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ICAO COMMITTEE ON AVIATION ENVIRONMENTAL 

PROTECTION 

WORKING GROUP 3 – EMISSIONS TECHNICAL 

London, England

April 1-3, 2009

Response to U.S. EPA Papers 14 and 16

(Presented by ICCAIA)

1. Introduction

ICCAIA would first of all like to thank the U.S. EPA for once again participating 

directly in the CAEP Working Group 3 meeting. This enables more direct contact on 

issues both important to the Agency and important to the manufacturers. This paper is 

written in response to several issues with regards to the 3 working papers submitted to 

the 6th meeting of CAEP Working Group 3 during the CAEP8 cycle.

2. WP14 Production Cut-Offs for NOx Standards

At the September 2008 Steering Group Meeting in Seattle, the meeting agreed to 

proceed with further studies of a production cut-off for the CAEP/6 NOx standards in 

FESG and MODTF (CAEP-SG/20082_SD/4). These studies would focus on the 

analysis of costs and benefits of a CAEP/6 NOx production cut-off. 

In the current EPA paper they suggest various reasons why they wish to push for 

production cut-off regulations for aviation with the following paragraph being one of 

the main reasons: “In domestic U.S. programs, for mobile sources (except aircraft), 

manufacturers must recertify their product lines each year, thus creating some form of 

a production cut-off on the first year of a new emission standard. To accommodate 

reasonable business practice, the U.S. EPA has incorporated various provisions to 

Summary

This working paper responds to the issues brought to CAEP WG3 by the U.S. 

Environmental Protection Agency (EPA) in Working Papers 14 and 16.

ICCAIA is pleased that the U.S. EPA are once again directly involved in the CAEP 

process and within CAEP work on analysis on whether there is a need for production 

cut-offs for NOx standards. ICCAIA believes the evidence presented within CAEP 

proves that market forces do indeed show that the manufacturers voluntarily comply 

with new CAEP NOx standards. For CAEP6 ICCAIA can state with confidence that it 

is highly likely that all commercial engines in production by the end of 2010 will meet 

the CAEP6 NOx standards. ICCAIA recommends that any analysis for the 

requirement for production cut-off provisions for any future CAEP8 standard 

should not be considered in advance of any CAEP8 standard setting procedure be 

completed.

ICCAIA supports the work to include suitable exemption text and guidance in 

Annex 16 and the ETM and recommends that CAEP WG3 support the inclusion 

of this work in the future work programme.
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ensure an orderly product phase-in and phase-out (e.g., annual % phase-in/phase-out 

requirements by models or production), but in no case are previously certified engine 

families grandfathered into the new program indefinitely. Such provisions are very

workable in other sectors, but may be less attractive in the aviation sector. As 

discussed in CAEP-SG/20071-WP/26, ultimately, for the U.S. and the nations of 

many participating CAEP members, the aviation sector stands as the only source that 

is allowed to indefinitely produce existing engines that do not meet the latest emission 

standards.”

ICCAIA wish to state a few points with regards to this statement: -

(i) It has been proven within CAEP that market forces mean that aircraft 

engine manufacturers have voluntary complied with CAEP NOx standards 

within a suitable timeframe from when the regulations were first agreed.

(ii) Aircraft engines are covered by airworthiness regulations throughout their 

life and any changes to such engines have to get approval from the 

airworthiness authorities. It is noted that there are virtually no examples 

where an aircraft engine has been re-certificated with inferior NOx 

emissions after the original certification date. 

(iii) Furthermore CAEP has accepted advice on the minor affect of in-service 

deterioration CAEP-WG3-CETG-WP5-6 on NOx emissions.

(iv) Finally at this meeting a paper is being presented, that has been accepted 

by the EPA on applicability of emissions standards for engines that covers 

the issue of post certification changes CAEP-WG3-CTG6-WP6-Att A.

EPA makes various further claims that engine manufacturers do not voluntary comply 

with CAEP NOx standards and the EPA states, “For the same reasons, a production 

cut-off should be considered for the CAEP/8 NOx stringency increase. Although 

CAEP-SG/20082-WP6, Production Cut-Off for Engine NOx Standards (Presented by 

FESG Rapporteurs, September 4, 2008), asserts that market forces have worked in the 

absence of a production cut-off, we believe there is still much to gain by considering 

and possibly adopting a production cut-off provision. Ultimately, a production cut-off 

may best ensure that backsliding does not occur and that the emission reduction 

benefits expected from the new standards are achieved.” In the recommendations EPA 

suggest production cut-off standards “8 years” after the agreement on NOx 

regulations. 

On the one hand this paragraph accepts the FESG assertion that market forces are 

working, and yet on the other hand it still wishes to push for production cut-off rules 

for CAEP8.

(a) ICCAIA expects the continued work of the FESG will maintain that a 

production cut-off provision for the CAEP6 standard is not required due to 

market forces providing the incentive.

(b) ICCAIA asks that the meeting note that ICCAIA member companies have 

always voluntarily met and often bettered the “8 years” criterion used in the 

EPA Working Paper in the past.

(c) ICCAIA suggests that any discussion on CAEP8 production cut-off 

regulations be referred directly to SG, but ICCAIA wish to note that 

imposition of this work during this cycle is inappropriate, as FESG will not 

have time to consider this in their analysis. 
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(d) ICCAIA recommends that any work on CAEP8 production cut-off 

considerations does not start until some time into the CAEP9 cycle, and 

ICCAIA further notes that its membership does not believe there is a necessity

to complete such work as history has shown that manufacturers voluntarily

comply with CAEP NOx standards.

3. WP16 Exemption Working Paper

ICCAIA supports the work to include suitable exemption text and guidance in Annex 

16 and the ETM. This is primarily covered in the work of the ad-hoc group on Annex 

16 and ETM referenced in CAEP-WG3-CTG6-WP5, and ICCAIA thanks the EPA for 

becoming involved in this ad-hoc group. ICCAIA does not believe that just including 

such provisions in the CAEP recommendations should be some kind of green light for 

production cut-off regulations for the reasons stated in section 3.

EPA makes the following very good points that ICCAIA supports: -

“The language for these allowances, which is contained in 2.1.1.1 of Volume II, can 

be interpreted and implemented in a variety of ways. The U.S. has applied this 

allowance in its regulations (40 CFR 87.7) to create three broad categories for 

potential exemptions from U.S. emissions standards: (1) temporary exemptions, (2) 

very low production exemptions, and (3) hardship exemptions. The temporary

exemptions address situations such as aircraft manufactured in the U.S. that are being 

exported. The exemption for very low production models allows for consideration of 

exemptions of a total production for U.S. civil aviation of up to 200 units covered by 

the same type certificate after January 1, 1984. The hardship provision potentially

allows exemptions based on other factors. The term “exemption” is not defined in 

U.S. aircraft regulations, but the regulatory exemptions are drafted such that exempted 

aircraft engines are exempted only from emission standards while remaining subject 

to the regulations overall.”

“Reciprocity. The language related to exemptions does not address whether 

exemptions issued by one certificating authority should necessarily be accepted by 

other authorities. Whether or not such reciprocity is assumed directly affects the need 

for the Annex to include detailed provisions related to exemptions in this area. 

Increased specificity of the Annex would likely increase the likelihood that 

reciprocity would be seen as appropriate. Some degree of reciprocity is already 

covered under existing bilateral agreements. Greater specificity in these provisions 

would promote a harmonized approach to granting exemptions and thus reinforce the 

utility of current reciprocity agreements.”

5. Recommendations

ICCAIA recommends that any analysis for the requirement for production cutoff provisions for any future CAEP8 standard should not be considered in 

advance of any CAEP8 standard setting procedure be completed.

ICCAIA supports the work to include suitable exemption text and guidance in 

Annex 16 and the ETM and recommends that CAEP WG3 support the inclusion 

of this work.