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CAEP.8.WP.056.2.en.doc

COMMITTEE ON AVIATION ENVIRONMENTAL PROTECTION (CAEP)

EIGHTH MEETING 

Montréal, 1 to 12 February 2010 

Agenda Item 2: Review of technical proposals relating to aircraft engine emissions

ADOPTION OF PRODUCTION CUT-OFF FOR EMISSION STANDARDS

(Presented by the United States)

SUMMARY

CAEP/8 is invited to agree that a production cut-off for the CAEP/6 NOx 

emission Standards and the associated exemption provisions developed in the 

revised ETM and Annex 16, Volume II should be adopted, and then 

implemented on the earliest practical ICAO effective date. Ultimately, a 

CAEP/6 production cut-off provides certainty that non-compliant engines will 

eventually no longer be produced – but with the flexibility of exemptions 

allowing for time adjustments to ensure we lessen economic impacts. A 

production cut-off takes full advantage of the CAEP/6 NOx Standards

environmental benefits, ensures no backsliding, and communicates to the 

public the aviation sector’s commitment to improving its environmental 

performance. 

Action by the CAEP is in paragraph 3.

1. BACKGROUND

1.1 Originally the CAEP/2 emission Standards incorporated, in addition to a future effective 

date for inclusion in the relevant ICAO annexes, a later production cut-off to ensure that appropriate 

emission control technologies were incorporated into all new engine designs and in-production engines by 

a certain date. Subsequently, CAEP/4 and CAEP/6 NOx Standards were adopted without such a 

production cut-off. The lack of a production cut-off at CAEP/6 was based on the view that market forces 

were sufficient to bring non-compliant engines into compliance with the new requirements (voluntary 

compliance). As a result, engines that do not meet current emission requirements have continued to be 

International Civil Aviation Organization

WORKING PAPER

CAEP/8-WP/56

15/12/09

English only
CAEP/8-WP/56 - 2 -

produced and introduced into the fleet after the CAEP/6 NOx Standards became effective on January 1, 

2008 (the ICAO effective date).1

1.2 At the first meeting of the CAEP Steering Group for the CAEP/8 cycle in Zurich, 

Switzerland (November 26-30, 2007) the U.S. recommended that CAEP assess a production cut-off for 

the CAEP/6 NOx Standards during the CAEP/8 cycle (CAEP-SG/20071-WP/26). The CAEP Steering 

Group requested that the Forecasting and Economic Analysis Support Group (FESG) and Working Group 

3 conduct appropriate analyses and report to the 2008 Steering Group meeting (CAEP-SG/20071-SD/4).

1.3 FESG presented the result of the analyses at the second meeting of the CAEP Steering 

Group meeting in Seattle, Washington (September 22-26, 2008), (CAEP-SG/20082-WP/6). FESG 

presented information showing that two non-compliant engine families remained in production at very 

low sales volumes and would soon be out of production. Accordingly, FESG reported that the 

environmental benefit from implementing a production cut-off for the CAEP/6 NOx Standard would be 

negligible. CAEP-SG/20082-SD/1 and CAEP-SG/20082-SD/4 document the discussions that took place 

regarding this issue. Due to the concerns of some CAEP members, the Steering Group directed FESG 

and the Modelling and Database Task Force (MODTF) to further analyze the costs and benefits 

associated with a CAEP/6 NOx emission Standard production cut-off.

1.4 At the Working Group 3 (WG3) meeting in London, United Kingdom (April 1-3, 2009) 

the U.S. EPA submitted CAEP-WG3-WP6-14 that invited the Group to recommend that the Steering 

Group consider recommending that CAEP adopt a CAEP/6 NOx Standard production cut-off at the 8th

meeting of CAEP in February 2010. Additionally, the U.S. EPA submitted CAEP-WG3-WP6-16 

regarding potential revisions to the existing exemption provisions of Annex 16, Volume II. Also, the 

International Coordinating Council of Aerospace Industries Associations (ICCAIA) presented a flimsy 

asserting that ―[f]or CAEP/6 ICCAIA can state with confidence that it is highly likely that all commercial 

engines in production by the end of 2010 will meet CAEP/6 NOx Standards.‖ 

1.5 At the last CAEP Steering Group meeting in Salvador, Brazil (June 22-26, 2009), 

Working Group 3 reported (CAEP-SG/20093-WP/18 and CAEP-SG/20093-SD/4) that additional work 

had been initiated to provide guidance on the process and criteria for granting exemptions against CAEP 

NOx production cut-off requirements. The U.S. presented CAEP-SG/20093-WP/39 recommending that at 

CAEP/8, CAEP adopt a production cut-off for the CAEP/6 NOx Standard and develop production cut-off 

associated flexibilities in the form of exemption provisions. Also at this meeting, CAEP-SG/20093-IP/19 

was submitted discussing FESG’s estimate of the cost and environmental benefit resulting from a 

production cut-off for the CAEP/6 NOx Standard. FESG found that it would not result in any significant 

environmental benefit, and if exemptions are granted, the costs would be negligible. 

Also, the Steering Group stated (CAEP-SG/20093-SD/2) that ―although there was no objection in 

principle from the [Steering Group] members for a production cut-off of CAEP/6 NOx Standards 

production cut-off, there were some outstanding issues. CAEP SG agreed to address appropriately the 

issues related to exemptions and timing for the earliest implementation to allow for recommending to the 

ICAO Council at CAEP/8 the adoption of such a cut-off...‖ 

1.6 At the WG3 meeting in Montréal, Canada (September 28- October 2, 2009) the 

Certification Task Group (CTG) Environmental Technical Manual (ETM) ad-hoc group submitted 

CAEP8-WG-WP7-14 that contained an updated version of the ETM on the process and criteria for the 

exemptions to the NOx production cut-off requirements. These provisions were approved by WG3, and 

 

1 The effective date for the CAEP/6 NOx Standards in Annex 16, Volume II is after December 31, 2007.
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two papers (CAEP/8-WP/17 and CAEP/8-WP/18) from the Working Group referencing the Group’s 

approval of these exemption provisions via revisions to Annex 16, Volume II and guidance material in the 

Emissions Environmental Technical Manual is expected at CAEP/8.

2. DISCUSSION

2.1 Below are additional points worth noting regarding a production cut-off for the CAEP/6 

NOx Standard. We believe it is necessary that once we have established a technology-following (as 

opposed to technology-forcing) Standard, we should consider its application in the form of a production 

cut-off in order to take advantage of its environmental benefits, ensure no backsliding, and communicate 

to the public the aviation sector’s commitment to improving its environmental performance. We believe 

it is important for the regulatory framework to offer certainty.

2.2 The production cut-off is not new. All NOx stringency Standards through CAEP/2 

included a production cut-off as part of the Standard. It was only in CAEP/4 that a new NOx stringency 

did not include such consideration. By recommending a production cut-off at the CAEP/6 stringency 

level, we are returning to past practice.

2.3 We realize that there may be concern by some over the possibility of economic costs for 

some manufacturers and operators. However, such issues would be addressed with exemptions to allow 

for the continued support of existing aircraft types. This would include, for example, exemption 

provisions for spares; that would be used as replacements for engines and for maintenance purposes, and 

production of a small volume of non-compliant new engines over a certain period. Additionally, engines 

built for military applications would not be covered by the cut-off.

2.4 We also realize that there may be concern by some that adopting a CAEP/6 production 

cut-off may be inconsistent with CAEP’s terms of reference (technical feasibility, economic 

reasonableness, environmental benefit, and potential interdependence). 

2.5 With regard to technological feasibility, we have already agreed to the CAEP/6 Standard. 

It is technology-following. It would never have been set if it was not technologically feasible. With 

regard to economic reasonableness, we believe that the exemptions developed by WG3 will fully mitigate 

this concern. CAEP/8-WP/17 and CAEP/8-WP/18 states the Group’s approval of the exemptions as 

listed, and as described earlier, FESG in paragraph 3.2 of CAEP-SG/20093-IP/19 states that this proposal 

will not result in any significant costs in the event that exemptions are offered. With regard to 

environmental benefit, the production cut-off provides certainty of meeting the Standard. In the short 

term, we would see a small benefit, but this would grow over time. With regard to interdependencies –

this was also addressed when ICAO set the CAEP/6 NOx Standard – so it is not an issue for a production 

cut-off.

2.6 We believe that ultimately a CAEP/6 production cut-off provides certainty that noncompliant engines will eventually no longer be produced – but with the flexibility of exemptions allowing 

for time adjustments to ensure we lessen economic impacts. 

2.7 In addition, the statement from the ICCAIA flimsy described above in paragraph 1.4 

makes it clear that within three years after the implementation date of newly certified engines (after 

December 31, 2007 for CAEP/6 Standards), industry will have completely responded to the market 

demand for CAEP/6-compliant engines. Given these circumstances, a production cut-off for CAEP/6 
CAEP/8-WP/56 - 4 -

NOx Standards would appropriately codify current practice into Annex 16, Volume II. While plans are in 

place for all commercial engines in production to meet CAEP/6 NOx Standards early in the next decade, 

as of today, not all production models meet the CAEP/6 NOx emission Standards. Applying a production 

cut-off ensures progress in reducing aircraft engine NOx emissions. 

3. ACTION BY THE CAEP

3.1 The CAEP is invited to:

a) agree that a production cut-off for the CAEP/6 NOx emission Standards and the 

associated exemption provisions developed in the revised ETM and Annex 16, 

Volume II should be adopted, and then implemented on the earliest practical ICAO 

effective date by which the CAEP Secretariat can obtain Council approval and 

incorporate into the Annex. 

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