive of a causal relationship between short - term exposures and cardiovascular effects, such as hospitalization for ischemic heart disease. There is also suggestive evidence of a causal relationship between short - term PM 10 - 2.5 exposure and mortality and r espiratory effects.

35 U.S. EPA (2009). Integrated Science Assessment for Particu late Matter (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R - 08/139F, 2009 . Section 2.3.1.1. 36 U.S. EPA (2009). Integrated Science Assessment for Particulate Matter (Final Report). U.S. Environmental Protection Agency, Washin gton, DC, EPA/600/R - 08/139F, 2009 . page 2 - 12, Sections 7.3.1.1 and 7.3.2.1. 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 . Section 2.3.2 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 35 of 153 Data are inadequate to draw conclusions regarding the health effects associated with long - 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 exp osures and cardiovascular effects, such as changes in heart rh ythm and blood vessel function. It also concludes that there is suggestive evidence of association between short - term exposure to UFPs and respiratory effects. Data are inadequate to draw conclusions regarding the health effects associated with long - term exposure to UFP’s. c. What are the Health Effects of 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. 38 The EPA h as concluded that the findings of epidemiologic, controlled human exposure, and animal toxicological studies provide evidence that is sufficient to infer a likel y causal relationship between respiratory effects and short - term NO 2 exposure. The I SA conclude s that the strongest evidence for such a relationship comes from epidemiologic studies of respiratory effects including sy mptoms, emergency

department visits, and hospital admissions. The I SA also draws two broad conclusions regarding airway responsivenes s following NO 2 exposure. First,

38 U.S. EPA (2008). Integrated Science Assessment for Oxides of Nitrogen

– Health Criteria (Final Report). EPA/600/R - 08/071. Washington, DC: U.S.EPA. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 36 of 153 the I SA concludes that NO 2 exposure may enhance the sensitivity

to allergen - induced decrements in lung function and increase the allergen - induced airway inflammatory response following 30 - minute exposures of asthmatics to 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 i nherent responsiveness of the airway to subsequent nonspecific challenges in controlled human exposure studies of asthmatic subjects. Enhanced airway responsiveness could have important clinical implications for asthmatics since transient increases in ai rway 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 expos ures and an array of adverse health effects that range from the onset of respiratory 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 - cause (non - accidental) mortalit y, hospital admissions or emergency department visits for cardiovascular disease, and decrements in lung function growth associated with chronic exposur e. 3. Environmental Effects Associated with Exposure to Ozone, PM and NO X***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 37 of 153 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 ac idification, 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 from nitrogen deposition is predominantly governed b y ge ology . Prolonged 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 invertebrates . In addition to the role nitrogen depos ition 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 38 of 153 Adverse impacts on soil chemistry and plant life have been observed for area s heavily influenced by

atmospheric deposition of nutrients, metals and acid species, resulting in species shifts, loss of biodiversity , forest decline and damage to forest productivity . Across the U.S. there are many terrestrial and aquatic ecos ys tems th at 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 enrichment 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. 39 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. 40 Particles affect materials principall y b y promoting and accelerating the cor rosion 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 acidic properties, and their ability to adsorb corrosive g ases (principall y sulfur dioxide).

39 U.S. EPA. (2008). Nitrogen Dioxide/Su lfur 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 . 40 U.S. EPA. (2005). Review of the N ational Ambient Air Quality Standards for Particulate Matter: Policy Assessment of Scientific and Technical Information, OAQPS Staff Paper. Retrieved on April 9, 2009 from http://www.epa.gov/ttn/naaqs/standards/pm/data/pmstaffpaper_20051221.pdf***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 39 of 1 53 b. Visibility Effects NOx e missions contribute to visibility impairment in the U.S. through the formation of secondary

PM 2.5 . 41 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 daily

activities in all parts of the country . Individuals value good visibility for the well - being it provides them directl y, 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 special emphasis is given to protecting visibility in these areas. For more information on visibility

see the final 200 9 PM ISA. 42

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 sen sitive 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

41 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 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 40 of 153 creat e 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 sensit ive 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, res ulting 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 ecosy stem goods and services. Lastl y, visible ozone injury to leaves can result in a loss o f 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 are

42 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 41 of 153 declining. 43 However as of 2008, approximately 127 million people lived in counties th at exceeded an y NAAQS. 44 These numbers do not include the people living in areas where there is a future risk of failing to maintain or attain the NAAQS. States with nonattainment areas are required to take action to bring those areas into compliance in the future. Based on the final rule designating and classifying 8 - hour ozone nonattainment areas for the 1997 standard (69 FR 23951, April 30, 2004), most 8 - hour ozone nonattainment areas will be required to attain the ozone NAAQS in the 2007 to 2013 time frame and then maintain the NAAQS thereafter. EPA is reconsidering the 2008 ozone NAAQS. If EPA promulgates different ozone NAAQS as a result of the reconsideration, these standards would replace the 2008 ozone NAAQS and EPA would subsequently designate nonattainment areas for the revised primary ozone NAAQS. The attainment dates for areas designated nonattainment for a revised primary ozone NAAQS could range from 2015 to 2032 , depending on the severit y of the problem. 45 Areas designated as not attaining the 1997 PM 2.5 NAAQS will need to attain the 1997 standards in the 2010 to 2015 time frame, and then maintain them thereafter. The

43 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.ep a.gov/airtrends/2010/ . 44 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/ . 45 U.S. EPA ( 2010 ) , Fact Sheet Revisions to Ozone Standards. This document can be accessed electronically at: http://www.epa.gov/groundlevelozone/pdfs/fs20100106std.pdf***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 42 of 153 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 re ductions 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 reduc ing 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). 46 In addition, our air quality modeling projects that in 2030 at least 9 counties with a population of almost 28 million may not attain the 1997 annual PM 2.5 standard of 15 μg/m 3 and 26 counties with a population of over 41 million may

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

. 47 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 o f the NAAQS.

46 U.S. EPA (2010). Regulatory Impact Analysis: Fina l 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. 47 U.S. EPA (2010). Regulatory Impact Analysis: Final Rulemaking to E stablish Light - Duty Vehicle Greenhouse Gas Emission Standards and Corporate Average Fuel Economy Standards. Chapter 7: Environmental and Health Impacts. EPA 420 - R - 10 - 009.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 43 of 153 There are currently

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

revised and a new 1 - hour NO2 standard was promulgated . 48 Nonattainment area designations for the 1 - hour NO2 standard are expected to be finalized in 2012 . These proposed aircraft NOx reductions would be useful to states in attaining or maintaining the NO2 standards. III. Details of the Proposed Rule We are proposing two different levels or tiers of increasingl y more stringent NOx emission standards for gas turbine engines with maximum rated thrusts greater than 26.7 kilonewtons (kN). 49 Each of the tiers would potentially appl y to newly - certified engines. Newl y - certified aircraft engines are those that would receive a new t yp e certificate after the effec tive date of the applicable standards . Such engine ty pes or models would not have begun production prior to the effective date of the new requirement. 50

48 U.S. EPA, "Primary National Ambient Air Quality Standards for Nitrogen Dioxide;" Final Rule, 75 FR 6474, February 9, 2010. 49 The proposed standards would apply to engines used in commercial and noncommercial aviation for which the FAA issues airworthiness certificates, e.g., non - revenue, general aviation service. The vast majority of these engines are used in commercial applications. See section V.A.2. for more information regarding noncommercial applications. 50 ICAO standards describe newly - certified engines as “...engines of a type or model for which the date of manufacture of the fir st 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 obtain ed from the ICAO website at www.icao.int .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 44 of 153 We are also proposing to apply the first tier of the two tiers of standards to n ewly manufactured eng ine 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 new ly - manufactured engines would need to comply with the same NOx limits as newly - certified engines but at a later date or cease production. 51 The end of this “phase in” period for the newl y - manufactured engine standards is sometimes referred to a

“ production cutoff, ” for obvious reasons. Again, w e are proposing onl y the first of the 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 acti on. 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 new NOx standards because of specific technical or economic reasons 52 . 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” of an

51 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 sp ecific emission standards, and the date beyond which an individual engine meeting those same requirements can not be made. So ICAO standards describe newly - manufactured engines as “...engines of a type or model for which the date of manufacture of the first individual production model was after....” the effective date of the applicable standards, and “...for which the date of manufacture of the individual engine was on or before....” a specific date that is later than the first effective date of the standards. S ee 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 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 45 of 153 originall y certified engine type, that it must be certifi ed to the latest emission standard. Third, we are proposing new CO and NOx standards for gas turbine engines that are used to propel supersonic aircraft. 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 treat y 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 meas urement procedures in our regulations that are intended to implement IC AO’s Annex 16 and to incorporate the entire annex in our regulations by

reference . Finally , as described in Section IV, we are proposing amendments to current regulatory provisions addressing definitions, acron yms 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 reflect those that were previo usly adopted b y ICAO or that CAEP has recommended for adoption b y ICAO in the near future. In this latter case, we are proposing these requirements at this time rather than wait until I CAO takes final action to help ensure that our standards, and the FAA’ s

52 These apply on ly to the Tier 6 NOx standards as discussed below . We are not yet proposing a production cut - off for the Tier 8 NOx standard.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 46 of 153 implementing regulations, are adopted in a timely manner once ICAO 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 enable the regulated industry to respond to new, globally

harmonized requirements in an orderly manner, which is important given the international nature of the market for the aircraft engines that would be affected b y today ’s proposed rule. It would also avoid continuing the significant lag ti me that has sometimes occurred between ICAO’s adoption of international standards and our adoption of corresponding standards under U.S. law. To the extent I CAO adopts standards that differ from those recommended b y 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 requirements was well documented b y our own anal ys es and CAEP as described later in this section and in s ection I . V . , Regulatory Impacts. We think that th e 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 of Transportation through the FAA regarding leadtim e, 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 47 of 153 section I. C ., because 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 conform our standards to I CAO’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 sta ndards. 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 Tier 6 and Tier 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 uses to differentiate the CAEP work cycle that produces new NOx standards. (The CAEP naming convention is described in section I.E.) As a result, the first tier of proposed NOx standards, which are consistent with CAEP/6, will be referred to as Tier 6 in the remainder of today ’s notice. The second tier of proposed standards***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 48 of 153 wil l be referred to as Tier 8, which is consistent with CAEP/8. We are also incorporating the new naming convention in the regulations for the existing NOx emission standards, i.e., Tier 0 , Tier 2, and Tier 4. There is no material change to the existing NOx standards themselves , except to the extent that upon the effectiveness of a final rule reflecting today ’s proposal the existing NOx standards would be superseded by Tier 6 standards . We acknowledge that this new naming convention is a change from the pa st practice of not describing aircraft engine emission standards as tiers. However, we believe the new naming scheme is a valuable tool that makes referring to individual NOx standards much easier. It is also similar to the terminology we use for other m obile source sectors that are subject to environmental regulation and for which standards have become more stringent or have otherwise been amended over time . A. NOx Standards for Newly - Certified Engines W e are proposing two different tiers of increasi ngly stringent NOx standards. These standards would apply for all for newly - certified gas turbine aircraft engines with maximum rated thrusts greater than 26.7kN. 53 (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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 49 of 153 pressure ratio is a ratio of the air pressure entering the engine to the air pressure at the entrance to the combustor, i.e., after the air has passed through the compressor section of the engine. Each of the proposed tiers is described separately below. 1. Tier 6 NOx Standards for Newl y - Ce rtified 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, 2007. Given that aircraft turbine engines are international commodities, engine manufacturers have already certified engine models introduced after that date in compliance with these international requirements, or are already 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 89kN, while lower output engines are defined as having rated thrusts less than 89kN but greater than 26.7kN. The proposed Tier 6 NOx standards for each of these power grouping are described separately below.

53 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 50 of 153 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 e ngines with a pressure ratio of 30 or less: g/kN rated output = 16.72 + (1.4080 * engine pressure ratio) • For engines with a pressure ratio of more than 30 but less than 82.6: g/kN rated output = - 1.04 + (2.0 * engine pressure ratio) • For engi nes with a pressure ration of 82.6 or more: g/kN rated output = 32 + (1.6 * engine pressure ratio) The corresponding CAEP/6 standards were derived by CAEP using the following methodology : • Make the CAEP/6 standard 12 percent more stringent than the CAEP /4 requirement at a pressure ratio of 30; • Retain the same percent reduction, i.e., 12 percent, for pressure ratios below 30;***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 51 of 153 • Retain the slope of the CAEP/4 standard for pressure ratios of 30 to 62.5 for pressure ratios of 30 to 82.6; • Retain the sl ope of the CAEP/4 standard for pressure ratios at or above 62.5 for pressure ratios at or above 82.6. 54 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 N Ox standards, which were based on CAEP/4, for comparison.

54 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 actuall y making CAEP/6 less stringent than CAEP/2. It has no practical value because current engines or anticipated engine designs do not utilize such high pressure ratios. Presently, there are no current engines with pressure ratios above approximately 42.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 52 of 153 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 on

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 ac ross 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 (CAE P/4). The relative stringency can also be illustrated at other pressure ratios. At pressure ratios less than 30 the reductions are also 12 percent. At pressure ratios above 30, however, the percent reduction decreases as the pressure ratio is increased. Based on the figure, the percent reduction for current technology engines ranges from about 8 to 12 percent.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 53 of 153 b. Numerical Emission Limits for Lower Thrust Engines The proposed Tier 6 NOx standards for newl y - certified gas turbine engines with rated thru sts between 26.7 and less than 89.0kN are differentiated by both pressure ratio and rated thrust as shown below. • For engines with a pressure ratio of 30 or less: g/kN rated output = 38.5486 + (1.6823 * engine pressure ratio) - (0.2453 * kN rated thrust) - (0.00308 * engine pressure ratio * kN rated thrust)) • For engines with a pressure ratio of more than 30 but less than 82.6: g/kN rated output = 46.1504 + (1.4285 * engine pressure ratio) - (0.5298 * kN rated thrust) + (0.00642 * engine pressure ratio * kN rated thrust) In developing the corresponding NOx standards for low thrust engines, CAEP recognized the technical challenges that ph ys ically smaller - sized engines represent relative to incorporating some of the lowest NOx technology , which is otherwise available to their larger counterparts. These technical difficulties are well documented***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 54 of 153 and increase progressively as size is reduced (from around 89kN). 55 For example, the relativel y small combustor 56 space and section height of these engin es creates constraints on the use of low NO x fuel - staged 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 n eed is not compatible with the relativel y smaller total fuel flows of lower thrust engines. (Reductions in fuel flow per nozzle are difficult to attain without having clogging problems due to the small sizes of the fuel metering ports.) In addition, lowe r 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 emissio ns control. 57 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 CAEP/4, as the rated output and phy sical size of the engines decrease. We agree with this approach.

55 I CAO/CAEP, “Report of Third Meeting, Montreal, Quebec, December 5 - 15, 1995,” Document 9675, CAEP/3. 56 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 chambe r, 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 exists the combustor so that the final temperatures will not exceed the allowable limit at the tur bine inlet. 57 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 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 55 of 153 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 can not be represent ed in a simple figure, i.e., no single line graph showing the standards for all engines within the thrust range is possible as it was for higher thrust engines. Regardless of this complexity , however, some general observations are useful to characterize the proposed Tier 6 NOx standards for lower thrust engines based on the engine size versus technological challenge described in the previous paragraph. C omparing the proposed lower and higher thrust standards at 89kN, which is the demarcation point betwee n 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 techno logies are the same at 89.0kN delineation point. Again focusing onl y on 89kN 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 represented b y almost all current engine designs. At higher pressure ratios, the relative numerical reduction is progressively less because the slope of the two standards is essentially the same.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 56 of 153 Fi gur e 2: P ro posed Ti er 6 NOx St andar ds fo r Low er T hr ust E ngi nes Rated 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 S tandar d Pr opos ed Tie r 6

12% R educt ion Current En gine PR s

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, the relative stringency of CAEP NOx standards is generally compared at this point as a matter of convention. As shown in the figure for current engines, the reduction ranges from 12 percent at the upper end of the thrus t range to 0 percent at the lower end of the range. The pattern is similar for the other pressure ratios. Only the actual numerical value for percentage reduction at 89kN, as shown on the far right of the figure, may vary by pressure ratio, as described at the beginning of this paragraph. However, in the region of pressure ratios represented by***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 57 of 153 today ’s engines, the results are identical to those shown in the figure, i.e., a 12 percent reduction at 89kN decreasing to 0 percent at 26.7kN.

Figure 3: Pr opose d T ie r 6 N Ox Standards for Low er T hr ust Engine s A

t Pr es sur e Ra tio 30

40 50 60 70 80 90 100

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

Pr opos ed T ie r 6

0% R educ ti on at 26.7k N 12% R educ ti on at 89k N Cu rre nt E

ngine T hr us ts

2. Tier 8 NOx Standards for Newl y - Certified Engines The second tier of proposed standards, i.e., Tier 8, are equivalent to the NOx limits that were most recently recommended at CAEP/ 8 in February 2010 for adoption b y ICAO. 58 The CAEP/8 recommended standards have a reco mmended effective date after December 31, 2013. As discussed further in section I . V . o f today ’s notice, we agree with

58 CAEP/7 did not adopt new aircraft engine NOx standards.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 58 of 153 CAEP that this provides engine manufacturers with adequate leadtime to respond to these more stringent NOx standards considering the technical feasibility and cost associated with the requirements. Therefore, we are proposing that this tier of proposed standards would take effect on January 1, 2014 , provided ICAO adopts CAEP/8’s recommended standards and effective date. If ICAO adopts dif ferent 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 th e Tier 8 standards for gas turbine engines is different for higher - and lower - rated thrust engines. Higher output engines are defined as having rated thrusts equal to or greater than 89kN, while lower output engines are defined as having rated thrusts les s than 89kN but greater than 26.7kN. The longer - term standards for each of these power grouping are described separately below. a. Numerical Emission Limits for Higher Thrust Engines The proposed Tier 8 NOx standards for newl y certified gas turbine engin es 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)***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 59 of 153 • For engines with a pressure ratio of more th an 30 but less than 104.7: g/kN rated output = - 9.88+ (2.0 * engine pressure ratio) • For engines with a pressure ration of 104.7 or more: g/kN rated output = 32 + (1.6 * engine pressure ratio) The corresponding CAEP/8 standards were derived by CAEP using the following methodology : • Make the CAEP/8 standard 15 percent more stringent than the CAEP/6 requirement at a pressure ratio of 30; • Retain the slope of the CAEP/6 standard for pressure ratios below 30; • Retain the slope of the CAEP/6 standard for pressure ratios of 30 to 82.6 for the CAEP/8 pressure ratios of 30 to 104.7;***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 60 of 153 • 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. 59 The resulting proposed Tier 8 N Ox standards for these higher thrust engines are presented in Figure 4 along with the proposed Tier 6 standards for comparison.

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% Reduc ti on

15% Reduct ion 11% Reduc ti on

59 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 poi nt and thereby actually making CAEP/8 less stringent than CAEP/2. It has no practical value because current engines or anticipated engine designs do not utilize such high pressure ratios. Presently, there are no current engines with pressure ratios above approximately 42.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 61 of 153 As noted previousl y, as a matter of convention the relative stringency from one CAEP standard to another is generall y express ed relative to a pressure ratio of 30. Using that convention, the proposed Tier 8 standards (CAEP/8 ) are referred to as being 15 percent more stringent than the proposed Tier 6 NOx standards (CAEP/6). The relative stringency

can also be illustrated at o ther pressure ratios. At pressure ratios less than 30 the reductions increase. At pressure ratios above 30, however, the percent reduction decreases. Based on the figure, the percent reduction for current technology engines ranges from about 11 to 19 pe rcent. 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 89.0kN are differentiated b y both pressure ratio and rated thrust as shown below. • For engines with a pressure ratio of 30 or less: g/kN rated output = 40.052 + (1.5681 * engine pressure ratio) - (0.3615 * kN rated thrust) - (0.0018 * engine pressure ratio * kN rated thrust) • For engines with a pressure ratio of mo re than 30 but less than 104.7:***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 62 of 153 g/kN rated output = 41.9435 + (1.505 * engine pressure ratio) - (0.55823 * kN rated thrust) + (0.005562 * engine pressure ratio * kN rated thrust) In developing the corresponding CAEP/8 NOx standards for low thrust engi nes, 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 technical difficulties were describ ed in the previous section for the proposed Tier 6 low - thrust engine standards. Also as previously

described, no single line graph showing the standards for all engines within the thrust range is possible as it was for higher thrust engines, because the equations have two variables. However, some general observations are useful to characterize the proposed Tier 8 NOx standards for lower thrust engines based on the engine size versus technological challenge described in the previous paragraph. First, the p roposed 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 89kN, where the engine sizes and ability to incorporated low - NOx technologies are co mparable. This same characteristic was observed for the proposed Tier 6 standards. Second, as shown below in Figure 5 for 89kN engines, at this thrust rating the proposed Tier 8 standards represents a 15 percent reduction from the proposed Tier 6 standar ds 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 63 of 153 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 ion

Third, at other thrust ratings the percent reduction between the proposed Tier 6 and Tier 8 stan dards 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 current engines, the reduction ranges fr om 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 for percentage reductions at both en ds of the thrust range, i.e., 26.7 to 89kN, may vary by pressure ratio . In the region of pressure ratios represented by today ’s engines, the results are identical to those shown in F igure 6 at 26.7kN, i.e., a 5 percent reduction at all pressure ratios fo r that thrust rating .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 64 of 153 However , percent reductions increase linearl y up to a maximum 23 percent reduction for 89kN engines with pressure ratios of about 15.

Fi gure 6: P ro posed Ti er 8 NOx St andards fo r Low er 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 En gine Th rus ts 15% Reducti on at 89 kN 5% Reducti on at 2 6. 7 kN

B. Application of the Tier 6 NOx Standards to Newly - 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 problems complying with these requirements. Also , although , consisten t with CAEP/8, we are not proposing to appl y the Tier 8 NOx standards to newl y - manufactured engines at this time, this section concludes with a description of future efforts to examine such a possibility .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 65 of 153 1. Phase - In of the Tier 6 NOx Standards for New ly - 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 rule. We are also proposing to phase - in these same NOx limits for newly - manufactured engines within engine models (and their derivatives) that were originall y certified to less stringent requirements ( i.e ., Tier 2 or Tier 4) and were already being produced for installation on new aircraft prior to the rule’s effecti ve date. 60 As a result, manufacturers would need to bring newly - manufactured engines of these previousl y certified models into compliance with the applicable Tier 6 standards by a future date or cease production of those engine models. 61 As we discussed and described in our anal ys is of the need for a CAEP 6 production cut - off during the CAEP process, establishing a date certain for compliance with an y emission standard is foundational to its basic design and purpose and helps to ensure that the full benefits of newer, more stringent requirements will be achieved in a reasonable time. 62 We are, however, proposing certain limited flexibilities for engines that can not be made compliant because of specific technical or economic reasons, as discussed later in th is section.

60 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,” wh ich 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. 61 After this date the production of any noncompliant engines would cease bec ause the FAA would discontinue issuing an airworthiness approval tag (FAA Form 8130 - 3) to these engines. 62 ICAO, Committee on Aviation Environmental Protection (CAEP), Eight Meeting, Montreal, 1 to 12 February 2010, Agenda 2: Review of Technical Propos als Relating to Aircraft Engine Emissions, Adoption of Production Cut - Off 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 66 of 153 The proposed effective date of January 1, 201 3 63 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 64 , 65 , 66 and our more 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 noncompliant 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 d ate of the CAEP/6 standards (corresponding to our proposed Tier 6 NOx standards ) for

63 The proposed regulatory text sp ecifies that engine models certified at or below the Tier 4 NOx standards may be produced through December 31, 2012 without meeting the Tier 6 NOx standards. Therefore, the effective date of the proposed standards for new - manufactured engines is effective ly January 1, 2013. 64 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 2009, Agenda 6: Emissions Technical - WG3, Production Cut - Offs and Associated Flexibilities for ICAO Engine Emission S tandards, WP/39, Presented by U.S. Representative, August 6, 2009. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 65 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Salvador, Brazil, 22 to 26 June 2009, Agenda Item 3: Forecasting and Economic Analysis Support Group (FESG), CAEP/6 NOx Production Cut - Off 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. 66 ICAO, Committee on Aviation Environmental Protection (CAEP), Steering Group Meeting, Seattle, 22 to 26 September 2008, Agenda Item 3: Forecastting and Economic Analysis Support Group***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 67 of 153 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 pur chasing decisions. 67 , 68 T his phase - in period for applying the Tier 6 NOx standards to newly - manufactured engines is identical to the date for this same requirement that CAEP /8 has recommended to I CAO for adoption. 69 Therefore, we are proposing that all engi nes newl y - manufactured after December 31, 2012 must comply with the Tier 6 NOx standards. Again, if IC AO ultimately adopts a production cut - off date that differs from this proposed date, we would evaluate whether to adopt a correspondingly different date in the final rule or to seek further public comment on the change. 2. Exemption from the Tier 6 Production Cutoff In conjunction with the implementation of the Tier 6 NOx standards, we are proposing provisions which would allow engine manufacturers to reques t 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 sectio n 87.7 would (FESG), Production Cut - Off 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. 67 The ICAO CAEP/6 NOx standards became effective after December 31, 2007. 68 This period of time is also consistent with the phase - in period associat ed with previous ICAO standards. CAEP’s predecessor, the Committee on Aircraft Engines Emissions, established the first international emission standards with an effective date four years after adoption, i.e., effectively a four year phase - in. CAEP2 inclu ded a phase - in period of 4 years for newly - manufactured engines. 69 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 68 of 153 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 ) that has been recommended b y C AEP / 8 for adoption by I CAO . 70 , 71 The provisions in this ETM were crafted in the context of the CAEP/6 NOx production cutoff deliberations leading up to the CAEP /8 meeting in February 2010. While we are proposing to revise our regulations, the process for evaluating any request for an exemption and an y final decision on its disposition would be unchanged. In this regard, the FAA is the process owner under its enforcement authority contained in section 232 of the Clean Air Act . 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, EPA and the FAA may exempt low - production volume engines from being full y compliant with the emission st andards. 72 Several such short - term exemptions were granted in the 1980s when emission standards were first

70 ICAO, “Committee on Aviation Environme ntal 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. 71 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 Cut - Off, ” CAEP9_WG3 - CTG - 2_IP01, September 23, 2010. A c opy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687. 72 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 69 of 153 applied. These exemptions have since expired, and requests for new exemptions under those pr ovisions have not been submitted ; therefore, we believe that the provisions allowing for such exemptions are no longer of an y 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 apply to aircraft certificated by the FAA , and the FAA does not address in the certification process whether an aircraft will be used for short durations or infrequent intervals . Hence, the provisions are of no utility . The current regulations also provide for permanent exemptions based on consideration of the certain factors specified in §87.7(c) . We are proposing to repl ace these provisions with new regulatory text 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 f or 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 Provisi ons for Spare Engines need to meet the current emission standards for other pollutants. Exempted engines must also meet a less***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 70 of 153 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 l ogisticall y difficult. Also, under our proposed regulations, there would be no adverse environmental effect from allowing the use of a spare engine as a direct replacement for an existing engine, because a spare could be used only whe n the emissions of th e 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 repo rt 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 . ” Exemptions fo r 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 - stringent NOx emission standard. Exempted engines must therefore still get FAA certification.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 71 of 153 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 allowing manufacturers to produce new engines for use as spares . The proposed regulatory provisions would allow this practice to continue. Under the proposed regu lations, engines meeting the requirements for spare engines could be produced and enter into commerce 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 and have an Airworthiness Approval Tag. (This process would essentially s erve as the approval step envisioned by I CAO 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 or 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 72 of 153 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 cut - off. It addresse s engines reaching the end of their production cy cles 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 ear s, and then fall off over a few more y ears. When new emission standards are 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 comp liance with the new standards becomes required. The 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 i f 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 73 of 153 vary from unexpected pro blems with technology upgrade programs to labor disruptions to 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 new 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 The 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 grante d, the exemption would allow manufacturers to pr oduce 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 r equirements. More specificall y, an engine exempted from the Tier 6 NOx standards would need to be covered b y a previously issued ty pe certificate showing***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 74 of 153 compliance with the Tier 4 NOx standards, 73 as well as the current HC, CO, fuel venting, and smoke standards. ii . Production L imit The number of engines exempted would generally not be allowed to exceed 75 engines per manufacturer

– or more precisel y per ty pe certificate holder . 74 However, an y given approved exemption would include a specific limit base d on the information laid out in the manufacturer’s exe mption request. It is worth noting that this limit of 75 differs slightly

from the current ICAO ETM exemption language, which would generall y allow up to 75 engines per type certificate . 75 While our proposal would be technicall y different from , and potentially more stringent than, the current ETM language, it would have practical significance only to the extent that any

manufacturer seeks exemptions for more than one engine family and could separately justify exempting sufficient numbers of each famil y to exceed the 75 total. We do not expect this situation to occur for the Tier 6 NOx standards. For example, individual manufacturers produced only 15 engines

73 Engines certified only for compliance with earlier NOx standards would not be eligible for exemptions. This is also consistent with the exemption language in the ICAO ETM. Note that where such engines have emissions actually meeting the Tier NOx they may be recertified to the Tier 4 standards, but only before the effective date of the proposed regulations. 74 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. Th is is especially likely to be the case in joint ventures. In such cases, we would expect 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 75 of 153 under the most recent exemption we have granted. 76 Since current engine emission data suggest that most engine models already meet the Tier 6 emission standards, 77 it is very unlikely th at an y manufacturer wo uld seek exemptions for multiple engine families, let alone more than two families , and this difference should not adversel y affect the industry. Nonetheless, we have submitted a paper through the I CAO/CAEP process seeking to align the ETM provision with those in this proposal. 78 Under both our proposed regulations and the ETM, this production c ap would apply for total worldwide sales , so coordination between the certificating authorities is important to assure this program is implemented as envisioned in the ETM. O ur proposed exemption from the production cutoff is for up to 75 engines per ty p e certificate holder. In this context each corporation or joint venture that holds a ty pe certificate would be a separate t ype certificate holder. For the purposes of the se proposed exemption provisions, a list of likely entities that would be considered separate ty pe certificate holders would include the following manufacturers: Honey well, General Electric , Pratt & Whitney, P ratt & Whitney Canada , and Rolls Royce (to include the BMW and Allison as separate entities ). In addition to these manufacturers, there are

75 CAEP/8

– WP/18, Environmental Technical Manua l (ETM), Vol II on the Use of Procedures in the Emission Certification of Aircraft Engines, Appendix ”ICAO Emissions Environmental Technical Manual” 76 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, October 2010. A copy of this document is in docket number EPA - HQ - OAR - 2010 - 0687. 77 United Kingdom, Civil Aviation Authority, “ ICAO Engine Emissions Databank.” Available from the CAA website located at www.caa.co.uk/default.aspx?catid=702 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 76 of 153 several joint ventures active in the aircraft engine market, such as CFM International and Engine Alliance. We propose to also treat these joint ventures as ty pe certificate holder s apart from those manufacturers mak ing up the joint venture. We ask for comment on our proposed approach for defining the corporate entity for the purposes of applying the production limit . We are requesting comment on whether the limit of 75 engines per ty pe certificate holder is the appropriate value. Sevent y - five engines per ty pe certificate holder is reasonable based on our assessment of historic production patterns . In support of this proposal, we anal yz ed past production histories and projected future orders of engine models that may

need exemptions to further verify that a limit of 75 would be appropriate . To conduct this analy sis, we used data from the ASCEND Database 79 , which contains information on past production volumes and estimates production volumes in the future years based on information on actual or potential new orders. Based on this analy sis, it appears highl y unlikel y that an y ty pe certificate holder would need exemptions for more than 75 engines during the y ears exemptions will be available. Be yond this, a reasonably tight limit on production v olumes reflects the economics of aircraft engine production. Engine modifications to meet more stringent

78 ICAO, “Ne wly Produced Engine Exemptions for CAEP/6 NOx Production Cut - Off, ” CAEP9_WG3 - CTG - 2_IP01, September 23, 2010. A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687. 79 AS CEND Online ( www.ascendworldwide.com) is a database that i ncludes comprehensive transaction data, orders and deliveries, and airline fleet histories***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 77 of 153 standards and subsequent recertification are often an expensive undertaking. When future sales are projected to be larger in number, manufacturers hav e argued that economics favor a return on investment and that market forces dictate that they make the investment to so that they

have full y compliant engines to meet customer demands . Inthese cases exemptions would not be necessary . However, in transit ions, economics are less attractive and the market forces argument is less compelling. While it is not possible to know how man y engines (if an y at all) would be exempted during the four - ye ar period, we can estimate a worst case scenario. For example, pre vious CAEP anal ys is indicated that there are four engine manufacturers with product which does not yet meet the proposed Tier 6 NOx standard . If each applied for and were granted the maximum allowable 75 exemptions over the four - ye ar period, the total of 300 exempted engines worldwide would only be 2 - 3 percent of the newly produced fleet. 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 curr ent process. We are proposing that manufacturers be required to submit their requests to both the EPA and FAA , in order to facilitate the timely consultation process of the two agencies .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 78 of 153 To ensure that we have the information necessary to evaluate exemp tion 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;

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

• 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 flagged; and***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 79 of 153 • 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

• Projected future production volumes and plans for producing a compliant version of the engine model in question. Other Factors

• Hardship: Impact of unforeseen technical circumstances , business events. Or other natural or manmade ca lami ties beyond your control, and***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 80 of 153 • 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 expect to take a broad perspective in evaluating what is or is not in the public interest. This is why

the manufacturer justifications would need to include a quantified description of the environmental effects of granting the exemption, as well as discussion of economic and technical issues related to bringing the engine into compliance. The analy sis of environmental impacts would need to specify by how much the exempted engines wo uld 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 wo uld apply onl y for NOx emissions, the analy sis could also include possible benefits regarding noise levels or reduced emissions of pollutants other than NOx. Relevant economic impacts could include impacts on the engine manufacturer, airframe manufacturer , airline(s), and/or the general public. In the past, some manufacturers have requested exemptions based on the largest number of engines they

hoped to continue producing without knowing how many they would actuall y be able to produce or who would purchase them. The new exemption***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 81 of 153 language calls for manufacturers to target their requests 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 cap . We would then review the revised request. For e xemptions that have alread y been approved , manufacturers could also ask for additional engines , again subject to the cap . If they 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 engines. 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 exe mption to cover a higher number of engines. Manufacturers also would be required to notify us if they determine after submitting a request that the information is not accurate, either from an error or from changing circumstances. While we expect a manuf acturer 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 82 of 153 If, after co nsult ing with FAA, we determine that the exemption request is 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 approv e 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 on exempt engines similar to the information about spare exempt engines. The permanent record for each engine exempted under this provision would need to indicate that the engine is an exempted engine and the engine itself would need to be labeled as “EXEMPT NEW ”. iv . Foreign Aircraft We are proposing that manufacturers also include in their requests a list of countries in which the aircraft would be expected to be registered (sometimes called

“ flagged ”) . While not specificall y listed in the ETM, we believe that this information is consistent with the ETM as it would be necessary to ensure proper coordination with other countries in which these aircraft will be registered and used. This coordination is 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 83 of 153 exemption for engines used on aircraft that would be registered in countries opposing the exemption. It is worth emphasizing that the proposed req uirement for EPA and FAA approval would apply

equall y for engines that were exempted by foreign authorities if any of them would be used on aircraft subject to U.S. regulations. The ETM includes a presumption that each member country will recognize exempt ions granted b y other countries. However, this presumption is conditioned upon the exemption being granted consistent with the guidelines of the ETM. Significantl y, the ETM requires 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 operator of the aircraft to which they are to be fitted. Given the international n ature 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 certification is done through a reciprocity agreement between or among membe r states, the states involved should coordinate on the processing of exemptions and concur before approval is granted. 80

80 ICAO, “Committee on Aviation Environmental Protection (CA EP), 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 84 of 153 Thus in most cases, manufacturers should be getting approval from all relevant authorities at the same time. However, whether they see k approval at the same time or in sequence, requiring EPA and FAA approval 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 foreign 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 woul d not expect to object to exemptions to engines properly exempted b y other countries under those procedures. Finally , the proposed regulations state that the production limit would apply to worldwide sales of the exempted engines. For example, where a man ufacturer requesting an exemption alread y has an exemption issued by a foreign competent authority for 20 engines not subject to EPA emission standards because they will not operate in the U.S., the maximum number of engines that we would exempt would be a n additional 55. We believe that to approve more than 55 would be inconsistent with the ETM. We would also likely

include as a condition of our exemption approvals that manufacturers could not obtain exemptions for more than 75 engines worldwide.

c . V oluntary

Emission Offsets***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 85 of 153 We are requesting comment on establishing a voluntary program b y which manufacturers could receive emission credits to offset higher emissions from exempted engines. An example of such a program is summarized in a memorandum to the docket. 81 We would expect manufacturers to be interested in generating offsets for one of three purposes. First, manufacturers might choose to generate offsets as part of their justifications for exemptions. For example, where we determine that an exe mption 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 choo se to generate offsets as part of a justification for being allowed to exceed the cap of 75 exempted engines per manufacturer. Note that since this is not specifically allowed in the proposed regulations, 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. Third , 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.

81 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 86 of 153 Under this approach, generati on 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 b elow the otherwise applicable standard (e.g., at least 10 percent below) . Another concept would be to allow credits onl y to the degree which the NOx characteristic level was more than 10 percent below the standard. For example, an engine that was 15 perc ent below the standard would generate credits equivalent to 5 percent of the standard. This would ensure a net improvement in emissions. If we were to finalize such a program, we could reserve the right to restrict the use of credits so that they were us ed 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 trul y offset the higher emissions from another model. For example, emissions from regional airc raft may

not be directly

equivalent to emissions from aircraft designed for longer cross - country

or international flights. Equivalency factors could be developed to account for differences in the number of LTOs per mile, the number of LTOs per years, and the lifetime of the aircraft. 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 87 of 153 We are not proposing to phase - in the proposed Tier 8 NOx standards for newly manufactured engines at this time , since such a feature is not included in the CAEP/8 recommendation to ICAO . This means that engine manufac turers may continue to produce Tier 6 compliant engines within alread y certified models after the proposed 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 eng ine 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 em ission 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 cut - off.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 88 of 153 Assuming a CAEP/8 production cutoff is adopted at som e time in the future, we will re - examine the permanent exemption provisions to ensure a timel y and orderl y 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 throu gh 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 slight changes to an engine model that is in production while keeping the same engine co re design. Depending on the degree of these changes, a decision must be made whether the modified design was significant enough that a new ty pe certificate is necessary , or if the changes were minor relative to the base engine so that it still conformed t o the original t ype certificate of the 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 t ype certificate 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 confirmed b y the FAA’s certificating directorate. As part of the ICAO/CAEP deliberations leading up to the February 2010 CAEP /8 meeting, a new standardized protocol was agreed upon. The protocol included specific criteria for deciding when a***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 89 of 153 modification constitute d a new model that required a new t ype certificate, or when a modification was simple enough to be considered a derivative of an already ty pe - certified engine model. Toward that end, we are proposing to allow manufacturers to ask for a determination that an engine model is a derivative of a previousl y certified engine having sub stantially

the same engine core design. Where we determine the engine model to be sufficiently

similar to be considered a derivative engine model, we would allow continued production of engine model to the same extent as allowed for the original engine mo del. Where the FAA determines that an engine model is not a derivative of a previously

certified engine model, it would be required to be certified to the same standards as other new engine models certified at that time . Consistent with I CAO provisions, we would consider a modified engine to be a derivative engine for emissions purposes if 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) Al l 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 must be equivalent to or lower than the original engine.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 90 of 153 The proposed regulations speci fy 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:

± 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 engineering anal ys is. In all other cases, the manufacturer would be required to test the new engine model to show 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 91 of 153 Practices, Environmental Protection” and was split into tw o volumes

– Volume I addressing Aircraft Noise topics and Volume II addressing Aircraft Engine Emissions. Annex 16 has continued to grow and today Annex 16 Volume II includes a list of mandatory

requirements to be satisfied in order for an aircraft engine to meet the I CAO emission standards . 82 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 supplemented with voluntarily reported information which has been assembled into an electronic spreadsheet entitled “Emissions Databank” (EDB) 83 for turbofan engines with maximum thrust rating s greater than 26.7 kN in orde r 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 model level. The EDB is a useful tool for providing a general overview of the aircraft fleet, as it contains information on engine exhaust emissions and performance tests . H owever, it is not updated on a consistent basis, it contains a varying amount of voluntarily

reported data from each manufacturer, and it does not specificall y

82 ICAO, “ Annex 16 to the Convention on International Civil Aviation, Environmental Protection, Volum e 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 - 0687 83 United Kingdom, Civil Aviation Authority, “ICAO Emissions Databank.” Available at the Civil Aviation Authority websit e www.caa.co.uk/default.aspx?catid=702 .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 92 of 153 list every engine sub - model . 84 It also does not contain information on smaller thrust category turbofans or turboprops, and contains no informat ion on past or recent e ngine production volumes. We need this data to conduct accurate emission inventories and develop appropriate policy ; therefore, the EDB is not necessaril y the proper tool for us to use in order inform our policy decisions , including future standard - setting actions . Furthermore, while the situation is unique here, in the context of the roles of EPA and FAA with regard to aircraft engine emission standards, it is consistent with EPA policy and practice to ask for timely and reasonable reporting of emission certification testing and other information that is relevant to our emission standards . Under the Clean Air Act, we are authorized to require manufacturers to establish and maintain necessary records, make reports, and provide such other information as we may reasonably

require to carry out our functions under the Act. See 42 U.S.C. § 7414 (a)(1). T herefore, we are proposing to require the submission of specific information from an y engine manufacturer for each individual engine subm odel 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 specificall y, the scope of the proposed 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 to turbofans with maximum rated thrusts less than or equal to 26.7 kN and all turboprop

84 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 ”. Engines with slightly different designs would be***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 93 of 153 engines, i.e., those onl y subject to smoke standards. We are also proposing that this specific exhaust emission related information be reported to us in a timely manner , which will allow us to conduct proper emissions inventory anal ys es of the existing fleet and to ensure that an y public policy we creat e 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 manufac turers to the EDB . We feel that this minimizes the reporting burden for each manufacturer while still providing us with the proper amount of information we need to do our job. With the exception of requiring total annual engine production volumes, all of the specific reporting items we are proposing are same as requested for the EDB . We have assessed the potential reporting burden associated with the proposed annual reporting requirement. That assessment is presented in section V. of this notice. We are proposing to require the information listed below for each affected gas turbine engine sub - model in order to establish our own independent engine exhaust emissions database. We are seeking comment on the proposed data reporting elements .

• Company corpor ate name as listed on the engine ty pe certificate ;

• Calendar y ear for which reporting ; defined to be an “engine model”.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 94 of 153 • 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. )

• 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);

• Date of issue of t yp e certificate and / or exemption, i.e. month and year;

• Emission standards to which the engine is certified, i.e. Annex 16, Volume II, edit ion number and publication date;

• If this is a derivative engine, identify the original certified engine model;

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

• U.S. directed production volume of the sub - model for the previous calendar year , or if zero, state that the engine model is not in production and list the date of manufacture (month and y ear) of the last engine produ ced ;

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

• Reference pressure r atio ;

• 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 w atts (W) (depending on engine ty

pe) ;***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 95 of 153 • 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; 85

• Unburned h ydrocarbon characteristic level (i.e. mass of hydrocarbons over LTO cycle / Rated Thrus t (Dp/Foo) ; 86

• 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)) ;

• Nitro gen 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) ;

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

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

• Smoke number characteristic level ;

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

• Number of tests run per sub - model ;

• Number of engines tested per sub - model ;

85 See Regulation Part 87 - Control of Air Pollution from Aircraft and Aircraft Engines , Subpart E , §87.42 Certification report to EPA for definitions.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 96 of 153 • Fuel flow (grams / second) total (weighted) and over eac h segment of the Landing and Take - off Cycle (LTO) (i.e. Take - off, Climb, Approach, Taxi / Ground Idle) ; 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 af fected gas turbine engine . These reports would be due by February 28 of each y ear , starting with the 2014 calendar ye ar . This report w ould be sent to the Designated EPA Program Officer. Where information provided for any previous ye ar remains valid and complete, you may report yo ur 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 spr eadsheet or database template that we provide to each manufacturer. Note that this annual report does not affect the existing regulatory requirement s in § 87.64 to report CO 2 and NOx emission data for purposes of greenhouse gas reporting. We are, however , clarifying those provisions to specify that CO 2 reporting should be for individual modal values rather than a weighted composite value. Additionally , both the greenhouse gas reporting and this reporting will be incorporated into one submission in order t o minimize the r eporting burden to the manufacturer. Our intent for utilizing this proposed reported information is to help inform any public policy

we create , including future emissions standards, as well as help provide

86 Dp/Foo : total gross emission of each gaseous pollutant (mass) / rated thrust (g/kN).***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 97 of 153 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 data 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 proposed information on EPA’s website, we will be able to calculate turbine exhaust emission rates and demonstrate to the public how the fleet meets the current emission requirements. We believe that this information will also be useful to the general public to help inform aircraft exhaust emission values. We ask for comment on our proposed plan to post this information on our website. E. Proposed Standards for Supersonic Aircraft Turbine Engines We are proposing CO and NOx em ission standards for engines that are used to propel supersonic aircraft to compliment our existing HC standard for these engines. These proposed standards were originall y adopted by I CAO in the 1980s , and our adoption of NOx and CO standards for commerci al engines in 1997 omitted coverage of the se pollutants for supersonic commercial engines that were then in use . The lack of EPA CO and NOx standards for supersonic aircraft has had no practical effect, because no such engines have been certified b y the F AA. Also, none of these engines are currentl y in production and we are not aware of any substantive work by

engine manufacturers to develop new engine designs in the immediate future. However, to meet our treat y obligation s under the Convention on Inter national Civil Aviation as previousl y***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 98 of 153 described in section I.B. and to account for the possibility that supersonic engines could be placed in future use, we believe it is necessary and appropriate to propose these conforming standards. F . Amendments t o 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 Standards 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 amen dments that have alread y been adopted b y ICAO 87 , 88 and those that have been recommended b y CAEP for adoption by

I CAO. 89 The amendments that have already been adopted by ICAO are:

87 A strikeout and highlighted version of the amendments is contained in Attachment A to ICAO state letter AN 1/61.2, AN 1/62.2 - 07/32 entitled, “Proposed Amendment to International Standards and Recommended Practices, Environmental Protection, Annex 16 to the Convention on International Civil Aviation, Volume II Aircraft Engi ne Emissions, May 27, 2007. A copy of this document is in docket n umber EPA - HQ - OAR - 2010 - 0687. 88 ICAO, “International Standards and Recommended Practices, Annex 16 to the Convention on International Civil Aviation, Environmental Protection, Volume II Aircr aft Engine Emissions,” Third Edition July 2008, International Civil Aviation Organization. This document contains the full text of ICAO standards and practices and is in docket num ber EPA - HQ - OAR - 2010 - 0687. 89 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 99 of 153 • 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 terminology 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, 20 08. 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 absence of a final rule . Our adoption of these test procedure amendments will therefore not likel y require new action b y manufacturers beyond what they are alread y undertaking to mee t ICAO’s adopted and recommended amendments .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 100 of 153 G . Possible Future Standards for New Technology Turbine Engines and Supersonic Aircraft Turbine 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. E ssentially , the fan of an open rotor engine is not contained within the 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 manufacturer s are actively pursuing such designs for certification in the 2018 timeframe. It now appears that certain aspects of the current gas turbine engine emission standards may

be incompatible with these new designs. For example, the current landing and takeoff cycle for emissions certification is based on conventional engine designs where a significant amount of thrust is generated by an idli ng engine. Specifically , idle emissions are measured and calculated at seven percent of the engine’s rated thrust. Howe ver, 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. Al so, future aircraft using these engine designs may fl y at somewhat slower speeds. This might affect the time these aircraft spend during the climbout mode of the landing and takeoff cy cle. Therefore, the traditional landing and takeoff cycle used in turb ine engine emissions certification may

need to be revised in the future to accommodate open rotor engines.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 101 of 153 We will be working within CAEP to evaluate the differences between conventional turbine engine and open rotor engine technologies , and to revis e th e 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 or test procedures for future supersonic transport (SST) aircraf t engines. The emission standards for these engines were originally developed in the earl y 1970s in response to the Aerospatiale - BAC Concorde. Since that time, there have been varying levels of interest in develop ing 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. Our recent 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 re quest comments on the status and timing of open rotor and future supersonic engine designs and how the aircraft engine emission standards and test procedures may

need to be modified to accommodate these ty pes of engines .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 102 of 153 I V. Description of Other Revision s to the Regulatory Text In addition to the proposed changes discussed above, we are proposing a number of other changes to the regulatory program. Most of these changes are designed to bring the program into conformity with current technology

and current technical or policy practice. Each of these is discussed below. A. Applicability Issues This section discusses how the proposed rule relates to engines used in military and noncommercial civilian aircraft . We do not believe the proposed changes w ould have practical significance for current engine models because the changes align with manufacturers’ current practice in certifying their engines. 1. Military

Engines We are not proposing any specific provisions with respect to engines installed on mil itary aircraft, and we do not believe our proposal would have an y impact on such engines. Military

aircraft are not required to have FAA airworthiness certificates , and our 1997 endangerment finding for NOx and CO emissions and resulting standards did not cover military

aircraft (see 62 FR at 25359) . As such, engines used in military aircraft are not required to meet EPA emission standards, since our current regulations define “aircraft” subject to our rules as an y airplane for which a U.S. standard***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 103 of 153 airwo rthiness certificate (or foreign equivalent) is issued. ( See 40 C.F.R. § 87.1(a) of the existing regulations. ) C urrentl y , m anufacturers voluntarily certify some engines used in military aircraft with the FAA (with respect to emissions as well as airworth iness), especiall y in cases where an engine model may have both military

and commercial use and the commercial engines would be required to be certified . Our proposed new standards and requirements would continue to apply onl y to engines for which standar d airworthiness must be issued (without regard to whether engines of the same model are also used in military

aircraft). We do not intend our proposed regulatory changes to interfere with voluntary

certification for individual engines actually used in mil itary aircraft . For example, regarding engine models that are currently being certificated to meet our existing NOx standards, FAA would continue to be able to allow production and use of such engines in military aircraft, even after the production cut - o ff takes effect for engines used in civilian aircraft required to obtain standard air worthiness certificates . Likewise, it may

still be appropriate for manufacturers to continue to voluntarily certify engines used in military

aircraft to the proposed revised NOx standards, even though military aircraft are not required to obtain standard airworthiness certificates. 2. Noncommercial Engines***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 104 of 153 The current section 87.21 (d) specifies that gaseous emission standards apply to commercial engines with rated thr usts greater than 26.7 kN. These are engines intended for use b y 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 used in aircraft certified by the FAA for use in non - revenue, general aviation service are not subject to the current HC, CO, and NOx standards. They are subject, however, to the current standards for smoke and fuel venting. We are proposing to apply the p roposed gaseous emission standards for commercial engines to their noncommercial civilian counterparts that are required to obtain standard airworthiness certificates. There are a number of reasons for doing this. First, the ICAO Annex 16 standards and r equirements apply equall y to commercial noncommercial engines, and our rules’ current failure to reflect this means that they do not fully conform to I CAO’s standards. Extending applicability of these standards would allow us to meet our treaty obligation under the Convention on International Civil Aviation as previousl y described in section I.B. Second, manufacturers already voluntarily

c ertify their noncommercial engines to these standards with the FAA, as expected under the IC AO standards. The international nature of the aviation business compels engine manufacturers to offer a product that fully complies with the international requirements. Third, the secondary market for potential purchasers of any non compliant, multi - million dollar aircraft that w ould be used in non - revenue service essentially

demands that the standards be made applicable. These aircraft, e.g., large***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 105 of 153 business jets, absent certification to our standards, could not be re sold into commercial service or in other countries that require conformance with the ICAO Annex 16 requirements. Therefore, overall this proposal simply incorporates the status quo and allows us to meet our treaty obligations. In order to make our standards conform to I CAO’s, we need, in addition to promulgating the necessary regulatory

amendments, to update the underl yi ng finding regarding the need to limit gaseous emissions from commercial and non - commercial civilian aircraft , pursuant to CAA section 231(a)(2)(A) . In 1997, our analy sis and finding, and hence our re gulations, 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 from both commercial and non - commercial civilian aircraft engines with rated thrusts greater than 26.7 kN. These noncommercial and commercial engines have a great deal in common. First, they

each use the same thermodynamic engine cycle (i.e., a gas (air) compressor, fuel combustor, and expansion turbine), engine design, and technology . That means they emit the same emissions relative to HC , CO, and NOx emissions. 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 area s. That means their emissions are geographically , spatiall y, and temporally similar, and that they collectivel y contribute to ozone and CO nonattainment concentrations and are projected to continue to***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 106 of 153 do so. Third, noncommercial engines are usually the s ame engine model and sometimes submodel as engines used in commercial operations, which makes distinguishing between commercial and noncommercial engines somewhat artificial. These attributes, taken together, demonstrate that noncommercial engines have th e same effect on health and welfare as their commercial counterparts. Therefore, the Administrator is proposing to find that commercial and noncommercial applications for turbofan and turbojet engines with rated thrusts greater than 26.7kN collectively c ause or contribute to air pollution which may

reasonably

be anticipated to endanger the public health or welfare. Our emissions assessment supporting this conclusion is contained in the docket for this proposed rulemaking. 90 B. Non - substantive Revisions W e 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 since then. We are proposing changes to the text related to some o f 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 def initions, and clear up a variety

of terms and current practices that have not been adequately addressed.

90 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 107 of 153 Except as discussed in previous sections, the proposed changes to part 87 are not intended to significantly

change the certification and compliance p rogram. We are not reopening for comment the substance of an y part of the program that remains unchanged substantively . Specifically , for those instances where we propose to move a provision to a different section or reword a provision in clearer languag e, we do not consider those changes to be substantive. It is also important to note that the changes to the regulation apply starting with the date that the final rule takes effect. In particular, it is worth emphasizing that while we are restating the HC, CO, and smoke standards , as they

would apply

to Tier 6 and later NOx standard - subject engines, in a new §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 §87.23 are identical to the existing standards of §87.21 and are being copied into the new section merel y for clarit y to readers. The proposed rule includes the following definitions and other minor changes in addition to those changes described earlier in this s ection or in Section III: The definition of the term “aircraft” is being revised to be consistent with its meaning under FAA regulations in 14 CFR 1.1. The existing part 87 definition limits “aircraft” to be onl y those craft issued an airworthiness certif icate. This was done as a way to specify

the applicability

of the standards. However, this can cause confusion in a***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 108 of 153 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 Ac t and the Federal Aviation Act. The proposed definition aligns with these statutory definitions. The changed wording is intended to clarify

the existing policy

without changing it . Text specifying general applicability is being added to §87.3 to be consi stent with the new definition of “aircraft” and maintain the effective applicability of the existing regulations, which uses narrow definitions to limit applicability . For example, the existing regulation s limit the applicability of the standards b y defin ing “aircraft” to onl y include fixed - wing airplanes with airworthiness certificates. They exclude non propulsion engines from the definition of “aircraft engine” and turboshaft engines from the definition of “aircraft gas turbine engine . ” We believe it i s more appropriate to explicitly exclude these engines in an applicability section than to rel y on readers finding these exclusions in the definitions section. We are also renaming §87.3 as “General applicability

and requirements” and reorganizing the content for clarit y. Finally, we are replacing the existing regulatory text related to federal preemption for exempted engines in §87.7(f) with a codification of the statutory preemption language in §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 being incorporated b y reference for test procedures. This involves a broader reference to Annex 16, with less content repeated in part 87.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 109 of 153 However, this doe s not substantively change the test procedures that appl y since the existing procedures are based directly 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. 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 app ly 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 w ill be no more engines required to be certified to the standards specified in §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 comment on those definitions :

• Aircraft engine • Aircraft gas turbine engine • Class TP • Class TF • Class T3 • Class T8 • Class TSS***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 110 of 153 • Commercial aircraft ga s turbine engine • Fuel venting emissions Specific provisions are being added to define and require the use of “good engineering judgment.” This applies for instances where the regulation cannot spell out every detail of how a manufacturer should comply w ith the regulation. The general approach for implementing the good - engineering - judgment standard is to allow EPA or FAA to require a different approach for future work if we disagree with a manufacturer’s judgment. Improper judgments would onl y be addres sed on a retroactive basis if the manufacturer deliberately used incorrect information, acted irrationally , or otherwise failed to make a decision in good faith. We believe these provisions reflect the approach being used today

by FAA to interpret the app licable regulations. Provisions are being added specifying rounding practices for rated output, rated pressure ratio, and calculated emission standards; generally specifying that they

be expressed to at least three significant figures. These specification s are consistent with how manufacturers are generally certifying engines today . Defining how to round these values would prevent manufacturers in the future from effecting small changes in the level of the emission standards to which they certify their en gines. 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 111 of 153 calculated standard itself. While this has not been an issue in the past, it is important to maintain a level playing field for a ll manufacturers as standards become more stringent. There will be no more engines certified to the standards specified in §87.21, so the specified procedures for rounding these values will change the requirements for engines certified to the Tier 4 or earlier standards Definitions are being added for “turbofan engine , ” “turbojet engine , ” “turboprop engine , ” “turboshaft engine , ” “supersonic , ” and “subsonic” to avoid any uncertaint y about how the standards apply to different ty

pes of engines. The proposed definitions are intended to reflect the plain meaning of these terms. The proposed regulations include the following additional amendments: Regulation cite Description of Amendment Notes 87.1 Add definition of

“characteristic level”. The characteristic level is established by ICAO Annex 16 as a means of calculating a statistical adjustment to measured emission results to take into account the level of uncertainty corresponding to the number of tests run for a given pollutant. 87.1 Remove definitions for

“emission measurement system”, “power setting”, “sample system”, “shaft power”, “taxi/idle (in)”, and taxi/idle (out). These terms will no longer be used in part 87. There will be no more engines certified to the standards specified in §87.21, so removin g these definitions will not change the requirements for engines certified to the Tier 4 or earlier standards .***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 112 of 153 87.1 Revise definition of “exhaust

emissions” and “smoke”. The new language references the emission testing procedures, since that is the practi cal 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 c ertified 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 al so refer to new turboprop engines and new supersonic engines, 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 reference to the 1976 U.S. Standard Atmosphere, (2) correct a typographical error in the humidity specification, and (3) change the atmospheric pressure units from Pa to kPa. The editorial changes do not involve any substantive change in the specified conditions.

87.2 Remove FAA from the list of

acronyms in §87.2 and add it to the set of defined terms in §87.1. Thi s 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 in individ ual subpart s, 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 113 of 1 53 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 proce dures to §87.60. This provision, and the similar provision from §87.3(a), should be described together in the context of the testing requirements in subpart G. 87.21 Identify the specific date

when the smoke standard started to apply for turbofan engines with rated output less than 26.7 kilonewtons. This corrects a typographical error from the Federal Register .

87.21 Revise paragraph (f) to

correctly reference the regulatory sections that describe the applicable test procedures. This change is strictly ed itorial.

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 specifie d in §87.21, so any changes to the test procedures will not change the requirements for engines certified to the Tier 4 or earlier standards . Moreover, engine manufacturers are expected to perform all their testing based on the current test procedures fro m ICAO Annex 16, regardless of the standards that apply.

C . Clarifying Language for Regulatory Text***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 114 of 153 The proposed regulations incorporate the changes described in this preamble. The following table highlights and clarifies several provisions that may no t 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 d efinition 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 ci rcumstances that could possibly occur, but that are not addressed by the Annex. For example, our definition would provide a date of manufacture for an engine not previously documented by a manufacturer. 87.1, Definition of “ d erivative engine” Itis important to consider this definition in combination with the definition of “engine type certificate family”. 87.1 Definition of “ e ngine model” A manufacturer or FAA may further divide an engine model into sub - models. Engines from an engine model must be cont ained within a single engine type certificate family. Where FAA determines that engines are not sufficiently similar to be included under a single type certificate, they will not be considered to be the same engine model for purposes of part 87. 87.1, De finition of “ military aircraft” This definition is not limited to aircraft belonging 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 cut - off date” The productio n 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”, tier s apply only for NOx standards. Tiers do not apply for HC, CO, and smoke standards because the same standards continue to apply, independent of the NOx standards. 87.23(d)(2) The allowance to continue production of Tier 6 engines after the Tier 8 standards start to apply is not necessary for engines with rated pressure ratio at or above 104.7 because the Tier 6 and Tier 8 standards are the same. 87.42(c)(1) § 87.42 requires that manufacturer report the engines it produces b y sub - model. The manufacturer must specify***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 115 of 153 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. We will n ot concur with an exemption where we determine that such an exemption would be contrary

to the public interest. 87. 50 ( a ) (1 ) (iv)(F) This provision states that manufacturers requesting exemptions should describe equity issues. As an example of equity issue s related to an exemption request , a manufacturer might provide a rationale for granting the exemption when another manufacturer has a compliant engine and does not need an exemption, taking into account the implications for operator fleet composition, commonality , and related issues in the absence of the engine model in question. 87. 50 ( a ) (6 ) This provision requires manufacturers to promptly notify the FAA if new or changed information c ould have affected approval of an exemption . For corrections to an ex emption request that would not affect the approval of the exemption , manufacturers may include the updated information in the annual report described in §87.50 (e).

V. Technical Feasibility, Cost Impacts , Em ission Benefits Aircraft engines are internatio nal commodities, and thus, they are designed to meet international standards. Today 's action will have the benefit of establishing consistency

between U.S. and international emission standards and test procedures. Thus, an emission certification test whi ch meets U.S. requirements will also be applicable to all I CAO requirements. Engine manufacturers are already developing improved technology

in response to I CAO standards that match standards promulgated here, and EPA does not believe that the costs incur red b y the aircraft industry as a result of the***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 116 of 153 existing I CAO standards should be attributed to today 's regulations. Also, the test procedure amendments necessary to determine compliance are already being adhered to by manufacturers during current engine certification tests , or will be even in the absence of a final rule . Therefore, EPA believes that today’s proposed standards and test procedure amendments will impose no additional burden on engine manufacturers. T here will , however, be some cost associated with our proposed annual reporting requirement, which is discussed later in this section. 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 . 91 , 92 EPA participated in these anal ys es and supported the results. CAEP considered certain factors as pertinent to the cost estimates of a technology level for engine changes, and these factors or technology levels are described below. The first technology level was regarded as a minor change, and it could include modeling work, minor design changes, and additional testing and re - certification of emissions. The second technology level was considered a scaled proven technology . At this level an engine manufacture r applies its best - proven, combustion technology that was already

certified in at least one other engine

91 CAEP/6 NOx standards: CAEP Forecasting and Economic Analysis Support Group , Economic Analysis of NOx Emissions Stringency Options , CAEP/6 - IP/13 (Information Paper 13), January 15, 2004. A copy of this document is in docket num ber EPA - HQ - OAR - 2010 - 0687. 92 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 Manage ment Tool for Economics***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 117 of 153 family to another engine ty

pe. This second technology level would include substantial modeling, design, combustion rig testing, modification and testi ng of development engines, and flight testing. The third technology level was regarded as new technology or current industry

best practice, and it was considered where a manufacturer has no proven technology

that can be scaled to provide a solution and s ome technology acquisition activity

is required. (One or more manufacturers have demonstrated to have the necessary

technology, and the other manufacturers would need to acquire the technology

to catch up.) Since the effective date for the CAEP/6 NOx standard was January 1, 2008 and nearly

all in - production engines currently meet this standard, we will limit our discussion below of appl yi ng these technology levels to engines that needed to comply with the CAEP/8 NOx standard. For higher thrust engines , i.e., 89.0kN or more , the CAEP/8 NOx standard would apply to a total of 15 engine families. For these families the following technology level response was anticipated: 6 families would require no change, 1 family would need the first technology

level chan ge, 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 89.0kN, CAEP listed a total of 13 engine families in their analy sis of the CAEP/8 NOx standard. The following technology level response was estimated for these

(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 EPA - HQ - OAR - 2010 - 0687.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 118 of 153 families: 11 families would require no change, 1 family would need the first technology level change, and 1 family would require a second technology . As noted above, there will be some cost 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 turbo fan engines with rated thrusts greater than 26.7kN, which are alread y voluntaril y report ed to the I CAO - 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 elements from those requested in the EDB, and 2) are adding onl y one item to those already requested b y the EDB . Also, four of the eight manufacturers make smaller turbofan and turboprops engines that will be reporting for the first time. This will add a small incremental burden for these four manufacturers that otherwise already voluntarily

report to the EDB. There are also two engine manufacturers that onl y produce turbofan engines with rated thrusts less that or equal t o 26.7kN and they will be reporting for the first time. For these two manufacturers we believe that the reporting burden will be small because all of the information we are proposing to require should be readil y available , and these manufacturers have a v ery limited number of engine models. See section IX.B . for our estimate of the hours and cost associated with the annual certification report.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 119 of 153 Turning to emission benefits , CAEP’s assessments indicated that the CAEP/8 NOx standards would provide global NO x 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., i t was estimated that this would translate to LTO NOx reductions in the U.S. of about 0.7 percent in 2020 and 1.1 percent in 2030, 93 and the cumulative LTO NOx reductions from 2014 to 2030 (2014 is the implementation date of the CAEP/8 NOx standards) were pr ojected to be about 17,000 NOx tons. V I . Coordination with FAA The requirements contained in this action are being proposed after consultation with the Federal Aviation Administration (FAA). Section 231(a)(2)(B)(i) of the CAA requires EPA to “consult with the Administrator of the [FAA] on aircraft engine emission standards” 42 U.S.C. 7571(a)(2)(B)(i), and section 231(a)(2)(B)(ii) indicates that EPA “shall not change the aircraft engine emission standards if such change would significantl y increase nois e....” 42 U.S.C. 7571(a)(2)(B)(ii). Section 231(b) of the CAA states that “[a]ny

regulation prescribed under this section (and an y revision thereof) shall take effect after such period as the Administrator finds necessary (after consultation with the Sec retary

of Transportation) to permit the development and application of the

93 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 120 of 153 requisite technology , giving appropriate consideration to the cost of compliance within such period.” 42 U.S.C. 7571(b). Section 231(c) provides that any regulation under section 231 “shall not apply if disapproved by

the President...on the basis of a finding by the Secretary

of Transportation that any such regulation would create a hazard to aircraft safet y.” 42 U.S.C. 7571(c). Under section 232 of the CAA, the Department of Trans portation (DOT) has the responsibility to enforce the aircraft emission standards established by

EPA under section 231. 94 As in past rulemakings and pursuant to the above referenced sections of the CAA, EPA has coordinated with the FAA of the DOT with resp ect to today 's action. 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. 95 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, W orking Group 3 made recommendations to CAEP on these elements. These recommendations were approved b y CAEP/6 meetings prior to their adoption by ICAO in 2004. Similarl y , the more recent Working Group 3 recommendations were approved b y CAEP/8 and subseque ntly recommended to I CAO for adoption.

94 The functions of the Secretary of Transportation under part B of title II of the Clean Air Act (§§ 231 - 234,***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 121 of 153 In addition, as discussed above, FAA will have the responsibility to enforce today 's requirements. As a part of its compliance responsibilities, FAA conducts the emission tests or delegates that responsibility to th e engine manufacturer, which is then monitored by

the FAA. Since the FAA does not have the resources or the funding to test engines, FAA 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 test equipment, and the final testing report sent to FAA. DERs' responsibilities are determined by the FAA and tod ay 's rulemaking will not affect their duties. Finally

as part of its enforcement function, 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 any decision regarding such requests. VII. Public Participation We request comment on all aspects of this proposal. This section describes how yo u can participate in this process. 42 U.S.C. 7571 - 7574) have been delegated to the Administrator of the FAA. 49 CFR 1.47(g). 95 The Sixth Meeting of CAEP (CAEP/6) occurred in Montreal, Quebec from February 2 through 12 in 2004.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 122 of 153 How Do I Submit Comments? We are openi ng a formal comment period by publishing this document. We will accept comments during the period indicated in the DATES section at the beginning of this document. I f you have an interest in the proposed emission control program described in this document, we encourage you to comment on an y 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 to provide specific suggestions for an y changes to any aspect of the regulations that they believe need to be modified or improved. You should send all comments, except those containing proprietary

information, to our Air Docket (see ADDRESSES located at the beginning of this document) bef ore 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 comm ent. 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 123 of 153 In formation (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 public 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 Divisio n, 2000 Traverwood Drive, Ann Arbor, MI , 48105, Attention Docket ID EPA - HQ - OAR- 2010 - 0687 . You may claim information that you submit to EPA as CBIby marking any part or all of that information as CBI (if you 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 the 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 124 of 153 procedures for claiming CBI, please consult the person identified in the FOR FURTHER INFORMATION CONTACT section at the beginning of this document. Will There Be a Public Hearing? We will hold a public hearing on [Insert date no fewer than 15 days before and at least 30 days befo re 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. 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 hearing. We will make a tentative schedule for the order of testimony based on the notifications we receive. This schedule will be available on the morning of the hearing. In addition, we will reserve a block of time for anyone else in the audience who wants to give testimon y.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 125 of 153 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 supplementary information. You may make arrangements for copies of the transcript directly with the court reporter.

Comment Period The comment period for this rule will end on [Insert date 60 days after date publication ] . What Should IConsider as I Prepare M y Comments for EPA? You may find the following suggestions helpful for preparing y our 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 su pport your views.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 126 of 153 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 Authority 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 dis cussion of how EPA meets the CAA's statutory requirements. IX. Statutory and Executive Order Reviews A. Executive Order 12866: Regulatory Planning and Review***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 127 of 153 Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993), this action is a "significant regulatory

action.” This action proposes the adoption of new aircraft engine emissions regulations and as such, requires consultation and coordination with the Federal Aviation Administration (FAA). Accordingl y, EPA submitted this action to the Office o f Management and Budget (OMB) for review under EO 12866 and any changes made in response to OMB recommendations have been documented in the docket for this action. As discussed further in section V, we do not attribute an y costs to the compliance with today’s proposed regulations. However, there is a small burden associated with the proposed reporting requirements, as discussed in section IX.B. B. Paperwork Reduction Act The information collection requirements in this proposed rule have been submitted fo r 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 2300.0 9 . Manufacturers keep substantial re cords 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 urrent fleet, and develop appropriate policy

in the form of future em ission standards. M ost m anufacturers are***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 128 of 153 alread y accustomed to reporting much of this information to I CAO. We are therefore proposing to require that engine manufacturers send us this information to EPA on an annual basis. We also propose to require manufacturers to send us their annual production volumes, which is the only item we would treat as confidential business information. Under the Clean Air Act, we are authorized to require manufacturers to establish and maintain necessary records, make report s, and provide such other information as we may

reasonably

require to carry

out 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. We have estimated the total burden of this reporting requirement to be 60 hours, and the total cost to be $ 3,646 . The burden and cost per response is estimated to be 6 hours and $ 365 . Burden is defined at 5 CFR 1320.3(b). An agency

may not conduct or sponsor, and a person is not required to respond to, a collection of information unless it display s a currently valid OMB control number. The OMB control numbers for EPA's regulations in 40 CFR are listed in 40 CFR part 9. To comment on the Agency 's need for this information, the accuracy of the provided burden estimates, and any suggested methods for minimizing respondent burden, EPA has established a public docket for this rule, whi ch includes this I CR, under Docket ID EPA

–HQ

– OAR

–2010 - 0687 . Submit any comments related to the ICR to EPA and OMB. See the ADDRESSES section at the beginning of this notice for where to submit***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 129 of 153 comments to EPA. Send comments to OMB at the Office of Infor mation 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 colle ction requirements contained in this proposal. C. Regulatory

Flexibility

Analy sis The Regulatory

Flexibility

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

flexibility

analy sis of any

rule subject to notice and comment rulemaking requi rements under the Administrative Procedure Act or an y other statute unless the agency certifies that the rule will not have a significant economic impact on a substantial number of small entities. Small entities include small businesses, small organizatio ns, and small governmental jurisdictions. For purposes of assessing the impacts of today 's rule on small entities, small entity is defined as: (1) a small business as defined by SBA size standards; (2) a small governmental jurisdiction that is a governme nt 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 130 of 153 any not - for - profit enterprise which is independently owned and operated and is not dominant in its field. The follo wing Table IX - C - 1 provides an overview of the primary SBA small business categories potentially affected by

this regulation. Table IX.C - 1

– Primary

SBA Small Business Categories Potentially Affected by

This Regulation Industry NAI CS a Codes Defined b y SBA a s 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), bus inesses 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, I certify

that this action will not have a significant economic impact on a substantial number of small entities. Small governmental jurisdictions and small organizations as described above will not be impacted. We have determined that the estimated effect of the proposed rule ’s reporting requirement is to affect one small entity turbofan engine manufacturer with costs less than one percent of revenues. This one compan y represents all of the small businesses impacted b y the proposed regulations. An anal ys is of the impacts of the proposed rule on small businesses has been prepared and placed in the docket for this rulemaking. 96

96 “ Small Business Impact Memo, Pro posed Aircraft Engine Emission Standards

– Determination of No SISNOSE ,” EPA memo from Solveig Irvine to Alexander Cristofaro, November, 2010.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 131 of 153 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 di scussed in Section IV, today ’s proposed action will establish consistency

between U.S. and existing international emission standards. The engine manufacturers are already developing the technology to meet the existing 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 co ntains no regulatory

requirements that might significantl y or uniquely affect small governments. The provisions of this proposal apply to the manufacturers of aircraft and aircraft engines, and as such would not affect small governments. E. Executive Ord er 13132: Federalism This action does not have federalism implications. It will not have substantial direct effects on the States, on the relationship between the national government and the***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 132 of 153 States, or on the distribution of power and responsibilities amo ng 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 mere ly modifies existing EPA aircraft engine emission standards and test procedures and therefore will merel y continue an existing 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 Indian Tribal Governments 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 appl y to this action. EPA specificall y solicits additional comment on this proposed action from tribal officials.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 133 of 153 G. Executive Order 13045: Protection of Children from Environmental Health & Safety Risks This rule is not subject to Executive Order 13045 bec ause it is not a significant regulatory

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. for a discussion of the health impacts of NOX emissio ns. 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 Use This action is not a “significant energy action” as defined in Executive Order 13211 (66 FR 28355 (May 22, 2001)), because it is not likely to have a significant adverse effect on the supply , distribution, or use of energy . These proposed aircraft engine emiss ions regulations are not expected to result in any changes to aircraft fuel consumption.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 134 of 153 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 specific ations, 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 app licable 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 I CAO International Standards and Recommended Practices Environmental Protection, with the modifications contained in this rulemaking. 97 These procedures are currentl y used by all manufacturers of aircraft gas turbine engines (with thrust greater than 26.7 kN) to demonstrate compliance with I CAO emissions standar ds.

97 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).***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 135 of 153 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 provision 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 effects of their program s, 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 minority or low - inc ome 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 pop ulation. List of Subjects in 40 CFR Part 87***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 136 of 153 Environmental protection, Air pollution control, Aircraft, Incorporation by reference. List of Subjects in 40 CFR Part 1068 Environmental protection, Administrative practice and procedure, Confidential business in formation, Imports, Incorporation by reference, Motor vehicle pollution, Penalties, Reporting and recordkeeping requirements, Warranties. Dated: Lisa P. Jackson , Administrator.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 137 of 153 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 a ll 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 th e 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 whi ch is manufactured for installation in an aircraft. Aircraft gas turbine engine means a turboprop, turbofan, or turbojet aircraft engine. Characteristic level has the meaning given in Appendix 6 of IC AO Annex 16 (as of July 2008) . The characteristic leve l is a calculated emission level for each pollutant based on a statistical assessment of measured emissions from multiple tests. Class TP means all aircraft turboprop engines. Class TF means all turbofan or turbojet aircraft engines or aircraft engines de signed 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 eng ines of the JT8D model family . Class TSS means all aircraft gas turbine engines employed for propulsion of aircraft designed to operate at supersonic flight speeds. Commercial aircraft engine means an y aircraft engine used or intended for use by an “air carrier,” (including those engaged in “intrastate air transportation”) or a “commercial operator” (including those engaged in “intrastate air transportation”) as these terms are defined in the Federal Aviation Act and title 14 of the Code of Federal Regulati ons . Commercial aircraft gas turbine engine means a turboprop, turbofan, or turbojet commercial aircraft engine. Date of introduction or introduction date means the date of manufacture of the first individual production engine of a given engine model or family to be certifi cat ed. This does not include test engines or other engines not placed into service.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 138 of 153 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 alread y covered b y a t ype certific ate issued b y FAA under 14 CFR part 34 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 Department of Transportation and any 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 submodel. Engine model means an engine manufacturer’s designation for an engine grouping of engines and/or engine sub - models within a single engine 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 - mo del 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 s ufficiently common design with respect to the core engine and combustor to be grouped together under a t ype certificate . EPA means the U.S. E nvironmental Protection Agency . 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 regulations. Exempted engines are deemed to be “subject to” the standards of this part even thou gh they

are not required to compl y with the otherwise applicable requirements. Engines exempted with respect to certain standards must comply with other standards as a condition of the exemption. E xhaust emissions means substances emitted to the atmosphe re 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 139 of 153 Fuel venting emissions means raw fuel, exclusive of h ydrocarbons i n 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 i nformation, subject to the provisions of 40 CFR 1068.5. ICAO Annex 16 means Volume II of Annex 16 to the Convention on International Civil Aviation (incorporated by reference in §87.8). In - use aircraft gas turbine engine means an aircraft gas turbine eng ine which is in service. 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. Rated output (rO) means the maximum power/thrust available for takeoff at standard day conditions as approved for the engine by FAA , including reheat contribution where applicable, but excluding any contrib ution 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. Spare engine means an engine installed (or intended to be in stalled) 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 capable of fl yi ng faster than the speed of sound. Tier 0 means relating to an engine that is subject to the Tier 0 NOx standards specified i n §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 sub ject to the Tier 6 NOx standards specified in §87.23.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 140 of 153 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 fr om air that by passes the combustion process and is accelerated in a ducted space between the inner (core) engine case and the outer engine fan casing. Turbojet engine means a gas turbine engine that is designed to create all of its propulsion from exhaust gases. Turboprop engine means a gas turbine engine that is designed to create most of its propulsion from a propeller driven b y a turbine, usually through a gearbox. Turboshaft engine means a gas turbine engine that is designed to drive a rotor transmiss ion sy stem or a gas turbine engine not used for propulsion . U.S. - registered aircraft means an aircraft that is on the U.S. Registry . We (us, our) means the Administrator of the Environmental Protection Agency and any authorized representatives. 3. Revise §87 .2 to read as follows: §87. 2 Abbreviations. The abbreviations used in this part have the following meanings: % p ercent ° d egree CO c arbon monoxide CO 2 carbon dioxide g gram HC hydrocarbon(s) 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 certificated by FAA und er 14 CFR part 34 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 helicop ters . (3) Engines used onl 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 141 of 153 (b) Under section 232 of the Act, the DOT Secret ary issues regulations to e nsure compliance with the standards and related requirements of this part (42 U.S.C. 7572) . (c) The DOT Secretary shall apply these regulations to aircraft of foreign registry in a manner consistent with obligations assumed b y th e United States in an y treaty, 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 unles s 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 provisio ns 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 safet y hazard. §87.7— [Removed] 7. Remove §87.7. 8. Revise §87.8 to read as follows: §87.8 Inco rporation 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 materia l 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 University

Street, Montreal, Quebec, Canada H 3C 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 142 of 153 copies 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 e mission standards for Tier 4 and earlier engines. This section describes the emission standards that apply for Tier 4 and earlier engines that apply for aircraft engines manufactured through [I NSERT EFFECTIVE DATE OF FINAL RULE] and certain engines exempte d 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) T he 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. * * * * ****E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 143 of 153 (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 eng ines manufactured on or after [I NSERT EFFECTIVE DATE OF FINAL RULE], except where we specify that they apply differently

by y ear , or where the engine is exempt from one or more tnadards 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 formula, calculate and round the standard to three significant figures or to the nearest 0.1 g/kN (for standards at or above 100 g/kN). Engines comply with an applicable standard if the testing results show that the engine t ype certificate family ’s characteristic level does not exceed the numerical level of that standard, as described in §87.60. The tier of standards identified for an engine relates to NOx emissions and that the specified standards for HC, CO, and smoke emissions apply independent of the changes to the NOx emission standards. (a) New turboprop aircraft engines with rated output at or above 1,000 k ilowatts must comply with a smoke standard of 187• rO - 0.168

. (b) New supersonic engines must comply with the standards shown in the following table : Table 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 ar e installed in subsonic aircraft must comply with the following standards: (1) The applicable smoke, HC, and CO standards are shown in the following table:***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 144 of 153 Table 2 to §87.23

– Smoke, HC, and CO Standards for New Subsonic Turbofan or Turbojet Engines Rat ed 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 19.6 118 (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 th is 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).***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 145 of 153 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•rPR (d) This paragraph specifies phase - in provisions that allow continued productio n of certain engines after the Tier 6 and Tier 8 standards begin to appl y. (1) Engine 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 introdu ced before [INSERT EFFECTIVE DATE OF FINAL RULE] may be produced through December 31, 2012 without meeting the Tier 6 NOx standards of paragraph (c)(2) of this section . This also applies for derivative engines covered b y the same ty

pe certificate. After this production cutoff date for the Tier 6 NOx standards, such engines may be produced only

if they are covered by

an exemption under §87.50. (2 ) Engine 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 146 of 153 §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 Certification report to EPA. Engine manufacturers must submit an annual certification 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 du e by February 28 of the following calendar year. If you produce exempted engines, you may submit a single report with information on both certificated and exempted engines. (b) Send the report to the Designated EPA Program Officer. ( c ) In the report, sp ecify

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 c alendar 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 or exemption under which it was produced. Identify all the following: (i) The t ype certificate number. Specify if 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 orig inal ty pe certificate for an engine ty pe certificate family . (3) The calendar - ye ar production 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 for NOx include percent of standard for all the NOx standards specified in §§87.21 and 87.23. You may

omit the following items specified in Part III, Section 2.4 of I CAO Annex 16 :***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 147 of 153 (i) Fuel specifications including 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 for each regulated pollutant in units of g/kN or g/kW. (d) [Reserved] ( e ) Include the following signed statement and endorsement by an authorized representative of your company : “We submit this report under 40 CFR 8 7.42. 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. §87.44 Reporting CO 2 emissions . (a)(1) For an y ty

pe certificates involving compliance with NOx emission standards that are issued on or after January 1, 2014 , you must report CO 2 emissions to the Designated EPA Program Officer . You may include this information in the certification report described in §87.42 or in a separate submission. (2) For an y ty

pe certificates involving compliance with NOx emission standards that are issued before January 1, 2014 , you must report CO 2 emissions along with your emission levels of regulated NOx to the Designated EPA Program Officer . (b) D etermine CO 2 emission rates b y direct measurement or b y calculation from measured fuel mass flow rates. T hese methods are described in Appendices 3 and 5 to ICAO Annex 16 (incorporated b y reference in §87.8). Report CO 2 emissions separatel y for each operating mode. If you test more than one engine, report the average value of CO 2 emissions for each operating mode. Round CO 2 emissions to the nearest whole gram and gram/kilonewton. §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 engines. (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 derivative engine under this part, it must have been derived from an original engine that was certifi cat ed to the require ments of this part, and one of the following conditions must be met:***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 148 of 153 (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 must meet th e criteria specified in paragraph (b) of this section. (b) Emissions equivalency . The engine manufacturer must demonstrate that a derivative 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 must be within the following allowable ranges: (i) ± 3.0 g/kN for NOx. (ii) ± 1.0 g/kN for HC. (iii) ± 5.0 g/kN for CO. (iv) ± 2.0 SN for smoke. (2) If the characteristic level of the parent engine before modification is at or above 95% of the applicable standard for an y pollutant, you must measure emissions for all pollutants to demonstrate that the deri vative 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 applicable emission standards, consistent with g ood 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) N on - derivative engines . Where FAA determines that an engine model is not a derivative of a previously certifi cat ed engine model, you must certify the modified engine as a new engine t ype certificate family . 12. Add a new subpart F containing §87.50 to part 8 7 to read as follows: Subpart F —Exemptions Sec. 87.50 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 requir ements. Engines 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 149 of 153 consultations with FAA and providing written concurrence for engines that qualify for an exemption under the provisions of this section. ( a) E ngines 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 from engines that are covered b y a valid type certificate issued by FAA. Under normal circumstances, this number may n ot exceed 75 en gines per manufacturer. However, in unusual circumstances , you may ask us to waive this limit . For purposes of this production limit, “manufacturer” includes the parent corporation and all wholly and majorit y - owned subsidiaries. ( 1 ) S ubmit your request for an exemption before producing the engines to be exempted to both FAA and the Designated EPA Program Officer. This requirement applies equall y for engine models that have already bee n exempted by a competent authority outside 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 produ ce 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. I dentify 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 . T his information will be used to ensure proper coordination with other countries in which these aircraft will be registered. (iv) A justification of why the exemption is appropriate. Justifications must include a description of the environmental impact of granting the exempti on. In clude other relevant information such as the following. (A) Technical issues, from an environmental and airworthiness perspective, which may

have caused a delay

in compliance with a production cutoff. (B) Economic impacts on the manufacturer, operator(s), and aviation industry at large. (C) Environmental effects. This should consider the amount of additional air pollutant emissions that will result from the exemption. This could include consideration of items such as: ( 1 ) The amount that the engine model exceeds the standard, taking into account an y other 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.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 150 of 153 ( 3 ) The impact of changes to reduce the applicable air pollutant on other environmental factors, including emission rates of other air pollutants, community

noise , and fuel consumption . ( 4 ) The degree to which the adverse impact would be offset by cleaner engines produced in the same time period (unless we decide to consider earlier engines). (D) Impact of unforeseen circumstances and hardship due to business circumstances beyond your control (such as an 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 competin g parties. (G) List of other certificating authorities 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 al l information included in the request is accurate. ( 2 ) In consultation with the EPA, the FAA may specify additional conditions for the exemption. ( 3 ) You must submit the annual report specified in paragraph ( d) of this section. ( 4 ) The permanent record for each engine exempted under this paragraph (a) must indicate that the engine is an exempted new engine. ( 5 ) Engines exempted under this paragraph (a) must be labeled with the following statement: “EXEMPT NEW”. ( 6 ) You must notify the FAA if you determi ne 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 meet ing the definition of “spare engine” are exempt as follows: (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 submodel 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 engines they are replacing, for all pollutants.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 151 of 153 ( 4 ) Manufacturers are not required to obtain approval before producing or shipping spare engines. However, engine manufacturers must submit the annual report specifie d in paragraph ( d ) of this section with information 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) mus t be labeled with the following statement: “EXEMPT 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 Office r a report describing your p roduction of exempted engines for each calendar year 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 th at the information in your initial request is still accurate, or describe any relevant changes. (2) Provide the information specified in this paragraph ( d)(2). For purposes of this paragraph ( d), treat spare engine exemptions separate from other new engin e 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 carrier(s) using spare engines. (3) Include information in th e report onl y for engines having a date of manufacture within the specific calendar year. Subpart G

— Test Procedures 13. The heading for subpart G is revised as set forth above. 14. Revise §87.60 to read as follows: §87.60 Testing engines. (a) Use the equipment and procedures specified in Appendix 3, Appendix 5, and Appendix 6 of 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 part . Measure the em issions 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 demo nstration consists of establishing a mean value from testing some 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***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 152 of 153 turboprop engines, use the procedures specified for turbofan engines, consistent with good engineering judgment. (b) Use a test fuel meeting the specifications described in App endix 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 available with production engines if they

can reasonably

be expected to influence emissions. The test engine may not extract shaft power or bleed service air to provide power to auxiliary gearbox - mounted components required to drive aircraft 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 specified procedure. (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 §87.6 0.***E.O. 12866 Review - Draft - Do Not Cite, Quote, or Release During Review***

Page 153 of 153 §§87.61 - 87.71 — [Removed] 15. Remove §§87.61 - 87.71. Subpart H— [Removed] 16. Remove subpart H. PART 1068 -- GENERAL COMPLIANCE PROVISIONS FOR ENGINE PROGRAMS 17. The authorit y citation for part 1068 continues to read as follows: Authority : 42 U.S.C. 7 401 - 767 1q . Subpart A— [Amended] 18. 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 und er 40 CFR parts 89 or 94. * * * * *