(20 pages) 

 CAEPSG.20082.WP.018.7.en.doc

 COMMITTEE ON AVIATION ENVIRONMENTAL PROTECTION (CAEP) 

STEERING GROUP MEETING 

Seattle, 22 to 26 September 2008 

Agenda Item 7: Emissions Technical – WG3

NOX STRINGENCY TECHNOLOGY RESPONSE ASSESSMENT 

(Presented by Rapporteurs from WG1 and WG3) 

SUMMARY 

In furtherance of the CAEP/8 WG3 remit E.08.1(“Analyse the technological 

response to a range of NOx stringency options up to CAEP/6 minus 20% at 

OPR = 30 for application no sooner than 2012”), this paper presents the 

methodology and results of an assessment of technology responses to the 

range of proposed NOx stringency options which were agreed at the SG/20071 

meeting (SD/4). 

These results from WG1 and WG3 were presented to the MODTF and FESG 

meetings in June as input into their cost-effectiveness analysis of these 

stringency options for CAEP/8, which will be reported separately for small 

and large engines. 

Action by the CAEP-SG is in paragraph 9. 

1. INTRODUCTION 

1.1 In furtherance of the CAEP/8 WG3 remit E.08.1(“Analyse the technological response to 

a range of NOx stringency options up to CAEP/6 minus 20% at OPR = 30 for application no sooner than 

2012”), WG3 had previously performed an analysis of emissions certification data for in-production 

engines and recently certified engines. A range of potential options for a CAEP/8 NOx stringency 

assessment was subsequently presented at the SG/20071 meeting in November last year. 

1.2 During this meeting, it was agreed in SD/4 that, “...WG3 would assess the proposed 

WG3 NOx stringency levels and implementation dates in SG20071 WP/12 with the two additional 

stringency levels in SG20071 WP/25. Lastly, the meeting added a work item to perform a cost 

effectiveness analysis of these stringency options, reporting separately on the analyses for small and 

large engine categories”. 

International Civil Aviation Organization

WORKING PAPER 

CAEP-SG/20082-WP/18 

25/9/08

English only
CAEP-SG/20082-WP/18 - 2 -

1.3 This paper summarises the WG1-WG3 analysis of the technology responses to these 

stringency options and presents the results as input for the CAEP/8 cost effectiveness analysis. 

2. ICAO CERTIFICATION DATABASES 

2.1 Significant work has been performed in updating both the ICAO certification databases 

(NoisedB and the Aircraft Engine Emissions Databank) so as to ensure they were fit for use in CAEP/8 

policy assessments. These databases were then linked together in order to facilitate the assessment of 

potential trade-offs between noise and emissions. 

2.2 Using the production status listed against entries in the ICAO certification databases, an 

“In-production” Database was extracted containing both noise and emissions data. This database was 

used to help identify which engine types would respond to the CAEP/8 NOx stringency options, and 

should therefore form part of the WG1-WG3 technology response assessment. It also formed part of the 

ICAO “Growth and Replacement (G&R)” Database (see SG/20081 WP/16) and identified those engine 

types to be considered in the FESG CAEP/6 NOx production cut-off analysis (see SG/20081 WP/06). 

3. ANALYSIS METHODOLOGY 

3.1 Appendix A to this paper summarises the “Modification Status (MS)” methodology for 

assessing engine technology responses to the proposed CAEP/8 NOx stringency options. It includes 

Minor Changes (MS1), Scaled Proven Technology (MS2) and New Technology (MS3). The approach is 

similar to that from CAEP/6, while avoiding the potential confusion between the use of the previous term 

“Technology Level (TL)” with the research orientated “Technology Readiness Level (TRL)”. Appendix 

B lists the important assumptions which underpin this analysis. 

3.2 The current non-recurring cost estimates are $10M ($1-15M) for MS1, $75M ($50-

100M) for MS2 and $300M ($100-500M) for MS3. MS1 costs have remained the same as CAEP/6 TL1. 

While there has been a general increase in MS2 costs ($75M) compared to the equivalent CAEP/6 TL2 

($50M), the assumptions underpinning these cost inputs into CAEP assessments were consistent. 

Additional experience gained in the PW4168, 4x58 / TALON II and the CFM56-5B, -7B / TIP projects 

have led to the figure being revised upwards. The range of MS costs reflect the uncertainty and 

variability on a project by project basis. 

3.3 Due to the lack of CIS1

 certification data, several attempts have been made to contact CIS 

representatives in order to obtain information on these products. Unfortunately this has not been 

successful and consequently CIS products have not been included in the technology response assessment. 

In addition, it should be noted that some in-production engine types are not expected to respond to 

proposed CAEP/8 NOx stringency options (e.g. RB211-524G-T). Therefore, in line with FESG market 

based assumptions, if these engine types do not meet a new standard then it is assumed they will not be 

produced beyond the date at which the standard becomes effective. 

3.4 Where an engine would respond to a stringency change, the amount of improvement that 

an MS1 change can provide has been defined as less than 5%. For MS2 and MS3 changes, the amount of 

improvement may vary between engines due to differences in: 

 

1

 Commonwealth of Independent States (CIS) is an alliance of 11 former Soviet Union countries including Russia and Ukraine 
- 3 - CAEP-SG/20082-WP/18 

• The current technology used in the engine. A new engine, or an engine that has had a 

recent combustor design update, may have less potential for improvement than an 

older engine. 

• The scale and cycle of the engine. Not all technologies can be applied to all engines. 

It may prove difficult to implement lean-staged technology in very high-pressure 

ratio engines due to fuel auto ignition issues. 

• The existing architecture of the engine. Some technologies might require more space 

or control functionality than is available in an existing engine. 

3.5 The expected NOx improvement from an MS2 modification will be relatively well 

known to the manufacturer as MS2 is based on “best available” technology. MS3 modifications are based 

on technology that is not yet available to the manufacturer. So the manufacturer has often been forced to 

propose MS3 solutions that are not fully understood. In this situation, manufacturers use best engineering 

judgement in deciding whether sufficient improvement is achieved to meet the next stringency level, 

although there is no guarantee of success. In a few cases, the manufacturer may have a new technology at 

a high TRL that is better understood and, in such a case, it may be possible to confidently predict 

significant margin with an MS3 change. 

3.6 In estimating the NOx benefits associated with an MS modification, it was assumed to be 

halfway between the options where the MS level changes from one to the other. For example, take the 

case of an engine family that currently only meets CAEP/6, but is shown to be capable of meeting: 

• 5% stringency increase at 30 OPR with an MS1 modification 

• 10 and 15% stringency increase at 30 OPR with an MS2 modification 

• 20% stringency increase at 30 OPR with an MS3 modification 

3.7 For the 5% stringency increase, it was assumed that the NOx emissions level for the 

highest thrust variant of the engine family, following the MS1 modification, provided a margin of 7.5% to 

CAEP/6. For the 10% and 15% stringency increases, the NOx emissions level for the highest thrust 

variant of the engine family, following the MS2 modification, provided a margin of 17.5% to CAEP/6. 

All other engine variants in that family were assumed to have the same % delta to the highest thrust 

variant as prior to the MS modification. 

3.8 The MS3 process usually starts with MS2 best practice combustor technology that has 

evolved and been proven in service over many years. Each of the steps below would yield relatively 

small incremental improvements and would be the preferred “low risk, small benefit” approach to 

meeting a new CAEP standard set in the short term. Since each of these steps involves potential tradeoffs 

with engine durability and/or operability, the manufacturer would move carefully to meet the new 

stringency without risking engine capability. This has been demonstrated in the V2500 Select 1 and the 

GE90 PEC performance improvement packages which are currently being certified to make the engine 

families compliant with CAEP/6 (see Column L notes in Appendix E). 

• First, without any major changes to the combustor design philosophy, the 

manufacturer will analyze and test: 
CAEP-SG/20082-WP/18 - 4 -

i) small changes in the fuel injector atomizer airflow, with a tradeoff for 

smoke or lean blowout, to try to reduce NOx formation in the rich stage of 

combustion; 

ii) combustor cooling flow reductions, with a tradeoff for durability, to 

increase air available for quenching NOx formation; and 

iii) liner dilution hole patterns, with a tradeoff with combustor exit profile and 

turbine durability, to increase the mixing rate and rate of NOx quenching. 

• Secondly, if the first stage is not successful in meeting the new stringency, the 

manufacturer may analyze and test: 

i) new fuel injector concepts to improve fuel air mixing, with a tradeoff for 

operability; and 

ii) new liner cooling approaches to reduce the need for cooling air (e.g. 

advanced tiled bulkhead and/or liners). 

• The third level of change may be a reduction in combustion chamber volume, with a 

tradeoff for relight margin, to reduce overall residence time for NOx formation. 

• Finally, if the new stringency has not been met, then manufacturer would consider 

cycle changes, such as reduced engine pressure ratio, although this option would be 

rare as it would involve considerable cost and technical challenges. 

3.9 Another MS3 approach, which is “high risk, large benefit” and speculative in terms of 

meeting new standards in the short term, is that the manufacturer will successfully develop improved 

combustor technology between now and the time that the new level of stringency goes into effect. If an 

engine is suited for that technology (e.g. combustor envelope is large enough, control functionality is 

sufficient and hot section is adaptable to changes in exit temperature profiles), it is possible that the 

technology would be applied. For most engine families at the present moment, there is no proven 

technology to meet the highest stringency with large margins over a range of engine architectures. With 

this in mind, it was assumed that all MS3 modifications followed the “low risk , small benefit” approach 

in 3.8. 

3.10 As such, for the 20% stringency increase option, it was assumed that the NOx emissions 

level for the highest thrust variant following the MS3 modification provided a margin of 25% to CAEP/6, 

unless the agreed minimum 10% improvement exceeded this. In reality, not all engines will achieve the 

same margin, however, taking into account measurement and test uncertainties, manufacturers would aim 

to ensure engine families meet a certain stringency by at least 2% margin and some may have up to 8% 

margin. So, on average, an assumed margin of 5% was considered appropriate. 

4. ANALYSIS RESULTS 

4.1 Appendices C and D summarise the technology responses of the “In-production” large 

and small engine families for each of the proposed CAEP/8 NOx stringency options. Appendices E and F 

provide a more detailed perspective with margins to the new proposed limits and, for modelling purposes, 

the improved NOx emissions performance following the application of the relevant MS modification. 
- 5 - CAEP-SG/20082-WP/18 

5. MS3 FUEL BURN TRADE-OFF PENALTY 

5.1 One of the Appendix B assumptions which underpins this assessment is that engine 

technology responses will be focused on combustor modifications, and associated modifications required 

to accommodate this. It does not envisage additional engine performance improvements, which 

manufacturers would usually try to incorporate at the same time. Including these additional technology 

responses would require further assumptions on benefits and costs which may off-set each other and 

therefore not affect the overall ranking of the policy options. 

5.2 WG3 recognised that, associated with this assumption, there was the potential for a fuel 

burn penalty. The CAEP/6 fuel burn penalty of 2% was based on a similar assumption and Dual Annular 

Combustor (DAC) technical data, however this technology is not expected to be used in responses to a 

CAEP/8 standard. As such, a fuel burn penalty range of 0% to 0.5% was agreed for MS3 modifications. 

6. MS3 NOISE TRADE-OFF PENALTY 

6.1 In line with the CAEP terms of reference, WG1 reviewed the likelihood of noise tradeoffs associated with the engine technology responses to new NOx standards. It was agreed by WG1 that a 

noise penalty was only likely to occur if an MS3 modification contained cycle changes. As mentioned in 

the fourth point of paragraph 3.8, this option was considered rare with a 5-10% probability of a cycle 

change forming part of a MS3 technology response. 

6.2 WG1 finally agreed that two possible scenarios may occur, with no preferred option, and 

that both should be analysed by MODTF and FESG. These included: 

• Firstly, 10% of the engines which include MS3 modifications would incur a noise 

penalty of 0.5dB at each of the three measurement points. Additional costs, 

associated with this noise increase would have to be taken into account in this case. 

• Secondly, that no noise penalty is expected even for the MS3 engines that require a 

cycle change. However, for these engines, which comprise 10% of the MS3 engines, 

estimates would need to be made for additional costs that manufacturers may incur in 

order to eliminate the noise penalty caused by the cycle change. 

6.3 In terms of both fuel burn and noise trade-off penalties, it is worth noting that MS3 

modifications only apply to the two highest NOx stringency options for large engines and that there are 

no MS3 modifications associated with small engine families. 

7. FESG COORDINATION 

7.1 Following a request from FESG, WG1-WG3 will continue to provide support on the 

issue of recurring costs associated with the technology responses (e.g. production, maintenance, 

interchangeability). 

8. FUTURE NOx IMPROVEMENTS 

8.1 Based on the CAEP7 LTTG NOx review, there is an expectation that significant 

improvements in NOx technology will be available by 2016. 
CAEP-SG/20082-WP/18 - 6 -

8.2 Progress towards those goals will be monitored within CAEP and could be considerable. 

As such, WG3 felt that if the rate of technology development meets the Mid-Term Technology Goals, 

there may be justification to review the Annex 16 Volume II NOx standards once again. This would be in 

line with the CAEP approach to continuously review existing certification standards and to consider 

setting future standards on a short term basis. 

9. ACTION BY THE CAEP-SG

9.1 The CAEP-SG is invited to: 

a) note, and provide comment, on the technology response assessment of the CAEP/8 

NOx stringency options; 

b) note that the results have been passed to MODTF and FESG as input for the CAEP/8 

cost effectiveness analysis; and 

c) note that WG1-WG3 continue to support FESG on the issue of recurring costs 

associated with the technology responses. 

— — — — — — — — 
 

APPENDIX A

MODIFICATION STATUS (MS) METHODOLOGY FOR ASSESSING 

TECHNOLOGY RESPONSES TO NOX STRINGENCY OPTIONS 

1. INTRODUCTION 

This methodology covers the situation when an engine family fails a NOx stringency option and then 

suggests the different categories that may be used to fix any in-production engine failing a new CAEP8 

NOx regulation. The paper follows previous practice used at CAEP/6 but uses up to date assumptions 

based on numerous programmes of the nature described. 

It is important to recognize that this paper discusses the changes that would be applied to in-production 

engines and hence the changes are constrained by the engine architecture. It is therefore assumed that any 

cycle performance changes will either not exist or be very minor. Any such changes would be 

commercially sensitive. It is also assumed therefore that more significant changes are more likely to have 

adverse impacts on engine performance in terms of fuel burn and noise, as any programme to recover 

such aspects would result in significant other non-recurring costs. 

2. MINOR CHANGE (MS1) 

The MS1 designation covers a range of possible minor changes to existing engines, including but not 

limited to: 

• Change to cooling flows in and around the combustor 

• Change to control laws and engine control system 

• Change or reclassification of engine performance 

• Additional engine testing and re-certification of emissions 

In all cases, it was assumed that there would be no substantive material change to the engine combustor 

hardware or operating costs. The typical NOx reduction with such a change would be of the order of 1-

5%. 

Given the diverse nature of these solutions, the work content and hence cost is difficult to estimate. While 

one would expect that costs in this category would be of a minimum nature, based on what appears to be 

minor changes, costs in fact will not be insignificant and vary over a wide range based on the actual 

certification requirements. Running additional engine testing may appear to be the least expensive, but in 

fact costs could be significantly higher than anticipated. Typically, manufacturers do not have spare 

production configuration engines to do these tests. Further, using production engines targeted for delivery 

to customers may not be possible because of schedule limitations, and what limits can be put on testing 

prior to delivery to customers. Thus, it may be necessary to “build” specific engines for the sole purpose 

of emissions certification testing. This could run several millions of dollars. Even if engines are 

available, test cell costs will be high as a result of test cell charges, manpower costs, specific 

CAEP-SG/20082-WP/A 

Appendix A 
CAEP-SG/20082-WP/A 

Appendix A A-2 

instrumentation requirements and certification documentation costs. Changes to cooling, while 

apparently a “simple” change, may require the development of new materials and significant levels of 

testing in both combustor rigs and full-up engines. Likewise, changes to control software will require 

flight-testing which again is very costly. Reclassification of engine performance requiring the validation 

of revised rotating hardware, which requires significant levels of ground testing and flight testing is 

probably the most expensive in this class of changes. Considering all of the requirements, total costs for 

changes falling in the MS1 category could range from $1-15M. 

One example of an MS1 modification was the performance improvement program completed for the 

CFM56-5C family that then allowed it to meet the CAEP6 regulation. Note that in this example, the 

primary purpose of the program was to improve fuel efficiency. 

For cost analyses, the range of $1-15M could be used for sensitivity studies or a Monte Carlo cost 

analysis. If a single typical value is needed for cost analysis, ICCAIA recommends an estimated cost of 

$10M be used. 

3. SCALED PROVEN TECHNOLOGY (MS2) 

This response is defined as where an engine manufacturer applies its best-proven, TRL9, combustion 

technology (e.g. GE LEC, RR Phase 5, P&W TALON II), certified in at least one other engine family 

with comparable scale and OPR, into another engine type which would otherwise fail the proposed 

standard. Such solutions have been used to comply with previous CAEP NOx standards (e.g. the 

installation of the Phase 5 combustor into the RB211-535E4, the installation of the TALON II combustor 

into the PW4168 and PW4x58 and the Technology Insertion combustors recently fitted to the CFM56-5B 

and CFM56-7B engine families. These changes gave significant reductions in emissions greater than 20% 

of CAEP/6, however it must be recognized that these combustors replaced older technology combustors, 

and now nearly all in-production engines use manufacturers’ best practice). 

The MS2 solution would require substantial modeling, and design work. In addition, significant levels of 

testing in combustion rigs and modified development engines (ground testing including cyclic running) 

will be required. Flight-testing of a set of production-standard engines and all the associated certification 

authority paperwork will also need to be completed. Another significant consideration when one 

discusses the installation of scaled proven technology into other engine models is the inevitable impact it 

will have on other engine modules in order to accept the improved combustors. For example, highpressure engine cases may need to be re-designed. Rotating and/or static turbine hardware may also need 

to be re-designed to accept changes in combustor exit temperature profiles or pattern factors. Fuel system 

changes may be required which will impact engine externals and in turn could impact the nacelle 

configuration and loft lines further escalating costs and required validation testing. New production 

tooling and assembly line training/accreditation will also be required, and increased activity is typically 

needed after the change is introduced to cover customer questions and new issues that come up with 

respect to operation in the field, repair procedures, etc. The effort and resulting cost of a MS2 change are 

known to manufacturers from the above examples, and therefore can be predicted by the manufacturers. 

Note that in most cases several engine models within a family can be treated using one solution, and so 

the cost of a solution is counted only once per family. The cost of these programmes is expected to be 

between $50-100M. If a single value is needed for cost analysis, ICCAIA recommends a value of $75M. 
A-3 

CAEP-SG/20082-WP/A 

Appendix A 

The improvements such a change could produce will be greater than MS1 but will very much depend on 

the engine family such a change is applied to and the combustion technology already used on the engine 

family. Manufacturers will suggest what percentage reduction in emissions this will produce on an engine 

family by engine family basis but a lower bound of improvement has been agreed as 6% so the change 

will bring at least 6%+ improvement in emissions. 

4. NEW TECHNOLOGY APPLYING COMBUSTOR FROM 

RESEARCH PROGRAMMES (MS3) 

When a manufacturer has no proven technology that can be scaled to provide a solution then it is clear 

that some technology acquisition activity is required ahead of the validation activities described for scaled 

proven technology. Where one or more manufacturers have proven, as evidenced by certification data 

(TRL8), to possess the necessary technology, the acquisition of technology by the other manufacturers to 

catch up is judged to carry a medium risk; all research activity carries the risk of not delivering the 

desired goals and scaling best practice combustors to smaller or larger engine sizes often needs extra 

research work as well. 

In fact, the technology that affects the emissions metric (Dp/Foo) goes well beyond the combustor. The 

emissions values are reported relative to sea level static engine operation, while engines are typically 

designed considering takeoff, climb and cruise operation, all of which occur at flight Mach numbers 

above 0. The most obvious engine characteristic that can affect Dp/Foo is bypass ratio. At sea level 

static conditions, an engine with high bypass ratio will produce more thrust (Foo) than a comparable 

engine with lower bypass ratio, so Dp/Foo will be reduced for a given combustor technology. The 

engines might be equivalent at elevated Mach number where the drag due to the larger fan and nacelle 

tend to reduce the net thrust of the engine system. Engine architecture, component characteristics or even 

details of design philosophy might also affect the relationship between thrust and Mach number. For 

competitive products, these effects are not usually large, but might affect Dp/Foo by up to 10%. This 

means that for two competing engines having the same combustor technology, one could have 5% margin 

to CAEP/6 and the other could have 15% margin. In most cases, if there is 10% difference in two 

competing products, it is probably not even possible to pinpoint how much of a gap is in combustor 

technology, as opposed to engine architecture or component design without knowing proprietary details 

of the engine architecture and component performance. 

A typical path to reduce NOx emissions without changing to a totally new combustor concept would 

normally start with improvements to the design of the existing combustor fuel injectors, cooling and air 

mixing features (possibly including combustor pressure drop). Such a change would go beyond the 

manufacturer’s available technology, so the minimum cost would be comparable to the top of the MS2 

range. 

If analysis and rig testing shows that changes to the existing combustion structure are not sufficient, the 

next step might be to reduce combustion volume (trading off air start margin and possibly carbon 

monoxide emissions, with a small impact on combustion efficiency). This would add to the program cost 

because additional iterative engine tests at altitude conditions might be needed. If these more significant 

combustor changes are not sufficient, there might be no option other than to look at a more significant 

change in the engine – for example, a higher flow fan for increased bypass ratio, at significantly higher 

program cost. 
CAEP-SG/20082-WP/A 

Appendix A A-4 

As described above, quantifying the costs and timescales of technology acquisition programmes is 

difficult – no two programmes face the same goals or obstacles, the reporting of costs is not transparent 

and the differences between laboratory demonstrations and in-service technology can be several years and 

more than $100M. These factors make it difficult to derive a single cost for one manufacturer to catch-up 

with the industry leaders. At best, a MS3 development program would be equivalent to a MS2 

development program with the addition of some applied research for technology acquisition and 

potentially extended cyclic testing to prove the durability that is required for ETOPS. For example, if the 

changes are confined to improvements in fuel injector, cooling and mixing features it might be necessary 

to conduct several iterations on the typical MS2 analysis, design, component test and engine verification 

tests before a successful design has been identified that is capable of meeting all airworthiness and 

emissions requirements. That would be the lower limit, in this case. The upper limit on cost of a MS3 

program was selected to approximate the maximum amount that a manufacturer would be willing to 

invest, where the alternative would be to drop production of an engine type. 

This designation also relates to past, present and future research programmes. Quantifying the costs and 

timescales of such programmes is difficult but it is indicative to consider the costs of similar programmes 

undertaken in the recent past: 

a) NASA contributed ~ $300m per year through the “Advanced Subsonic Transport 

Program” (AST) (1994-1999) and “High Speed Research” programmes addressing 

noise and emissions and funding continued through UEET. Industrial partners also 

contributed similar levels of funds, which took some technology as far as the TRL 

(technology readiness level) 6 stage. The basis for the TALON II and LEC 

technologies emerged from this research, but both required significant further 

development and validation by Pratt & Whitney and GE, respectively. 

b) The EU ANTLE and CLEAN demonstrator programmes have spent over $100 

million taking advanced combustion technology and demonstrating them in an 

experimental engine environment. 

c) The “Luftfahrtforschung” LUFO/E3E programme in Germany invested 48.6 MEUR 

on staged combustion development at Rolls-Royce Deutschland: 

• E3E III (2004-2007) 5.3 MEUR (gross) 

• E3E II (1999-2003) 12.5 MEUR (gross) 

• E3E I (1994-1998) 30.8 MEUR (gross) 

•

The gross funds include an industry contribution of ~60%. 

Each of the above programmes has required matching resources on the part of the manufacturers (often on 

a one-to-one basis), and the programmes have typically only progressed to TRL 4 to 6. The costs of more 

expensive TRL 7-9 tasks are typically borne by the manufacturers alone. 

If emissions requirements cannot be met with available combustor technology, the cost to make more 

extensive engine changes could be several hundred million dollars. If this is the case, rather than make 

the engine cycle change, the manufacturer might choose the option to use new combustor technologies 
A-5 

CAEP-SG/20082-WP/A 

Appendix A 

that are not yet at TRL 8. These technologies will typically be the GE TAPS combustor, the P&W 

TALON X combustor and the RR lean burn combustor. These combustors are typically at TRL5-7 and 

hence actually do not meet the criteria for stringency considerations. However, ICCAIA have included 

this category to complete the cost/benefit analysis. The total costs of these technology acquisition 

programmes will ultimately be similar over the life of the whole acquisition programmes and trying to 

attribute a current TRL for each technology is part of the LTTG review process. For ICCAIA to decide 

which programme is more advanced and which costs the least is clearly not possible. Therefore the total 

costs for the MS3 category have been estimated to be between $100-500M, with a typical value of $300M 

and no further disaggregating is proposed. 

The emissions improvement of this category will be greater than MS2 and the improvement will depend 

on the technology proposed for the improvement and the engine and combustor performance it is 

replacing. The manufacturers who may apply this to meet stringency will suggest the NOx improvement 

on an engine family by engine family basis. ICCAIA has judged that for the investment this category 

would have to give at least a 10% NOx improvement. 

A MS3 category change will also require more lead-time to bring the technology into production. While 

a lead-time of three to four years might be sufficient to implement a MS1 or MS2 category product, 

several additional years will typically be needed for a manufacturer to acquire the required technology for 

MS3. This needs to be considered in setting the implementation date for a new standard. 

The manufacturers are naturally not able to discuss the detail of their research programmes in the public 

domain, but it is known that while all the engine manufacturers have been assessing advanced concepts 

such as staged combustion technologies for many years, only the CFM56 DAC engine has entered 

service. However, there have been trade-off issues associated with the DAC. Specifically, for CAEP/6 

analysis, a fuel burn penalty of 2% was assumed for advanced technologies, based on DAC experience. It 

should be noted that DAC technology is not offered for in-production engines. 

The goal of advanced combustor technology programs is to achieve emissions reductions with no increase 

in fuel consumption. However, past experience in aviation and other industries that use gas turbines (such 

as power generation) indicates that technologies to reduce NOx emissions (e.g. catalytic clean up or water 

injection) almost always result in a small increase in fuel consumption. Most advanced low NOx 

technologies, but not all, use staged combustion systems that require an increased number of combustor, 

fuel system and control parts, so it is reasonable to expect a potential small increase in fuel consumption 

when a combustor modification is considered in isolation with no other performance enhancements. For 

these future advanced combustion technologies the fuel burn penalty is expected to be between 0 and 

0.5%. A value of 0.25% fuel burn penalty could be assumed for these technologies. 

5. FAMILY APPROACH 

The engine family approach is to be applied to the analysis such that when one engine of a family is 

affected, the fix to that engine would apply to all the family. This gives one non-recurring cost for a 

family (manufacturers aiming to minimize costs), but it also means that emissions benefits are increased 

because smaller stringency increases actually can affect many engine models within a family even though 

only the higher thrust versions might be the only models affected. The benefits to the family are obviously 

greater because the fix is applied to all the family. 
CAEP-SG/20082-WP/A 

Appendix A A-6 

6. POSSIBILITY OF NON-COMPLIANCE 

In cases where sales of an engine family are very low or a new engine is being developed to replace a 

current one in the near future, the manufacturer might judge that it is not cost effective to respond to an 

increase in stringency. For example, non-compliant engines for the Boeing 757 aircraft family were 

considered in the CAEP/6 cycle, but the aircraft went out of production before CAEP/6 standard went 

into effect, so the engines were not affected. 

There might also be engine families with recent combustor designs where implementation of a MS3 

technology would only reduce NOx emissions by a few percent. In such a case, the manufacturer might 

judge that rather than developing evolutionary technology to improve emissions by a few percent, it is 

more effective to invest available resources to develop more revolutionary technology that will have a 

chance of providing substantially greater reductions, even though it might not be ready for introduction 

into the product before the new standard becomes effective. 

Decisions on whether and when these revolutionary engines would comply with a new standard will 

sometimes depend on future market conditions and future status of technological development that are 

impossible to predict. FESG and MODTF should consider whether and how to address such cases in their 

modelling studies. 

7. NOISE IMPACT 

As stated in the introduction, the assumption is that there is no change in engine thrust and any cycle 

changes will be especially small. Therefore, the 0dB noise impact shown for MS1 and MS2 is based on 

the fact that no thrust or significant cycle changes are envisaged for these categories. 

For MS3 it is already known that the advanced technology DAC engine produced more noise than a 

similar SAC engine. It is also possible that some of the MS3 solutions involve minor changes to cycle 

conditions which may have an adverse noise impact. However the probability that this would occur is 

considered rare (approx. 10%). It has been agreed that two possible scenarios may occur, with no 

preferred option, and that both should be analysed by MODTF and FESG. These include: 

• Firstly, 10% of the engines which include MS3 Mods. would incur a noise penalty of 

0.5dB at each of the three measurement points. Additional costs, associated with this 

noise increase would have to be taken into account in this case. 

• Secondly, that no noise penalty is expected even for the MS3 engines that require a cycle 

change. However, for these engines, which comprise 10% of the MS3 engines, estimates 

would need to be made for additional costs that manufacturers may incur in order to 

eliminate the noise penalty caused by the cycle change. 
A-7 

CAEP-SG/20082-WP/A 

Appendix A 

8. SUMMARY 

Modification 

Status Level Title 

NOx 

Improvement 

(%) 

Noise Impact 

(dB) 

Fuel Burn 

Impact (%) 

Cost 

Estimate 

($M) 

MS1 Minor Change 1-5% 0 0 10 

(1-15) 

MS2 Scaled Proven 

Technology 

Min. 6% 0 0 75 

(50-100) 

MS3 Combustor Technology 

from Research 

Programmes 

Min. 10% 0.5dB per 

cert. point for 

10% of 

engines 

0 – 0.5% 300 

(100-500) 

— — — — — — — — 

 
 

APPENDIX B

ASSUMPTIONS IN ASSESSING TECHNOLOGY RESPONSES TO NOX 

STRINGENCY OPTIONS 

Various simplifying assumptions have been taken in performing the NOx stringency technology response 

assessment. These underpinning assumptions are: 

 i) Engine technology response focused on combustor

Technology responses will be focused on combustor modifications, and associated modifications 

required physically to accommodate these combustor modifications (e.g. engine casings). 

Technology responses will not include additional engine performance improvements, which 

manufacturers would usually try to incorporate at the same time, for instance, to redress any 

deterioration in fuel burn or noise which the combustor modifications might create. Therefore, 

the group recognized that, associated with this assumption, there was the potential for a fuel burn 

and noise impact. 

The group agreed not to include the additional technology responses as they would require further 

assumptions on benefits and costs which, in the event they off-set each other, may not affect the 

overall ranking of the policy options. Fuel burn and noise improvements may be greater if the 

additional engine performance modifications were incorporated without the NOx combustor 

technology. 

The CAEP/6 fuel burn penalty of 2% was based on a similar assumption and Dual Annular 

Combustor (DAC) technical data, but this technology is not expected to be used in responses to a 

CAEP/8 standard. As such, an MS3 fuel burn penalty range of 0% to 0.5% was agreed by FESG 

and WG3, although the commercial unacceptability of increased fuel burn was noted. 

 ii) Constant %NOx reduction across the thrust curve

Combustor modifications are assumed to provide the same % improvements in engine NOx 

performance at all the four emissions certification thrust settings of 100, 85, 30 and 7%. 

 

 iii) No change in aircraft performance

Any changes in aircraft performance characteristics are assumed to be negligible. 

iv) MS categories applicable to all engines types 

Aircraft types covered in the CAEP/8 assessments range from large wide bodies to business jets. 

It is assumed that the proposed MS categories are equally applicable to all of these aircraft types 

in terms benefits and costs. 

v) No PM technology response 

The technology response assessment only considers affects on the source emissions of NOx, CO2 

and noise. WG3 does not have sufficient confidence to assess the affects on aircraft engine PM 

emissions and, as such, it does not form part of this analysis. 

 vi) Engine technology response is only developed to meet a stringency increase 

CAEP-SG/20082-WP/B 

Appendix B 
CAEP-SG/20082-WP/B 

Appendix B B-2 

Engine combustion technology will remain at its current state, that is, current engines will have 

the same NOx characteristics in 2020 as they do today unless they are changed to meet a 

stringency option. As a result, costs and benefits values reflect the effects of the stringency 

options alone. 

vii) Static aircraft mission and payload 

In order to preserve aircraft value and maximum operational utility, known engine technologies 

developed to meet stringency options should not compromise aircraft mission and payload. 

viii) Technology changes applied across engine family 

Production and in-development engine models, having a common build standard, will be grouped 

into engine families. If any engine model within a given engine family fails a given stringency 

option, then all the engine models within the family will receive the same level of technology 

insertion. This assumption is based on the need for fleet commonality amongst engines of 

differing thrust levels using the same combustor design to minimize manufacturer and operator 

costs, and has been demonstrated in practice. 

ix) Market-driven non-compliant engine production cut-off 

It is assumed that a market-driven production cut-off of non-compliant engines occurs on the date 

a CAEP/8 stringency option becomes effective. At that point, only previously compliant engines 

and those that have been made compliant are produced. Those in-production engines which are 

currently non-compliant with CAEP/6 will be considered on a case by case basis to see whether 

there is sufficient justification for them to respond to a CAEP/8 stringency option. 

— — — — — — — — 
APPENDIX C 

APPENDIX 3 - CAEP/8 LARGE ENGINE NOx STRINGENCY TECHNOLOGY RESPONSE S

Engine Family CAEP 6 Option 1 CAEP6- 5% Slope 2 Option 2 CAEP6- 10% Slope 2.2 Option 3 CAEP6- 10% Slope 2 Option 4 CAEP6- 15% Slope 2.2 Option 5 C

15% Slo

CF6-80C2 OK OK OK OK OK OK 

CF6-80E2 OK MS2 MS2 MS2 MS2 MS2 

CFM56-5B OK OK OK OK OK OK CFM56-5C OK MS2 MS2 MS2 MS2 MS2 CFM56-7B OK OK OK OK OK OK 

GE90-115B OK OK OK MS1 MS1 MS3 

GE90-94B (PEC) OK OK OK MS1 MS1 MS3 

GP7200 OK OK OK OK OK MS1 

PW4090 No response No response No response No response No response No resp

PW4168 Floatwall No response No response No response No response No response No resp

PW4168 TALON II OK OK OK OK OK OK 

PW4X62 MS1 MS2 MS2 MS2 MS2 MS2 

PW6120A OK OK OK OK OK OK 

RB211-524G/H-T OK OK OK No Response No Response No Resp

Trent 500 OK OK OK OK MS1 MS2 Trent 700 OK OK OK MS2 MS2 MS3 

Trent 800 OK OK No Response No Response No Response No RespTrent 900 OK OK OK OK OK OK 

V2500 OK MS2 MS2 MS2 MS2 MS2 

Total Engine Families 19 17 16 15 15 15 

OK 13 12 8 7 6 

MS1 0 0 2 3 1 MS2 4 4 5 5 5 MS3 0 0 0 0 3 

— — — — — — — — 
CAEP-SG/20082-WP/C 

Appendix C C-2 
APPENDIX D 

APPENDIX D – CAEP/8 SMALL ENGINE NOx STRINGENCY TECHNOLOGY RESPONSE 

Engine Family CAEP 6

Option 1 

CAEP/6 - 5% (26.7)

CAEP/6 - 5% (89)

Option 2

CAEP/6 - 5% (26.7)

CAEP/6 - 15% (89)

Option 3

CAEP/6 - 10% (26.7)

CAEP/6 - 10% (89)

Option 4

CAEP/6 - 10% (26.7)

CAEP/6 - 20% (89)

Option 5

CAEP/6 - 15% (26.7)

CAEP/6 - 15% (89)

Opt

CAEP/6 - 

CAEP/6 

AE3007A1E OK OK OK OK OK OK O

AE3007C / C1 OK OK OK OK OK OK O

AS907-1-1A MS1 MS1 MS1 MS1 MS1 MS2 M

BR710-A2-20 OK OK OK OK MS1 MS1 M

BR710-C4-11 OK OK OK OK OK OK M

BR725 OK OK OK OK OK OK O

Tay 611-8C MS1 No Response No Response No Response No Response No Response No Re

CF34-3 OK OK OK OK OK OK OCF34-8 OK OK OK OK OK OK O

CF34-10 OK OK OK OK MS1 OK M

CFM56-7B OK OK OK OK OK OK O

PW306A OK OK MS2 MS2 MS2 MS2 MPW307A OK OK OK OK OK OK O

PW308C OK OK OK OK OK OK O

Total Engine Families 14 13 13 13 13 13 

OK 12 11 11 9 10 

MS1 1 1 1 3 1 MS2 0 1 1 1 2 MS3 0 0 0 0 0 

— — — — — — — — 
"In-production" large engine types with current airframe application in NoisedB CAEP/8 NOx stringency options

1 (-5% and 2 for OPR>30) 2 (-10% and 2.2 for OPR>30) 3 (-10% and 2 for OPR>30) 4 (-15% and 2.2 for OPR>30) 5 (-15% and 2 

EED UID EED Engine EED Combustor EED PR

EED

FooKN

EED NOx

Charac.

Level

CAEP/6

NOx

Limit

EED % to

CAEP/6

Limit

Engine

family no.

EstimatedEED NOx

Charac. Level

Estimated

EED % to

CAEP/6 Limit

Respond to

CAEP/8 NOx

standard?

Option 1

NOx limit

% to Option 1

NOx limit

MS Mod.

(1, 2 or 3)

Revised EED

NOx Charac.

Level

Revised % to

Option 1 NOx

limit Comments

Option 2

NOx limit

% to Option 2

NOx limit

MS Mod.

(1, 2 or 3)

Revised EED

NOx Charac.

Level

Revised % to

Option 2 NOx

limit Comments

Option 3

NOx limit

% to Option 3

NOx limit

MS Mod.

(1, 2 or 3)

Revised EED

NOx Charac.

Level

Revised % to

Option 3 NOx

limit Comments

Option 4

NOx limit

% to Option 4

NOx limit

MS Mod.

(1, 2 or 3)

Revised EED

NOx Charac.

Level

Revised % to

Option 4 NOx

limit Comments

Option 5

NOx limit

% to O

NOx 

2GE045 CF6-80C2B1F 1862M39 30.13 254.26 48.04 59.22 81.13 1 Yes 56.27 85.38 Complies 53.35 90.06 Complies 53.32 90.10 Complies 50.41 95.31 Complies 50.38 

2GE042 CF6-80C2B2 1862M39 27.53 231.08 43.66 55.48 78.68 1 Yes 52.53 83.10 Complies 49.58 88.05 Complies 49.58 88.05 Complies 46.64 93.60 Complies 46.64 

2GE046 CF6-80C2B2F 1862M39 27.60 231.35 43.69 55.58 78.60 1 Yes 52.63 83.01 Complies 49.68 87.94 Complies 49.68 87.94 Complies 46.74 93.47 Complies 46.74 

2GE043 CF6-80C2B4 1862M39 30.14 254.35 48.52 59.24 81.90 1 Yes 56.29 86.19 Complies 53.37 90.91 Complies 53.34 90.96 Complies 50.43 96.21 Complies 50.40 

2GE047 CF6-80C2B4F 1862M39 30.22 254.79 48.05 59.40 80.90 1 Yes 56.45 85.13 Complies 53.54 89.75 Complies 53.50 89.82 Complies 50.60 94.96 Complies 50.56 3GE057 CF6-80C2B5F 1862M39 32.82 272.53 53.00 64.60 82.04 1 Yes 61.65 85.97 Complies 59.26 89.43 Complies 58.70 90.29 Complies 56.32 94.10 Complies 55.76 

2GE044 CF6-80C2B6 1862M39 31.66 267.20 52.01 62.28 83.51 1 Yes 59.33 87.67 Complies 56.71 91.71 Complies 56.38 92.25 Complies 53.77 96.73 Complies 53.44 

2GE048 CF6-80C2B6F 1862M39 31.72 267.03 51.14 62.40 81.96 1 Yes 59.45 86.03 Complies 56.84 89.97 Complies 56.50 90.52 Complies 53.90 94.88 Complies 53.56 2GE055 CF6-80C2B7F 1862M39 31.72 267.03 51.14 62.40 81.96 1 Yes 59.45 86.03 Complies 56.84 89.97 Complies 56.50 90.52 Complies 53.90 94.88 Complies 53.56 8GE101 CF6-80C2B8F 1862M39 31.37 267.00 48.35 61.70 78.36 1 Yes 58.75 82.30 Complies 56.07 86.23 Complies 55.80 86.65 Complies 53.13 91.00 Complies 52.86 

1GE033 CF6-80E1A2 33.08 287.00 62.06 65.12 95.31 2 Yes 62.17 99.83 2 51.57 82.96 Insertion of advanced combustor 59.84 103.72 2 51.57 86.19 Insertion of advanced combustor 59.22 104.80 2 51.57 87.09 Insertion of advanced combustor 56.90 109.08 2 51.57 90.65 Insertion of advanced combustor 56.28 

5GE085 CF6-80E1A3 Standard 35.70 304.80 65.80 70.36 93.52 2 Yes 67.41 97.61 2 54.19 80.39 Insertion of advanced combustor 65.60 100.30 2 54.19 82.61 Insertion of advanced combustor 64.46 102.08 2 54.19 84.07 Insertion of advanced combustor 62.66 105.01 2 54.19 86.48 Insertion of advanced combustor 61.52 4GE080 CF6-80E1A4 Standard 34.50 297.44 66.74 67.96 98.20 2 Yes 65.01 102.66 2 55.64 85.59 Insertion of advanced combustor 62.96 106.00 2 55.64 88.38 Insertion of advanced combustor 62.06 107.54 2 55.64 89.66 Insertion of advanced combustor 60.02 111.20 2 55.64 92.71 Insertion of advanced combustor 59.12 8CM052 CFM56-5B1/3 Tech Insertion 30.20 133.40 45.60 59.36 76.82 3 Yes 56.41 80.84 Complies 53.50 85.23 Complies 53.46 85.30 Complies 50.56 90.19 Complies 50.52 

8CM053 CFM56-5B2/3 Tech Insertion 31.30 137.90 48.20 61.56 78.30 3 Yes 58.61 82.24 Complies 55.92 86.19 Complies 55.66 86.60 Complies 52.98 90.98 Complies 52.72 

8CM054 CFM56-5B3/3 Tech Insertion 32.60 142.30 51.20 64.16 79.80 3 Yes 61.21 83.65 Complies 58.78 87.10 Complies 58.26 87.88 Complies 55.84 91.69 Complies 55.32 

8CM055 CFM56-5B4/3 Tech Insertion 27.30 120.10 39.80 55.16 72.16 3 Yes 52.21 76.23 Complies 49.26 80.80 Complies 49.26 80.80 Complies 46.32 85.93 Complies 46.32 

8CM056 CFM56-5B5/3 Tech Insertion 23.10 97.90 33.00 49.24 67.01 3 Yes 46.29 71.28 Complies 43.34 76.13 Complies 43.34 76.13 Complies 40.40 81.67 Complies 40.40 

8CM057 CFM56-5B6/3 Tech Insertion 24.30 104.50 34.80 50.93 68.32 3 Yes 47.98 72.52 Complies 45.03 77.27 Complies 45.03 77.27 Complies 42.09 82.67 Complies 42.09 

8CM058 CFM56-5B7/3 Tech Insertion 27.30 120.10 39.80 55.16 72.16 3 Yes 52.21 76.23 Complies 49.26 80.80 Complies 49.26 80.80 Complies 46.32 85.93 Complies 46.32 

8CM059 CFM56-5B8/3 Tech Insertion 22.70 96.10 32.50 48.68 66.76 3 Yes 45.73 71.07 Complies 42.78 75.97 Complies 42.78 75.97 Complies 39.84 81.57 Complies 39.84 

8CM060 CFM56-5B9/3 Tech Insertion 24.20 103.60 34.50 50.79 67.92 3 Yes 47.84 72.11 Complies 44.89 76.85 Complies 44.89 76.85 Complies 41.95 82.23 Complies 41.95 

7CM047 CFM56-5C4/P SAC 30.50 149.90 59.00 59.96 98.40 4 Yes 57.01 103.49 2 47.06 82.55 Insertion of advanced combustor 54.16 108.94 2 47.06 86.90 Insertion of advanced combustor 54.06 109.14 2 47.06 87.06 Insertion of advanced combustor 51.22 115.19 2 47.06 91.88 Insertion of advanced combustor 51.12 

8CM062 CFM56-7B20/3 Tech Insertion 22.40 91.60 34.50 48.26 71.49 5 Yes 45.31 76.14 Complies 42.36 81.45 Complies 42.36 81.45 Complies 39.42 87.52 Complies 39.42 

8CM063 CFM56-7B22/3 Tech Insertion 24.20 101.00 37.10 50.79 73.04 5 Yes 47.84 77.54 Complies 44.89 82.64 Complies 44.89 82.64 Complies 41.95 88.43 Complies 41.95 

8CM064 CFM56-7B24/3 Tech Insertion 25.60 107.60 39.30 52.76 74.48 5 Yes 49.81 78.89 Complies 46.86 83.86 Complies 46.86 83.86 Complies 43.92 89.47 Complies 43.92 

8CM065 CFM56-7B26/3 Tech Insertion 27.70 117.00 43.10 55.72 77.35 5 Yes 52.77 81.67 Complies 49.82 86.51 Complies 49.82 86.51 Complies 46.88 91.93 Complies 46.88 

8CM066 CFM56-7B27/3 Tech Insertion 29.00 121.40 45.60 57.55 79.23 5 Yes 54.60 83.51 Complies 51.65 88.28 Complies 51.65 88.28 Complies 48.71 93.61 Complies 48.71 

7GE097 GE90-110B1 DAC 39.73 492.60 72.04 78.42 91.86 6 Yes 75.47 95.46 Complies 74.47 96.74 Complies 72.52 99.34 1 68.72 94.76 Additional engine tests / small improvements 71.53 100.72 1 68.72 96.07 Additional engine tests / small improvements 69.58 

7GE099 GE90-115B DAC 42.24 513.90 78.70 83.44 94.32 6 Yes 80.49 97.78 Complies 79.99 98.39 Complies 77.54 101.50 1 75.12 96.88 Additional engine tests / small improvements 77.05 102.14 1 75.12 97.50 Additional engine tests / small improvements 74.60 3GE062 GE90-76B DAC II 35.10 360.62 57.80 69.16 83.57 7 52.63 76.10 Yes 66.21 79.49 Complies 64.28 81.88 Complies 63.26 83.20 1 48.81 77.16 Additional engine tests / small improvements 61.34 85.80 1 48.81 79.57 Additional engine tests / small improvements 60.32 

5GE086 GE90-76B 34.88 360.60 62.36 68.72 90.75 7 57.22 83.27 Yes 65.77 87.01 Complies 63.80 89.70 Complies 62.82 91.09 1 53.43 85.06 Additional engine tests / small improvements 60.86 94.03 1 53.43 87.80 Additional engine tests / small improvements 59.88 

6GE087 GE90-76B DAC II 34.88 360.60 62.36 68.72 90.75 7 57.22 83.27 Yes 65.77 87.01 Complies 63.80 89.70 Complies 62.82 91.09 1 53.43 85.06 Additional engine tests / small improvements 60.86 94.03 1 53.43 87.80 Additional engine tests / small improvements 59.88 

3GE063 GE90-77B DAC II 35.30 363.42 58.30 69.56 83.81 7 53.10 76.34 Yes 66.61 79.72 Complies 64.72 82.05 Complies 63.66 83.41 1 49.25 77.37 Additional engine tests / small improvements 61.78 85.95 1 49.25 79.72 Additional engine tests / small improvements 60.72 

6GE088 GE90-77B DAC II 35.11 363.40 62.97 69.18 91.02 7 57.80 83.55 Yes 66.23 87.27 Complies 64.30 89.89 Complies 63.28 91.34 1 53.98 85.30 Additional engine tests / small improvements 61.36 94.19 1 53.98 87.96 Additional engine tests / small improvements 60.34 

3GE064 GE90-85B DAC II 38.00 395.31 65.60 74.96 87.51 7 60.00 80.04 Yes 72.01 83.32 Complies 70.66 84.91 Complies 69.06 86.88 1 55.78 80.77 Additional engine tests / small improvements 67.72 88.60 1 55.78 82.37 Additional engine tests / small improvements 66.12 

6GE089 GE90-85B DAC II 37.65 395.30 70.88 74.26 95.45 7 65.33 87.97 Yes 71.31 91.61 Complies 69.89 93.47 Complies 68.36 95.57 1 61.16 89.47 Additional engine tests / small improvements 66.95 97.58 1 61.16 91.35 Additional engine tests / small improvements 65.42 

3GE065 GE90-90B DAC II 39.80 418.13 72.10 78.56 91.78 7 66.23 84.30 Yes 75.61 87.59 Complies 74.62 88.75 Complies 72.66 91.15 1 61.76 85.00 Additional engine tests / small improvements 71.68 92.39 1 61.76 86.16 Additional engine tests / small improvements 69.72 

6GE090 GE90-90B DAC II 39.38 418.10 77.41 77.72 99.60 7 71.60 92.13 Yes 74.77 95.76 Complies 73.70 97.16 Complies 71.82 99.69 1 67.19 93.56 Additional engine tests / small improvements 70.76 101.19 1 67.19 94.96 Additional engine tests / small improvements 68.88 

8GE100 GE90-94B DAC II 40.53 432.80 82.00 80.02 102.47 7 76.02 95.00 Yes (1) 77.07 98.64 Complies 76.23 99.73 Complies 74.12 102.56 1 71.45 96.40 Additional engine tests / small improvements 73.29 103.73 1 71.45 97.5 Additional engine tests / small improvements 71.18 

9EA001 GP7270 / 7270E - 36.62 332.40 61.77 72.16 85.60 8 Yes 69.25 89.20 Complies 67.62 91.35 Complies 66.26 93.22 Complies 64.68 95.50 Complies 63.32 

9EA002 GP7277 / 7277E - 38.98 357.10 69.24 76.93 90.00 8 Yes 73.97 93.60 Complies 72.82 95.08 Complies 71.03 97.48 Complies 69.88 99.08 Complies 68.09 2PW060 PW4074 32.20 333.20 62.80 63.36 99.12 9 No 60.41 103.96 57.90 108.46 57.46 109.29 54.96 114.26 54.52 

2PW061 PW4077 33.20 343.00 65.30 65.36 99.91 9 No 62.41 104.63 60.10 108.65 59.46 109.82 57.16 114.24 56.52 

3PW064 PW4077D 32.83 343.00 72.80 64.62 112.66 9 No 61.67 118.05 59.29 122.79 58.72 123.98 56.35 129.20 55.78 3PW065 PW4084D 36.36 369.60 83.60 71.68 116.63 9 No 68.73 121.64 67.05 124.68 65.78 127.09 64.11 130.40 62.84 3PW066 PW4090 39.16 395.00 92.80 77.28 120.08 9 No (2) 74.33 124.85 73.21 126.76 71.38 130.01 70.27 132.06 68.44 1PW049 PW4164 Floatwall 31.24 284.68 70.13 61.44 114.14 10 No 58.49 119.90 55.79 125.71 55.54 126.27 52.85 132.70 52.60 1PW050 PW4168 Floatwall 33.10 302.48 75.58 65.16 115.99 10 No 62.21 121.49 59.88 126.21 59.26 127.53 56.94 132.73 56.32 4PW067 PW4168A Floatwall 33.10 302.48 75.60 65.16 116.02 10 No (3) 62.21 121.52 59.88 126.25 59.26 127.57 56.94 132.77 56.32 

7PW081 PW4164 Talon II 30.10 284.68 49.50 59.16 83.67 11 Yes 56.21 88.06 Complies 53.28 92.91 Complies 53.26 92.94 Complies 50.34 98.33 Complies 50.32 

5PW075 PW4168 Talon II 31.84 302.50 53.32 62.64 85.12 11 Yes 59.69 89.33 Complies 57.11 93.37 Complies 56.74 93.97 Complies 54.17 98.43 Complies 53.80 7PW082 PW4168A Talon II 31.84 302.50 53.30 62.64 85.09 11 Yes 59.69 89.29 Complies 57.11 93.33 Complies 56.74 93.94 Complies 54.17 98.40 Complies 53.80 1PW054 PW4x52 Phase 3 26.32 231.30 52.39 53.78 97.42 12 Yes 50.83 103.08 2 40.68 80.03 Insertion of Talon II combustor 47.88 109.43 2 40.68 84.97 Insertion of Talon II combustor 47.88 109.43 2 40.68 84.97 Insertion of Talon II combustor 44.94 116.59 2 40.68 90.52 Insertion of Talon II combustor 44.94 

1PW055 PW4x56 Phase 3 28.37 249.10 57.03 56.66 100.64 12 Yes 53.71 106.17 2 44.56 82.96 Insertion of Talon II combustor 50.76 112.34 2 44.56 87.79 Insertion of Talon II combustor 50.76 112.34 2 44.56 87.79 Insertion of Talon II combustor 47.82 119.25 2 44.56 93.18 Insertion of Talon II combustor 47.82 1PW057 PW4x60 Phase 3 30.68 266.90 63.06 60.32 104.54 12 Yes 57.37 109.91 2 49.64 86.52 Insertion of Talon II combustor 54.56 115.58 2 49.64 90.99 Insertion of Talon II combustor 54.42 115.87 2 49.64 91.22 Insertion of Talon II combustor 51.62 122.17 2 49.64 96.17 Insertion of Talon II combustor 51.48 1PW059 PW4x62 Phase 3 31.91 275.80 66.65 62.78 106.17 12 Yes (4) 59.83 111.40 2 52.59 87.90 Insertion of Talon II combustor 57.26 116.40 2 52.59 91.84 Insertion of Talon II combustor 56.88 117.18 2 52.59 92.46 Insertion of Talon II combustor 54.32 122.70 2 52.59 96.81 Insertion of Talon II combustor 53.94 

7PW083 PW6122A Talon II 25.70 98.31 38.10 52.91 72.02 13 Yes 49.96 76.27 Complies 47.01 81.05 Complies 47.01 81.05 Complies 44.07 86.46 Complies 44.07 

7PW084 PW6124A Talon II 28.00 105.87 45.70 56.14 81.40 13 Yes 53.19 85.91 Complies 50.24 90.96 Complies 50.24 90.96 Complies 47.30 96.61 Complies 47.30 

4RR036 RB211-524G-T 32.10 253.00 57.29 63.16 90.71 14 No 60.21 95.15 Complies 57.68 99.32 Complies 57.26 100.05 54.74 104.66 54.32 

4RR037 RB211-524H-T 34.00 264.00 61.54 66.96 91.91 14 No (5) 64.01 96.14 Complies 61.86 99.48 Complies 61.06 100.79 58.92 104.45 58.12 8RR044 Trent 553-61 Phase5 Tiled 35.19 251.90 60.70 69.34 87.54 15 Yes 66.39 91.43 Complies 64.48 94.14 Complies 63.44 95.68 Complies 61.54 98.64 1 58.98 95.84 Optimisation improvements 60.50 

8RR045 Trent 556-61 Phase5 Tiled 36.63 263.90 64.90 72.22 89.86 15 Yes 69.27 93.69 Complies 67.65 95.94 Complies 66.32 97.86 Complies 64.71 100.30 1 63.09 97.5 Optimisation improvements 63.38 3RR029 Trent 768 Improved traverse 34.00 300.30 60.50 66.96 90.35 16 Yes 64.01 94.52 Complies 61.86 97.80 Complies 61.06 99.08 2 56.76 92.96 Optimised Phase 5 design as per T900 58.92 102.68 2 56.76 96.33 Optimised Phase 5 design as per T900 58.12 3RR030 Trent 772 Improved traverse 35.80 316.30 65.30 70.56 92.55 16 Yes 67.61 96.58 Complies 65.82 99.21 Complies 64.66 100.99 2 61.31 94.82 Optimised Phase 5 design as per T900 62.88 103.85 2 61.31 97.50 Optimised Phase 5 design as per T900 61.72 2RR024 Trent 875 35.42 351.85 57.82 69.80 82.84 16 No 66.85 86.49 Complies 64.98 88.98 63.90 90.49 62.04 93.19 60.96 

2RR025 Trent 877 36.30 361.64 60.07 71.56 83.94 16 No 68.61 87.55 Complies 66.92 89.76 65.66 91.49 63.98 93.89 62.72 

2RR026 Trent 884 38.96 390.10 67.23 76.88 87.45 16 No 73.93 90.94 Complies 72.77 92.38 70.98 94.72 69.83 96.27 68.04 

2RR027 Trent 892 41.38 411.48 74.20 81.72 90.80 16 No 78.77 94.20 Complies 78.10 95.01 75.82 97.86 75.16 98.73 72.88 5RR040 Trent 895 41.52 413.05 78.60 82.00 95.85 16 No (6) 79.05 99.43 Complies 78.40 100.25 76.10 103.29 75.46 104.16 73.16 8RR046 Trent 970-84 Phase5 Tiled 38.97 334.70 57.40 76.90 74.64 17 Yes 73.95 77.62 Complies 72.79 78.85 Complies 71.00 80.85 Complies 69.85 82.17 Complies 68.06 

9RR047 Trent 972-84 Phase5 Tiled 38.64 345.90 58.10 76.25 76.20 17 Yes 73.29 79.27 Complies 72.07 80.62 Complies 70.35 82.59 Complies 69.13 84.05 Complies 67.41 

9RR048 Trent 972B-84 Phase5 Tiled 40.16 361.50 62.10 79.31 78.30 17 Yes 76.33 81.36 Complies 75.41 82.35 Complies 73.41 84.59 Complies 72.47 85.69 Complies 70.47 

3IA006 V2522-A5 25.60 102.66 53.32 52.76 101.05 18 47.55 90.11 Yes 49.81 95.44 2 40.90 82.11 Insertion of Talon II combustor 46.86 101.45 2 40.90 87.28 Insertion of Talon II combustor 46.86 101.45 2 40.90 87.28 Insertion of Talon II combustor 43.92 108.24 2 40.90 93.12 Insertion of Talon II combustor 43.92 3IA007 V2524-A5 26.90 109.06 56.10 54.60 102.76 18 50.12 91.81 Yes 51.65 97.06 2 43.21 83.66 Insertion of Talon II combustor 48.70 102.94 2 43.21 88.73 Insertion of Talon II combustor 48.70 102.94 2 43.21 88.73 Insertion of Talon II combustor 45.76 109.55 2 43.21 94.43 Insertion of Talon II combustor 45.76 1IA003 V2527-A5 27.20 111.20 56.22 55.02 102.18 18 50.20 91.24 Yes 52.07 96.41 2 43.21 83.00 Insertion of Talon II combustor 49.12 102.20 2 43.21 87.98 Insertion of Talon II combustor 49.12 102.20 2 43.21 87.98 Insertion of Talon II combustor 46.18 108.70 2 43.21 93.58 Insertion of Talon II combustor 46.18 8IA010 V2527E-A5 27.20 111.20 56.20 55.02 102.15 18 50.18 91.20 Yes 52.07 96.37 2 43.20 82.96 Insertion of Talon II combustor 49.12 102.16 2 43.20 87.94 Insertion of Talon II combustor 49.12 102.16 2 43.20 87.94 Insertion of Talon II combustor 46.18 108.66 2 43.20 93.54 Insertion of Talon II combustor 46.18 8IA09 V2527M-A5 27.20 111.20 56.20 55.02 102.15 18 50.18 91.20 Yes 52.07 96.37 2 43.20 82.96 Insertion of Talon II combustor 49.12 102.16 2 43.20 87.94 Insertion of Talon II combustor 49.12 102.16 2 43.20 87.94 Insertion of Talon II combustor 46.18 108.66 2 43.20 93.54 Insertion of Talon II combustor 46.18 1IA005 V2530-A5 32.10 133.40 67.23 63.16 106.45 18 60.32 95.50 Yes 60.21 100.18 2 52.10 86.54 Insertion of Talon II combustor 57.68 104.57 2 52.10 90.33 Insertion of Talon II combustor 57.26 105.34 2 52.10 91.00 Insertion of Talon II combustor 54.74 110.19 2 52.10 95.19 Insertion of Talon II combustor 54.32 3IA008 V2533-A5 33.44 140.56 71.40 65.84 108.44 18 64.19 97.5 Yes (7) 62.89 102.07 2 55.58 88.37 Insertion of Talon II combustor 60.63 105.88 2 55.58 91.67 Insertion of Talon II combustor 59.94 107.10 2 55.58 92.72 Insertion of Talon II combustor 57.69 111.28 2 55.58 96.34 Insertion of Talon II combustor 57.00 

Column L Notes

(1) Engine Family 7 (GE90-94) - PEC performance improvement package due to be certified soon with an assumed 5% CAEP/6 margin for the highest rated engine. Subesequent CAEP/8 technology responses are based on this.

(2) Engine Family 9 (PW4090) - not expected to respond to CAEP/8 standard. Needs to be considered in the FESG CAEP/6 production cut-off analysis

(3) Engine Family 10 (PW4160 Foatwall) - not expected to respond to CAEP/8 standard as PW4160 TALON II engne types already exist. Needs to be considered in the FESG CAEP/6 production cut-off analysis.

(4) Engine Family 12 (PW4x00 Phase 3) - no improvement package anticipated at present to make it compliant with CAEP/6 but expected to respond to CAEP/8 options

(5) Engine family 14 (RB211-524) - not expected to respond to CAEP/8 standard. Does not need to be considered in the FESG CAEP/6 production cut-off analysis

(6) Engine family 16 (Trent 800) - not expected to respond to CAEP/8 standard. Does not need to be considered in the FESG CAEP/6 production cut-off analysis.

(7) Engine Family 18 (V2500) - SELECT1 performance improvement package due to be certified during 2008 with an assumed 2.5% CAEP/6 margin for the highest rated engine. Subesequent CAEP/8 technology responses are based on this.
"In-production" small engine types with current airframe application in NoisedB CAEP/8 NOx stringency options

1 (-5% at 26.7kN / -5% at 89kN) 2 (-5% / -15%) 3 (-10% / -10%) 4 (-10% / -20%) 5 (-15% / -15%) 

EED UID EED Engine EED Combustor EED PR

EED

FooKN

EED NOx

Charac. Level

CAEP/6 NOx

Limit

EED % to

CAEP/6 Limit

Engine family

no.

Estimated

EED NOx

Charac. Level

Estimated EED

% to CAEP/6

Limit

Respond to

CAEP/8 NOx

standard?

Option 1

NOx limit

% to Option 1

NOx limit

MS Mod.

(1, 2 or 3)

EED NOx

Charac.

Level

Revised % to

Option 1 NOx

limit Comments

Option 5

NOx limit

% to Option 5

NOx limit

MS Mod.

(1, 2 or 3)

EED NOx

Charac.

Level

Revised %

to Option 2

NOx limit Comments

Option 2

NOx limit

% to Option 2

NOx limit

MS Mod. (1,

2 or 3)

EED NOx

Charac.

Level

Revised % to

Option 3 NOx

limit Comments

Option 6

NOx limit

% to Option 6

NOx limit

MS Mod.

(1, 2 or 3)

EED NOx

Charac.

Level

Revised %

to Option 4

NOx limit Comments

Option 3

NOx limit

% to Option

3 NOx limit

MS Mod.

(1, 2 or 3)

EED NOx

Charac.

Level

Revised % to

Option 5 NOx

limit Comments

6AL007 AE3007A1 Type 3 (reduced emissi1o7n.s9)7 34.91 44.62 58.28 76.56 1 Yes 55.26 80.75 Complies 54.48 81.90 Complies 52.24 85.42 Complies 51.46 86.71 Complies 49.21 90.68 Complies 

6AL010 AE3007A1/1 Type 3 (reduced emissi1o7n.s9)0 34.74 44.49 58.22 76.41 1 Yes 55.20 80.59 Complies 54.44 81.72 Complies 52.19 85.25 Complies 51.42 86.52 Complies 49.16 90.50 Complies 6AL013 AE3007A1/3 Type 3 (reduced emissi1o7n.s2)2 33.05 43.65 57.66 75.71 1 Yes 54.68 79.82 Complies 54.08 80.71 Complies 51.71 84.41 Complies 51.11 85.41 Complies 48.73 89.57 Complies 6AL020 AE3007A1E Type 3 19.06 37.16 46.81 59.32 78.92 1 Yes 56.22 83.26 Complies 55.23 84.75 Complies 53.13 88.10 Complies 52.14 89.78 Complies 50.03 93.56 Complies 6AL019 AE3007A3 Type 3 (reduced emissi1o7n.s2)0 33.00 43.26 57.64 75.05 1 Yes 54.67 79.13 Complies 54.07 80.00 Complies 51.70 83.68 Complies 51.10 84.66 Complies 48.72 88.79 Complies 6AL024 AE3007C1 Type 2 16.58 31.46 46.55 57.12 81.50 2 Yes 54.19 85.90 Complies 53.74 86.62 Complies 51.26 90.80 Complies 50.81 91.61 Complies 48.33 96.31 Complies 

8HN001 AS907-1-1A 21.95 30.62 66.26 65.89 100.56 3 Yes (1) 62.56 105.91 1 57.39 91.74 Additional engine tests / control changes 62.19 106.54 1 57.39 92.28 Additional engine tests / control changes 59.24 111.86 1 57.39 96.89 Additional engine tests / control changes 58.86 112.56 1 57.39 97.5 Additional engine tests / control changes 55.90 118.53 2 51.26 91.69 Inclusion of best practise RQL c

4BR009 BR700-710A2-20 24.16 65.61 49.25 58.22 84.60 4 Yes 55.05 89.47 Complies 51.37 95.88 Complies 51.89 94.91 Complies 48.20 102.17 1 47.00 97.5 Additional engine tests / small improvements 48.71 101.11 1 47.00 96.48 Additional engine tests / small im6BR010 BR700-710-C4-11 Annular 24.95 68.77 48.00 58.37 82.24 5 Yes 55.21 86.95 Complies 51.23 93.70 Complies 52.06 92.20 Complies 48.07 99.85 Complies 48.89 98.18 Complies 1GE035 CF34-3A1 LEC II 19.70 41.01 32.22 59.14 54.49 6 Yes 56.02 57.53 Complies 54.66 58.95 Complies 52.90 60.92 Complies 51.54 62.52 49.77 64.75 Complies 

5GE084 CF34-3B 19.30 41.01 30.50 58.52 52.12 6 Yes 55.42 55.04 Complies 54.07 56.41 Complies 52.33 58.29 Complies 50.97 59.84 49.22 61.97 Complies 5GE083 CF34-8C1 23.03 56.36 43.10 59.47 72.47 7 Yes 56.26 76.61 Complies 53.45 80.63 Complies 53.06 81.23 Complies 50.25 85.77 49.85 86.47 Complies 6GE096 CF34-8C1 Block 1 LEC 22.15 56.36 40.90 58.14 70.35 7 Yes 54.97 74.41 Complies 52.16 78.41 Complies 51.81 78.95 Complies 49.00 83.47 48.63 84.11 Complies 

8GE110 CF34-8C5 LEC 23.09 59.42 43.02 58.59 73.43 7 Yes 55.40 77.65 Complies 52.31 82.24 Complies 52.23 82.37 Complies 49.13 87.57 49.03 87.74 Complies 8GE107 CF34-8C5A1 LEC 23.49 60.62 43.73 58.81 74.36 7 Yes 55.62 78.63 Complies 52.41 83.44 Complies 52.44 83.39 Complies 49.22 88.84 49.24 88.81 Complies 8GE112 CF34-8C5B1 LEC 22.08 56.35 41.35 58.04 71.23 7 Yes 54.87 75.35 Complies 52.07 79.40 Complies 51.72 79.95 Complies 48.91 84.54 48.54 85.18 Complies 8GE108 CF34-8E5 LEC 23.18 59.68 43.18 58.64 73.63 7 Yes 55.45 77.86 Complies 52.33 82.51 Complies 52.28 82.60 Complies 49.15 87.85 49.08 87.97 Complies 

8GE105 CF34-8E5A1 LEC 24.12 62.49 44.87 59.15 75.86 7 Yes 55.96 80.19 Complies 52.57 85.35 Complies 52.77 85.03 Complies 49.38 90.87 49.57 90.53 Complies 8GE115 CF34-10E5 SAC 25.60 77.40 43.02 56.53 76.10 8 Yes 53.44 80.49 Complies 48.65 88.43 Complies 50.38 85.39 Complies 45.58 94.39 1 40.49 88.85 Additional engine tests / small improvements 47.29 90.97 Complies 8GE117 CF34-10E5A1 SAC 27.30 83.70 46.26 56.91 81.29 8 Yes 53.88 85.85 Complies 48.49 95.40 Complies 50.88 90.92 Complies 45.48 101.71 1 43.70 96.09 Additional engine tests / small improvements 47.84 96.69 Complies 

8GE116 CF34-10E6 SAC 25.60 77.40 43.02 56.53 76.10 8 Yes 53.44 80.49 Complies 48.65 88.43 Complies 50.38 85.39 Complies 45.58 94.39 1 40.49 88.85 Additional engine tests / small improvements 47.29 90.97 Complies 8GE118 CF34-10E6A1 SAC 27.30 83.70 46.26 56.91 81.29 8 Yes 53.88 85.85 Complies 48.49 95.40 Complies 50.88 90.92 Complies 45.48 101.71 1 43.70 96.09 Additional engine tests / small improvements 47.84 96.69 Complies 8GE119 CF34-10E7 SAC 27.30 83.70 46.26 56.91 81.29 8 Yes 53.88 85.85 Complies 48.49 95.40 Complies 50.88 90.92 Complies 45.48 101.71 1 43.70 96.09 Additional engine tests / small improvements 47.84 96.69 Complies 8CM061 CFM56-7B18/3 Tech Insertion 21.40 86.70 33.30 47.57 70.01 9 Yes 44.60 74.66 Complies 38.93 85.54 Complies 41.65 79.94 Complies 35.97 92.57 Complies 38.68 86.09 Complies 7PW077 PW306A Annular 20.00 26.87 58.90 63.95 92.11 10 Yes 60.75 96.96 Complies 60.73 96.98 Complies 57.55 102.34 2 49.87 86.65 Inclusion of advanced combustor 57.54 102.37 2 49.87 86.68 Inclusion of advanced combustor 54.35 108.37 2 49.87 91.76 Inclusion of advanced comb8PW091 PW307A TALON II 20.21 28.49 42.90 63.79 67.26 11 Yes 60.58 70.82 Complies 60.41 71.02 Complies 57.37 74.78 Complies 57.20 75.00 Complies 54.16 79.21 Complies 7PW080 PW308C Annular 20.70 31.15 48.10 63.75 75.46 12 Yes 60.51 79.49 Complies 60.09 80.05 Complies 57.28 83.97 Complies 56.86 84.60 Complies 54.04 89.00 Complies 

6RR042 TAY 611-8C Transply IIJ 15.75 61.61 48.21 46.94 102.70 13 45.77 97.5 No (2) 44.03 103.95 40.73 112.37 41.13 111.28 37.82 121.01 38.21 119.77 Column K Notes(1) AS907-1-1A does not comply with CAEP/6 standard but could following minor additional engine tests. The MS1 Mod. response associated with CAEP/8 standard would involve considerably more improvements.(2) Tay 611-8C additional engine tests / small improvements expected to make it compliant with CAEP/6. Do not need to include in FESG production cut-off analaysis

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