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1) Comment: Please provide a detailed outline of the provisions of this rulemaking that deviate 

from the recommendations of ICAO and provide a detailed justification and policy rationale for 

why EPA is proposing to deviate from these recommended standards. The United States has an 

obligation under the Article 2.4 TBT Agreement to follow international standards unless those 

standards would be ineffective and inappropriate. Specifically, Article 2.4 states, 

“Where technical regulations are required and relevant international standards exist or 

their completion is imminent, Members shall use them, or the relevant parts of them, as a 

basis for their technical regulations except when such international standards or relevant 

parts would be an ineffective or inappropriate means for the fulfillment of the legitimate 

objectives pursued, for instance because of fundamental climatic or geographical factors 

or fundamental technological problems.”

Response: There are only two provisions in this draft proposed rule which are different than 

those adopted by ICAO or its Committee on Aviation Environmental Protection (CAEP). The 

first is related to how potential exemptions from meeting Tier 6 (CAEP/6) NOx standards are 

defined and the second is related to reporting requirements. Each of these is discussed below.

This proposal implements a new requirement limiting the number of legacy engines that 

can continue to be sold even though they only comply with the previous NOx emission standards 

to 75 engines per type certificate holder (e.g., per manufacturer). The ICAO Working Group 

responsible for this issue developed similar language that limited the number of potential 

exemptions to 75 per type certificate rather than per type certificate holder. 

In our outreach to stakeholders preceding the drafting of this proposed rule, it became 

apparent that while the ICAO process resulted in 75 exemptions per type certificate the actual 

need expressed by the industry was for 75 exemptions per type certificate holder with some 

flexibility in case of unanticipated hardship as we have proposed. We worked these ideas with 

all of the manufacturers and they support the language we are proposing. The European Aviation 

Safety Agency (EASA) did not object to these ideas either, but they did indicate that their 

regulation to adopt ICAO’s production cut-off and exemptions was already too far along to be 

modified to align with the newly agreed upon interpretation of 75. The 75 per type certificate 

holder approach is the correct outcome; it helps to assure that the emission benefit of the 

standard is achieved, it meets the needs of industry, and it sets an appropriate basis (i.e. per type 

certificate holder) for future considerations. We plan to continue our dialogue with EASA with 

the goal of harmonizing ICAO’s ETM and their regulation with our draft proposal.

Regarding reporting requirements, ICAO sponsors an emissions data bank (EDB) to 

provide information to the public on aircraft engines and their HC, CO, NOx and smoke 

emission levels. This information is reported to the ICAO point of contact voluntarily and 
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aperiodically by the manufacturers. The point of contact has retired and despite our overtures to 

ICAO to address the EDB’s incompleteness we identified in the EDB, ICAO has taken no 

definitive steps to identify a new point of contact or to resolve the lack of currency and 

completeness of the EDB. As part of the mandatory GHG reporting rule

(http://www.epa.gov/climatechange/emissions/ghgrulemaking.html), we adopted mandatory

reporting requirements in 40 CFR Part 87 which require manufacturers to report aircraft engine 

CO2 emissions together with more general information describing the engine model and its 

characteristics. The provisions in this draft proposal simply add a separate requirement to report 

HC, CO, NOx, and smoke emissions, consistent with the existing ICAO database, includes the 

relatively few smaller thrust turbofan or turboprop engines not included in the EDB and asks for 

information on annual production and production status. It adds no significant burden on the 

manufacturers beyond what is required to respond to the EDB or required separately in the GHG 

reporting rule. Any incremental burden is minimal. The collection of this information is 

authorized under section 114(a)(1) of the Clean Air Act (CAA). Specifically, under the CAA, we 

are authorized to require any person who is subject to the Act to establish and maintain necessary records, 

make reports, and provide such other information as we may reasonably require in discharging our 

obligations under the Act. (See 42 U.S.C. § 7414(a)(1))

Such a reporting requirement is appropriate because we are the regulatory authority for 

aircraft engine emissions standards, and we need this information to work with FAA to develop the U.S. 

positions for emissions standards at ICAO. We also require it to review exemption requests, for 

example, by examining the history of production. Examples of how this type of information has already 

been used to develop ICAO policy are contained in the following recent ICAO/CAEP papers: 

 CAEP/8-WG3-WP6-14, Production Cut-Off Working Paper, March 2009

 CAEP WG3 Presentation, Production Cut-Off Provisions for Jet Engines, April 2009

 CAEP WG3 Presentation, Change in Average NOx Emissions, April 2009

 ICAO Steering Group, WP39, Production Cut-Offs and Associated Flexibilities for ICAO 

Engine Emission Standards Working Paper, June 2009

 ICAO Forecasting and Economic Analysis Support Group, IP Paper, Aircraft NOx 

Emissions Control Information Paper, October 2009

 CAEP/8-WP/52, NOx Stringency Working Paper, February 2010

 CAEP/8-WP/15, Environmental and Economic Assessment of the NOx Stringency 

Scenarios Working Paper, February 2010

 CAEP/8 –IP/14, Economic Assessment of the NOx Stringency Scenarios Information 

Paper, February 2010

2) Comment: How did EPA choose which non-attainment areas to display in Table 4 on page 

25? Why are areas that encompass some of the Nation’s larger “hub” airports (such as Boston, 

New York and Dallas-Fort Worth) not included?
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Response: We chose the nonattainment areas for illustrative purposes and have since expanded

the number of nonattainment areas described in the proposal. These now include the airports 

identified by the commenter. A draft of this list is attached. We anticipate that a total of 41

nonattainment areas will be identified in the proposal. To select these nonattainment areas, 

commercial service aircraft emissions inventories were analyzed for areas where airports had 

either a high number of commercial service operations or large populations in the nearby

vicinity. We identified the top 25 nonattainment areas in each of these two categories, and after 

eliminating duplicates, 41 nonattainment areas remained for the assessment. Collectively these 

41 nonattainment areas include 200 airports that account for 70 percent of commercial air traffic. 

3) Comment: It is acknowledged that section 233 of the Clean Air Act preempts States from 

adopting or enforcing any aircraft engine emissions standard unless such standard is identical to 

EPA’s. Nonetheless, because EPA is proposing to revise text in the Code of Federal Regulations 

with respect to this statutory preemption, additional discussion addressing EPA’s argument that 

this rule will not have federalism implications under Executive Order 13132 would be helpful. 

At a minimum, EPA should clarify the explanation provided on page 131 to remove some 

apparent inconsistencies in the text. Suggested revisions are: 

This action does not have federalism implications. It will not have substantial direct 

effects on the States, on the relationship between the national government and the States, 

or on the distribution of power and responsibilities among the various levels of 

government, as specified in Executive Order 13132. As discussed earlier, section 233 of 

the CAA preempts states from adopting or enforcing aircraft engine emission standards 

that are not identical to our standards. This rule proposes to revise the Code of Federal 

Regulations to more accurately reflect the statutory preemption established by the Clean 

Air Act. This rule does not impose any new preemption merely modifies existing EPA 

aircraft engine emission standards and test procedures and therefore will merely continue 

an existing preemption of State and local law. Thus, Executive Order 13132 does not 

apply to this action.

Response: We agree, and we made this change as the commenter indicated.

4) Comment: In the discussion in the preamble about military engines, EPA states that it is "not 

proposing any specific provisions with respect to engines installed on military aircraft," 

explaining that such aircraft fall outside the scope of the emissions rules by operation of the 

regulatory language that brings covered aircraft within the rules (because the FAA rules do not 

require the certification of military engines). In the table on page 114, however, EPA suggests 

that proposed § 87.1 ("Definitions") contains a definition of "military aircraft." In fact, consistent 

with the earlier discussion, there is no such definition in § 87.1.
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Response: The language in the draft proposal clarifies that our standards do not apply to military

engines. The definition is required to ensure that the regulations are not misinterpreted to mean 

that civilian aircraft engines produced for military applications are subject to the production 

cutoff, as described in our response to comments 1 and 5. 

5) Comment: Recommend revising the table to cite § 87.3 ("General applicability and 

requirements"), since it really pertains to applicability and since it doesn't actually refer to any

particular definition in § 87.1. For consistency with the statutory FAA provisions, EPA may also 

wish to use the terminology in 49 USC § 40125(c), i.e. "aircraft owned or operated by the armed 

forces." The note in the table on page 114 might be revised to say, for instance, "The regulations 

of this part do not apply to aircraft owned or operated by the Armed Forces, including aircraft 

owned by the U.S. Coast Guard, as well as some other aircraft not owned by DoD." 

Whether or not EPA changes the cite or uses the terminology in 49 U.S.C., EPA's 

clarification in the preamble that military/armed forces aircraft are not covered by the rules and 

that such aircraft includes non-DoD aircraft is very helpful and much appreciated.

Response: The definition states that military aircraft means "aircraft owned by, operated by, or 

produced for sale to the armed forces or other agency of the federal government responsible for 

national security (including but not limited to the Department of Defense)." The table entry has 

been revised accordingly.

6) Comment: Recommend adding the words "that are required to be" to § 87.3(a) to read: "The 

regulations of this part apply to engines on all aircraft that are required to be certificated by FAA 

under 14 CFR Part 34 except as specified...." In the preamble, EPA points out that 

manufacturers sometimes voluntarily certify engines that FAA does not require to be certificated 

and clarifies that it is EPA's intent to exclude engines which FAA does not require to be 

certificated, whether or not they are, in fact, certificated. The proposed language does not, 

however, say that and could be read that voluntary certification brings an engine within the 

purview of the regulations.

Response: We have made the change. The new language is below:

§87.3 General applicability and requirements.

(a) The regulations of this part apply to engines on all aircraft that are required to be 

certificated by FAA under 14 CFR part 33 except as specified in this paragraph (a). These 

regulations do not apply to the following aircraft engines:

(1) Reciprocating engines (including engines used in ultra light aircraft).

(2) Turboshaft engines such as those used in helicopters.

(3) Engines used only in aircraft that are not airplanes. For purposes of this paragraph (a)(4), 

“airplane” means a fixed-wing aircraft that is heavier than air. 
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(4) Engines not used for propulsion.

7) Comment: Recommend checking the internal cross-reference in §87.1 to ensure it is the 

correct cite.

Response: We validated the cross reference.

8) Comment: The draft rule contains provisions that may exceed reasonable interpretations of 

the statutory phrase “standards applicable to the emission of any air pollutant” (standards). If 

everything in the draft rule is considered a standard, an obligation would be created under CAA 

section 7572 for other agencies besides EPA to adopt and implement through their authorities. 

Response: Without specifying the provisions in question or even examples of such provisions, it 

is not possible for us to provide a specific response to this comment. However, the definition of 

a standard in section 302(k) of the CAA broadly defines “emission standard” to mean “a 

requirement established by the State or the Administrator which limits the quantity, rate, or 

concentration of emissions of air pollutants on a continuous basis, including any requirement 

relating to the operation or maintenance of a source to assure continuous emission reduction, and 

any design, equipment, work practice or operational standard promulgated under this chapter.” 

Within this context, provisions that are not simply a numerical expression of an emission limit or 

standard, but are necessary to make the numeric limit enforceable may be broadly considered as 

part of the “standards” EPA is directed to promulgate. Such provisions have historically been 

included in EPA programs, including emission standards for aircraft engines. Therefore, we 

believe that all of the provisions of the draft proposed rule are appropriately within the scope of 

EPA’s authority to promulgate emission standards. The U.S. Court of Appeals for the D.C. 

Circuit has read EPA’s aircraft engine emissions standard-setting authority to be particularly

broad. No one has challenged EPA’s authority to include in such standards provisions addressing 

exemptions (existing section 87.7); incorporation by reference of ICAO technical materials 

(existing section 87.8); or test procedures and emissions measurement, and determination of 

compliance (existing subparts G and H).

9) Comment: The EPA has proposed that a new annual report be submitted by engine 

manufacturers detailing the production of various engine models. Much of this information is 

available elsewhere. 

Response: See our response to comment 1) above. Some of the information that EPA is seeking 

is already submitted to the FAA. However, we have been informed that this information is 

unavailable to us because of FAA’s confidentially agreements with the engine manufacturers. 

Comment: It is unclear whether the report can be viewed as a standard .... 
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Response: Please refer to our discussion on the meaning of the term standard in our response to 

comment number 8). Our authority to request such information is discussed in response to 

comment 1).

Comment: ... there does not appear to be a clear regulatory need for the report. Can EPA 

provide a clear rationale for why this report would be required, or consider not requiring this 

report? What specifically would the information be used for? 

Response: See our response to comment 1).

Comment: Would collecting this information require approval under the Paperwork Reduction 

Act? 

Response: Yes, we have prepared a draft ICR for this purpose, See our response to comment 1)

for details on our authority.

10) Comment: The EPA has proposed a new “exemption” process under which manufacturers 

could continue to produce certain engines after the standards have changed. In general, industry

usage of exemptions has remained low. The new process includes joint filings and unclear lines 

of authority and decision.

Response: The exemption process is not new. Exemption provisions have been included in the 

EPA and FAA regulations for decades. The proposed revisions to the existing exemption 

provisions are virtually identical in all material respects to the process specified in ICAO’s 

Annex 16 and ETM.

The draft proposal would require that a manufacturer submit its exemption request 

simultaneously to EPA and to FAA. We believe that this would facilitate a more timely

consultation process between the two agencies. We think that a manufacturer would be very

willing to do this in order to help expedite this review. There should be no real burden 

associated with a duplicate submission because the contents would be identical, except perhaps 

for the addressee on the cover letter and the cost of mailing. Finally, both EPA’s current 

regulations and FAA’s require that exemption requests be submitted in duplicate to the FAA, 

presumably to facilitate dispatching a copy to EPA. Our proposal simply eliminates this two step 

handling process. 

We are unsure what could be unclear about the lines of authority and decision. The draft 

regulations clearly state that exemptions must be approved by the FAA under 14 CFR part 34. 

We have made the preamble clearer relative to the FAA being the process owner. Regarding 

EPA’s role in granting exemptions, our current §87.7(c) regulations and current §34.7(c) FAA 

regulations state that EPA must concur with the DOT/FAA decision to grant an exemption. The
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draft proposal clarifies that this would be a “written” concurrence to prevent any

misunderstandings and to provide a historical record of our decision.

Comment: It [the exemption process] appears inconsistent in its use of terms that are well known 

in the industry, and attaches new concepts to them. 

Response: We are unaware any significant terminology in the draft proposal regarding

exemptions that is inconsistent with terms that are well known in the industry, or attaches new 

concepts to them. Further, the lack of any specific examples in this comment makes it difficult

for us to respond. We have retained the word “exemption” in the draft proposal because it is 

used in the current EPA regulation, in ICAO’s Annex 16, and in ICAO’s ETM. Thus it is very

familiar to stakeholders and is unambiguous.

Comment: No attempt has been made to detail the costs of the new process to other agencies, or 

to industry applicants. 

Response: Addressing the other agencies first, our draft proposal does not describe the costs of 

the exemption process to any other government entity. As noted above, the exemption process is

not new. We have proposed some revisions to clarify what a manufacturer should include in the 

petition for exemption, which in large part is what is currently required or has generally been 

submitted by manufacturers in previous exemption requests. We believe the only definite 

incremental change in the process is differentiating spare engines from new engines (as 

discussed in our response to Comment 11). This differentiation should not represent substantial 

change relative to the status quo. The United States’ position at CAEP fully supported the spare 

engine versus new engine exemptions provisions, which were adopted by CAEP. The United 

States’ Interagency Group on International Aviation (IGIA) concurred on the United States’ 

position to support the adoption of these provisions at ICAO/CAEP. Thus, in following the 

United States’ position at CAEP, we have proposed these provisions, based upon ICAO’s Annex 

16 and ETM. 

Regarding cost to the industry, exemptions are a voluntary regulatory flexibility for the 

benefit of the engine manufacturers directly, and the airframe manufacturers and airlines 

indirectly. Exemptions can avoid costs that may otherwise be incurred by these entities if they

had to comply with certain emission standards. EPA and the industry consider these provisions 

to be useful voluntary flexibilities.

11) Comment: Similarly, the EPA proposes a new designation of “exempt-spare” engines that 

may be produced outside of production limits. The draft rule does not account for how this

would impact certification processes and regulations of other agencies. The draft rule does not 

acknowledge the regulatory requirements or their costs that would fall on other agencies from 

adopting a new category of engine marking ....”
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Response: Please refer to our response to Comment 10 on accounting for other agencies 

processes and costs with regard to spares.

Comment: “... and a new system by which the EPA expects them [spares] to be traceable. The 

concept of installing a “spare” engine presumes there is a system in place by which individual 

engines are tracked on individual aircraft by operation (emphasis added). The reality is that 

there is no such system in place to track engines with this new designation. The rule contains no 

acknowledgement of the cost that could result from a full consideration of such a requirement, 

including the tremendous cost on the FAA to promulgate and implement such a system.

Response: The current EPA and FAA regulations provide for exemptions regardless of the 

intended use of an engine, i.e., whether it is intended to be attached to an all new aircraft, or for 

temporary use as a spare engine when the original engine is removed for maintenance. Further, 

ICAO’s current Annex 16 specifies that such engines shall have their identification plates 

marked “EXEMPT” and the exemption noted in the permanent engine record. The FAA Part 45 

regulations currently require both of these.

The draft proposal follows ICAO’s ETM, which splits the overall exemption category

described above into “new” and “spare” engines. This division was made to recognize that spare 

engines have no adverse effect on the environment because a spare must have emissions that are 

equivalent or better than the engine it is replacing. Making this distinction allowed the 

exemption provisions for spare engines to be streamlined to the point that engine manufacturers 

are not required to obtain prior approval to produce or ship spare engines. Only an annual report 

containing such items as the engine serial number, type of aircraft receiving the engine(s), and 

use of each engine (spare or new installation) are to be reported to EPA. The streamlined 

requirements for spare engines do not require that “...individual engines are [be] tracked on 

individual aircraft by operations.” The draft proposal does not contemplate a new system by

which spare engines would be traceable.

12) Comment: EPA requests comment on a proposed “voluntary” emissions credit program. 

EPA has not acknowledged the lack of regulatory infrastructure on which to overlay such a 

program, or the fact that they intend for other agencies to administer it under its own regulations. 

Moreover, the offset program applies to engine manufacturers getting credit for producing a 

certain number of better engines in trade for ones that pollute more. However, manufacturers do 

not know or control where their engines are operated, nor can the presumption be made that all 

are operated the same amount, producing a comparable amount of pollutant. The idea is based 

on an unstated presumption that there will be some benefit in the United States, or even in certain 

domestic areas. It is further tied into the unclear exemption process described previously. The 

cost of such a system is not described, nor is the presumed benefit of its existence.
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Response: Voluntary emissions credit programs such as emissions credit averaging, banking, and

trading are a part of almost every EPA mobile source vehicle/equipment and fuel regulation. In 

all cases, participation in these programs is voluntary, as they are an optional compliance 

flexibility a manufacturer may elect to exercise if the manufacturer determines an advantage in 

doing so. It is simply the intent of these types of provisions to encourage engine manufacturers to 

certify and sell engines with emissions technology better than that required by the emission 

standards. These provisions essentially reward these efforts through a market-based emission 

credit program, which can be used to offset higher emissions from other models, which may

more difficult or more expensive to control. This flexibility is commonly used by manufacturers 

in sectors where it is available and is highly valued by them.

As noted in the comment at this point we are not proposing specific provisions; rather, in 

the Preamble to this draft proposal we are seeking comment and input on how such a program 

could be structured to enhance future compliance efforts and reduce compliance costs. We are 

including additional descriptive detail in a memo to the docket.

The comment asserts that there is an unclear link to possible future exemption 

allowances. While the viability of an emissions credit program for aircraft engines remains to be 

seen (hence the request for comment), one potential use of such credits could be substitution for 

exemptions or as part of a justification for an increase of the number allowed exemptions above a 

set maximum. Furthermore, the comment asserts that some other agency would implement such 

a program if ultimately enacted. Such an assertion is premature and unsubstantiated because we 

are only seeking comment at this time.

13) Comment: It is unclear why EPA is proposing to include ICAO guidance material (known as 

the Environmental Technical Manual or ETM for emissions) in the regulatory text. Adoption of 

international guidance material eliminates valid means of regulatory guidance already in place, 

changes it from advisory to mandatory (which was not ICAO’s intent) and eliminates 

compliance flexibility. A clear example is EPA’s proposal regarding what constitutes a 

derivative engine, which was clearly intended as guidance. No accounting for costs to other 

Agencies for implementing this requirement or industry compliance is accounted for. From a 

broader governmental perspective, this is an issue that goes beyond emissions, and would set a 

dangerous precedent. ICAO guidance material is not designed to function as mandatory

regulation, and often embodies compromises that the U.S. agrees to only because it is adopted as 

guidance. If the U.S. turns guidance into regulations, it could tempt others to adopt, as 

regulations, ICAO guidance material that we object to. It would also undermine countries' 

willingness to adopt guidance material in the future.

Response: This comment raises issues with regard to regulatory text in EPA’s draft NPRM,

which would incorporate language on when a derivative engine version is to be treated as new 
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for emissions purposes. EPA and FAA worked closely within ICAO/CAEP Working Group 3 

(WG3) Certification Task Group (CTG) in crafting this language. The United States position at 

CAEP supported this language, and the provisions were adopted at ICAO/ CAEP.

Provisions such as these with regard to derivative engines are needed in regulations to 

define the scope and applicability of the regulations; to give them context and clarity for the 

manufacturers; and to allow for their unambiguous and equitable implementation. If one 

examines the draft regulatory language, it is clear that it explains under what conditions new 

standards apply and under what conditions they do not. 

With respect to the specific comment on the definition of a derivative engine, we are 

adopting the definition and related provisions agreed to by ICAO. In response to the comment, 

we have revised the regulatory text to provide the certificating authority (i.e. FAA) with the 

discretion to apply good engineering judgment in the implementation of these provisions. 

However, we would assert that this definition is still necessary in the regulations because 

it is necessary to implement the provisions agreed to at ICAO and addresses a long standing 

shortcoming in the regulations by more fully prescribing the applicability of the standards in 

these situations. We cannot regulate through guidance.

14) Comment: In discussing the inclusion of ICAO materials, the draft rule engages in a 

discussion of “commercial” and “non-commercial” aircraft engines. The distinction between an 

engine used in commercial operation vs. non-commercial operation has no basis in the reality of 

regulated aircraft operations. An individual aircraft, for example, can switch status between 

flights. From a broader perspective, creating commercial and non-commercial definitions by

classes of equipment rather than usage would also set a dangerous precedent, and would conflict 

with existing statutory and regulatory definitions.

Response: The commenter may be unaware that the distinction between commercial and noncommercial aircraft turbine engines already exists in the current EPA regulations. This 

distinction was made in our 1982 final rule after consultation with the FAA. The draft proposal 

would actually do what the commenter prefers by applying the turbine engine standards without 

regard to operation category. Perhaps the commenter’s confusion arises from the fact that

current FAA regulations already apply the standards without distinction. In other words, the 

draft proposal actually updates and harmonizes EPA regulations to align with current FAA 

regulations. 

15) Comment: The draft rule includes the adoption of technical appendices to ICAO standards 

and recommended practices. EPA’s adoption of these standards through incorporation by 

reference (IBR) is inappropriate as there are legal implications of proper notice, the requirement 

to access a foreign publication to properly understand the requirements of a codified standard, 
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and even language and format. There are also issues of cost in adopting the technical changes 

that the EPA does not acknowledge.

Response: The Office of the Federal Register is charged by Congress to publish regulations. As 

part of this charge, Congress has specifically directed the Federal Register to work with federal 

agencies to use Incorporation by Reference to properly and efficiently communicate regulatory

requirements. We routinely use this approach in our regulatory text.

16) Comment: In several places, the proposed rule discusses military aircraft engines. While 

certain engine manufacturers certify engines that have both military and civilian applications, 

these are generally treated as civilian and under existing regulatory authorities. If the EPA finds 

that their authority extends to engines produced only for installation on military airplanes, then 

that regulation should remain within their sole jurisdiction and not be considered a standard that 

other agencies will adopt or enforce.

Response: To clarify, we are not intending to assert authority over exclusively military engines, 

and as needed, we have modified and clarified any text we thought the commenter could have 

found misleading. Our interest in addressing this issue in the proposal is discussed in the 

responses to comments 4) and 5). 

17) Comment: It is several reviewers’ view that the EPA draft would require another federal

agency to change its regulatory approach, add scope and costs to regulatory oversight with 

unclear benefits, incorporate practices not endorsed by aviation’s international standard-setting 

body, and produce confusion and misunderstanding in a global industry. There is no 

acknowledgment of the costs associated with such regulations, the changes to the current 

regulations, the burdens placed on other agencies for adoption and implementation, and no 

consideration of what benefits from the changes might accrue. If the EPA chooses to adopt them 

as its regulations alone, the provisions would be at considerable odds with the current regulatory

system of aircraft engine certification in place under existing regulations. One approach at least 

one reviewer recommends would be for EPA to limit its rulemaking proposal to adopting only 

the ICAO oxides of nitrogen (NOx) emissions standards agreed upon at the CAEP/6 and CAEP/8 

meetings. This approach could be implemented similarly to other historical ICAO CAEP 

outcomes.

Response: The commenter suggests that EPA is proposing sweeping changes from current 

practice. In our response to comment 1) we identified only one diversion from the outcome at 

CAEP/8 and one additional provision which EPA is proposing to implement under its own 

authority. Furthermore, while none of these are inconsistent with the basic ICAO provisions, 

there a few instances where we are adding clarifications and detail to help ensure the proper 
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implementation of the program. ICAO is not a regulatory body and thus has not included these 

details. 

18) Comment: The proposed rule does not indicate the fact that this EPA CAA rulemaking is 

subject to CAA section 307(d), 42 USC 7607(d). 

Response: We do not find this necessary because the CAA itself makes the proposed rule

subject to 307(d). (See section 307(d)(1)(F)). Otherwise, EPA rules that are subject to section 

307(d) similarly do not specify as such, but rather cite to the entire CAA as their authority. See, 

e.g., Primary National Air Quality Standard for Sulfur Dioxide; Final Rule, 75 FR 35520, 

35592/col.1 (June 22, 2010). However, we have no objection to adding his citation if it adds 

clarity.

19) Comment: “...§87.44 Reporting CO2 emissions. (a)(1) For any type certificates involving 

compliance with NOx emission standards that are issued on or after January 1, 2014, you must 

report CO2 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 any type certificates involving compliance with NOx emission standards that are 

issued before January 1, 2014, you must report CO2 emissions along with your emission 

levels of regulated NOx to the Designated EPA Program Officer. 

(b) Determine CO2 emission rates by direct measurement or by calculation from measured 

fuel mass flow rates for CO2 emissions from fossil and biogenic sources separately. These 

methods are described in Appendices 3 and 5 to ICAO Annex 16 (incorporated by reference 

in §87.8). Report CO2 emissions separately for each operating mode. If you test more than 

one engine, report the average value of emissions for each operating mode. Round CO2

emissions of CO2 emissions from fossil and biogenic sources to the nearest whole gram and 

gram/kilo-Newton...”

Response: We do not intend to revise the CO2 reporting requirements. The collection of 

information for CO2 under the mandatory GHG rules and the new information we are proposing 

to require for other pollutants is authorized under separate authorities. To make this clear and in 

response to the comment, we propose creating a new section in the regulations to cover these 

new requirements and leave the existing CO2 reporting requirements untouched in §87.64.
U.S. EPA Response to Summary of Interagency Working Comments on Draft 

Language under EO12866 Interagency Review.[rcvd February 17 2011] 

Subject to Further Policy Review.

Page 13 of 13

Attachment for Response to Comment 2

Nonattainment Area

Albuquerque, NM

Anchorage, AK

Aspen

Atlanta, GA

Baltimore, MD

Boston-Lawrence-Worcester (eastern MA), MA

Boston-Manchester-Portsmouth (southeast NH), NH

Charlotte-Gastonia-Rock Hill, NC-SC

Chicago-Gary-Lake County, IL-IN

Cincinnati-Hamilton, OH-KY-IN

Cleveland-Akron-Lorain, OH

Dallas-Fort Worth, TX

Denver-Boulder-Greeley-Fort Collins-Loveland, CO

Detroit-Ann Arbor, MI

El Paso, TX

Greater Connecticut, CT

Houston-Galveston-Brazoria, TX

Indianapolis, IN

Las Vegas, NV

Los Angeles South Coast Air Basin, CA

Louisville, KY-IN

Memphis, TN-AR

Milwaukee-Racine, WI

Minneapolis-St Paul, MN

New York-N. New Jersey-Long Island, NY-NJ-CT

Philadelphia-Wilmington-Atlantic City, PA-NY-MD-DE

Phoenix-Mesa, AZ

Pittsburgh-Beaver Valley, PA

Providence (entire State), RI

Raleigh-Durham-Chapel Hill, NC

Reno, NV

Riverside County (Coachella Valley), CA

Sacramento Metro, CA

Salt Lake City, UT

San Diego, CA

San Francisco Bay Area, CA

San Joaquin Valley, CA

Seattle-Tacoma, WA

St. Louis, MO-IL

Syracuse, NY

Washington, DC-MD-VA