(8 pages) 

 CAEPSG.20082.WP.006.3.en.doc

 COMMITTEE ON AVIATION ENVIRONMENTAL PROTECTION (CAEP) 

STEERING GROUP MEETING 

Seattle, 22 to 26 September 2008 

Agenda Item 3: Forecasting and Economic Analysis Support Group (FESG)

PRODUCTION CUT-OFF FOR ENGINE NOX STANDARDS 

(Presented by FESG Rapporteurs) 

SUMMARY 

At the first Steering Group meeting of the CAEP/8 cycle1, the United States 

representative presented a working paper2

 stating that a NOX production cutoff was required because market forces did not appear to be working. 

According to the paper, “in-production engines that are ‘non-compliant’ with 

the CAEP/6 NOX standard will likely not meet these standards in the future”. 

This paper presents additional information showing that market forces are 

working and that non-compliant engines currently in production have been or 

very soon will be made compliant with the CAEP/6 NOX standard, or have 

very low volume of sales and will soon be out of production, and hence that 

there is no environmental impact. As 99+% of in-production engines sold will 

meet the CAEP/6 NOX requirements by 2009, there is no need for a production 

cut-off, and the environmental benefit from such a production cut-off would 

be negligible. 

Action by the CAEP-SG is in paragraph 4. 

1. INTRODUCTION 

1.1 The purpose of ICAO NOX stringency requirements is to ensure that all newly developed 

airframes and engines incorporate the latest commercially available proven technologies across the entire 

product line, mindful that no single technology can be applied across the entire fleet3

. Unlike the CAEP/2 

standard set to ensure new NOX reduction technologies were incorporated into new engine designs as well 

as in-production engines by a certain date, the CAEP/4 and CAEP/6 NOX standards did not mandate a 

 

1

 Held in Zurich (Switzerland), from November 26 to 30, 2007. 

2

 Ref. [CAEP-SG/20071-WP/26]. “Production Cut-Off For Engine NOX Standards”. 3

 Ref. [CAEP/7-IP/2]. “Report of the FESG Industry Response Task Group”. Information paper submitted at the CAEP/7 meeting held in 

Montreal (Canada), from February 5 to 16, 2007. 

International Civil Aviation Organization

WORKING PAPER 

CAEP-SG/20082-WP/6 

4/9/08

English only
CAEP-SG/20082-WP/6 - 2 -

production cut-off for non-compliant engines. The CAEP/4 decision was based on the limited number of 

engines affected at the date of implementation and their expected future market share. The decision made 

at CAEP/6 was based on evidence that market forces were sufficient to bring non-compliant engines into 

compliance across the entire engine family. 

1.2 In CAEP-SG/20071-WP/26, the CAEP Steering Group was invited to direct WG3 and 

FESG to begin work to assess a production cut-off for the CAEP/6 NOX standard at a date 4 and 6 years 

after the implementation date for newly certificated engines, 31 December 2007, such that it can be 

considered at the CAEP/8 meeting. This suggestion was predicated on the notion that market forces did 

not appear to be working and the only way to assure compliance of non-compliant engines was through 

the introduction of a production cut-off. In response to CAEP-SG/20071-WP274

, the Steering Group 

agreed to follow a step process to the assessment of a CAEP/6 production cut-off. They agreed that if 

sufficient evidence was produced to support the assertion that market forces had driven compliance then 

they would consider not continuing with a second phase to a full cost benefit assessment. However, if 

such evidence was not forthcoming, the Steering Group could decide to task FESG with a full assessment 

of the effects of a CAEP/6 production cut-off. 

1.3 Although both FESG5

 and WG36 were tasked to look into the issue, it was agreed that 

FESG take the lead on providing a qualitative analysis that would provide sufficient evidence that market 

forces have driven compliance of in-production engines with the CAEP/6 NOX standard. This paper 

addresses in detail the list of engines that were labelled as “in-production” as of 2004 that did not meet 

the CAEP/6 standard. FESG pulled together information on upgrade programs for current in-production 

engines with assistance from ICCAIA and WG3. The following sections address the current status of 

implementation of technologies into engines to meet these standards. It also provides reasons that an 

engine remains non-compliant, such as low sales data or it is no longer in-production. 

2. INDUSTRY RESPONSE TO THE CAEP/6 NOX

STANDARD 

2.1 FESG reviewed the current status of the engines listed in CAEP/7-IP/2 Table 2.3 

reproduced in this paper as Table 1. This list of engines in Table 1 represents the in-production engines, 

as of 2004, identified as not meeting the CAEP/6 NOX standard. 

2.2 FESG noted in the CAEP/7-IP/2 that a sufficient period of time had not elapsed since the 

CAEP/6 NOX standard was adopted for complete industry responses to be observed. Since the time of the 

writing of the CAEP/7-IP/2 paper, (November / December 2006), approximately only 2.5 years have 

elapsed since the CAEP/6 meeting where the recommendation for the CAEP/6 NOX standard was made 

and only 2 years since it was formally adopted by the ICAO Assembly in October 2004. It was also noted 

that a full evaluation of the industry response to these standards would be reported at future CAEP 

meetings. FESG is reporting additional progress on industry responses to the CAEP/6 NOX standard in 

the following paragraphs. 

 

4

 Ref. [CAEP-SG/20071-WP27]. “Production Cut-Off For CAEP/6 Engine NOX Standards”. Information paper submitted by the International 

Coordinating Council of Aerospace Industries Associations (ICCAIA) in response to [CAEP-SG/20071-WP26]. 5

 Ref. FESG work programme for CAEP/8. Task F.08 “Conduct appropriate analysis on the projected number of engines that will not meet the 

CAEP/6 NOX standards and reasons why any in-production engines remain non-compliant. The analysis should provide current and forecast 

sales as well as assessment of engines still “in-production” as spares or new engines”. 6

 Ref. WG3 work programme for CAEP/8. Task E.08.1.b) “Working with FESG, conduct appropriate analysis to assist decision making 

regarding a CAEP/6 Production cut-off provision.” 
- 3 - CAEP-SG/20082-WP/6 

2.3 At the time of CAEP/6 in 2004, the CFM56 engine families did not meet the agreed upon 

recommendation for the new NOX standard. The CFM56 is an engine family with a high volume of 

annual sales and since 2004, all CFM56 in-production engines for the Boeing 737, Airbus A320 family, 

and Airbus A340-200/300 have been upgraded to meet the CAEP/6 NOX standards with margin. It is 

important to recognize that this engine upgrade program is a visible example that market forces do work. 

The CFM56-5B and CFM56-7B engines with CFM56 Tech Insertion have become the new production 

configurations. The engine upgrade reduces the NOX emissions to meet the CAEP/6 NOX standard with 

considerable margin plus provides some additional performance benefits. For the CFM56-5C family, a 

performance upgrade package, denoted with the “/P” suffix, has allowed the engine models in this family 

to meet CAEP/6 NOX standard with margin. 

2.4 The V2500 is another engine, with a high volume of annual sales, that is installed on the 

A320 aircraft family and the upgrade being developed for this engine family is another visible example of 

market forces at work. IAE7

 is currently certificating engine improvements under the V2500 SELECT 

program, available by third quarter 2008, which will bring the engine family into compliance with the 

CAEP/6 NOX standards. Additionally, this engine will offer improvements in fuel burn and a resulting 

reduction in CO2 emissions. 

2.5 The B757 is no longer in production and therefore the PW2040 and PW2043 engine 

models are now out of production. 

2.6 The PW4164 and PW4168 engine family has been certificated with a TALON II 

combustor, which meets the CAEP/6 NOX standard with considerable margin. The PW4164/68 with the 

original floatwall combustor is still offered for sale, primarily to fill spare engine requirements for 

customers requiring commonality with their existing fleet, however intermix of the engine models with 

the two different combustors is also allowed. Pratt & Whitney is currently completing development of an 

engine upgrade for the PW4168 family called Advantage70TM, available in early 2009, where the TALON 

II combustor will become the only combustor option available for new orders. Intermix of PW4164 / 68 

engines with or without the TALON II combustor on the same aircraft will be allowed. 

2.7 The PW4077D, PW4080D and PW4090 on the Boeing 777 have low annual sales, and 

although a technology has been identified to allow this engine family to meet the CAEP/6 NOX standards 

it is not cost effective to implement the technology. A table of current in-production aircraft-engine 

configurations with engines that do not meet the CAEP/6 NOX standard and have a low volume of orders 

was produced from the AvSoft Information Systems ACAS commercial fleet database and is attached as 

Table 2. The low order figures for aircraft with the PW4077D, PW4084D and PW4090 engines are 

shown in this attachment. There are outstanding orders for only 12 installed PW4090 engines. 

2.8 The PW4056, PW4060, PW4062, PW4156 and PW4158 engine models with a Phase 3 

build standard all belong to a common engine family. The TALON II combustor was certified on the 

PW4158, which powers the Airbus A300, and this combustor allows the PW4158 to meet the CAEP/6 

NOX standards with considerable margin. The PW4156 powers the A310 that is now out of production. 

The PW4056/60/62 phase 3 engines on the Boeing 767 and Boeing 747-400 have low sales figures and as 

a result have not been modified to comply with the CAEP/6 NOX standards. The TALON II combustor 

technology has been identified as the technology for these engine models to meet the CAEP/6 NOX

standard, but will only be implemented if a substantial order for these engines is obtained. Table 2 shows 

the outstanding orders for the PW4062 that are for 24 installed engines to be delivered by the end of 2009. 

 

7

 IAE – International Aero Engines. IAE is a multinational aero engine consortium whose shareholders comprise Pratt & Whitney, Rolls-Royce, 

the Japanese Aero Engines Corporation and MTU Aero Engines. 
CAEP-SG/20082-WP/6 - 4 -

2.9 There is an engine upgrade, (PEC), for the GE90-94B engine which allows this engine 

model to meet the CAEP/6 NOX standards with margin. 

2.10 There is a new combustor under development for the AS907 engine that will meet the 

CAEP/6 NOX standards with margin when certificated in 2009. 

2.11 The Tay 611-8C engine will be re-certificated for emissions to meet CAEP/6 NOX 

standards in 2009. 

2.12 Summary of in-production engine models that will not meet the CAEP/6 NOX standard 

by 2009. 

Engine Family Engine Model 

PW4000 with 

94inch fan 

PW4056 Phase 3 * 

PW4060 Phase 3 * 

PW4062 Phase 3 * 

PW4090 

PW4074D 

PW4077D 

PW4084D 

PW4090

* TALON II combustor that is certified on PW4158 could be installed and certified on PW4056/60/62, 

provided a substantial order for these engines was obtained to rationalize the incremental certification 

cost. 

3. PRODUCTION CUT-OFF WOULD PROVIDE VERY 

LITTLE ENVIRONMENTAL BENEFIT 

3.1 From the ACAS commercial fleet database, the total installed engines representing firm 

aircraft orders to be delivered in 2009 for commercial passenger and freighter regional jets, narrow body 

and wide body aircraft is estimated to be more than 2 650 engines. The total number of installed engines 

to be delivered for 2008, 2009 and 2010 that would not meet the CAEP/6 NOX standards adds up to 32 

engines, (see Table 2). The average annual deliveries of installed engines over this period that do not 

meet the CAEP/6 NOX standard is estimated to be about 11 engines per year. By 2009, the percentage of 

annual installed engine deliveries that meet the CAEP/6 NOX standard would be 99.6%, ((2 650-11)/2 

650). 

3.2 After 2012, the ACAS database estimates that there would be only 4 installed engines to 

be delivered that would not meet the CAEP/6 NOX standard. The estimated firm order deliveries of 

installed engines for 2012 is estimated to be more than 2 050. These 4 engines represent less than 0.2 

percent of calendar year 2012 projected engine deliveries. 

3.3 With over 99% of in-production engines to be delivered meeting the CAEP/6 NOX

requirements by 2009, the environmental benefit from implementing a production cut-off to the CAEP/6 

NOX standard would be negligible. Therefore, there is no need for a production cut-off. 

3.4 It can be concluded from these elements that market forces do work, provided sufficient 

time is given for Industry to respond. 
- 5 - CAEP-SG/20082-WP/6 

4. ACTION BY THE CAEP-SG 

4.1 The CAEP-SG is invited to: 

a) Recognize the progress that the engine manufacturers have achieved in bringing inproduction engines into compliance with the CAEP/6 NOX standards; 

b) Accept the market-driven production cut-off assumption made by FESG (and as 

described in CAEP/7-IP02) as a reasonable basis for CAEP/8 economic analysis of 

NOX stringency options; and 

c) Approve the recommendation of FESG to not implement a production cut-off for the 

CAEP/6 NOX standard. 

— — — — — — — —

 

CAEP-SG/20082-WP/6 

Appendix A

APPENDIX A 

Table 1 

As summarized in CAEP/7-IP02 Table 2.3 – Engines in production as of 2004 Not Meeting the 

ICAO CAEP/6 NOX standards. 

Large Engine Category 

CFM56-5B1/P 

CFM56-5B2/P 

CFM56-5B3/P 

CFM56-5C2 

CFM56-5C3 

CFM56-5C4 

CFM56-7B22 

CFM56-7B24 

CFM56-7B26 

CFM56-7B27 / -7B27-B3 

V2522-A5 

V2524-A5 

V2527-A5 

V2530-A5 

V2533-A5 

PW2040 

PW2043 

PW4164 (1) 

PW4168 (1) 

PW4056 Phase 3 

PW4156 Phase 3 

PW4158 Phase 3 

PW4060 Phase 3 

PW4062 Phase 3 

PW4074D 

PW4077D (1) 

PW4084D (1) 

PW4090 (1) 

GE90-94B 

Small Engine Category 

AS907 

Tay Mk. 611-8C

(1) Indicates that engine did not meet the CAEP/4 NOX standard 
CAEP-SG/20082-WP/6 

Appendix A A-2 

Table 2 

Review of Orders for In-Production Engines That Do Not Meet the CAEP/6 NOX standards 

– Low Volume of Orders 

 Engine Aircraft

Total 

Backlog 2008 2009 2010 2011 2012 2013 2014 2015

 PW4062A 747-400F / -400ERF 24 12 12

 PW4090 777-200 / -200ER 12 6 2 4

 Firm Order Backlog as of June 2008 - Number of Installed Engines

(Source: ACAS)8

 — END — 

 

8

 ACAS – AirCraft Analytical System: Aviation market information system database.