(99 pages)

CAEP.6.IP.013.1.en.wpd

CAEP/6-IP/13

15/1/04

COMMITTEE ON AVIATION ENVIRONMENTAL PROTECTION

SIXTH MEETING

Montreal, 2 to 12 February 2004

Agenda Item 1

:

Review of proposals relating to aircraft engine emissions, including the

amendment of Annex 16, Volume II

ECONOMIC ANALYSIS OF NOx EMISSIONS STRINGENCY

OPTIONS

(Presented by the Forecasting and Economic Analysis Support Group)

SUMMARY

This Information Paper is the full report of the economic analysis of NOx

stringency options on which CAEP/6-WP/19 is based.
CAEP/6-IP/13 - 2 -

1. INTRODUCTION ....................................................... 4

2. SCOPE AND LIMITATIONS OF THE ECONOMIC ANALYSIS ................. 4

3. KEY MODELS, DATABASES AND METHODS .............................. 6

3.1 Models for the assessment of NOx stringency options ......................... 6

3.2 Databases used for the assessment of NOx stringency options ................... 8

3.3 Methods used in the economic analysis ................................... 10

4. MODELLING ASSUMPTIONS .......................................... 13

4.2 FESG fleet forecast assumptions ....................................... 13

4.3 FESG EDMS assumptions ............................................ 15

5. BENEFITS ASSESSMENT OF STRINGENCY OPTIONS ...................... 21

5.2 Base-case results .................................................. 21

5.3 2002-2020 NOx stringency options results ................................ 22

5.4 2002-2030 NOx stringency options results ................................ 23

5.5 Ranking of 200-2020 and 2002-2030 cumulative LTO NOx benefits .............. 24

5.6 Emissions trade-offs ................................................ 24

6. ANALYSIS OF COSTS OF STRINGENCY OPTIONS ......................... 25

6.4 Non-recurring costs of technology improvements ........................... 25

6.5 Recurring costs due to stringency levels .................................. 28

6.6 Incremental recurring manufacturing cost per engine ......................... 29

6.7 Fuel burn penalty for TL5B engines ..................................... 29

6.8 Maintenance cost .................................................. 32

6.9 Spare engines inventory .............................................. 32

6.10 Diminution in value of the existing fleet ................................... 35

6.11 Total incremental cost impacts ......................................... 36

7. QUANTIFIERS OF COST-BENEFIT RESULTS ............................. 36

7.4 Assessment of recent events .......................................... 38

7.5 Effect of ICAO times in mode and aircraft performance ...................... 38

7.6 Effect of time period used ............................................ 39

7.7 Effect of no further stringency increase on benefits results .................... 39

7.8 Effect of no increased ticket price on demand (second order effects) ............. 40

7.9 Effect of the lead time for 2008 TL5B changes ............................. 40

7.10 Non recurring cost estimates .......................................... 40

7.11 Residual values .................................................... 40

7.12 Cost-benefit ranking of NOx stringency options ............................. 41

8. SUMMARY OF RESULTS OF CENTRAL ANALYSIS ........................ 41

APPENDIX A — FESG GLOBAL EMISSIONS MODEL REPORT
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APPENDIX B — DEFINITION OF TECHNOLOGY LEVELS & ENGINE FAMILY

APPROACH

APPENDIX C — TL5B ENGINE EMISSIONS CHARACTERISTICS & COST MODELLING

APPENDIX D — ESTIMATED REGIONAL DAMAGE COST OF GROUND LEVEL NOX

APPENDIX E — THE EMISSIONS AND DISPERSION MODELING SYSTEM (EDMS)

APPENDIX F — HISTORICAL TREND IN FUEL BURN REDUCTION & TECHNOLOGY

LEVEL

APPENDIX G — TL ASSIGNMENT TO INDIVIDUAL ENGINES BY ENGINE FAMILY

APPENDIX H — FLEET LTO NOX & AIRCRAFT DEPARTURES BY SEAT CATEGORY

APPENDIX I — TOTAL NOX REDUCTION BY OPTION

APPENDIX J — TL ASSIGNMENT TO INDIVIDUAL ENGINES BY ENGINE FAMILY

APPENDIX K — COMPARISON OF COST-BENEFIT DATA

APPENDIX L — FESG ANALYSIS OF ICAO TIMES IN MODE & AIRCRAFT

PERFORMANCE

APPENDIX M — FESG ANALYSIS OF NO FURTHER STRINGENCY ASSUMPTION
CAEP/6-IP/13 - 4 -

1 CAEP/3 Working Group 4 Coordination and Economic Analysis Economic Analysis Subgroup Final Report of the Economic

Analysis Subgroup: regarding economic analysis of CAEP/3 noise and emissions, Working Paper 4, Bonn, June 1995, and

subsequently resubmitted to CAEP/3, December 1995.

1. INTRODUCTION

1.1 FESG was tasked with conducting an economic analysis of stringency options to reduce

aircraft emissions of nitrogen oxides (NOx) relative to the ICAO CAEP/4 standard. Under the proposed new

standard, maximum certification values for carbon monoxide (CO), unburned hydrocarbons (HC), volatile

organic compounds (VOC), and smoke emissions are maintained at the CAEP/4 levels. Although only NOx

is reported, engines made compliant with option requirements meet all ICAO Annex 16, Volume II

certification requirements. Estimates of carbon dioxide (CO2) emissions are included int the report.

1.2 CAEP has accepted economic analysis as the most appropriate method for evaluating

emissions stringency options. It provides a logical framework in which the costs and benefits of each option

can be quantified and compared. The report discusses the modelling method, assumptions and rules, and

presents results for each option. Sensitivity analysis of key modelling assumptions is made to provide greater

insight of the magnitude of estimated values.

1.3 The analysis begins with a base case, a scenario in which ICAO does not implement any of

the options. The costs and benefits of each option are then estimated, and the results compared against the

base case. The CAEP Steering Group requested results of the economic analysis be expressed as cost per

metric tonne of NOx reduced. Costs are in constant 2002 U.S. dollars; benefits are not monetized.

1.4 The central analysis estimates total NOx emitted over the landing and take-off (LTO) cycle

using ICAO engine certification values and times in mode. Global CO2 emissions are presented. The

environmental and health effects of NOx and CO2 emissions have not been quantified. Terrestrial NOx has

both direct and indirect local environmental and health effects which are location specific; aviation specific

atmospheric models are not available. Total NOx and CO2 values are interpreted as the portion of the total

NOx and CO2 load contributed by commercial aviation. NOx and CO2 benefits are interpreted as the reduction

from the load contributed by commercial aviation. Establishing monetary values for NOx emissions and

regional estimates of damage costs from non-aviation sources are discussed. 

1.5 For the economic analysis, the costs that are incurred and the benefits that accrue for the

stringency options occur at different times over the forecast period. The technique of discounted cash flow

analysis accounts for time preference by adjusting future costs and benefits by "discount" factors such that

the values are expressed in a constant time frame. By discounting the costs and benefits for each of the

options can be compared to each other in a consistent and equitable manner.

2. SCOPE AND LIMITATIONS OF

THE ECONOMIC ANALYSIS

2.1 FESG established the NOx

 Emissions Modelling Task Group (NEMTG) at its Fourth Meeting

(22-23 August 2002, Washington) to review the economic analysis provided at CAEP/31 and develop an

appropriate assessment method for economic analysis of NOx stringency options for CAEP/6.
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2 The model is consistent with the NASA models discussed in the IPCC Special Report Aviation and the Global Atmosphere,

Section 9.3.4. It provides a general context for interpreting GEM results discussed in this report.

2.2 The objective of the FESG economic analysis is to provide comparative data relevant to

evaluating the environmental and economic impacts if the ICAO Annex 16, Volume II emissions standard

were changed. The comparative data are:

a) the reduction in NOx emitted over the landing and take-off cycle achieved by reducing

engine emissions certification requirements relative to the base case of no change; and

b) the additional recurring and non-recurring costs incurred by manufacturers and operators

to comply with these ICAO emissions stringency certification standards.

2.3 The economic analysis is designed solely to evaluate ICAO NOx

 stringency options. The

assumptions and rules made to model cost and benefit estimates are internally consistent. Sensitivity analysis

of key modelling assumptions is made to provide greater insight of the magnitude of estimated values.

2.4 Environmental benefits for the world fleet are measured as the amount of NOx

 reduced over

the standard day sea level landing and take-off cycle based on ICAO engine certification values and times

in mode. CO2 emissions are reported to provide additional information on the environmental benefits and

potential emissions trade-offs from each of the options.

2.5 These estimates are not sufficient for local air quality and atmospheric modelling purposes,

and further analysis of the environmental and health impacts of engine NOx emissions has not been made.

Estimates of NOx and CO2 emissions at altitude have been made; however, because they are not based on

the FESG fleet forecast and FESG modelling methods, they are only indicative of the total quantities emitted

for each of the options2. 

2.6 Economic reasonableness is measured as non-recurring manufacturer costs of engine

changes necessary to meet a given stringency option; and the operator acquisition costs and those associated

with fleet operations of aircraft equipped with the newly compliant engines. Operator acquisition cost is the

recurring materials and other production costs required to manufacturer engines that have been changed to

meet an option. As such, there is no double counting of costs.

2.7 The Third Steering Group (10-13 September 2002, Paris) agreed that FESG be tasked to

conduct an economic analysis for a new NOx stringency standard 5%, 10%, 15%, 20%, 25%, and 30% below

the CAEP/4 standard at pressure ratio of 30, and coming into effect 1 January 2012. It requested results of

the economic analysis be expressed as cost per tonne of NOx reduced.

2.8 Subsequently, Working Group 3 (Emissions Technical) requested FESG perform an economic

analysis on the same range of options coming into effect 1 January 2008. Addition of the 2008 effectivity date

was endorsed at the Fourth Steering Group Meeting (23-27 June 2003, Orlando) as were the modelling

methods, assumptions and rules for economic analysis of the NOx stringency options.

2.9 The economic analysis does not address interdependencies between noise and emissions

certification standards. Working Group 2 (Noise - Operations) assessed the noise certification value
CAEP/6-IP/13 - 6 -

3 CAEP/5-IP/12, Aircraft Engine Exhaust Emissions Trends Associated with Noise Stringency Options, concluded substitution of

existing replacement aircraft for those not meeting the CAEP/5 noise standard generally have higher NOx certification levels and

reduced fuel burn. The WG1 assessment did not consider new technologies

4 CAEP-SG20022-WP/13, Report of the FESG Group, Paris, 10 to 13 September 2002.

characteristics of aircraft that would successfully meet the various NOx stringency options. It found the

distribution of cumulative noise margin distributions would be unaffected for the -5% to -25% options. For the

-30% option the cumulative noise distribution shifts to lower margins which was not statistically significant.

The noise characteristics of replacement aircraft were not considered3. This was presented at the Fourth

Steering Group which noted the importance of noise-emissions trade-offs.

3. KEY MODELS, DATABASES AND METHODS

3.1 Models for the assessment of NOx

 stringency options

3.1.1 Two models were used to estimate benefit. One model was used for cost estimates.

3.1.2 Benefit models 

3.1.2.1 FESG reported to the Third Steering Group Meeting it had decided that two models would

be used to help carry out the assessment of benefits from a new NOx stringency standard:

a) the U.S. Federal Aviation Administration Emissions Dispersion Modeling System

(EDMS), which is a landing and take-off cycle model, for global estimates of local

emissions; and

b) the Boeing Global Emissions Model (GEM) for global estimates of local and at altitude

emissions.

The EDMS is the primary model for two reasons: the importance of NOx emission in LTO cycles and its use

of the CAEP/6 fleet forecast. The GEM is used only as an indicator to total emissions, as it uses its own fleet

forecast4. 

3.1.2.2 FESG reported GEM results at the Fourth Steering Group Meeting. Developments since that

time have allowed use of GEM in conducting sensitivity analysis. The GEM report is found in Appendix A.

3.1.2.3 The EDMS model required detailed engine emissions and fuel flow data for each aircraft

(airframe/engine combination) represented in the forecast. The FESG fleet forecast consists of two subsets

of fleet forecast data: the portion of the 2002 year-end fleet projected to remain in service; and, the new

delivery aircraft for fleet replacement and growth. The portion of the 2002 year-end fleet remaining in-service

is known by detailed airframe and engine model. The engine NOx emissions can be determined for this portion

of the fleet forecast. The new aircraft delivery portion of the fleet forecast is known only as “generic” aircraft

having a seat quantity classification, but absent any description of aircraft or engine model.

3.1.2.4 The first step in the analysis was to allocate real production and near term production

airframe/engine models to the "generic" aircraft in the forecast by seat category. This step required FESG
- 7 - CAEP/6-IP/13

to make airframe and engine manufacturer market share assumptions for the projected aircraft deliveries in

the forecast. The following assumptions were made regarding market shares: 

a) equal market split amongst the airplane manufacturers within each seat category;

b) if an airplane manufacturer offers more than one type within a seat category, aircraft

delivery quantities for that airplane manufacturer are split equally amongst aircraft model

types;

c) where applicable, equal market split amongst the engine manufacturers for a given

aircraft model; and

d) if an engine manufacturer offers a range of thrust from a given engine family on an

aircraft model, the most common thrust was chosen.

These assumptions are consistent with the theory of contested markets that states conditions approaching

perfect competition apply to industries characterized by two of more large, well capitalized competitors and

where collusion does not prevail. Market share assumptions should not have a large impact on the analysis

as competing aircraft engines within a given seat category have operability and performance characteristics

that are relatively similar to each other. 

3.1.2.5 EDMS documentation is found at:

http://www.aia-aerospace.org/issues/subject/edms_manual.pdf. The FAA website is:

http://www.aee.faa.gov/emissions/edms/edmshome.htm.

3.1.3 Cost model

3.1.3.1 The FESG worked with the Campbell-Hill Aviation Group to develop a spreadsheet model

for calculating the cost impacts using the FESG fleet forecast. The main inputs to the model are:

a) detailed FESG fleet mix and aircraft cycle forecast by airframe/engine combinations; 

b) recurring and non-recurring manufacturer, and operator cost data; and

c) aircraft fuel burn data from FESG CAEP/5 analysis of noise stringency.

Assumptions made in producing cost data are discussed in Chapter 6. 

3.1.3.2 The detailed fleet mix and cycle forecast data input into the cost model is the same data used

in the EDMS model for the benefits assessment. The fleet mix is represented by airframe/engine

combinations. Aircraft that fail a given stringency option are adjusted to include the technology necessary for

each of the new delivery engines to achieve compliance with a given stringency option. The cycle forecast

is represented as the number of departures.

3.1.3.3 The cost model then aggregates projected annual costs over the forecast period combining

recurring and non-recurring costs accounted for by manufacturers, and the recurring costs incurred by airline

operators into a total amount. Non-recurring manufacturer costs are one-time costs such as technology
CAEP/6-IP/13 - 8 -

acquisition and/or development, engine design, testing and certification, and tools and equipment. Recurring

manufacturing costs are the additional cost for each engine produced such as parts and material. Total

recurring costs are the sum of additional manufacturing costs per engine due to a technology change and the

additional fleet operating costs. There is no double counting.

3.2 Databases used for the assessment

of NOx stringency options

3.2.1 EDMS is designed to assess the air quality impacts of airport air-side emission sources

(aircraft engines, auxiliary power units and ground support equipment). Only aircraft emissions have been

assessed. The EDMS emissions inventory module aggregates emissions over the LTO cycle emitted from

the aircraft for a given year. The FESG fleet forecast and Working Group 3 in-production airframe/engine

database are inputs to the EDMS model. These are:

3.2.2 FESG fleet forecast

3.2.2.1 The Second Steering Group Meeting (23-24 May 2002, Madrid) requested FESG to make

a complete update of the fleet and traffic forecast made before CAEP/5 in light of world events and the

downturn in air traffic. The new forecast projects unconstrained traffic demand over the forecast period from

2000 to 2020 and is equivalent to an average annual growth rate of 4.3 percent. While the forecast is intended

to look at long-term trends to the year 2020, the near term period (2002-2005) was analyzed in more detail.

Traffic growth for this period has been projected to grow at an average annual growth rate of 2.2 percent.

3.2.2.2 The 2020 world passenger fleet is forecast to reach almost 25,000 aircraft to meet the

projected demand and replacement of older aircraft, of which approximately are 17,500 are growth and

replacement aircraft. Just over 4,700 aircraft in the current fleet are removed from passenger service during

the same period. Figure 3.1 shows retained, replacement and growth aircraft. The aircraft fleet is divided into

the nine seat categories as shown in Table 3.3, which were assigned to industry-defined regional jet, narrow

body and wide body aircraft categories.
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Table 3.3. Number of FESG passenger aircraft by seat category and aircraft type

Seat Category 2002 2020

Regional 20-49 180 1912

Regional 50-99 1711 4087

Narrow Body 100-150 5620 6701

Narrow Body 151-210 2086 5690

Wide Body 211-300 1650 3633

Wide Body 301-400 512 1632

Wide Body 401-500 548 668

Wide Body 501-600 10 379

Wide Body 601-650 0 282

Total Aircraft 12317 24984

3.2.2.3 The total freighter fleet remains the same as in the CAEP/5 forecast. The mix between new

and converted growth and replacement aircraft has changed, however. These are expected to reach 3,187

freighter aircraft by the year 2020, of which 500 would be new freighters and the remaining 2,687 are

retained cargo aircraft and conversions from the passenger fleet, as shown in Table 3.4.

Table 3.4. Freighter fleet and composition for selected years

1998 2002 2006 2009 2013 2020

Conversions and Retained 1,545 1,630 1,740 1,881 2,143 2,687

New Freighters 61 126 188 285 500

Total Additions 1,545 1,691 1,866 2,060 2,428 3,187

3.2.2.4 At the Fourth Steering Group Meeting FESG reported a complete update of the FESG

CAEP/5 forecast had been completed as requested. This forecast was used in the economic analysis of the

NOx stringency options contained in this report. The assumptions underlying the FESG fleet forecast are

discussed in Section 4.2. FESG further reported that in addition to the downturn in air travel following the 11

September 2001 terrorist attacks in the United States which were taken into account in the FESG fleet

forecast, the subsequent SARS epidemic and war in Iraq had significantly affected air travel in some regions.

At the request of the Fourth Steering Group Meeting, FESG was requested to assess their impact on the state

of the industry.

3.2.2.5 While it is not evident the longer term impact the SARS epidemic and war in Iraq will have

on the FESG forecast, the ICAO Secretariat has estimated these events have had a more significant negative

impact on air traffic than anticipated. The Secretariat estimated that the 2003 year end traffic will be about

2% below that of 2002, and the average annual traffic growth over the period 2000-2005 would be 1.2

percent, down from the 2.2 percent rate of growth in the revised FESG forecast. Applying the same growth

rates over the forecast period results in an average annual global growth rate of 4.1 percent, down from 4.3

percent for the prior 2002-2020 forecast period. Referring to Figure 3.1, under the revised forecast the 2010

fleet would be seen in 2012, and the 2020 fleet in 2022. The effect of this new information on the modelling

results is discussed in Chapter 7.
CAEP/6-IP/13 - 10 -

5 There were several engines in the FESG fleet forecast which have not yet been certified: the GP 7000 and Trent 900 for the A380,

the CF34-10E for the ERJ-190, and the PW6124 for the A318. NOx certification values and fuel flow rates were derived from trend

line analysis of known values from certificated engines with similar technology.

Dp/Foo by certification year

group

0

20

40

60

80

100

120

140

160

0 10 20 30 40 50 60

CAEP1

CAEP2

CAEP4

1970-1980

1980-1985

1986-1990

1991-1995

1995-now

Engine pressure ratio

Figure 3.2. NOx certification levels for new aircraft engines: 1970-1999

(Mass of NOx emitted divided by the maximum take-off power [Dp/F00])

3.2.3 In-production airframe/engine database

3.2.3.1 The Third Steering Group Meeting approved use of a database containing emissions data for

in-production engine/airframe combinations developed by Working Group 3 for the FESG economic analysis

of the NOx stringency options5. To populate the FESG forecast with real aircraft, the generic new delivery

aircraft in the FESG database were replaced by airframe/engine combinations from the in-production

database. The emissions characteristics for the retained 2002 year end fleet were obtained from the Working

Group 3 in-production database and the ICAO Emissions Databank.

3.2.3.2 Figure 3.2 shows NOx certification levels achieved by engines certified between 1970 and

1999. The 1993 CAEP/2 standard is 20 percent below the original 1981 standard. The 1998 CAEP/4 standard

is 16 percent below CAEP/2, and 33 percent below the original standard. 
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6 Two examples of TL2 solutions are installation of the Phase 5 combustor on the RB211-535 and the TALON combustor into the

PW4168 to meet the CAEP/4 standard.

3.3 Methods used in the economic analysis

3.3.1 Two modelling methods were used: "Technology Levels" for assessing improvements to

achieve compliance; and, discount rates to account for time preferences.

3.3.2 Technology levels to achieve compliance

3.3.2.1 The technology level (TL) concept used in the CAEP/3 economic analysis of noise and

emissions options was further developed and refined by Working Group 3 based on actual and expected

technologies available to manufacturers in the relevant time period. Specific TL's are established on the basis

of the nature of the technology change, and the effect on the combustor and engine design necessary for a

noncompliant engine to meet a given stringency option. The Fourth Steering Group Meeting endorsed the

engine technology level matrix. The TL definitions used in the economic analysis as provided by Working

Group 3 are given in Appendix B. In summary these are:

TL1 — Minor change

3.3.2.2 A change which does not require a complete engine recertification. Such a change would

be small enough that effects of the change on engine performance, operability and durability are within

regulatory limits. Limited ground testing of the modified engine might be required. Generally, a minor change

could improve NOx emissions by less than 5 percent.

TL2 — Major change with scaled proven technology

3.3.2.3 A change where known technology is applied within the exiting combustor envelope and is

compatible with the engine thrust and pressure ratio characteristics, and could be implemented within the

existing engine casing. A full engine certification program and aircraft flight test would be required to prove

airworthiness. Reductions with a major change might typically be in the 5 to 15 percent range6. 

TL3 — Substitution with other available

certified current technology engine

3.3.2.4 A given stringency level might be met by substituting an existing engine meeting the standard

for the non-compliant engine on specific aircraft. In most cases airframe, pylon and nacelle modifications

and/or development would be required. FESG found no cases where a TL3 solution was preferable to a

category "TL5" programme discussed below.

TL4 — Development of a new current technology engine

3.3.2.5 It might be possible to design and build an all-new engine operating at a lower pressure ratio

that could meet the stringency level being considered, particularly for the highest pressure ratio engines. At

this engine modification level extensive changes to the aircraft might be needed, and certification will be

required. FESG found no cases where a TL4 solution was preferable to a category "TL5" programs.
CAEP/6-IP/13 - 12 -

TL5 Category — New technology acquisition

3.3.2.6 A stringency level that cannot be met a TL2 change requires new technology be found or

developed. The level of development and certification testing that might be needed to introduce a new

technology on an existing engine will vary depending on the characteristics of the new technology. This

variability led to a further refinement of this category into TL5A and TL5B changes.

TL5A — New technology using current industry best practice

3.3.2.7 When a manufacturer has no proven technology that can be scaled to provide a solution (i.e.,

a TL2 solution fails to meet the required stringency), and where one or more manufacturer(s) have certified

the necessary technology, the acquisition of existing proven technology by the manufacturer(s) of the

noncompliant engine(s) would be necessary. At best, a TL5A program would be equivalent to a TL2

programme with the addition of some applied research for technology acquisition and potentially extended

cyclic testing to prove the durability that is required for extended twin engine operations. 

TL5B — New technology (beyond current best)

3.3.2.8 The designation TL5B covers the situation where no engine manufacturer has demonstrated

technology that meets the required NOx stringency. In this case extensive technology acquisition and

development, and full engine development programme are required. For all three engine manufacturers, lean

staged combustion technology concepts would be explored. Results of demonstration tests under government

programs and physics-based engine requirements indicate a fuel burn penalty would be encountered. This is

further explained in Appendix C.

Limitation to TL3 and TL4 engine programs

3.3.2.9 The TL3 and TL4 categories were not used in the economic analysis. A TL3 solution would

only be chosen if the manufacturer could not acquire the needed technology to maintain long term market

presence and remain competitive. A TL4 solution would only be chosen if the projected long term production

rates would justify encountering the costs of a new engine program, if competitive hurdles could be overcome,

and if acquisition of TL5A or TL5B technology were economically and/or technically unfavourable.

Additional CO2 emissions

3.3.2.10 Based on service experience, the TL5B technology level used in the analysis has a fuel burn

penalty of 2 percent. CO2 emissions, a by-product of combustion, increase directly in proportion to increases

in fuel consumption. The incremental fuel consumption for TL5B engines was determined, and CO2 emissions

were then calculated (3.16 units of CO2 per unit of aviation fuel). Figures 3.1 and 3.2 illustrate the NOx / CO2

trade-off. 
- 13 - CAEP/6-IP/13

-1,000,000

-800,000

-600,000

-400,000

-200,000

0

CAEP/4

Minus 5%

CAEP/4

Minus 10%

CAEP/4

Minus 15%

CAEP/4

Minus 20%

CAEP/4

Minus 25%

CAEP/4

Minus 30%

0

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

NOx CO2

Forecast Period: 2002 - 2020

Figure 3.1. Global LTO NOx and CO2 trade-offs: Options implemented in 2008

-1,000,000

-800,000

-600,000

-400,000

-200,000

0

CAEP/4

Minus 5%

CAEP/4

Minus 10%

CAEP/4

Minus 15%

CAEP/4

Minus 20%

CAEP/4

Minus 25%

CAEP/4

Minus 30%

0

20,000,000

40,000,000

60,000,000

80,000,000

100,000,000

NOx CO2

Forecast Period: 2002 - 2020

Figure 3.2. Global LTO NOx and CO2 trade-offs: Options implemented in 2012

3.3.3 Discount rates

3.3.3.1 Costs and benefits of stringency options occur over time. Those that occur in the future do

not have the same value as those that occur today. Discounting allows the costs and benefits to be compared

with one another even though they may accrue in different time periods. It was not possible to place a

monetary value on NOx benefits. An appropriate method to monetise health and environmental impacts

resulting from NOx reductions on a global scale is not available, and modelling individual localities is beyond

present FESG capability. This is explained further in Appendix D.

3.3.3.2 As benefits are not monetised, the analysis employs discounting of the annual tonnes of NOx

of the stringency options assessed. The rationale for discount physical units is the same as that for monetary

units. Expressing benefits in discounted physical units places the results in current year (2002) values showing

society places a higher value on immediate NOx reductions than on future reductions. There is no policy

difference between discounting the damage cost of NOx and discounting the quantity of NOx.
CAEP/6-IP/13 - 14 -

7 Discussion based upon CAEP-SG20031-IP/8, Report of the FESG/CAEP/6 Traffic and Fleet Forecast.

3.3.3.3 Three discount rates were applied to both costs and benefits: a 3 percent rate considered to

reflect the social preference value of time; 7 percent reflecting a normalized rate used by governments in

environmental policy analysis; and, a 9 percent rate reflecting a real rate of return used by industry to

compare investment alternatives.

4. MODELLING ASSUMPTIONS 

4.1 Simplifying assumptions have been made to develop data input for the economic analysis.

Knowledge of these assumptions is necessary to understand the findings presented in the report. Assumptions

significantly impacting modelling results have been subject to sensitivity analysis.

4.2 FESG fleet forecast assumptions 7

4.2.1 Assumptions underlying the projected fleet are:

Unconstrained demand

4.2.2 The Fleet Forecast assumes all future demand for commercial air services is fully met. Fleet

growth and the number of aircraft contained in the FESG fleet forecast accommodate all the consumer

demand, and represent an upper boundary given assumptions made regarding aircraft size and flight frequency

over the route structure. Starting at a 2002 level of nearly 3,018 billion revenue passenger kilometres (RPK),

traffic returns to its previous historical growth rates in 2006, and is projected to reach over 7,050 billion RPK

in 2020. 

Increased aircraft size and productivity

4.2.3 In the FESG forecast available seat kilometre (ASK) growth requirements are

accommodated by increased seating capacity (use of larger aircraft) and aircraft productivity. The increase

in aircraft productivity results from higher aircraft utilization, evolution of non-stops, and expected

improvements in load factors. Evolution of non-stop flights forecasts that more point to point traffic will

develop and that fewer stops will be made due to increased aircraft range.

4.2.4 The FESG forecast for aircraft flights by seat category is shown in Figure 4.1. Frequency

levels for regional airlines are assigned higher frequency limits than for narrow and wide body transport

category aircraft. Average load factors are assumed to increase from 70.0 percent in 2002 to 74.6 percent

in 2020. Average load factors assumed on domestic routes are 1.3 and 3.0 percent lower than on international

routes for 2002 and 2020 respectively.

4.2.5 Total aircraft movements are projected to increase by nearly 22.7 million from 20.2 million

in 2002 to 42.9 million in 2020. With a 51 percent share, utilization of aircraft in the 100-150 seat category

makes up the largest number of total operations in 2002, and declines throughout the forecast period to a 31

percent share by 2020. The 50-99 and the 151-210 seat category groups of aircraft show a large relative

growth over the forecast period, and utilization of aircraft in the 211-300 seat range grows faster than the

average.
- 15 - CAEP/6-IP/13

8 See, for example: CAEP/4-WP/36, Proposed CAEP Paper to be Presented to the ICAO World-Wide CNS/ATM Systems

Implementation Conference, Rio de Janeiro, Brazil - 11 to 15 May 1998 (the presentation was made); and, CAEP/5-WP/18,

Environmental Benefits Associated with CNS/ATM Initiatives.

-

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

2002 2006 2008 2012 2016 2020

Seat Category

Number of Flights

20-49

50-99

100-150

151-210

211-300

301-400

401-500

501-600

601-650

Seat 

Category

Figure 4.1. Aircraft movements by seat category for selected years

Airport and air traffic control constraints

4.2.6 The FESG Fleet Forecast assumes that world air traffic control systems (ATC) and airport

capacity are able to accommodate all of the projected future growth on a regional and airport basis. While

growth in demand is unconstrained, future fleet projections are based on current levels of aviation activity

whereby any influence ATC and airport constraints had on air traffic in the base year are carried forward

to future years.

4.2.7 FESG did not undertake a sensitivity analysis of this assumption. Working Group 4 and prior

CAEP studies indicate increased capacity and reductions in delay would lower fuel burn at altitude between

3 and 6 percent, and 3 and 11 percent at ground. The studies indicate that emissions of HC and CO at ground

would be reduced significantly, and NOx would be reduced by a meaningful extent8. To the extent ATC and

airport constraints impact traffic today, they are not further addressed in EDMS and the FESG fleet forecast

and continue throughout the forecast period.

4.3 FESG EDMS assumptions

4.3.1 The economic analysis models global air carrier operations up to 3,000 feet using a single

generic airport. A description of how EDMS was used is in Appendix E. Two kinds of modelling assumptions

were made for the economic analysis: those used in both the base case and options, and those that apply to

the options alone. These are:
CAEP/6-IP/13 - 16 -

4.3.2 Assumptions used in modelling both the base case on options

Engine technology is only developed to meet a stringency increase

4.3.2.1 It has been assumed that the engine combustion technology presented in the Working Group

3 in-production database case 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.

ICAO certification factors

4.3.2.2 The economic analysis is based on ICAO Annex 16, Volume II certification standard

requirements. Airports and airspace up to 3,000 feet are unconstrained, that is, there is infinite capacity and

no delay. Lacking airport specific data, and unlike MAGENTA, all airports are represented by a model airport

operating using sea level static and standard day conditions. Aircraft performance is calculated from engine

fuel flow. These are conservative assumptions.

4.3.2.3 A sensitivity test of the model airport, ICAO times in mode and aircraft performance more

representative of actual operations was conducted to determine the impact of this assumption on the modelling

results.

4.3.3 Assumptions used in modelling the options only

No further NOx stringency increases beyond the option effectivity

date

4.3.3.1 The economic analysis assumes that if a new stringency option is adopted, there will be no

subsequent stringency increase(s).

Static aircraft mission and payload, and no fuel burn penalty

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

technologies developed to meet stringency options do not compromise aircraft mission and payload. No new

airframes enter the fleet with the exception of the A380, and all replacement and growth aircraft are assumed

to fulfil their original mission and payload requirements. Switching of aircraft usage is not modelled. Full

mission and payload capability is maintained for all aircraft of a given type within the EDMS fleet.

4.3.3.3 No fuel burn penalty is incurred with a given technology level change with the exception of

a TL5B solution. Technology Level 5B changes require development of unknown technologies, that is, those

technologies that are at the pre-commercialisation stage of development. Known technologies in this category

would require staged combustor engine designs. Based on CO2-NOx-CO trade-offs exhibited on existing

double annular combustor designs a 2 percent fuel penalty was determined to be a reasonable assumption for

TL5B engine designs. This trade-off is not warranted in TL1 through TL5A cases. This is explained further

in Appendix C; the historical record in Appendix F; and, in Section 6.4.
- 17 - CAEP/6-IP/13

Technology changes applied across engine family

4.3.3.4 Production and near-term production engine models, having a common build standard, were

grouped into engine families. If any engine model within a given engine family failed a given stringency option,

then all the engine models within the family would 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.

An additional environmental benefit is achieved because a given change in stringency affects all engine

models within a family even though only the higher thrust versions might be affected. This is further explained

in Section 2 of Appendix B.

4.3.3.5 Table 4.1 summarizes the technology level (TL) required for each engine family to meet each

of the six NOx stringency options by manufacturer. These are based on the Working Group 3 in-production

database. Engine models for each engine family are shown in Appendix G.

Table 4.1. Technology level requirements by manufacturer and engine family

General Electric (GE)

Family Combusto

r

-5% -10% -15% - 20% -25% -30%

CF34-3

CF34-8

CF34-10

CF6-80C2 TL5B

CF6-80E1 TL2 TL2 TL2 TL5B

GE90-94 DAC II TL1 TL5A TL5A TL5B TL5B

GE90-115B DAC II TL5B TL5B TL5B

Pratt & Whitney (PW)

Family Combustor -5% -10% -15% - 20% -25% -30%

PW6000 TL5B TL5B TL5B

PW2000 TL2 TL2 TL2 TL5B TL5B

PW4000-94" Phase 3 TL2 TL2 TL2 TL2 TL5B

PW4000-94" TALON II TL5B

PW4000-100” TALON II TL5B

PW4000-112” PW4090 BOM TL2 TL2 TL5A TL5A TL5B TL5B

Engine Alliance (EA)

Family Combusto

r

-5% -10% -15% - 20% -25% -30%

GP7000 TL5B TL5B

Rolls-Royce (RR)
CAEP/6-IP/13 - 18 -

Reduction from CAEP/4 Standard -5% -10% -15% -20% -25% -30%

Total Engine Models (1) 80 80 71 71 71 71

Number of Models Failing

TL1 6 4 10 1

TL2 9 28 15 15 8

TL5A 15 16 3

TL5B 5 9 43 64

Total Types Failing 15 32 35 50 55 64

Percentage of Models Failing

TL1 8% 5% 14% 1%

TL2 11% 35% 21% 21% 11%

TL5A 21% 23% 4%

TL5B 7% 13% 61% 90%

Percentage Total Types Failing 19% 40% 49% 70% 77% 90%

(1 ) At 15% Stringency and above, the CFM56 engine family requires the same TL2 to TL5B

 "fix" regardles of whether the combustor is a SAC or DAC. Therefore, CFM56 SAC and

 DAC engine families are counted as one family with corresponding engine models for

 stringency options that are 15% and higher, thus reducing total engines from 80 to 71.

Family Combusto

r

-5% -10% -15% - 20% -25% -30%

AE3007

BR700 TL1 TL5B

RB211-535 Phase 5 TL5A TL5B TL5B

RB211-524 Phase 5 TL1 TL5A TL5B

TRENT500 TL1 TL5B TL5B

TRENT7/800 TL1 TL5B TL5B

TRENT900 TL5B TL5B

CFM International Engines (CFMI)

Family Combusto

r

-5% -10% -15% - 20% -25% -30%

CFM56-5B SAC TL2 TL5A TL5A TL5B TL5B

CFM56-5B DAC II TL5A TL5A TL5B TL5B 

CFM56-5C SAC TL1 TL2 TL5A TL5A TL5B TL5B

CFM56-7B SAC TL2 TL2 TL5B TL5B TL5B TL5B

CFM56-7B DAC II TL5B TL5B TL5B TL5B 

International Aero Engines (IAE)

Family Combusto

r

-5% -10% -15% - 20% -25% -30%

V2500 TL1 TL2 TL2 TL2 TL5B TL5B

4.3.4 The number of non-compliant engines for each stringency level and the percentage of

total engines affected are shown in Table 4.2. 

Table 4.2. Number and percentage of types failing stringency levels
- 19 - CAEP/6-IP/13

4.3.4.1 Table 4.3 illustrates the number of installed engines that would fail NOx

 stringency options

implemented in 2008 by technology level for cumulative projected aircraft deliveries through 2020.

Comparison of affected engines is summarized as a percentage of total installed engine deliveries for aircraft

having 100 seats of more and as a percentage of total installed engine deliveries. These totals for options

implemented in 2012 are shown in Table 4.4.

4.3.4.2 Narrow body and wide body aircraft having 100 seats and more make up approximately 75

percent of the fleet by 2020, accounting for over 90 percent of available seats.
CAEP/6-IP/13 - 20 -

Reduction from CAEP/4 Standard -5% -10% -15% -20% -25% -30%

Number of INSTALLED Engines 

Failing By TL: 

TL1 4,298 154 - 3,998 998 -

TL2 4,159 14,214 5,499 5,500 1,837 -

TL5A - - 5,205 5,524 849 -

TL5B - - 3,902 5,310 20,088 26,048

 Total Quantity Failing 8,458 14,368 14,606 20,332 23,772 26,048

Total INSTALLED Engines for 100 

Seat Aircraft and Up 30,764 30,764 30,764 30,764 30,764 30,764

Total INSTALLED Engines 39,830 39,830 39,830 39,830 39,830 39,830

Percent Failing Engines of 100 Seat 

Aircraft and Up

TL1 14% 0.5% 13% 3%

TL2 14% 46% 18% 18% 6%

TL5A 17% 18% 3%

TL5B 13% 17% 65% 85%

 Total 27% 47% 47% 66% 77% 85%

Percent Failing Engines of Total Fleet

TL1 11% 0% 10% 3%

TL2 10% 36% 14% 14% 5%

TL5A 13% 14% 2%

TL5B 10% 13% 50% 65%

 Total 21% 36% 37% 51% 60% 65%

Table 4.3. Number of engines affected by stringency options implemented

in 2008 on cumulative projected aircraft deliveries: 2008-2020 

Table 4.4. Total number of engines affected by stringency options implemented in 2012

on cumulative projected aircraft deliveries 2012-2020

Below CAEP/4 Standard - 5% -10% -15% -20% -25% -30%

Percent Failing Engines for 100

Seat Aircraft and Up

20% 34% 34% 47% 56% 61%

Percent Failing Engines for Total

Fleet

15% 26% 26% 36% 43% 47%

Competition to maintain market share

4.3.4.3 The EDMS model required detailed engine emissions and fuel flow data for the aircraft /

engine combinations represented in the forecast. The FESG fleet forecast consists of two subsets of fleet

forecast data: 1) the portion of the 2002 year-end fleet projected to remain in service, and 2) the new delivery

aircraft for fleet replacement and growth. The portion of the 2002 year-end fleet remaining in-service is

known by detailed aircraft and engine model. The engine NOx emissions can be determined for this portion
- 21 - CAEP/6-IP/13

of the fleet forecast. However, the new aircraft delivery portion of the fleet forecast is known only as

"generic" aircraft having no description of aircraft model or engine model, only having a seat quantity

classification. Therefore, the first step in the analysis was to allocate real production and near term production

airplane / engine models by seat category to these "generic" aircraft in the forecast. This step required FESG

to make market share assumptions for the airframe and engine manufacturers for the projected aircraft

deliveries in the forecast. For the purposes of the analysis, the following assumptions were made regarding

market shares: 

a) equal market split amongst the airplane manufacturers within each seat category;

b) if an airplane manufacturer offers more than one type within a seat category, aircraft

delivery quantities for that airplane manufacturer are split equally amongst aircraft model

types;

c) where applicable, equal market split amongst the engine manufacturers for a given

aircraft model; and

d) where more than one engine model, representing a range of thrust from a given engine

manufacturer is offered on an aircraft model, the most common model was chosen.

The reason the above market share assumptions were chosen was to keep the analysis simple. Today's

market shares may not reflect the market shares 20 years out into the future and to avoid debate over market

share projections in future years of the fleet forecast, an equal split assumption was the simplest and least

debatable. Market share assumptions should not have a large impact on the analysis as competing aircraft

engines within a given seat category have operability and performance characteristics that are relatively

similar to each other.

Market-driven noncompliant engine production cut-off

4.3.4.4 It is assumed that a market-driven production cut-off of noncompliant engines occurs on the

date a stringency option becomes effective. At that point, only previously compliant engines and those that

have been made compliant are produced.

Table 4.5. Status of engines not meeting CAEP/4 NOx standard

Engine Status in Meeting CAEP/4 Standard (1)

1998 In-Production

PS 90A Unknown

JT-8D Not in production

PW2040 TL1 – compliant

PW4090 Out of production (replaced with new engine family) (3)

PW4164, 68 TL2 – compliant (Talon II)

RB211-524 series TL2 – compliant (Phase 5)

RB211-535 series TL2 – compliant (Phase 5)

New Types (2)

PW4074D (3) Compliant

PW4077D, 84D, 90 (3) Technology identified

PWC Growth Engines Compliant

Source: CAEP/4-WP/4, Economic Assessment of the EPG NOx Stringency Proposal, Table 3.1.
CAEP/6-IP/13 - 22 -

9 Airclaims CASE Database

FESG Seat Group 2002 2006 2008 2012 2016 2020

20 - 99 12,630 15,507 18,886 26,555 34,255 42,225

100 - 210 148,485 165,375 179,619 210,325 242,176 275,168

211 - 650 108,877 132,888 156,600 216,729 288,356 381,380

Total - All Seat Groups 269,992 313,770 355,104 453,609 564,786 698,773

Percent Total NOx

20 - 99 5% 5% 5% 6% 6% 6%

100 - 210 55% 53% 51% 46% 43% 39%

211 - 650 40% 42% 44% 48% 51% 55%

20 - 99 3,615,302 4,500,883 5,448,739 7,608,327 9,735,241 11,911,474

100 - 210 13,596,379 14,764,100 15,700,006 17,746,231 19,926,451 22,284,635

211 - 650 2,986,015 3,534,049 4,045,619 5,299,321 6,812,078 8,693,656

Total - All Seat Groups 20,197,696 22,799,032 25,194,364 30,653,879 36,473,770 42,889,765

Percent Total Cycles

20 - 99 18% 20% 22% 25% 27% 28%

100 - 210 67% 65% 62% 58% 55% 52%

211 - 650 15% 16% 16% 17% 19% 20%

NOx (Tonnes)

LTO Cycles

(1) TL1 and TL2 are consistent with definition provided in Appendix B.

(2) Engines programs nearing completion but not certified in 1998.

(3) PW4074D, 4077D, 4084D, and 4090 are one engine family with common build of material (B.O.M.).

The new PW4090 is different from the out of production model.

4.3.4.5 This assumption is supported by Table 4.5. It contains 1998 then in-production engines that

did not meet the CAEP/4 NOx standard, and new engines in the design and development process that were

expected to be certified shortly after 1998. Of the 642 passenger aircraft produced in 2002 with more than

100 seats, eight aircraft representing one airframe/engine combination did not comply with the CAEP/4 NOx

standard9. 

5. BENEFITS ASSESSMENT OF STRINGENCY OPTIONS

5.1 Benefits are calculated as the difference in NOx emitted by the global commercial aviation

fleet under an option compared to the base case. Environmental and health effects of NOx are not quantified.

5.2 Base-case results

5.2.1 Table 5.1 illustrates FESG fleet forecast dynamics, reflecting how changes in fleet

composition affect NOx emissions. Data by individual seat category is given in Appendix H.

Table 5.1. Total and percentage departures and NOx emissions by aircraft category

5.2.2 Regional jets account for 5-6 percent of total NOx over the forecast period. In 2002 these

aircraft account for nearly 20 percent of total departures, growing to almost 30 percent by 2020. Narrow body
- 23 - CAEP/6-IP/13

Implementation Date of 2008:

Year Baseline 0% 3% 7% 9% 0% 3% 7% 9% 0% 3% 7% 9%

2008 355,104 -456 -382 -304 -272 -1,367 -1,145 -911 -815 -1,835 -1,537 -1,223 -1,094

2012 453,609 -2,516 -1,872 -1,279 -1,063 -7,459 -5,550 -3,792 -3,151 -10,023 -7,458 -5,095 -4,234

2016 564,786 -4,853 -3,208 -1,882 -1,452 -14,368 -9,499 -5,572 -4,299 -19,326 -12,777 -7,495 -5,783

2020 698,773 -7,490 -4,399 -2,216 -1,588 -22,276 -13,085 -6,591 -4,722 -29,965 -17,602 -8,866 -6,352

Total 8,502,117 -49,340 -32,605 -19,369 -15,122 -146,413 -96,750 -57,473 -44,871 -196,900 -130,107 -77,284 -60,337

Year Baseline 0% 3% 7% 9% 0% 3% 7% 9% 0% 3% 7% 9%

2008 355,104 -2,026 -1,696 -1,350 -1,208 -2,691 -2,254 -1,793 -1,605 -2,951 -2,472 -1,967 -1,760

2012 453,609 -11,055 -8,226 -5,620 -4,670 -14,829 -11,034 -7,538 -6,264 -16,253 -12,094 -8,262 -6,865

2016 564,786 -21,320 -14,095 -8,268 -6,380 -28,569 -18,887 -11,080 -8,549 -31,392 -20,754 -12,175 -9,394

2020 698,773 -33,066 -19,423 -9,783 -7,010 -44,673 -26,241 -13,217 -9,470 -49,184 -28,891 -14,552 -10,427

Total 8,502,117 -217,229 -143,538 -85,261 -66,564 -292,002 -192,892 -114,534 -89,401 -320,921 -211,966 -125,836 -98,214

Implementation Date of 2012:

Year Baseline 0% 3% 7% 9% 0% 3% 7% 9% 0% 3% 7% 9%

2012 453,609 -515 -383 -262 -217 -1,523 -1,133 -774 -643 -2,047 -1,523 -1,041 -865

2016 564,786 -2,852 -1,886 -1,106 -854 -8,432 -5,574 -3,270 -2,523 -11,350 -7,504 -4,402 -3,396

2020 698,773 -5,489 -3,224 -1,624 -1,164 -16,340 -9,598 -4,834 -3,464 -21,989 -12,916 -6,506 -4,662

Total 8,502,117 -26,418 -16,787 -9,417 -7,129 -78,384 -49,800 -27,930 -21,142 -105,488 -67,020 -37,587 -28,453

Year Baseline 0% 3% 7% 9% 0% 3% 7% 9% 0% 3% 7% 9%

2012 453,609 -2,257 -1,679 -1,147 -953 -3,034 -2,258 -1,542 -1,282 -3,325 -2,474 -1,690 -1,405

2016 564,786 -12,523 -8,279 -4,857 -3,747 -16,774 -11,090 -6,505 -5,020 -18,465 -12,207 -7,161 -5,525

2020 698,773 -24,268 -14,255 -7,180 -5,145 -32,879 -19,313 -9,728 -6,970 -36,257 -21,297 -10,727 -7,686

Total 8,502,117 -116,402 -73,953 -41,475 -31,395 -156,880 -99,644 -55,865 -42,281 -172,813 -109,756 -61,528 -46,565

20% Option 25% Option 30% Option

Discount Rate Discount Rate Discount Rate

5% Option 10% Option 15% Option

Discount Rate Discount Rate Discount Rate

20% Option 25% Option 30% Option

Discount Rate Discount Rate Discount Rate

5% Option 10% Option 15% Option

Discount Rate Discount Rate Discount Rate

aircraft account for two thirds of 2002 departures, decreasing to approximately 50 percent by the end of the

forecast period. These aircraft account for 55 per cent of NOx emissions in 2002, dropping to nearly 40

percent in 2020. The wide body fleet contributes 40 per cent of total NOx in 2002, growing to 55 percent in

2020. This is due to the thrust requirements of higher weight aircraft used for long-haul operations in addition

to their increased share of total aircraft movements 

5.3 2002-2020 NOx stringency options results 

5.3.1 Projected NOx saved for each stringency option for 2008 and 2012 implementation is

illustrated in Table 5.2. Benefits accrue from the time the stringency options become effective as aircraft

meeting the new standard enter into service.

Table 5.2. Undiscounted and discounted LTO NOx benefits: selected years to 2020

(Tonnes NOx)
CAEP/6-IP/13 - 24 -

-2.3%

-1.0%

-3.0%

-4.0%

-4.4%

-6.0%

-6.6%

-2.3%

-3.1% -3.4%

-4.7%

-5.2%

-0.6%

-3.8%

-1.7%

-2.6%

-3.4%

-2.0% -1.8% -1.4%

-1.2%

-0.9% -0.3%

-0.8%

-8%

-7%

-6%

-5%

-4%

-3%

-2%

-1%

0%

CAEP/4

Minus 5%

CAEP/4

Minus 10%

CAEP/4

Minus 15%

CAEP/4

Minus 20%

CAEP/4

Minus 25%

CAEP/4

Minus 30%

2002 - 2020, Implementation Date= 2008 2002 - 2030, Implementation Date= 2008

2002 - 2020, Implementation Date= 2012 2002 - 2030, Implementation Date = 2012

Figure 5.4. Cumulative global LTO NOx saved: 2002-2020 and 2002-2030

5.3.2 The percent cumulative reduction in global LTO NOx

 that could be achieved for each NOx

stringency option relative to the base-case is illustrated as the red and blue bars in Figure 5.1. An earlier

implementation date leads to greater NOx reduction benefits by 2020. A lower stringency level implemented

earlier can result in a benefit similar to a more stringent option implemented later.

5.4 2002-2030 NOx stringency options results 

5.4.1 The time period for measuring benefits resulting from a stringency option was raised at the

Fourth Steering Group Meeting. Benefits from reduced NOx emissions are expected to accrue over the long

term as compliant aircraft enter the fleet and in-service aircraft retire.

5.4.2 The rate of increase in total benefits accelerates and then decelerates over time until the

entire fleet complies with the new standard. At that point there are no further benefits to be added. The shape

of the benefits curve is a function of the retirement curves. The accrual rate of total benefits is due primarily

to the "S" shape of the retirement curves and the time horizon over which the steeply vertical part of the

curves exercise their influence, and the number of aircraft effected by the stringency standard.

5.4.3 The confidence interval for the FESG fleet forecast is 2020, the forecast period of the central

analysis. Uncertainty of results increases rapidly for projections beyond this period as the time period

increases. Results from the central analysis were extrapolated to 2030 by determining the average growth

in NOx during the last 4 years of the forecast (2016-2020) and projecting this rate forward. This assumes

traffic growth rates, aircraft retirements and deliveries to 2030 follow those of the last 4 years of the forecast.

Estimated 2002-2020 and 2002-2030 cumulative benefits are shown in Figure 5.1. Total 2020 NOx reductions

are graphically illustrated in Appendix I. 
- 25 - CAEP/6-IP/13

5.5 Ranking of 200-2020 and 2002-2030

cumulative LTO NOx benefits

5.5.1 Results from Figure 5.4 show a lower option implemented early can provide equivalent

benefits to a higher stringency implemented later. The relative ranking of benefit results are presented in

Table 5.3. Interpretation of these results is dependent on the time period studied and factors discussed in

Section 4. 

Table 5.3. Ranking of cumulative LTO NOx benefits: 2020 and 2030

Rank 2002-2020 2002-2030

highest 2008 -30% 2008 -30%

2nd 2008 -25% 2008 -25%

3rd 2008 -20% 2012 -30%

4th 2008 -15% 2012 -25%

5th 2012 -30% 2008 -20%

6th 2012 -25% 2008 -15%

7th 2008 -10% 2012 -20%

8th 2012 -20% 2012 -15%

9th 2012 -15% 2008 -10%

10th 2012 -10% 2012 -10%

11th 2008 -05% 2008 -05%

lowest 2012 -05% 2012 -05%

5.6 Emissions trade-offs

5.6.1 The physics-based principles underlying emissions trade-offs was presented to interested

CAEP members prior to the Third Steering Group Meeting in the Emissions Technology Workshop

sponsored by the International Coordinating Council of Aerospace Industries Associations. Table 5.3

shows the relationship between changes in LTO NOx and CO2 for each stringency option. The rapidly

rising rate of change in the NOx/CO2 trade-off for the higher stringency values is due to the accelerated

development of TL5B lean staged combustion technology.

Table 5.3. Cumulative change in of engine emissions
CAEP/6-IP/13 - 26 -

 (Thousands of Tonnes)

Forecast Period

Implementation Date

Study Option NOx CO2 NOx CO2 NOx CO2 NOx CO2

CAEP/4 Minus 5% -49 0 -26 0 -181 0 -140 0

CAEP/4 Minus 10% -146 0 -78 0 -538 0 -417 0

CAEP/4 Minus 15% -197 6,804 -105 3,629 -723 19,051 -561 11,340

CAEP/4 Minus 20% -217 10,886 -116 5,897 -798 30,845 -619 19,051

CAEP/4 Minus 25% -292 58,968 -157 31,752 -1,082 196,408 -840 131,543

CAEP/4 Minus 30% -321 83,915 -173 45,813 -1,191 282,591 -927 193,686

2002 - 2020 2002 - 2030

2008 2012 2008 2012

6. ANALYSIS OF COSTS OF STRINGENCY OPTIONS

6.1 Two types of parties incur the costs of a new NOx

 certification standard: manufacturers who

must develop technology to meet the standard; and, airline operators who purchase and maintain that

technology while also maintaining the technology in their existing fleets. The analysis identifies the various

non-recurring and recurring costs associated with the NOx stringency options. The costs are calculated where

they occur; no attempt is made to project how these costs might be translated into prices, either the price of

the engine or the fare to be paid by the users of air transport services.

6.2 One time non-recurring costs of technology acquisition, and engine design and certification,

are accounted for by manufacturers. Recurring manufacturing, maintenance and operating costs are

accounted for by the air carrier. Each cost category is independent of the others and there is no double

counting. All costs borne by the airlines are not passed through as higher ticket prices.

6.3 Non-recurring manufacturing costs are incurred at the beginning of the forecast period.

Recurring manufacturing costs and operator costs occur throughout the forecast period, and yearly totals

increase as a greater number of improved technology aircraft enter the fleet in later years. Yearly NOx

benefits increase in proportion to the number of improved technology aircraft entering the fleet, thus accruing

in larger proportions later in the forecast period. Marginal compliance cost-benefit results, that is, yearly costs

compared to yearly benefits, vary across the forecast period. Total compliance cost-benefit results used in

the economic analysis depend on the time scale, and the 2020 totals extrapolated out to 2030 show this effect.

6.4 Non-recurring costs of technology improvements

6.4.1 Factors relevant to the cost estimates for each technology level are: 

TL1 — Minor change

6.4.2 Given the diverse nature of a TL1 solution, the work content and hence cost is difficult to

estimate. A minimum requirement would be expected to be some modelling work, minor design changes,

ground running of either a production or development engine to verify airworthiness and emissions
- 27 - CAEP/6-IP/13

compliance, and a re-issuing of associated certification authority paperwork. It was agreed that a

non-recurring cost of $10 million per engine family would be a fair estimate for this type of change. Since the

work programme associated with the TL1 is of modest size, it is proposed that this cost would be incurred

in the year preceding the introduction of the stringency.

TL2 — Scaled proven technology

6.4.3 The TL2 solution would require substantial modelling, design, combustion rig testing,

modification and testing of development engines, flight testing of a set of production-standard engines, and

the costs of certification. New production tooling and assembly line training/accreditation may also be

required. The effort and resulting cost of a TL2 change are similar to the expenditures required for a new

engine type design, and are relatively well understood by the manufacturers. The non-recurring costs borne

by the manufacturers for the modification and certification activities have been estimated to be $50 million

(2003 year dollars) per engine type affected. In some cases several engine models within a family can be

treated using one solution, and the cost of the solution is counted only once per family.

6.4.4 It has been assumed that the TL2 solution would take 4 years to deliver the required certified

engine family, so the above spending has been assumed to be evenly spread over the four years preceding

the introduction of the stringency.

TL5A — New technology (current industry best practice)

6.4.5 Where one or more manufacturers have demonstrated 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.

6.4.6 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 hundreds

of millions of dollars. Publicly supported programmes (e.g. NASA or EU programmes) do link costs and

deliverables in openly published documents, but these programmes often address several engine attributes,

include funding from several sources and often span several years' work. Understanding which goal cost how

much remains a point for speculation. This is discussed in greater detail under TL5B.

6.4.7 These factors make it difficult to derive a single non-recurring cost for one manufacturer to

catch-up with the industry leaders. The minimum cost for a TL5A programme would be equivalent to a TL2

programme with the addition of some applied research for technology acquisition. For example, it might be

necessary to conduct several iterations on the typical TL2 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. The upper limit on cost of a TL5A programme would depend on the amount that

a manufacturer could justify investing rather than cease production of an engine type, thereby ceding the

market for that engine type to other manufacturers (equivalent to a TL3). It has been estimated by the

manufacturers and agreed to by FESG that the range $75-150 million represents the costs of a medium risk

technology acquisition programme and the associated costs of introducing that technology into service.
CAEP/6-IP/13 - 28 -

10 CAEP-SG20031-IP/2, Technology Readiness Level Scale as Applied to Low Emission Combustors for Civil Aircraft, Fourth

Steering Group Meeting, 23-17 June 2003, Orlando

6.4.8 It has been assumed that the TL5A solution would take 4 years to deliver the required

certified engine family, so the above spending range has been assumed to be evenly spread over the four

years preceding the introduction of the stringency.

TL5B — New technology (beyond current best)

6.4.9 The designation TL5B covers the situation where no engine manufacturer has demonstrated

the required NOx stringency. It relates to targets of current 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. Industrial partners also contributed similar levels of funds, which took

some technology as far as the TRL6 stage. The bases for the TALON and LEC

technologies emerged from this research, but both required significant further

development and validation by Pratt & Whitney and GE respectively;

b) the EU EEFAE programme is spending over $100 million taking technology and

attempting to demonstrate its viability in an experimental engine environment; and

c) the E3E programme in Germany has spent $50 million on staged combustion

development.

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 a technology level (TRL) of 4 to

6

10

. The designation TL5B covers the situation where no engine manufacturer has demonstrated the required

NOx stringency. It relates to targets of current and future research programmes. Quantifying the costs and

timescales of such programmes is difficult. The costs of similar programmes are used to provide the order

of magnitude of such costs. This is discussed in Appendix C.

6.4.10 Given the difficulties described in defining the costs and timescales of a major step forward

in combustion technology it has been possible only to set lower and upper bounds. Bearing in mind that a

totally new engine type (based on available technology) is reputed to cost over $1 billion to develop, and that

new combustion technology may not be compatible with existing engine geometry, this could represent the

upper limit to the estimate for this solution. Low-NOx combustors developed for ground-based power

generation have been developed but adapting this technology for flight would require significant changes to

conventional engine design. Bearing in mind that staged combustion research has taken about 20 years to

deliver a system (GE's DAC), and in recognition of the sums detailed above concerning annual spend on these

programmes, the next step forward in combustion technology could be expected to involve a similar amount

of work. A figure of half this upper bound has been used to represent the minimum cost of a major research

programme.
- 29 - CAEP/6-IP/13

6.4.11 It has been assumed that the TL5B solution would take 8 years to develop the new

technology through to delivery of a certified engine family. In the case of the 2012 implementation of proposed

stringencies, the range of costs has been assumed to be evenly spread over the eight years preceding the

introduction of the stringency. In the case of the 2008 implementation, there is not enough time between

CAEP/6 and the date of implementation for this, so the costs have been spread over the preceding four years

for the purposes of this analysis.

6.4.12 The work content of each technology change is summarized in Table 6.1, and the costs

associated with these changes in Table 6.2.

Table 6.1. Manufacturer work content associated with each technology level

Category

Technology level (TL)

1 2 5A 5B

Product design

Certification analysis/ground test

Product development

Certification flight test

Post certification product improvement

Applied technology development

Post certification redesign

New Technology research

Potential engine architecture change

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

Table 6.2. Non-recurring manufacturing costs associated with Table 6.1

Technology

Level

Non-Recurring Costs 

1 $10m

2 $50m

5A $75-150m

5B $500-1,000m

6.5 Recurring costs due to stringency levels

6.5.1 In addition to the non-recurring costs discussed above, the following categories of recurring

cost impacts resulting from the proposed NOx stringency options have been identified:

a) increase in the production cost of each engine due to increased engine complexity and

the use of more expensive materials as necessitated by the new standard; 

b) increase in engine maintenance cost resulting from increased engine complexity and the

use of more expensive materials as necessitated by the new standard;
CAEP/6-IP/13 - 30 -

c) increase in spare engines inventory to maintain "split" fleets (i.e., having to maintain

aircraft with new NOx technology level engines while also maintaining the existing fleet);

d) cost of additional fuel due to increased fuel consumption in the operation of TL5B

engines;

e) cost of additional maximum takeoff weight (MTOW) to preserve aircraft mission

capability in the operation of TL5B engines;

f) increase in landing fees resulting from the increased gross weight of aircraft using TL5B

engines; and

g) diminution in value of the existing fleet.

The assumptions and methodology used to calculate the costs from each of these categories are discussed

below. 

6.6 Incremental recurring manufacturing cost per engine

6.6.1 Estimates for the increase in incremental engine production costs (initially derived as a

percentage of the total engine cost, and then converted into a dollar cost) resulting from increased engine

complexity and the use of more expensive materials are shown in Table 6.3:

Table 6.3. Incremental recurring manufacturing costs per engine

Technology

Level

Recurring Costs 

1 No cost increase

2 $ 20,000 increase

5A $ 40,000 increase

5B $150,000 increase

6.6.2 The estimates are based upon the following assumptions:

a) the combustor is 5% of the engine cost;

b) TL2 and TL5A modifications increase combustor costs by a relatively small amount; and

c) TL5B modifications increase combustor costs by 50% (i.e., 2.5% of engine cost).

6.7 Fuel burn penalty for TL5B engines

6.7.1 Projected TL2 and TL5A modifications are assumed by the engine manufacturers to have

fuel burn characteristics substantially similar to current TALON, Phase 5 and LEC ("known") combustor

technologies. This is based upon their experience with in-service applications of similar technologies. These

current combustor technologies have essentially 100% fuel efficiency; consequently, no fuel burn penalty is
- 31 - CAEP/6-IP/13

11 Engine improvements not involving the combustor are required to improve the fuel efficiency of current engine technologies

12 SAS operates a B737NG fleet powered by CFM dual-annular combustor (DAC) engines. Finnair and Swiss operate a similarly

powered A320 aircraft family fleet.

13 Note: These rates were not actually used in the final FESG CAEP/5 cost impact model for noise policy analysis

attributed to TL2 or TL5A modifications11. While TL5B technologies are, at this time, "unknown," staged

combustor (e.g., DAC) technology has been determined to be an appropriate surrogate for projecting the

characteristics of TL5B modifications. Nominal aircraft performance databases show a fuel burn difference

of 1-2% and empirical data from SAS, Finnair and Swiss operations using DAC engines confirm the increase

in fuel consumption of approximately 2%12. Fuel burn may be increased in staged combustors due to higher

pressure loss (either the result of a longer or wider combustor configuration, or an intentional increase in

pressure drop to improve fuel-air mixing) and/or non-standard temperature profile at the combustor exit,

particularly during partial staging, that can affect turbine efficiency and cooling flow requirements. This fuel

burn penalty is deemed to be representative of TL5B modifications, as discussed further in Appendix C.

6.7.2 The fuel burn penalty is reflected in two separate categories: (1) the cost of additional fuel

that will be purchased by operators of TL5B engines; and, (2) the cost of additional maximum takeoff weight

(MTOW) needed to preserve mission capability.

Cost of additional fuel

6.7.3 Based upon its work in preparation for CAEP/5, Campbell-Hill used U.S. DOT Form 41 for

U.S. airlines and IATA fuel burn data for non-U.S. airlines to establish average fuel burn per seat-block hour

rates for each of the FESG forecast aircraft seat size categories13. For each aircraft type, these rates were

then multiplied by the "actual" seats from Boeing used in the CAEP/5 cost impact model for noise and the

FESG forecast block hours in the CAEP/6 forecast to arrive at base fuel burn for each affected new delivery

in the forecast. Affected new deliveries are those aircraft with engines receiving a TL5B fix to comply with

the new NOx standard. The effect of the new NOx standard is to increase the fuel burn of these aircraft by

two percent. To calculate the cost impact, the increased fuel consumption was then multiplied by the average

fuel price per gallon, in the amount of $0.95. This amount was determined to be reasonable within the

NEMTG carrier cost subgroup based upon the input of carrier fuel purchasing experts.

Cost of additional MTOW

6.7.4 The unit cost per pound and number of pounds of increased MTOW needed to preserve the

mission capability of forecasted new-delivery aircraft using higher fuel consumption TL5B engines is

estimated. The increase in MTOW preserves mission capability by allowing the aircraft to carry the additional

fuel necessary for the TL5B engine. If the MTOW is not increased, the additional fuel burn would reduce

the payload-range for a marginal (MTOW-limited) mission. The analysis assumes that each carrier using

affected aircraft either operates or will desire to operate a marginal mission using the aircraft. The additional

MTOW is necessary in order to maintain fleet flexibility and service levels on all routes, and must be added

to all affected aircraft because it is not feasible to designate exclusive use of individual aircraft to particular

routes. Consequently, all new aircraft deliveries using TL5B engines following the implementation date of the

new NOx standard will require the increased MTOW to preserve full airline mission capability. This

assumption results in the inclusion of all aircraft using TL5B engines in the costs calculation. While this
CAEP/6-IP/13 - 32 -

14 The regression is significant at the 10-7 level

assumption might overstate the actual use of these aircraft in marginal missions that do not require additional

MTOW, the additional MTOW is required to preserve the asset value of all such aircraft which is based in

part on payload-range capability.

6.7.5 The unit cost calculation is based upon an average cost of additional MTOW of $217 per

pound. To determine this amount, the aircraft list price for low and high gross weight versions of the

B737-700, B757-200, B767-300ER, B777-200ER, and B747-400 were regressed against the aircrafts'

maximum gross takeoff weights. The regression resulted in a line with a slope of $217 per pound14. This is

the average total cost per additional pound of MTOW. Because it is the regression of aircraft price, it includes

the price of incremental engine thrust needed to accommodate the additional weight.

6.7.6 The question of whether non-structural changes could be used as a cost of additional MTOW

was examined. These changes to existing airframes could perhaps be had for less than $100 per pound.

However, more would have to be spent if the aircraft needs structural changes or additional thrust. In the

global fleet many different weight options of each aircraft are operated so, on average, it can be expected

that some aircraft will require structural and thrust changes to restore their capability. The cost of increased

MTOW calculated via the regression can be thought of as averaging the effect of both relatively high-cost

and low-cost modifications.

6.7.7 The take-off weights prior to being increased to restore mission capability of affected aircraft

having TL5B engines were calculated using the average takeoff weights for the aircraft in the FESG fleet

database. Where a takeoff weight was not available, the highest available MTOWs were used for new

deliveries of older aircraft types that can be assumed to have "grown" over time, and the lowest MTOWs

were used for the newest types or variants.

6.7.8 Once the base takeoff weights were established, the amount of additional takeoff weight

required to restore the range lost due to increased fuel consumption was calculated using the average of the

payload-range curves of the CF6-80C2B powered B747-400 (at both 800,000 lbs. MTOW and 875,000 lbs

MTOW) and the Trent 800 powered B777-200ER (at 656,000 lbs. MTOW). The increase in specific fuel

consumption caused by the TL5B engine shifts the fuel-limited weight curve to the left, reducing payload

range. The incremental MTOW is calculated to shift the intersection of the fuel and MTOW curves back an

equal amount to the right to reclaim the lost payload-range assuming extra fuel can be carried. The secondary

effect of extra weight needed for fuel to carry the added fuel is not included. The model uses as its input the

percentage change in range divided by the percentage change in MTOW, producing a value of 1.06. Using

this methodology, a 1.88% (i.e., 2/1.06) increase in MTOW is needed to offset a 2% increase in fuel

consumption.

Landing fees due to additional take-off weight

of aircraft using TL5B engines

6.7.9 The calculation assumes that increases in maximum landing weight (MLW) are proportional

to increases in MTOW, and is based upon average landing fee dollar costs per 1,000 lbs of MLW (in the

U.S.) or MTOW (in all other regions). Boeing has performed an analysis of worldwide landing fees and has
- 33 - CAEP/6-IP/13

15 34% of total forecast global operations are assumed to occur in the United States and 66% in the remainder of the world

16 Spares functions were provided by SAS, American Airlines and FedEx.

determined that the average rate of "international" landing fees (all regions except the U.S.) is $4.50 per 1,000

pounds of MTOW. The average rate of landing fees in the U.S. is $1.70 per 1,000 pounds of MLW.

6.7.10 For each forecast year, the increase in landing fees has been calculated by deriving the total

incremental fee increase resulting from an aircraft weight increase and multiplying it by forecasted operations

in the appropriate region15. This calculation did not take into consideration any environment-related elements

in average global landing fees. The total incremental fee increase was calculated by applying the landing fee

rates to the average weight increases for all TL5B aircraft delivered in that forecast year and all prior years

(total TL5B aircraft operating) resulting from a 1.88% increase in MTOW (and corresponding MLW) in the

affected aircraft.

6.8 Maintenance cost

6.8.1 Previous NOx stringency increases have increased carriers' maintenance costs. To estimate

this impact in relation to the proposed NOx stringency options, the NEMTG carrier cost subgroup determined

it would be reasonable to again use DAC technology as a surrogate for TL5B modifications. Empirical data

from SAS, Finnair and Swiss operations using DAC engines indicate an increase in maintenance costs in the

range of $4-5 ($4) per engine flight hour (EFH) resulting from the increased complexity of the engine design,

and higher cost and reduced durability of certain materials. On the basis of this information, TL5A

modifications result in increased maintenance costs in the range of $1-3 ($2) per EFH, and TL2 modifications

would result in increased maintenance costs in the range of $0-2 ($1). These latter ranges (for TL5A and

TL2) have been established proportionally to the increase in maintenance costs projected for TL5B

modifications.

6.8.2 Engine flight hours have been determined by subtracting average taxi time from total block

hours. ICAO times-in-mode used in the economic analysis provide an average taxi time of 26 minutes. Actual

average taxi time is most likely less, which leads to a conservative estimate of engine flight hours. The cost

calculation is based upon engine flight hours and average cost per hour. No sensitivity analysis was done in

connection with these costs.

6.9 Spare engines inventory

6.9.1 Spare engines are required by airlines to operate reliably. By exchanging a ready-to-fly spare

engine for an on-wing engine in need of repair, an expensive aircraft can be kept flying with minimum lost

time on the ground while the engine is repaired off wing. The engine spares ratio is the number of spare

engines required to support a given level of aircraft operator fleet reliability divided by the number of on-wing

engines. The engine spares ratio falls as the size of the installed engine fleet grows. That is, there is a spare

engine economy of scale with respect to on-wing engine fleet size due to maintenance schedules and engine

reliability as shown in Figure 6.316. 
CAEP/6-IP/13 - 34 -

American, FedEx, SAS Average Engine Spares Function

y = 0.624x-0.3758

R

2

 = 1

0 %

5 %

10%

15%

20%

25%

30%

0 50 100 150 200 250 300

Installed Engines

Engine Spares Ratio

Figure 6.3. Distribution of spare engines required by engine fleet size

The number of required spare engines to support an operator's fleet also depends upon the degree of

commonality between different thrust rating engine models on a given aircraft type and the degree of

commonality on engine models across different airframe/engine combinations. The greater the degree of

commonality provides for a "pooling" effect resulting in an investment savings for spare engines. The spare

engine inventory cost was developed by grouping engine models of common build standard together in engine

families even if those engines are installed on multiple aircraft installations. The analysis does not consider

the effect of companies that specialize in leasing engines to small fleet operators.

6.9.2 As an example of the economy of scale of spares with increasing fleet size, assume an airline

with a 35 twin engine (70 engines) on the effective date of the new NOx standard that grows to 50 twin

engine aircraft (100 engines) ten years later. In the absence of the new NOx standard, the airline might have

required 7%, or roughly 5, spares to support its 70 engine fleet and a total of 6%, or 6 spare engines to support

its larger 100 engine fleet. The spares ratio declines as the fleet size increases because of the economy of

scale.

6.9.3 The implementation of the NOx

 stringency options could create a situation that imposes

additional costs on an operator. If an operator was taking delivery of aircraft and spare engines to support

that fleet and if the engine has to be designed differently so as to comply with the stringency option, this could

create a "split fleet". If this were the case, the operator would now have to invest in additional spare engines

to support the engine model with the design change in addition to the spare engines the operator to support

the pre-existing aircraft fleet type. While operating with a split engine fleet adds incremental cost over

operating a fleet with uniform engines, the amount of such additional cost is less than the cost of re-engining

the existing fleet with new engines to maintain engine uniformity.
- 35 - CAEP/6-IP/13

6.9.4 Engines requiring TL1 technology, which does not involve any mechanical alteration of the

engine, are assumed to not interfere with inter-operability after the NOx stringency effective date, therefore

the incremental spare engine cost impact for TL1 technology changes is assumed to be zero. The cost impact

calculation for TL2 technology spare engines assumes that on average, the engines manufactured after the

stringency implementation date will share approximately 50% commonality with their corresponding engine

family models manufactured prior to the stringency implementation date. This 50% commonality will minimize

the incremental spare engine cost impact for TL2 technology insertions from a situation if there had been no

commonality. TL5A, and TL5B technology insertions are assumed to fundamentally change the engine design

such that engines designated with either a TL5A or TL5B technology after the stringency implementation date

will require their own dedicated fleet of spare engines.

6.9.5 Continuing the example in Section 6.9.2 above, in the presence of the new standard the airline

is left with two incompatible fleets which each require their own set of spare engines. In this case, the airline

would still require roughly 5 spare engines for its 70 engine pre-stringency option fleet. It would require

10.4%, or roughly 3, spares for the incremental 30 engine compliant fleet delivered after the effective date.

The net effect of the new standard, requiring the airline to operate a split fleet, has increased the number of

spares needed to support the same 100 total engines from 6.0 engines for the uniform fleet to 8.0 engines (5

+ 3) for the split fleet. The incremental spare engine cost in the economic analysis is the investment cost for

the additional 2 spare engines.

6.9.6 To complete the incremental spares engine cost impact analysis, an estimated engine price

is required. FESG derived an average spare engine price range of $5 to $12 million as a function of a number

of installed engines in various aircraft seat categories. This price range was derived by gathering estimated

list prices of engines for the production engines in the FESG fleet forecast from commercially available pricing

guides such as AVITAS Jet Engine Values. These price estimates were then multiplied by the number of

installed engines, by engine model, to be delivered in the FESG forecast period of 2002 to 2020 and then

divided through by the total number of delivered installed engines for each seat category to arrive at a range

of estimated engine prices. The analysis uses the following equation:

Spares Cost Impact = (number of incremental engines required) X (weighted average engine price)

A complete illustration of the calculation is shown for the 5% stringency option implemented in 2008 in

Appendix K. An analysis of the portion of the engine fleet that would be affected by a NOx stringency option

requiring a TL2, TL5A or TL5B technology level shows that the overall increase in number of engines to

support the global "split" fleet is on the order of 2 to 3 percent.

6.9.7 The FESG fleet forecast did not predict the number of engines for each aircraft and engine

combination by year for each airline. The current forecast only predicts the total number of airframe/engine

combinations in the global fleet. Accordingly, the spares requirement for each airline could not be calculated

after the forecast base year. Modelling calculations were a global fleet spares requirement using the average

fleet size in the base year grown by each fleet's individual growth rate. The number of spares required is

calculated by weighting the individual fleet engine spares function by the base year fleet distribution as shown

in Figure 6.3.
CAEP/6-IP/13 - 36 -

17 CAEP-SG20031-IP/9, FESG Assessment of Applying a Production Cut-Off to the CAEP/4 NOx

 Standard, Orlando, United States,

23-27 June 2003

Figure 6.4. Size distribution of global fleet

6.9.8 The distribution of fleets by number of engines was calculated for the base year fleet. An

engine fleet was defined as all engines for a single airline sharing a common engine family in the ICAO NOx

database. The fleet sizes were then grouped into ranges of 25 engines. For example, there are approximately

200 fleets with sizes between 26 and 50 engines and nearly 1,800 between 1 and 25 engines. Finally, a

continuous mathematical function was fit to the discrete distribution of fleet sizes to use as the weighting

function. This is shown in Figure 6.4. 

6.9.9 To determine the number of spares for each individual fleet, this weighting function was

shifted proportionally along the x-axis (to the right as the average fleet size grew with time), multiplied by the

spare engines function (spares ratio multiplied by the number of engines), and integrated to create a weighted

average spares ratio curve.

6.10 Diminution in value of the existing fleet

6.10.1 It is assumed the announcement of a new NOx standard will initiate a market-driven

production cut-off effective on the same date as the implementation date for the new NOx standard for new

engine types. Consistent with the FESG economic analysis of a CAEP/4 NOx standard production cut-off17,

such market activity may be expected to result in lost value in existing fleets. In view of the uncertainty

surrounding the impact of emissions options on fleet values, a sensitivity test has been included presenting

results excluding any loss of residual value.

6.10.2 One method for calculating lost value in existing engine fleets is to estimate the "upgrade"

retrofit cost required to bring the current engines into "compliance" with the new standard through engine

improvements. Although it is unknown whether such upgrades would be feasible or available, as a means of

capturing diminution in residual value, the engine manufacturer experts have scaled the costs of existing
- 37 - CAEP/6-IP/13

emissions kits to develop cost estimates for hypothetical engine modification packages. These cost estimates

are shown in Table 6.5.

6.10.3 To calculate the total cost impact, estimated costs were applied to the total number of

noncompliant engines on active aircraft delivered between 2002 and the effective date of the option. This

method was employed to quantify the residual value impact of a new NOx standard on the existing engine

fleets, and does not presume retrofits would be available and/or occur.

Table 6.5. Loss in fleet value of affected aircraft from a change in NOx stringency

Technology

Level

Loss in Fleet Value

TL1 No modification package

TL2 -$ 250,000

TL5A -$ 500,000

TL5B -$1,000,000

6.11 Total incremental cost impacts

6.11.1 Total incremental costs are the sum of: non-recurring manufacturing costs, recurring

manufacturing and operator costs, and lost fleet value. An analysis was made of the importance of lost fleet

value and of landing fees to the results. They have no independent or combined effect on the rank ordering

of results; however, the costs for stringency options where they apply would change.

6.11.2 Undiscounted total airline costs associated with each option by cost category for the central

analysis are summarized in Table 6.6 for the 2020 time period and in Table 6.7 for 2030 (see next page).

These tables are reproduced in Appendix J, which shows the same information in discounted and

undiscounted values. 

7. QUANTIFIERS OF COST-BENEFIT RESULTS 

7.1 The economic analysis is designed to demonstrate the effect of more stringent ICAO Annex

16, Volume II certification values on the fleet. Tonnes of NOx reduced, operator costs and identification of

the types of technology change required of noncompliant engines to meet a stringency option have been

developed using an internally consistent set of assumptions. These three variables provide a relative ranking

of the cost per tonne of NOx from different stringency options to guide decision makers according to the

ICAO terms of reference of environmentally beneficial, technically feasible and economically reasonable.

7.2 The results of the modelling scenarios of future costs and benefits are not predictions of the

future, nor are they designed for use in local air quality and climate models. The results are uncertain to the

degree the assumptions of the future are uncertain. The longer the time horizon the more uncertain the results

become. Projections within a fifteen to twenty year time frame are considered to be reasonably certain.

7.3 The FESG base year from which the fleet data was developed is 2002. The central analysis

is from the base year to 2020. To measure longer term costs and benefits the central analysis was

extrapolated to 2030. Costs are expressed in 2002 year dollars; benefits are not monetized. Key assumptions

have been further analyzed to determine their impact on the results. These assumptions are: the revised fleet

forecast; use of the landing and take-off cycle; lead time for developing TL5B engines; the effect on demand

of passing a portion of operator cost on to passengers; lack of further stringency increases; and, discounting.
CAEP/6-IP/13 - 38 -

Operator

Cost

Stringency 

Option

Engine 

Production

Aircraft 

Production 

Incremental 

MTOGW

Engine 

Maintenance FuelLanding 

Fees

Spares 

Inventory

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 120 $ 120 $ 83 $ - $ 74 $ - $ - $ 1,175 $ 177 $ 1,452 $ 1,452 $ 1,629 $ 1,629

10% $ 360 $ 360 $ 284 $ - $ 283 $ - $ - $ 2,040 $ 651 $ 2,967 $ 2,967 $ 3,618 $ 3,618

15% $ 1,000 $ 1,800 $ 904 $ 1,264 $ 605 $ 667 $ 222 $ 3,379 $ 1,403 $ 8,041 $ 8,841 $ 9,444 $ 10,244

20% $ 2,530 $ 4,830 $ 1,128 $ 2,227 $ 742 $ 1,063 $ 385 $ 4,830 $ 1,680 $ 12,906 $ 15,206 $ 14,586 $ 16,886

25% $ 7,185 $ 14,260 $ 3,085 $ 12,347 $ 1,826 $ 5,833 $ 1,879 $ 6,628 $ 3,881 $ 38,783 $ 45,858 $ 42,664 $ 49,739

30% $ 10,500 $ 21,000 $ 3,909 $ 16,846 $ 2,314 $ 8,296 $ 2,519 $ 7,416 $ 4,725 $ 51,799 $ 62,299 $ 56,523 $ 67,023

Stringency Year = 2012

5% $ 120 $ 120 $ 60 $ - $ 40 $ - $ - $ 1,052 $ 464 $ 1,272 $ 1,272 $ 1,736 $ 1,736

10% $ 360 $ 360 $ 204 $ - $ 152 $ - $ - $ 2,138 $ 1,652 $ 2,854 $ 2,854 $ 4,506 $ 4,506

15% $ 1,000 $ 1,800 $ 653 $ 915 $ 326 $ 356 $ 119 $ 3,563 $ 3,608 $ 6,933 $ 7,733 $ 10,540 $ 11,340

20% $ 2,530 $ 4,830 $ 816 $ 1,596 $ 400 $ 571 $ 205 $ 4,704 $ 4,323 $ 10,822 $ 13,122 $ 15,145 $ 17,445

25% $ 7,185 $ 14,260 $ 2,231 $ 9,011 $ 983 $ 3,152 $ 1,023 $ 7,096 $ 9,723 $ 30,680 $ 37,755 $ 40,404 $ 47,479

30% $ 10,500 $ 21,000 $ 2,830 $ 12,257 $ 1,255 $ 4,528 $ 1,374 $ 8,106 $ 11,915 $ 40,849 $ 51,349 $ 52,764 $ 63,264

Fleet Value

Engineering & 

Development

Manufacturer Costs Manufacturer Costs Operator Costs Fleet Value

Non-recurring Costs Recurring Costs Without Loss With Loss

Expressed as Millions of Constant 2002 U.S. Dollars

Totals

Table 6.6. Undiscounted incremental cost impacts of NOx stringency options: 2002-2020

Table 6.7. Undiscounted incremental cost impacts of NOx stringency options: 2002-2030
- 39 - CAEP/6-IP/13

Operator

Cost

Stringency 

Option Total to 2020

Estimated Total 

to 2030

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 120 $ 120 $ 1,332 $ 1,981 $ 177 $ 2,101 $ 2,101 $ 2,278 $ 2,278

10% $ 360 $ 360 $ 2,607 $ 3,698 $ 651 $ 4,058 $ 4,058 $ 4,709 $ 4,709

15% $ 1,000 $ 1,800 $ 7,041 $ 12,975 $ 1,403 $ 13,975 $ 14,775 $ 15,378 $ 16,178

20% $ 2,530 $ 4,830 $ 10,376 $ 19,834 $ 1,680 $ 22,364 $ 24,664 $ 24,044 $ 26,344

25% $ 7,185 $ 14,260 $ 31,598 $ 76,274 $ 3,881 $ 83,459 $ 90,534 $ 87,340 $ 94,415

30% $ 10,500 $ 21,000 $ 41,299 $ 101,297 $ 4,724 $ 111,797 $ 122,297 $ 116,521 $ 127,021

Stringency Year = 2012

5% $ 120 $ 120 $ 1,152 $ 1,740 $ 464 $ 1,860 $ 1,860 $ 2,324 $ 2,324

10% $ 360 $ 360 $ 2,494 $ 3,499 $ 1,652 $ 3,859 $ 3,859 $ 5,511 $ 5,511

15% $ 1,000 $ 1,800 $ 5,933 $ 10,831 $ 3,608 $ 11,831 $ 12,631 $ 15,439 $ 16,239

20% $ 2,530 $ 4,830 $ 8,292 $ 16,150 $ 4,323 $ 18,680 $ 20,980 $ 23,003 $ 25,303

25% $ 7,185 $ 14,260 $ 23,495 $ 62,612 $ 9,723 $ 69,797 $ 76,872 $ 79,520 $ 86,595

30% $ 10,500 $ 21,000 $ 30,349 $ 83,262 $ 11,915 $ 93,762 $ 104,262 $ 105,677 $ 116,177

Fleet Value

Engineering & 

Development

Manufacturer Costs Mfg + Operator Costs Fleet Value

Non-recurring Costs Recurring Costs Without Loss With Loss

Expressed as Millions of Constant 2002 U.S. Dollars

Totals Estimated to 2030

7.4 Assessment of recent events

7.4.1 The assessment of recent events places economic analysis results forward two years. Adding

the 2008 cost-benefit results for any stringency option to the corresponding 2012 option, and dividing this

number by two will give a number that approximates the 2010 value. How close this number is to the 2010

cost-benefit results had it been modelled cannot be made a priori although there is a high degree of confidence

it lies close to this average value. This method supports the conclusion relative cost, benefits and cost-benefit

results rankings would remain unaffected, and all 2020 and 2030 absolute values would be less than 2 percent

lower.

7.5 Effect of ICAO times in mode and aircraft performance

7.5.1 FESG conducted an analysis of ICAO times in mode, aircraft performance and use of

generic airports. The CAEP/5 FESG fleet forecast and CAEP/5 Working Group 1 (Noise - Technical)

in-production database was used in EDMS for purposes of comparison with the Boeing Global Emissions

Model (GEM). The CAEP/5 fleet forecast approximates that used in GEM. The CAEP/5 fleet forecast was

used in EDMS to produce a base case for comparison with GEM. Quantities of NOx and CO2 emissions up

to 1 kilometre altitude using both ICAO times in mode and aircraft performance, and approximate actual

aircraft performance and times in mode using Boeing Method 2 were estimated with the GEM model. Results

of GEM and EDMS ICAO times in mode and aircraft performance were found to be comparable. This
CAEP/6-IP/13 - 40 -

supports the finding that relationships between GEM ICAO and Boeing Method 2 results apply to the EDMS

model. Detail is given in Appendix L.

7.5.2 There is a high degree of confidence EDMS overestimates of NOx

 emissions using ICAO

times in mode and power settings. If times in mode and power settings more representative of actual

operating practices were modelled, new EDMS values would be expected to be approximately 20% lower

than reported. Airport altitude does not affect the result that as a consequence of using approximate actual

operating conditions rather than ICAO certification procedures, the benefits would be lower.

7.6 Effect of time period used

7.6.1 Benefits from reduced NOx emissions are expected to accrue over the long term, as

compliant aircraft enter the fleet and in-service aircraft having engines exceeding the new NOx standard

retire. The FESG aircraft fleet forecast extends to the year 2020 and the main benefits analysis cover this

forecast period. A longer-term view could indicate the possible scale of these greater benefits, and this might

be helpful to the decision makers. Extending the NOx reduction benefits to 2030 was completed as a

sensitivity test. Results showing benefits extended to 2030 are reported in Table 5.3, with comparisons of

costs and benefits extended to 2030 against 2020 results.

7.6.2 As discussed in Section 5.4, and notwithstanding the market-driven production assumption,

it takes several years for new aircraft having engines with combustion technology that would meet the new

stringency options to enter the fleet in significant quantities, and for aircraft having engines that do not comply

with the new standard to retire. The full benefits from a stringency option will not be realized for several years

after a stringency option is implemented; this might take 3 decades or more, during which time other changes

might also affect civil aviation, particularly further NOx stringency standards. 

7.7 Effect of no further stringency increase on benefits results

7.7.1 The analysis assumes no further stringency increase over the period used to conduct the

analysis. The effect of the CAEP/4 standard embedded in the Working Group 3 in-production aircraft

database is the baseline from which the benefits of the CAEP/6 stringency options are derived. The

assumption of no further stringency increase influences the quantity of long term benefits resulting from the

original stringency increase. An analysis was made using EDMS data and the FESG fleet forecast. Detail

is given in Appendix M, and progress in meeting more stringent emissions certification standards is presented

in Figure 3.2.

7.7.2 If an option implemented in 2008 were followed by another stringency increase in 2012,

benefits from the original certification standard could be diminished beginning in 2012. At one extreme, if all

engines made compliant to the 2008 standard became noncompliant under the later standard, in 2012 no

further benefits would accrue from the original standard if all 2012 engines were installed on newly purchased

aircraft. On the other extreme, if all engines made compliant to the 2008 standard were also compliant with

the 2012 standard, benefits from the original standard would continue to accrue unabated. 

7.7.3 If an initial stringency increase is followed by further stringency increase(s), starting the year

the later standard(s) becomes effective, benefits attributable to the original standard are adjusted downward.

The magnitude by which benefits of the initial standard change depends on the effectivity date of the latter

standard(s) relative to the effectivity date of the original standard. This change becomes larger the shorter
- 41 - CAEP/6-IP/13

18 CAEP/5-WP/24, Economic Analysis of Potential Market-Based Options for Reduction of CO2

 Emissions from Aviation; and,

CAEP/5 FESG Final Report: analysis of market-based options for the reduction of CO2 emissions from aviation with the AERO

modeling system, November 2000.

19 This is an average drawn from broad range of differing engine and technology programs which exhibit a high degree of variation in

the time period to bring the product to market. 

the time period is between the effectivity dates of the two stringency changes due to the smaller number of

aircraft subject to the original standard entering the fleet. The proportion by which the benefits accruing to

the earlier standard are diminished depends on the number of airframe/engine combinations affected by each

standard, and the rate at which newly affected aircraft enter the fleet under each standard and the retirement

curves that apply to them. 

7.8 Effect of no increased ticket price on demand

(second order effects)

7.8.1 Costs to improve noncompliant engines are not passed onto passengers through increased

ticket price and demand is unaffected. No account has been taken of wider local, regional or national impacts.

The demand effect for cost increases in the corresponding range of magnitudes made in the CAEP/5

economic analysis, should they have been modelled, indicates any reduction in demand would lie between 0.3

and 0.35 percent and would be insignificant18. Lower demand for aviation services resulting from costs passed

through to consumers is negligible.

7.9 Effect of the lead time for 2008 TL5B changes

7.9.1 It is assumed eight years are needed for the development of a TL5B engine19. A 2008 NOx

stringency implementation date for delivery of a TL5B engine does not allow for an eight year development

period. A more realistic time frame for TL5B technology changes resulting from a 2008 implementation date

would be entry into service in 2012 or later. In this case, the benefits would occur later in the forecast period.

7.9.2 For modelling purposes the assumption is made the TL5B development process is

compressed to meet the 2008 implementation date with the non-recurring development costs accruing over

the preceding four years beginning in 2004. Benefits are unaffected and begin in 2008 consistent with

modelling the other stringency options. The discounted non-recurring costs, now occurring over a four year

period, would be slightly affected as they have been reduced by half from the full eight year discounting

period, but because they occur at the beginning, this discrepancy is quite small. The cost-benefit results for

2008 TL5B technology changes would be lower than reported, yet would not meet the equivalent stringency

option implemented in 2012 due to the earlier introduction of TL1, TL2 and TL5A enhanced engines under

the 2008 options. 

7.10 Non recurring cost estimates

7.10.1 To reflect the uncertainties associated with the non-recurring costs of developing new

technologies, a range of cost estimates was adopted for TL5A and TL5B solutions. These results are reported

in Section 6.4 and Appendices J and K. Whether the high or low estimates are chosen does not affect the

cost-benefit results.
CAEP/6-IP/13 - 42 -

7.11 Residual values

7.11.1 It has been assumed that a new NOx standard will result in a reduction in value of those

in-production aircraft in the existing fleet delivered prior to the NOx stringency implementation date whose

NOx emissions do not meet the new standard. The costs of retrofitting have been used as a surrogate

measure of quantifying this loss of residual value. In view of the uncertainty surrounding the impact of

emissions options on fleet values, a sensitivity test has been included presenting results excluding any loss of

residual value.

7.12 Cost-benefit ranking of NOx

 stringency options

7.12.1 Although the standard approach in a cost benefit analysis would be to include monetary

benefits for NOx reductions by assigning monetary values to adverse health effects on humans, there are

several reasons why this approach is problematic. The health effects resulting from NOx emissions, in terms

of morbidity and mortality rates vary between locations and are imperfectly understood, and are difficult to

assess and quantify. Secondly any monetary values attached to health effects of NOx would vary by regions

of the world with differences in statistical values of life used between countries. As a result any values that

could be derived would be inappropriate for global application. Monetisation of environmental impacts is also

problematical. Data is provided in Appendix K. 

8. SUMMARY OF RESULTS OF CENTRAL ANALYSIS 

8.1 In this section, the benefits have been compared to the costs in order to rank the NOx

stringency options relative to each other. Figures 8.1 and 8.2 (pages 37-38) present undiscounted and

discounted cost-benefit results of the NOx stringency options for each of the two implementation dates, with

and without loss of fleet value and using high and low estimates of manufacturing non-recurring costs. The

tables are based on data from Appendix J.

8.2 Ranking of the options from lowest to highest cost per tonne of NOx is provided in Table 8.1

(see next page). The CAEP/4 NOx minus 10 percent stringency option has the lowest cost per tonne of NOx

reduced, and minus 30 percent the highest. 

8.2.1 The relative ranking amongst the NOx stringency options does not change under any of the

major assumptions tested for sensitivity or for duration of the forecast period under study, although the

absolute values do. For example:

a) the most recent revision to the FESG fleet forecast places costs and benefits out two

years, that is, 2020 results would occur in 2022, reducing their absolute values no more

than an estimated 2 percent. Relative cost-benefit result would remain unchanged;

b) a later date of introduction of TL5B enhanced engines for options implemented in 2008

would diminish 2008 benefits and non-recurring costs to 2012 values for this technology

alone. Relative cost-benefit results would remain unchanged; and

c) using actual times in mode and aircraft power settings would reduce benefits by

approximately 20 percent. Relative cost-benefit results would remain unchanged.
- 43 - CAEP/6-IP/13

20 The applicability date of the CAEP/2 standard was 11 November 1993, nearly 12 years after that of the first ICAO standard

(CAEP/2, 18 February 1982); the CAEP/4 standard applied to new engine certifications as of 31 December 2003, about twelve

years after the CAEP/2 standard. 

Table 8.1. Ranking of cost per tonne of NOx: 2002-2020(1)

(tonnes annually)

Ranking

(Lowest to highest)

Stringency option

1 -10% 2008

2 - 5% 2008

3 -10% 2012

4 - 5% 2012

5 -15% 2008

6 -15% 2012

7 -20% 2008

8 -20% 2012

9 -25% 2008

10 -25% 2012

11 -30% 2008

12 -30% 2012

(1) The relative ranking amongst the NOx

 stringency options

does not change under any of the major assumptions

tested for sensitivity or for duration of the forecast period,

although the absolute values do.

8.3 The six NOx

 stringency options implemented in 2012 result in cumulative total NOx reductions

of between 1 to 5 percent by the year 2020 relative to the base-case. If the implementation date was 4 years

earlier (2008), the resulting cumulative NOx reductions by 2020 are between 1 to 7 percent. A lesser NOx

stringency increase, if implemented in 2008, could provide the same amount of cumulative NOx saved over

the forecast period as a much higher stringency implemented in 2012.

8.4 ICAO NOx

 stringency standards have been increased approximately every twelve years20.

Accordingly, the assumption of no further stringency increase made in this report could overstate the long

term benefits derived from the initial stringency increase. Delaying the effectivity date for a given stringency

level has a large effect on the total benefits for any given out-year. This suggests there are two alternative

approaches to achieve a given amount of total NOx reduction in the given long term year, namely, a larger

single reduction or the combination of two smaller reduction.
- 44 - CAEP/6-IP/13

Figure 8.1 Comparison of Cumulative 2002-2020 Cost-Benefit Results: 2008 Implementation Date

 (Cost per Tonne of NOx Saved)

$0

$50,000

$100,000

$150,000

$200,000

$250,000

$300,000

$350,000

$400,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2008 Discount Rate: 0%

$0

$50,000

$100,000

$150,000

$200,000

$250,000

$300,000

$350,000

$400,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2008

Discount Rate: 3%

$0

$50,000

$100,000

$150,000

$200,000

$250,000

$300,000

$350,000

$400,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2008

Discount Rate: 7%

$0

$50,000

$100,000

$150,000

$200,000

$250,000

$300,000

$350,000

$400,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2008

Discount Rate: 9%
- 45 - CAEP/6-IP/13
- 46 - CAEP/6-IP/13

— — — — — — — —

Figure 8.2 Comparison of Cumulative 2002-2020 Cost-Benefit Results: 2012 Implementation Date

 (Cost per Tonne of NOx Saved)

$0

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2012

Discount Rate: 0%

$0

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2012 Discount Rate: 3%

$0

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2012 Discount Rate: 7%

$0

$100,000

$200,000

$300,000

$400,000

$500,000

$600,000

5% 10% 15% 20% 25% 30%

Percentage Below CAEP/4 NOx Standard

Without Loss Fleet Value, Lower Est. of Mfg Non-Recurring

Without Loss Fleet Value, Higher Est. of Mfg Non-Recurring

With Loss Fleet Value, Lower Est. of Mfg Non-Recurring

With Loss Fleet Value, Higher Est. of Mfg Non-Recurring

U.S. Dollars (2002 Dollars) per Tonne of NOx Saved

Forecast Period: 2002 - 2020 

Effectivity Date: 2012 Discount Rate: 9%
- 47 - CAEP/6-IP/13
CAEP/6-IP/13

Appendix A

APPENDIX A

FESG GLOBAL EMISSIONS MODEL REPORT

1. INTRODUCTION

1.1 Emissions calculation models

1.2 One of the present tasks of the Forecasting and Economic Support Group (FESG) is providing

cost and benefit analysis of NOx stringency options proposed for adoption at the CAEP/6 meeting. At the

August 2002 meeting in Washington, the FESG decided that two separate models would be used to assess

the benefits from a new NOx stringency standard. These are: 1) A benefits model based on the Emissions

Dispersion Modeling System (EDMS), which was originally designed by the U.S. Federal Aviation

Administration to calculate emissions for the landing and takeoff cycle and 2) a model to be developed by

Boeing which would calculate changes in global NOx emissions of the commercial fleet. The EDMS-based

model would incorporate the CAEP/6 FESG traffic and fleet forecast and would be the primary model, with

the Boeing-developed model providing further guidance and information. The Boeing model would use the

Boeing traffic and fleet forecast. The Steering Group approved these decisions at the September 2002

meeting. This paper outlines the development of the Boeing Global Emissions Model and shows the results

obtained by the model.

2. BOEING MODEL DEVELOPMENT

2.1 Basis of Boeing global emissions model

2.1.1 The Boeing Model is based on the forecasts, assumptions, methods and results detailed in

NASA/CR-2003-212331, Commercial Aircraft Emission Scenario for 2020: Database Development and

Analysis (Sutkus, et. al., 2003). This three dimensional emissions inventory for the year 2020 was created

using Boeing-developed emissions calculation methods and models, and joins those created for the years 1976,

1984, 1992, 1999, and 2015 (all NASA studies) and 2050 (for the IPCC).

2.1.2 The Boeing Model calculates the effects of proposed NOx

 stringency options by factoring

the individual airplane emissions in the baseline 2020 NASA inventory of those airplane-engine combinations

that would be subject to a new stringency rule. The model calculates the effects if the proposed rule were

applied only to new types or to all deliveries, and can apply the rule in any selected year from 2008 to 2016.

If one assumes that deliveries of all types would be affected, either through direct rule application (a

production cutoff) or through market response, the time lag between rule application to new types alone and

to all deliveries can be selected. The model calculates the reduction in global NOx produced relative to the

baseline values shown in the NASA report, and, for this study, to an extrapolation of the year 2020 inventory

to 2030. The reduction in NOx is calculated as an absolute value (metric tonnes/day) and as a percentage

change. 
CAEP/6-IP/13

Appendix A A-2

1 2.2% 2000-2005; 5.4% 2006-2010; 5.0% 2011-2015; 4.7% 2016-2020

COMPARISON OF BOEING 2001 FORECAST USED FOR 2020 BASELINE INVENTORY 

CALCULATIONS WITH 2002 BOEING FORECAST AND FESG CAEP/6 FORECAST

2000

3000

4000

5000

6000

7000

8000

9000

1995 2000 2005 2010 2015 2020

YEAR

TOTAL WORLD PASSENGER DEMAND - RPK's IN 

BILLIONS

2001 BOEING FORECAST (4.7% FROM 2000 - 2020, PRE-SEPT. 11)

2002 BOEING FORECAST (4.5% FROM 2000 - 2020)

CAEP/6 FESG FORECAST (4.3% FROM 2000 - 2020)

-16%

-3%

Figure 2.1. Comparison of traffic demand forecasts

2.2 Traffic and fleet forecast

2.2.1 The traffic forecast used in the NASA 2020 emissions inventory that forms the base case

for the Global Emissions Model was that published in the Boeing 2001 Current Market Outlook, which

predicted an average annual growth rate of 4.7% in passenger demand (RPK) from 2000 to 2020. The

commercial fleet (including non-scheduled traffic, freighter airplanes, regional jets and Russian-built aircraft)

was projected to grow from 14,548 units in 2000 to 32,954 units in 2020. This forecast was created and

published before the events of September 11, 2001, which has had a severe effect on air travel.

2.2.2 The sensitivity of the base case to the downturn in travel demand is addressed by the

Boeing 2002 Current Market Outlook forecast. The 2002 forecast projects an average annual growth rate

of 4.5% over the 2000 to 2020 time period. Traffic demand in 2020 is now expected to be about 3% less than

in the 2001 forecast, and the year 2020 fleet is expected to have about 5% fewer units. An emissions

inventory calculation based on this new view of the year 2020 would probably result in a ~3% lower value

for global aircraft emissions, an acceptable error given the uncertainties of forecasting.

2.2.3 The CAEP/6 FESG forecast of passenger demand for 2020 has an average annual growth

rate of 4.3%1 from 2000 to 2020. The FESG forecast also “begins” in year 2000 with a global traffic RPK

value 10.5% less than the 2001 Boeing forecast, a result of excluding nonscheduled traffic. The lower starting

value and the lower growth rate in the FESG forecast together produce a year 2020 traffic demand almost

16% lower than the 2001 Boeing forecast used to calculate the 2020 emissions inventory. (Figure 2.1) 

The EDMS model benefits calculation will be based on this lower CAEP/6 FESG demand forecast.
CAEP/6-IP/13

A-3 Appendix A

YEAR 2020 EMISSIONS INVENTORY FLEET DEVELOPMENT FROM YEAREND 

2000 FLEET

19196

15793

12942

10269

7077

4874 10411 16873 24749

824

1767

3068

4951

0

5000

10000

15000

20000

25000

30000

35000

40000

2000 2000-2005 2005-2010 2010-2015 2015-2020

5- YEAR TIME PERIOD

NUMBER OF AIRPLANES IN FLEET

+ USED

+ NEW

YE2000-RETIREMENTS

21491

25120

30210

36777

YEAR 2020 EMISSIONS INVENTORY FLEET DEVELOPMENT FROM YEAREND 

2000 FLEET

19196

15793

12942

10269

7077

4874 10411 16873 24749

824

1767

3068

4951

0

5000

10000

15000

20000

25000

30000

35000

40000

2000 2000-2005 2005-2010 2010-2015 2015-2020

5- YEAR TIME PERIOD

NUMBER OF AIRPLANES IN FLEET

+ USED

+ NEW

YE2000-RETIREMENTS

21491

25120

30210

36777

Figure 2.2 Development of year 2020 fleet used in emissions

inventory calculation

FLEET DEVELOPMENT TREND EXTENDED TO 2030 FOR ESTIMATE OF 

YEAR 2030 EMISSIONS BASELINE

19196

15793

12942

10269

7077

3925

594

4874 10411 16873 24749

34380

46241

824

1767

3068

4951

6527

8192

0

10000

20000

30000

40000

50000

60000

2000 2000-2005 2005-2010 2010-2015 2015-2020 2020-2025 2025-2030

PERIOD

NUMBER OF AIRPLANES

+ USED

+ NEW

YE2000-RETIREMENTS

21491

25120

30210

36777

44832

55028

FLEET DEVELOPMENT TREND EXTENDED TO 2030 FOR ESTIMATE OF 

YEAR 2030 EMISSIONS BASELINE

19196

15793

12942

10269

7077

3925

594

4874 10411 16873 24749

34380

46241

824

1767

3068

4951

6527

8192

0

10000

20000

30000

40000

50000

60000

2000 2000-2005 2005-2010 2010-2015 2015-2020 2020-2025 2025-2030

PERIOD

NUMBER OF AIRPLANES

+ USED

+ NEW

YE2000-RETIREMENTS

21491

25120

30210

36777

44832

55028

Figure 2.3 Extrapolation of year 2020 fleet to 2030

2.2.4 The year 2020 active fleet was forecast for the NASA emissions inventory calculation based

on the year 2000 year end fleet and the forecast travel demand, using a proprietary Boeing fleet development

model. The base year 2000 fleet and the forecast year 2020 fleet includes all jet and turboprop passenger and

freighter commercial airplanes in service, including Russian-built jets. The total fleet is forecast to grow from

19,196 units at year-end 2000 to 36,777 at year-end 2020. The forecast fleet growth is the net of new

deliveries, aircraft retirements from the fleet, and used airplanes returning to service, usually as freighters.

The year 2020 baseline inventory fleet contains 407 different airplane/engine combinations, 270 in the

passenger fleet and 137 freighters. 

2.2.5 In order to calculate the longer-term effects of proposed new NOx stringency levels, the

baseline year 2020 emissions calculations have been extended to the year 2030 by extrapolating the fleet

growth (or reduction) trends of each major airplane type. The extended fleet totals are shown in Figure 2.3.

These values are not the result of an “official” Boeing forecast.
CAEP/6-IP/13

Appendix A A-4

2.3 Baseline NOx emissions for 2020

and 2030 stringency benefits analysis

2.3.1 Calculation of the 2020 NOx emissions scenario documented in (Sutkus, et. al. 2003) included

certain assumptions:

a) a 10% fuel efficiency improvement was assumed for production airplanes delivered after

2009 if the number delivered after 2009 is 50% of the 2020 fleet of that type; and

b) all CFM-56 engines in the 2020 fleet were assumed to have improved emissions

characteristics — approximately 8% lower NOx emissions than present certification

levels. This assumption was made as a way of accounting for the two combustors

presently available for this engine model. The manner in which the combustion stages

activate make the certification data of the optional dual-annular combustor (DAC)

unsuitable for use by the emissions calculation model (Boeing Method 2, as outlined in

Baughcum, et. al., 1996). The optional DAC has a certified NOx level 60% below that

of the standard single-annular combustor (SAC), but has a smaller share of the market.

It was assumed that this market share would continue, with the fleet average NOx level

about 8% below the SAC.

The second of these assumptions is now deemed to be incorrect — the market share of the DAC combustor

engine is decreasing. The 8% lower NOx assumption as an average is therefore probably too optimistic. For

the Global Emissions Model calculations, the total NOx emissions calculated for the 2020 NASA study has

been adjusted by assuming all CFM-56 engines in the 2020 fleet are the standard single-annular combustor

configuration (SAC). This adjustment adds less than 1% to the NOx emission total, and allows all

airplane/engine combinations to be treated equally in the benefits model. Table 2.1 shows the baseline NOx

values shown in (Sutkus, 2003) as calculated and the values modified for this study. 

Table 2.1. Calculated global NOx emissions from commercial aircraft

Year 2020 (NASA -

XXX)

Year 2020 as

modified

Year 2030

extrapolation

Passenger aircraft NOx emissions

(Metric Tonnes/day)

11,624 11,752 18,075

Freighter aircraft NOx emissions

(Metric Tonnes/day)

1,782 1,782 2,642

Total 13,406 13,535 20,717

The “as modified” values for the year 2020 are used as a baseline in all benefits calculations made by the

model. The year 2030 value is an extrapolation of this baseline.
CAEP/6-IP/13

A-5 Appendix A

ILLUSTRATION OF ASSUMED METHOD OF REACHING LOWER CERTIFICATION NOx LEVEL -

EQUAL PERCENTAGE REDUCTION IN NOx EMISSIONS INDEX AT ALL CERTIFICATION MEASURING POINTS 

(CONTRASTED WITH ANOTHER POSSIBLE METHOD OF REACHNG THE SAME LEVEL)

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70 80 90 100

PERCENT OF RATED THRUST

NOx EMISSION INDEX (gm. NOx/kg. FUEL)

BASE ENGINE NOx EMISSION INDEX

NOx EMISSION INDEX FOR 15% REDUCTION IN LTO CHARACTERISTIC FOR 

GLOBAL EMISSIONS MODEL (EQUAL % REDUCTION AT ALL POINTS)

NOx EMISSION INDEX FOR 15% REDUCTION IN LTO CHARACTERISTIC

(UNEQUAL PERCENTAGE REDUCTION AT EACH POINT)

ILLUSTRATION OF ASSUMED METHOD OF REACHING LOWER CERTIFICATION NOx LEVEL -

EQUAL PERCENTAGE REDUCTION IN NOx EMISSIONS INDEX AT ALL CERTIFICATION MEASURING POINTS 

(CONTRASTED WITH ANOTHER POSSIBLE METHOD OF REACHNG THE SAME LEVEL)

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70 80 90 100

PERCENT OF RATED THRUST

NOx EMISSION INDEX (gm. NOx/kg. FUEL)

BASE ENGINE NOx EMISSION INDEX

NOx EMISSION INDEX FOR 15% REDUCTION IN LTO CHARACTERISTIC FOR 

GLOBAL EMISSIONS MODEL (EQUAL % REDUCTION AT ALL POINTS)

NOx EMISSION INDEX FOR 15% REDUCTION IN LTO CHARACTERISTIC

(UNEQUAL PERCENTAGE REDUCTION AT EACH POINT)

Figure 3.1 Model assumption of method of reaching

lower NOx certification level

3. DETAILS OF GLOBAL STRINGENCY BENEFITS

ESTIMATION MODEL CALCULATION METHOD

3.1 Overview

3.1.1 The benefit of increased NOx

 certification stringency are measured as the reduction in the

forecast global NOx emissions from commercial aviation in 2020 and 2030 with increased NOx certification

stringency in place relative to the global NOx emissions in the absence of new stringency. Identification of

the size of the fleet of each airplane/engine combination affected by stringency and the amount of emissions

reduction required to meet the new stringency is needed to calculate the emissions benefit from new

stringency levels. Affected engines that do not meet the proposed stringency are assumed to be modified to

meet the new certification level (with a variable margin), and the global emissions of the airplanes attached

to the affected engines reduced by the ratio of the new level to the original emissions certification value.

3.1.2 It is assumed that the a percentage reduction in the certified LTO NOx

 characteristic value

required to meet a new level of stringency reflects the reduction in NOx emissions in all flight regimes. In

other words, a 15% reduction in LTO NOx characteristic means a 15% reduction in NOx emissions at all four

certification points. As can be seen in Figure 3.1, a 15% reduction in LTO characteristic value can also be

obtained from other, variable percentage reductions at the certification points. 
CAEP/6-IP/13

Appendix A A-6

CONTRIBUTION OF AIRPLANE CATEGORIES TO YEAR 2020 BASELINE FUEL AND NOx

(BOEING GLOBAL STRINGENCY EFFECTS ESTIMATION MODEL)

32.96%

52.07%

14.97%

32.22%

51.17%

16.60%

0%

10%

20%

30%

40%

50%

60%

NEW TYPES IN PRODUCTION OUT OF PRODUCTION

AIRPLANE CATEGORY

PERCENTAGE OF YEAR 2020 BASELINE FUEL AND 

NOx

NOx

FUEL

Figure 3.2 Percentage contribution of airplane/engine categories to year 2020

baseline fuel burned and NOx emissions

3.2 Identification of airplanes affected by stringency

3.2.1 The proposed CAEP/6 options for increasing NOx certification stringency are to apply only

to new type engines after some future date (study values are 2008 and 2012). For the study of NOx benefits

using the Global Emissions Model, it is assumed that 74 out of the 407 airplane/engine combinations could be

powered by new engine types subject to the stringency rules. These 74 airplane/engine combinations span

all the airplane size/range categories, engine manufacturers, and engine thrust ratings.

3.2.2 In addition to the 74 airplane/engine combinations that would be directly subject to a new

stringency rule, another 131 airplane/engine combinations could be affected by increased stringency. These

are airplanes that are in production today and forecast to still be in production on the stringency application

date (2008 or 2012). Although not strictly subject to a stringency that applies only to new types, market forces

or an eventual production cutoff rule could make these 131 airplane/engine combinations effectively subject

to the stringency.

3.2.3 The remaining 202 airplane/engine combinations in the year 2020 emissions inventory data

base will not be affected by new NOx stringency rules, as they are not in production today or are forecast to

be out of production by the 2008 - 2012 stringency application dates. A stringency rule that requires the phase

out of in-service airplanes has not been considered.

3.2.4 The contribution to the baseline global NOx emissions of the three categories of airplanes (74

new types, 131 in-production types and 202 out of production types) is shown in Figure 3.2.
CAEP/6-IP/13

A-7 Appendix A

IDENTIFICATION OF AFFECTED FLEET

(NUMBER AFFECTED BY STRINGENCY APPLICATION YEAR)

0

500

1000

1500

2000

2500

2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020

YEAR

SIZE OF FLEET - NEW DELIVERIES

ALL DELIVERIES AFTER

“EFFECTIVE” YEAR ASSUMED TO MEET

NEW STRINGENCY LEVEL

66% OF YE2020 FLEET

MEET STRINGENCY IF

EFFECTIVE YEAR IS 2008

49% OF YE2020 FLEET

MEET STRINGENCY IF

EFFECTIVE YEAR IS 2012

IDENTIFICATION OF AFFECTED FLEET

(NUMBER AFFECTED BY STRINGENCY APPLICATION YEAR)

0

500

1000

1500

2000

2500

2000 2002 2004 2006 2008 2010 2012 2014 2016 2018 2020

YEAR

SIZE OF FLEET - NEW DELIVERIES

ALL DELIVERIES AFTER

“EFFECTIVE” YEAR ASSUMED TO MEET

NEW STRINGENCY LEVEL

66% OF YE2020 FLEET

MEET STRINGENCY IF

EFFECTIVE YEAR IS 2008

49% OF YE2020 FLEET

MEET STRINGENCY IF

EFFECTIVE YEAR IS 2012

Figure 3.3 Identification of proportion of 2020 fleet affected by

proposed stringency

3.2.5 The Model calculates the effects of NOx

 stringency on either new types only (the 74 airplane

engine combinations), or on all deliveries (which includes new types and the 131 airplane/engine combinations

that could be affected). When calculating the effects on all deliveries, the Model allows for a “production

cutoff lag” — a lag between the effective year of stringency for new types (74 combinations) and for the rest

of all deliveries (131 combinations). 

3.3 Identification of size of affected fleet

3.3.1 All deliveries of each airplane/engine combination affected by a new stringency level are

assumed to meet the new stringency level (with or without a margin) on and/or after the year that the new

stringency becomes effective. Both the effective year of stringency and the production cutoff lag are

variables that can be input to the Model. These values determine what portion of the year 2020 fleet of each

affected airplane/engine combination will meet the new stringency level. Figure 3.3 below diagrams the logic

— for a given airplane/engine, deliveries enter the fleet from the forecast base year of 2001 until the

emissions base year of 2020. Depending on the year that stringency is effective, a smaller or greater

percentage of the 2020 fleet will meet the new stringency level. (The effective year for the in-production

airplanes that are not new types can be different from the effective year for new types).

3.4 Treatment of airplane/engine combinations

that fail a proposed NOx stringency level

3.4.1 Airplane/engine combinations with engines that fail to meet a proposed NOx

 stringency

certification level are identified in the Model, based on whether only new types or all deliveries are subject

to the stringency. In order to calculate the benefit of increased NOx stringency, it is assumed that each

affected airplane/engine combination failing to meet the stringency level is somehow modified to meet that

level. Uncertainties in the performance of these modifications are such that the design target reduction must
CAEP/6-IP/13

Appendix A A-8

( ) 











= × − + × ×

old

new

m b b

Dp

Dp E E 1 Fp E Fp

CAEP/4 CERTIFICATION LIMIT, PROPOSED NEW STRINGENCY,

AND TREATMENT OF ENGINES THAT FAIL NEW STRINGENCY

40

50

60

70

80

90

100

20 25 30 35 40

ENGINE PRESSURE RATIO

CHARACTERISTIC - Dp/Foo

CAEP/4 CERTIFICATION LEVEL

PROPOSED CAEP/6 CERTIFICATION LEVEL

CERTIFIED ENGINE LEVEL

(MEETS CAEP/4, FAILS CAEP/6)

POSSIBLE NEW LEVEL

(JUST MEETS CAEP/6)

MORE LIKELY NEW LEVEL

(WITH CERTIFICATION MARGIN)

CAEP/4 CERTIFICATION LIMIT, PROPOSED NEW STRINGENCY,

AND TREATMENT OF ENGINES THAT FAIL NEW STRINGENCY

40

50

60

70

80

90

100

20 25 30 35 40

ENGINE PRESSURE RATIO

CHARACTERISTIC - Dp/Foo

CAEP/4 CERTIFICATION LEVEL

PROPOSED CAEP/6 CERTIFICATION LEVEL

CERTIFIED ENGINE LEVEL

(MEETS CAEP/4, FAILS CAEP/6)

POSSIBLE NEW LEVEL

(JUST MEETS CAEP/6)

MORE LIKELY NEW LEVEL

(WITH CERTIFICATION MARGIN)

Figure 3.4 . Diagram of treatment of engines

that fail proposed stringency

be greater than the minimum needed to just meet the new stringency level. Thus it is likely that the actual

reduction will exceed the requirement by some amount. This “design certification margin” can be selected.

Figure 3.4 illustrates this concept. 

3.4.2 The benefit (reduction in global NOx

 emissions in 2020 or 2030) obtained from lowering the

emissions level of a given airplane/engine combination to meet a new stringency level is found using the

following relationship:

Em = Global emissions in 2020 or 2030 for the airplane/engine combination that now meets the target

emissions characteristic of the new stringency level (with margin).

Eb = Global emissions is 2020 or 2030 for the airplane/engine combination that fails to meet the emissions

characteristic that represents the new stringency level.

Fp = Percentage of the 2020 or 2030 fleet delivered after the effective date of the new stringency.

Dp new= Emissions characteristic value (Dp/Foo) for the airplane/engine combination that now meets the new

stringency level (with margin). 

Dp old = Emissions characteristic value (Dp/Foo) for the airplane/engine combination that did not meet the new

stringency level.

(Note: Again, this calculation assumes that a change in engine certification characteristic Dp/Foo accurately
CAEP/6-IP/13

A-9 Appendix A

reflects the change in overall aircraft emissions.)

The benefit (reduction in global NOx for the ith airplane/engine combination that failed the proposed

stringency) is (Eb - Em)i. For the entire 2020 or 2030 fleet the global benefit Bgis found by summing over all

failed airplane/engine combinations.

B (E E ) where N is the number of airplane/engine combinations that fail a given stringency g b m i

i

N

= −

=

∑

1

level.

4. RESULTS OF MODEL CALCULATIONS

4.1 Stringency options considered

4.1.1 Global benefits of stringency were calculated for the 2020 and 2030 fleet with the following

options:

Option Number

Nominal percentage reduction in

NOx certification characteristic

value at Operating Pressure

Ratio = 30

1 5

2 10

3 15

4 20

5 25

6 30

Options 1 through 6 are those specified by the Steering Group for analysis by FESG. The 6 stringency options

were analyzed assuming year 2008 and 2012 effective dates, applicable to new types only and to new types

plus all deliveries of in-production types. The effective date for stringency application to in-production types

was assumed to be a). the same as for new types and b). delayed four years. All cases were run assuming

zero and 10% certification margin.

4.1.2 The benefits of NOx

 reduction stringency are calculated as:

a) percentage reduction in global NOx in years 2020 and 2030;

b) reduction in global NOx in years 2020 and 2030;

c) number of airplane/engine combinations failing the stringency option; and

d) the contribution of the failing airplanes to the year 2020 baseline global NOx.
CAEP/6-IP/13

Appendix A A-10

A tabulation of these values is shown in Appendix A; percentage reductions are shown

plotted in Appendix B [which is not included here]. 

REFERENCES

Baughcum, S. L., S. C. Henderson, T. G. Tritz, and D. C. Pickett, Scheduled Civil Aircraft Emission

Inventories for 1992: Database Development and Analysis, NASA CR-4700, 1996.

Baughcum, S. L., S. C. Henderson, and T. G. Tritz, Scheduled Civil Aircraft Emission Inventories for

1976 and 1984: Database Development and Analysis, NASA CR-4722, 1996.

Baughcum, S. L., S. C. Henderson, and D. J. Sutkus, Scheduled Civil Aircraft Emission Inventories

Projected for 2015: Database Development and Analysis, NASA CR-1998-207638, 1998.

Boeing Commercial Airplanes, 2001 Current Market Outlook, June 2001.

Boeing Commercial Airplanes, 2002 Current Market Outlook,

(http://www.boeing.com/commercial/cmo/sitemap.html), July 2002.

Henderson, S. C., U. K. Wickrama, S. L. Baughcum, J. J. Begin, F. Franco, D. L. Greene, D. S. Lee, M.

L. McLaren, A. K. Mortlock, P. J. Newton, A. Schmitt, D. J. Sutkus, A. Vedantham, and D. J. Wuebbles,

“Aircraft Emissions; Current Inventories and Future Scenarios”, Chapter 9 in the Intergovernmental Panel

on Climate Change (IPCC) Special Report, Aviation and the Global Atmosphere [Penner, J. E., D. H.

Lister, D. J. Griggs, D. J. Dokken, and M. McFarland (eds)], , Cambridge University Press, 1999.

International Civil Aviation Organization (ICAO), ICAO Engine Exhaust Emissions Databank,

(http://www.qinetiq.com/aviation-emissions-databank/) (accessed 9/26/02).

Sutkus, D. J., S. L. Baughcum, and D. P. DuBois, Scheduled Civil Aircraft Emission Inventories for 1999:

Database Development and Analysis, NASA/CR-2001-211216 (2001)

Sutkus, D. J., S. L. Baughcum, and D. P. DuBois, Commercial Aircraft Emission Scenario for 2020:

Database Development and Analysis, NASA/CR-2003-212331
CAEP/6-IP/13

A-11 Appendix A

ONLY NEW TYPES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2008

NO PRODUCTION CUTOFF

CERTIFICATION MARGIN = 0%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.09% 0.18% 0.32% 0.65% 1.17% 1.70%

Percentage NOx reduction 2030 0.13% 0.26% 0.45% 0.91% 1.64% 2.40%

NOx reduction in 2020 (Tonnes/Day) 12.61 24.99 43.19 87.71 157.99 230.62

NOx reduction in 2030 (Tonnes/Day) 27.39 54.22 93.63 189.52 340.74 497.05

Number of airplane types failing stringency 7 12 23 31 40 58

Contribution of failing airplanes to 2020 base

NOx

3.2% 4.0% 7.3% 13.4% 16.8% 24.0%

ONLY NEW TYPES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2012

NO PRODUCTION CUTOFF

CERTIFICATION MARGIN = 0%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.07% 0.13% 0.22% 0.46% 0.83% 1.22%

Percentage NOx reduction 2030 0.11% 0.23% 0.39% 0.79% 1.43% 2.08%

NOx reduction in 2020 (Tonnes/Day) 8.85 17.52 30.40 62.30 112.89 165.23

NOx reduction in 2030 (Tonnes/Day) 23.63 46.75 80.84 164.11 295.63 431.66

Number of airplane types failing stringency 7 12 23 31 40 57

Contribution of failing airplanes to 2020 base

NOx

3.2% 4.0% 7.3% 13.4% 16.8% 23.7%
CAEP/6-IP/13

Appendix A A-12

ONLY NEW TYPES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2008

NO PRODUCTION CUTOFF

CERTIFICATION MARGIN = 10%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.28% 0.42% 0.74% 1.52% 2.23% 3.28%

Percentage NOx reduction 2030 0.75% 0.95% 1.25% 2.35% 3.14% 4.61%

NOx reduction in 2020 (Tonnes/Day) 38.04 57.00 99.50 206.27 302.11 444.44

NOx reduction in 2030 (Tonnes/Day) 156.32 196.85 258.84 487.65 651.28 955.55

Number of airplane types failing stringency 7 12 23 31 40 58

Contribution of failing airplanes to 2020 base

NOx

3.2% 4.0% 7.3% 13.4% 16.8% 24.0%

ONLY NEW TYPES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2012

NO PRODUCTION CUTOFF

CERTIFICATION MARGIN = 10%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.20% 0.30% 0.52% 1.09% 1.60% 2.36%

Percentage NOx reduction 2030 0.65% 0.82% 1.08% 2.04% 2.73% 4.01%

NOx reduction in 2020 (Tonnes/Day) 26.62 40.16 70.18 147.90 216.66 319.64

NOx reduction in 2030 (Tonnes/Day) 134.89 170.06 223.54 423.30 565.83 830.75

Number of airplane types failing stringency 7 12 23 31 40 57

Contribution of failing airplanes to 2020 base

NOx

3.2% 4.0% 7.3% 13.4% 16.8% 23.7%
CAEP/6-IP/13

A-13 Appendix A

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2008

PRODUCTION CUTOFF LAG = 0 YEARS

CERTIFICATION MARGIN = 0%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.38% 0.78% 1.49% 2.64% 4.12% 5.60%

Percentage NOx reduction 2030 0.54% 1.11% 2.13% 3.75% 5.84% 7.93%

NOx reduction in 2020 (Tonnes/Day) 50.80 105.35 202.12 357.27 558.10 758.42

NOx reduction in 2030 (Tonnes/Day) 111.56 230.65 440.60 775.91 1210.10 1643.74

Number of airplane types failing stringency 30 48 74 95 115 147

Contribution of failing airplanes to 2020 base

NOx

14.1% 24.8% 35.9% 46.2% 55.4% 69.8%

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2012

PRODUCTION CUTOFF LAG = 0 YEARS

CERTIFICATION MARGIN = 0%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.26% 0.55% 1.06% 1.88% 2.94% 4.00%

Percentage NOx reduction 2030 0.47% 0.96% 1.84% 3.25% 5.07% 6.88%

NOx reduction in 2020 (Tonnes/Day) 35.70 74.33 143.38 254.24 397.67 540.89

NOx reduction in 2030 (Tonnes/Day) 96.46 199.63 381.87 672.89 1049.68 1426.21

Number of airplane types failing stringency 29 47 71 90 109 137

Contribution of failing airplanes to 2020 base

NOx

13.8% 24.5% 33.4% 43.3% 52.3% 64.0%
CAEP/6-IP/13

Appendix A A-14

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2008

PRODUCTION CUTOFF LAG = 0 YEARS

CERTIFICATION MARGIN = 10%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 1.10% 2.14% 3.34% 5.16% 7.12% 9.39%

Percentage NOx reduction 2030 2.13% 3.60% 5.00% 7.58% 10.08% 13.27%

NOx reduction in 2020 (Tonnes/Day) 148.23 289.33 451.54 699.04 963.37 1270.28

NOx reduction in 2030 (Tonnes/Day) 441.10 746.14 1036.48 1570.05 2088.38 2749.16

Number of airplane types failing stringency 30 48 74 95 115 147

Contribution of failing airplanes to 2020 base

NOx

14.1% 24.8% 35.9% 46.2% 55.4% 69.8%

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2012

PRODUCTION CUTOFF LAG = 0 YEARS

CERTIFICATION MARGIN = 10%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.77% 1.52% 2.37% 3.69% 5.08% 6.71%

Percentage NOx reduction 2030 1.84% 3.12% 4.34% 6.58% 8.75% 11.52%

NOx reduction in 2020 (Tonnes/Day) 104.17 205.64 320.83 498.86 687.04 908.00

NOx reduction in 2030 (Tonnes/Day) 381.54 647.03 898.37 1362.47 1812.05 2386.88

Number of airplane types failing stringency 29 47 71 90 109 137

Contribution of failing airplanes to 2020 base

NOx

13.8% 24.5% 33.4% 43.3% 52.3% 64.0%
CAEP/6-IP/13

A-15 Appendix A

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2008

PRODUCTION CUTOFF LAG = 4 YEARS

CERTIFICATION MARGIN = 0%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.27% 0.55% 1.07% 1.90% 2.99% 4.08%

Percentage NOx reduction 2030 0.47% 0.97% 1.85% 3.26% 5.10% 6.94%

NOx reduction in 2020 (Tonnes/Day) 35.95 74.95 144.40 256.95 404.78 552.53

NOx reduction in 2030 (Tonnes/Day) 96.71 200.25 382.89 675.60 1056.79 1437.84

Number of airplane types failing stringency 29 47 71 90 109 138

Contribution of failing airplanes to 2020 base

NOx

13.8% 24.5% 33.4% 43.3% 52.3% 64.3%

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2012

PRODUCTION CUTOFF LAG = 4 YEARS

CERTIFICATION MARGIN = 0%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.14% 0.30% 0.58% 1.03% 1.64% 2.25%

Percentage NOx reduction 2030 0.39% 0.80% 1.53% 2.69% 4.22% 5.74%

NOx reduction in 2020 (Tonnes/Day) 19.16 40.24 77.97 139.50 221.76 304.11

NOx reduction in 2030 (Tonnes/Day) 79.92 165.54 316.45 558.15 873.77 1189.43

Number of airplane types failing stringency 29 47 71 90 109 137

Contribution of failing airplanes to 2020 base

NOx

13.8% 24.5% 33.4% 43.3% 52.3% 64.0%
CAEP/6-IP/13

Appendix A A-16

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2008

PRODUCTION CUTOFF LAG = 4 YEARS

CERTIFICATION MARGIN = 10%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.77% 1.53% 2.38% 3.76% 5.19% 6.93%

Percentage NOx reduction 2030 1.84% 3.13% 4.35% 6.63% 8.82% 11.66%

NOx reduction in 2020 (Tonnes/Day) 104.74 207.13 322.78 509.50 702.09 937.38

NOx reduction in 2030 (Tonnes/Day) 382.17 648.58 900.32 1373.11 1827.10 2416.25

Number of airplane types failing stringency 29 47 71 90 109 138

Contribution of failing airplanes to 2020 base

NOx

13.8% 24.5% 33.4% 43.3% 52.3% 64.3%

ALL NEW DELIVERIES AFFECTED

STRINGENCY EFFECTIVE IN YEAR 2012

PRODUCTION CUTOFF LAG = 4 YEARS

CERTIFICATION MARGIN = 10%

OPTION> 1 2 3 4 5 6

Nominal reduction in allowable NOx at

OPR=30

5% 10% 15% 20% 25% 30%

Percentage NOx reduction 2020 0.41% 0.83% 1.29% 2.07% 2.85% 3.87%

Percentage NOx reduction 2030 1.52% 2.59% 3.59% 5.48% 7.30% 9.67%

NOx reduction in 2020 (Tonnes/Day) 55.80 112.37 174.32 280.24 386.36 523.57

NOx reduction in 2030 (Tonnes/Day) 315.51 536.24 743.55 1135.55 1511.37 2002.45

Number of airplane types failing stringency 29 47 71 90 109 137

Contribution of failing airplanes to 2020 base

NOx

13.8% 24.5% 33.4% 43.3% 52.3% 64.0%

— — — — — — — —
CAEP/6-IP/13

Appendix B

APPENDIX B

DEFINITION OF TECHNOLOGY LEVELS

& ENGINE FAMILY APPROACH

ICAO/CAEP/Working Group 3 Sixth Meeting

Berlin, Germany - 25-26 September 2003

Definition of Technology Levels (TL) and Engine Family Approach

Presented by ICCAIA

1. TECHNOLOGY LEVELS (TL)

TL1 — Minor change

The designation TL1 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 reclassify engine performance

Additional engine testing and re-certification of emissions

In all TL1 cases, it was assumed that there would be no material change to the engine hardware or operating

costs. No hard limit was specified on the emissions improvement possible with a TL1 change, but that the

typical NOx reduction with such a change would be on the order of 3%.

Given the diverse nature of a TL1 solution, the work content and hence cost is difficult to estimate. A

minimum requirement would be expected to be some modelling work, minor design changes, ground running

of either a production or development engine to verify airworthiness and emissions compliance, and a

re-issuing of associated certification authority paperwork. 

TL2 — Scaled proven technology

A TL2 modification is where an engine manufacturer applies its best-proven combustion technology (GE

LEC, RR Phase 5, P&W TALON), 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
CAEP/6-IP/13

Appendix B B-2

RB211-535E4, the installation of the TALON combustor into the PW4168 and PW4x58 to meet CAEP/2

production cut-off and the CAEP/4 standards respectively).

The TL2 solution would require substantial modelling, design, combustion rig testing, modification and testing

of development engines (ground testing including cyclic running), flight testing of a set of production-standard

engines, and all the associated certification authority paperwork. New production tooling and assembly line

training/accreditation may also be required. The effort and resulting cost of a TL2 change are similar to the

expenditures required for a new engine type design, and are therefore relatively well understood 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. 

TL3 — Substitution with other available

certified current technology engine

Where a compliant current engine is available for use as an alternative to a noncompliant engine, and the

manufacturer of the noncompliant engine does not have the technology to bring that engine into compliance,

that manufacturer must decide either to cede the market for the aircraft in question to the competition (TL3),

or to acquire technology equivalent to that which the competition has already applied. In considering these

options, the consensus of the group was that, except in circumstances where an engine/aircraft combination

was near the end of it’s production run (where the cost/benefit ratio would be high), a manufacturer would

first try to acquire the needed technology to stay in the market. This assumption leads to a TL5 case where

some technology acquisition is required, but it is not unproven technology since there are competitive engines

that meet the required stringency. Therefore the associated costs would be somewhat less than the normal

TL5 case where there is absolutely no technology available to meet the requirement. This case, designated

TL5(A) — New Technology — Current Industry Best Practice, was therefore used in lieu of the TL3 option.

TL4 — Development of a new current technology engine

There was only one case of a TL4 change to a current production engine that is not included in the FESG

analysis. This was a small, low production engine/aircraft combination that has negligible effect on the overall

cost/benefit analysis. In general, TL4 is the least attractive solution commercially and will only be chosen if

advanced technology solutions are lacking and if production rates justify the cost of a new engine program,

including any nacelle, pylon and/or engine control system changes, and aircraft recertification, costs that are

also incurred with TL3, TL5(A) and TL5(B) changes. 

TL5(A) — New technology (current industry best practice)

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 above. Where one

or more manufacturers have claimed 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.

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 hundreds of millions of dollars.

These factors make it difficult to derive a single cost for one manufacturer to catch-up with the industry

leaders. At best, a TL5 (A) program would be equivalent to a TL2 program with the addition of some applied
CAEP/6-IP/13

B-3 Appendix B

research for technology acquisition and potentially extended cyclic testing to prove the durability that is

required for ETOPS. For example, it might be necessary to conduct several iterations on the typical TL2

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. The upper limit on cost of a TL5(A)

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, thereby giving the market for that engine

type to the other manufacturers (equivalent to TL3). 

TL5(B) — New technology (beyond current best)

The designation TL5(B) covers the situation where no engine manufacturer has demonstrated the required

NOx stringency. It relates to targets of current 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. Industrial partners also contributed similar levels of funds, which

took some technology as far as the TRL6 stage. The basis for the TALON and LEC

technologies emerged from this research, but both required significant further

development and validation by Pratt & Whitney and GE respectively;

b) the EU EEFAE programme is spending over $100 million taking technology and

attempting to demonstrate its viability in an experimental engine environment; and

c) the E3E programme in Germany has spent $50 million on staged combustion

development.

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 a technology readiness level (TRL)

of 4 to 6 (Reference WG3 TRL Paper). The more expensive TRL 7-9 tasks are typically bourn by the

manufacturers alone.

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 staged combustion

technologies for many years, only one has entered service and that has trade-off issues with Carbon

Monoxide emissions (bearing in mind that staged combustion research has taken about 20 years to deliver a

system (GE’s DAC), and the next step forward in combustion technology could be expected to involve a

similar amount of work.

2. ENGINE FAMILY APPROACH

The engine family approach is to be applied to the ICCAIA 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 minimise costs), but it also means that smaller stringency increases actually can

affect many engine models within a family even though only the higher thrust versions might seem to be

affected. The benefits to the family are obviously greater because the fix is applied to all the family.
CAEP/6-IP/13

Appendix B B-4

The CFM56 DAC engine is a special case. Above 10% stringency, the manufacturer would have to decide

whether to develop a new SAC engine to meet the requirement, or work to reduce DAC CO emissions,

which do not currently meet ICAO standards for the lowest thrust ratings of the CFM56-5B and -7B engines.

In light of trade-offs with the DAC (as covered in the ICAO Steering Group Emissions Workshop), it was

assumed that a low NOx SAC would be developed, if possible, rather than attempting to reduce DAC CO.

In order to avoid double counting of costs, it was assumed that only the CFM56 SAC engines would be

upgraded to meet the stringency under consideration. Since less than 5% of applicable engines currently have

DAC combustors this approach should also give the greatest benefit.

With some engine families, it is possible to have a gradual phase-in or technology as stringency options are

increased, with application of increasing levels of technology (TL1, TL2, TL5A and TL5B changes) that are

able to meet increasing levels of stringency. With other engine families, the only option might be a TL5B

change.

The CFM56-5B family of engines with single annular combustors (SAC) is an example of an engine family

that has several options with increasing stringency:

a) at the 5% stringency level, the family does not require any change;

b) at 10% stringency, there is LEC technology available to the manufacturer (TL2);

c) at 15 t0 20% stringency; there is a TL5A technology claimed by a competing

manufacturer (V2500 family); and

d) at 25% stringency and above, new technology (TL5B) is required.

This situation arises because there is room for improvement in combustion technology for both the CFM56-5B

and V2500 engine families.

The CF6-80C2 is an example of an engine family that would meet increased stringency levels up to 25% with

no change, but any higher level would require a step up new (TL5B) technology. This is simply an indication

that the CF6-80C2 already incorporates the best available low NOx technology that has been demonstrated

or is claimed by any of the manufacturers. In fact, the CF6-80C2 has been cited by its manufacturer as the

best example of demonstrated low NOx combustor technology in the CAEP Steering Group Emissions

Workshop (June 2002) and several Working Group 3 Working Papers.

3. RECOMMENDATION

Working Group 3 approve the description of technology levels and engine family approach, and recommend

FESG to incorporate them into its report to CAEP/6 on the cost-benefit analysis of NOx stringency options.

— — — — — — — —
CAEP/6-IP/13

Appendix C

APPENDIX C

TL5B ENGINE EMISSIONS CHARACTERISTICS

& COST MODELLING

General Electric, Pratt & Whitney and Rolls-Royce have differing TL5B approaches. These face identical

physics-based constraints from the different engine combustors developed by the three manufacturers. One

constraint is a fuel burn penalty. The technologies are currently in the late stages of pre-competitive R&D

programs, and there is no direct experience on which to base future non-recurring costs for TL5B engines.

There is, however, adequate industry cost and performance experience with an in-production engine that

experienced a similar fuel penalty to estimate the TL5B fuel penalty, materials and maintenance costs. 

Several inherent tradeoffs between emissions and engine efficiency were discussed at the CAEP Steering

Group Emissions workshop (Paris, September 2002). These are:

1. One potential issue with staged combustion systems is increased weight due to added valves,

manifolds and nozzles in addition to a potential increase in combustor volume, which leads to

increased engine size and weight, resulting in increased fuel consumption.

2. Another potential cause of increased fuel consumption is elevated combustor pressure loss potentially

caused by higher combustor frontal area. Pressure loss may also be intentionally increased to provide

the rapid fuel-air mixing needed to minimize emissions.

3. A third potential cause of increased fuel burn is a trade-off with combustor exit temperature

uniformity. The exit temperature profile from a conventional combustor is typically designed to

optimize turbine efficiency and minimize airflow needed to cool the turbine. In a low emissions

combustor design, the exit temperature profile may be optimized for lowest emissions at the expense

of turbine efficiency and cooling requirements. 

4. A more serious effect of lean staged combustors on future engine designs might be the need to limit

engine pressure ratio and turbine inlet (combustor exit) temperature to levels consistent with low NOx

emissions. High engine pressure ratio leads to very high combustor inlet temperatures that can make

fuel-air premixing impossible. 

Combustor exit temperatures in current engines are near the limit required to control NOxformation. Limiting

engine pressure ratio and turbine inlet temperature will also limit the ability to design for maximum

thermodynamic efficiency, as required to minimize fuel consumption.

Experience with current engine development and production programs, and with the operation and

maintenance of in-production engines has been used as much as possible in the economic analysis. The costs

associated with the production and operation of the CFM56 dual annular combustor engine was used as the

basis to model the post-certification costs associated with TL5B technologies. The non-recurring costs

associated with in-production DAC engines offers the most credible means to estimate the potential fuel

penalty effect of future lean staged combustor technology on aircraft engine performance.
CAEP/6-IP/13

Appendix C C-2

— — — — — — — —
CAEP/6-IP/13

Appendix D

APPENDIX D

ESTIMATED REGIONAL DAMAGE COST OF GROUND LEVEL NOX

Estimating monetary values of environmental and health benefits received from a given quantity of NOx,

damage costs, expresses the physical quantity in economic terms whereby the cost of actions to reduce NOx,

prevention costs, may be compared to the damage cost avoided in a common unit of measure. This does not

invalidate comparing the quantity of NOx to the prevention cost. 

Oxides of nitrogen are short-lived gases. The environmental and health effects of NOx are specific to locality

where it is emitted. Use a single global monetary value for local air quality, ecosystem and health effects is

not scientifically justified. This must be done on a location by location basis. For example, health effects can

be expressed in monetary terms as the value of statistical life (VSL). These vary by region. For example,

VSL estimates for selected countries are:

1. Canada: $4.7-$4.9 million Canadian (2000 Canadian dollars)

2. European Union: $0.8-$3.0 million (2001 U.S. dollars)

3. United Kingdom: $1.2 million (1998 U.S. dollars)

4. United States: $6.1 million (1999 U.S. dollars)

Damage cost estimates conducted in the United States and European Union are given in Table AppD.1.

Table AppD.1. United States a European Community studies of damage and prevention cost

Title of Study Source Damage Cost 1, 2 Prevention Cost 1 Description of Study

United States: Cost-Effective

NOx Control in the Eastern

United States; Discussion

Paper 00-18, April 2000.

Electric

utilities

$3,618/ton Regulation: $2,195/ton 

Trading: $1,194/ton 

Cost-effectiveness of

reducing NOx using two

policy options, 1990

dollars. 

Europe: Position Paper on

Air Quality: Nitrogen

Dioxide , European

Commission DG-XI,

November 1997.

Road 

vehicles

Rural: $ 5,900/tonne 

Urban: $59,300/tonne

Cost-effectiveness of

measures to reduce

vehicle emissions, 1996

dollars.

Europe: Estimates of the

Marginal External Costs of

Air Pollution in Europe,

NETCEN (for EC DG

Environment) circa 2001.

All 

 sources

$4,700/tonne Cost of rural and urban

SO2, NOx, VOCs, and

PM emissions in 14

European countries,

1998 dollars.

1. Values expressed in constant 2002 U.S. dollars. European currencies are converted to U.S. dollars.

2. Damage cost of health effects of named species.

— — — — — — — —
CAEP/6-IP/13

Appendix E

APPENDIX E

THE EMISSIONS AND DISPERSION MODELING SYSTEM (EDMS)

1. DESCRIPTION OF EDMS

1.1 The Emissions and Dispersion Modeling System (EDMS) is an FAA model developed to

inventory aircraft emissions, among other uses. EDMS is the FAA required model for performing air quality

analyses of aviation sources associated with airport development projects in the U.S. It is updated periodically,

and Version 4.1 is the latest release.

1.2 EDMS is designed to assess the air quality impacts of airport emission sources, particularly

aviation sources, which consist of aircraft, auxiliary power units, and ground support equipment. EDMS also

offers a limited capacity to model other airport emission sources that are not aviation-specific, such as ground

access vehicles and stationary sources. EDMS is one of the few air quality assessment tools specifically

engineered for the aviation community. It includes emissions and dispersion calculations, the latest aircraft

engine emission factors from the International Civil Aviation Organization (ICAO) Engine Exhaust Emissions

Data Bank, and EPA-validated dispersion algorithms. EDMS can be used to create an emissions inventory

for any individual sources (such as aircraft), or combination of sources. To create an emissions inventory, the

user enters fleet and activity data. EDMS combines these inputs with default or user-specified emission

factors to calculate total emissions in tons.

2. EDMS SETTINGS USED IN THE ECONOMIC

ANALYSIS

2.1 ICAO times in mode have been used in the FESG economic analysis of NOx

 stringency

options. ICAO times in mode, and corresponding power settings and default aircraft weights shown in

Table App E.1 are appropriate for certification purposes to ensure regulatory consistency, but do not reflect

how aircraft are normally operated. All calculations were made using ICAO standard day sea-level static

conditions. 

Table App E.1. ICAO landing-takeoff mission times in mode & fuel calculations

Mode Minutes Power setting

(% rated thrust)

Fuel use

Takeoff 0.7 100% Calculated from engine fuel flow

Climb out 2.2 80% Calculated from engine fuel flow

Approach 4.0 30% Calculated from engine fuel flow

Idle 26.0 7% Calculated from engine fuel flow
CAEP/6-IP/13

Appendix E E-2

Of the four modes the taxi/idle mode is the most variable due to its airport specific nature. The taxi/idle time

in mode has three components: landing roll time, taxi time, and queue time. Landing roll time is the time spent

at idle power after touchdown and is dependent on aircraft performance. The taxi and queue time is the time

spent in taxi and queue between gates and runways. The approach and climb out time will vary depending

on the aircraft performance and mixing height. 

2.2 Aircraft emissions are calculated as: The emissions inventory module of the EDMS Model

aggregates the pollutants emitted from the engines of the aircraft entered into the model for all the LTO

cycles for a given study year. NOx emissions from aircraft engines were the only pollutant considered. In

each of the four modes, the engines operate at correspondingly different power settings as show in column 3

of Table App E.1. The power settings determine the rate at which fuel is burned which in turn determines

the quantity of emissions generated from an aircraft in a specific mode. Table 3.2 displays the equation for

calculating NOx emissions generated from an aircraft for the LTO cycle.

Table App E.1. EDMS NOx emissions calculation method

Eij = S (TIMjk * FFjk/1000 * EIijk * NEj)

where

:

Eij Total pounds of pollutant I produced by aircraft type j over one LTO cycle.

TIMjk Time in mode for mode k, inn minutes, for aircraft type j.

FFjk Fuel flow for mode k, in pounds per minute, for each engine used on the aircraft

type j.

EIijk Emission index for pollutant I, in pounds of pollutant per thousand pounds of fuel, in

mode k for aircraft type j.

NEj Number of engines used on aircraft type j.

3. FESG INPUTS TO EDMS

3.1 Input data was developed for 2002, 2006, 2008, 2012, 2016 and 2020.

3.2 Individual aircraft inputs, based on the Campbell Hill global fleet, was produced by “mapping”

specific airframe/engine combinations to replicate the generic aircraft provided in the FESG Fleet Forecast.

The airframe/engine combinations were taken from the Working Group 3 in-production database.

3.3 Engine certification values and fuel flow from the ICAO Engine Exhaust Emissions Data

Bank resident in EDMS were used. Values for missing, new and TL-modified engines were developed by

ICCAIA.

3.4 Based on the data inputs into EDMS, annual quantities of NOx

 were estimated for the

baseline and each of the six stringency options. Individual runs were made for each scenario and year.
CAEP/6-IP/13

E-3 Appendix E

— — — — — — — —
1 Aylesworth, Howard and P.Newton, “Qualitative Summary of the Environmental Effectiveness of International Civil Aviation

Organization Emissions Standards and Recommended Practices”, Handbook of Airline Strategy, McGraw Hill Companies, New

York, 2001.

State-of-the-Art Subsonic Engine SFC

1.1

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

1.2

1950 1960 1970 1980 1990 2000 2010 2020

Uninstalled

Cruise SFC,

lb/hr/lb

Certification Date

Turbojets

CJ805-3

JT3C

JT3D

CJ805-23

Low bypass

turbofans

JT8D-9

JT8D-15

JT8D-209

RB211-22B JT9D-7A

CF6-6D

TF39

CFM56-2

RB211-524D4

CF6-50C1

CF6-50C2

PW2037

Demo

UDF

E

3

Unducted

engines Study engines

with very high bypass

10%

GE90 CF6-80C

CFM56-3 JT9D-7R4

CF6-80A1

High bypass

turbofans

R

1993 EIS 2005 EIS

}

35,000 ft., 0.8M, Standard Day

Figure App F.1. Evolutionary and revolutionary engine technology development

CAEP/6-IP/13

Appendix F

APPENDIX F

HISTORICAL TREND IN FUEL BURN REDUCTION

& TECHNOLOGY LEVEL

Figure App F.1 shows the evolutionary and revolutionary progression in engine technology has produced

important efficiencies in specific fuel consumption (fuel consumed per unit of thrust) reflecting improvement

in engine performance. The associated reductions in aircraft emission are not linear. Emissions reduction has

been achieved through development of new types of engines as well as the application of new technology to

existing engine types.

The leap from turbojet to low by-pass turbofan, and from low to high by-pass ratio engines represent

revolutionary developments in engine design. The Working Group 3 in-production database represents the

latest generation of engines. Manufacturer TL5B responses to the stringency options fall within this category

of change. The leaps between technologies may also be compared with movements along the curve, that is,

evolutionary technology advances for a given technology level. These are represented by TL1 through TL5A

changes.1
CAEP/6-IP/13

Appendix F F-2

TL’s 1, 2, 3, 4, and 5A are defined by demonstrated technologies, the performance of which is known. No

fuel penalty is incurred. The future performance characteristics of engines falling within this TL range can

be estimated with a high degree of certainty (± 2-3% relative to option). These values have been used in the

EDMS model.

TL5B is defined by unknown technologies where the performance characteristics of these engines are

unknown. The performance characteristics of these engines are set 2.5% over the option inducing the change.

A fuel penalty of up to 2% was endorsed by the Third Steering Group.

— — — — — — — —
Appendix G

CAEP/6-IP/13

APPENDIX G

Manufacturer Engine Family Engine Model Combustor- 5%- 10%- 15%- 20%- 25%- 30%

TL ASSIGNMENT TO INDIVIDUAL ENGINES BY ENGINE FAMILY

CFMI CFM56-5B CFM56-5B3/P SAC TL2 TL5a TL5a TL5b TL5b

CFM56-5B CFM56-5B2/P SAC TL2 TL5a TL5a TL5b TL5b

CFM56-5B CFM56-5B4/P SAC TL2 TL5a TL5a TL5b TL5b

CFM56-5B CFM56-5B6/P SAC TL2 TL5a TL5a TL5b TL5b

CFM56-5B CFM56-5B9/P SAC TL2 TL5a TL5b TL5b TL5b

CFM56-5B CFM56-5B3/2P DAC II TL5a * TL5a * TL5b * TL5b *

CFM56-5B CFM56-5B2/2P DAC II TL5a * TL5a * TL5b * TL5b *

CFM56-5B CFM56-5B4/2P DAC II TL5a * TL5a * TL5b * TL5b *

CFM56-5B CFM56-5B6/2P DAC II TL5a * TL5a * TL5b * TL5b *

CFM56-5C CFM56-5C4 SAC TL1 TL2 TL5a TL5a TL5b TL5b

CFM56-5C CFM56-5C2 SAC TL1 TL2 TL5a TL5a TL5b TL5b

CFM56-5B CFM56-7B27 SAC TL2 TL2 TL5b TL5b TL5b TL5b

CFM56-5B CFM56-7B26 SAC TL2 TL2 TL5b TL5b TL5b TL5b

CFM56-5B CFM56-7B24 SAC TL2 TL2 TL5b TL5b TL5b TL5b

CFM56-5B CFM56-7B22 SAC TL2 TL2 TL5b TL5b TL5b TL5b

CFM56-5B CFM56-7B20 SAC TL2 TL2 TL5b TL5b TL5b TL5b

CFM56-5B CFM56-7B27/2 DAC II TL5b * TL5b * TL5b * TL5b *

CFM56-5B CFM56-7B26/2 DAC II TL5b * TL5b * TL5b * TL5b *

CFM56-5B CFM56-7B24/2 DAC II TL5b * TL5b * TL5b * TL5b *

CFM56-5B CFM56-7B22/2 DAC II TL5b * TL5b * TL5b * TL5b *

CFM56-5B CFM56-7B20/2 DAC II TL5b * TL5b * TL5b * TL5b *

IAE V2500 V2533-A5 TL1 TL2 TL2 TL2 TL5b TL5b

V2500 V2530-A5 TL1 TL2 TL2 TL2 TL5b TL5b

V2500 V2524-A5 TL1 TL2 TL2 TL2 TL5b TL5b

V2500 V2527-A5 TL1 TL2 TL2 TL2 TL5b TL5b

TL Assignment to Engine Families by Engine Production Number
Appendix G

CAEP/6-IP/13

G-2

GE CF34-3 CF34-3B1

CF34-8 CF34-8C1

CF34-8 CF34-8C5

CF34-8 CF34-8E5

CF34-10 CF34-10E

CF6-80C2 CF6-80C2B5F 1862M39 TL5b

CF6-80C2 CF6-80C2B6F 1862M39TL5b

CF6-80C2 CF6-80C2B7F 1862M39 TL5b

CF6-80C2 CF6-80C2A8 1862M39 TL5b

CF6-80C2 CF6-80C2B1F 1862M39 TL5b

CF6-80C2 CF6-80C2A5F 1862M39 TL5b

CF6-80C2 CF6-80C2B4F 1862M39 TL5b

CF6-80E1 CF6-80E1A3 TL2 TL2 TL2 TL5b

CF6-80E1 CF6-80E1A4 TL2 TL2 TL2 TL5b

CF6-80E1 CF6-80E1A2 TL2 TL2 TL2 TL5b

GE90-94 GE90-94B DAC II TL1 TL5a TL5a TL5b TL5b

GE90-94 GE90-90B DAC II TL1 TL5a TL5a TL5b TL5b

GE90-94 GE90-85B DAC II TL1TL5a TL5a TL5b TL5b

GE90-94 GE90-77B DAC II TL1 TL5a TL5a TL5b TL5b

GE90-115B GE90-115B DAC II TL5b TL5b TL5b

GE90-115B GE90-110B1 DAC II TL5b TL5b TL5b

EA GP7000 GP7XXX TL5b TL5b

(GE/PW) GP7000 GP727X TL5b TL5b
CAEP/6-IP/13

G-3 Appendix G

PW PW6000 PW612X TL5b TL5b TL5b

PW2000 PW2043 TL2 TL2 TL2 TL5b TL5b

PW2000 PW2040 TL2 TL2 TL2 TL5b TL5b

PW2000 PW2037 TL2 TL2 TL2 TL5b TL5b

PW4000-94" PW4062-3 Phase 3 TL2 TL2 TL2 TL2 TL5b

PW4000-94" PW4060-3 Phase 3 TL2 TL2 TL2 TL2 TL5b

PW4000-94" PW4056-3 Phase 3 TL2 TL2 TL2 TL2 TL5b

PW4000-94" PW4156-3 Phase 3 TL2 TL2 TL2 TL2 TL5b

PW4000-94" PW4158-3 Phase 3 TL2 TL2 TL2 TL2 TL5b

PW4000-94" PW4158-3 Talon II TL5b

PW4000-100" PW4168A Talon II TL5b

PW4000-112" PW4090 ** TL2 TL2 TL5a TL5a TL5b TL5b

PW4000-112" PW4084D ** 4090 BOM TL2 TL2 TL5a TL5a TL5b TL5b

PW4000-112" PW4077D 4090 BOM TL2 TL2 TL5a TL5a TL5b TL5b

PW4000-112" PW4074D 4090 BOM TL2 TL2 TL5a TL5a TL5b TL5b

RR AE3007 AE3007A1

AE3007 AE3007A3

BR700 BR715C1-30 TL1 TL5b

RB211-535 RB211-535E4-B Phase 5 TL5a TL5b TL5b

RB211-535 RB211-535E4 Phase 5 TL5a TL5b TL5b

RB211-524 RB211-524H-T Phase 5 TL1 TL5a TL5b

RB211-524 RB211-524G-T Phase 5 TL1 TL5a TL5b

TRENT500 TRENT556 TL1 TL5b TL5b

TRENT500 TRENT553 TL1 TL5b TL5b

TRENT700/800 TRENT772B-60 TL1 TL5a TL5b

TRENT700/800 TRENT895 TL1 TL5b TL5b

TRENT700/800 TRENT892 TL1 TL5b TL5b

TRENT700/800 TRENT884 TL1 TL5b TL5b

TRENT700/800 TRENT 877 TL1 TL5b TL5b

TRENT700/800 TRENT 875 TL1 TL5b TL5b

TRENT900 TRENT9XX TL5b TL5b

TRENT900 TRENT97X TL5b TL5b
Appendix G

CAEP/6-IP/13

G-4
CAEP/6-IP/13

G-5 Appendix G

— — — — — — — —

Number of in-production engines(1) 80 80 80 80 80 80 80

Number of engines failing option 16 33 45 60 65 74

Percent Failure 20% 41% 56% 75% 81% 93%

 * Does not meet CO standard, thus requires a new technology combustor. 

** Does not meet CAEP/4.

(1) These figures differ from those presented in Table 4.2 due to inclusion of DAC engines.
Appendix G

CAEP/6-IP/13

G-6
Total Global NOx during LTO Cycle by Seat Class (Base Case)

-

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

2002 2006 2008 2012 2016 2020

Year

NOx (Tonnes)

20 - 49

50 - 99

100 - 150

151 - 210

211 - 300

301 - 400

401 - 500

501 - 600

601 - 650

Seat 

Category

Figure AppI.1. Total global NOx during LTO cycle by seat class (base case)

FESG Aircraft Departure (Cycle) Forecast

-

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

2002 2006 2008 2012 2016 2020

Seat Category

Number of Flights (LTO)

20-49

50-99

100-150

151-210

211-300

301-400

401-500

501-600

601-650

Seat 

Category

Figure AppI.2. FESG aircraft departures by seat category

CAEP/6-IP/13

Appendix H

APPENDIX H

FLEET LTO NOX & AIRCRAFT DEPARTURES BY SEAT

CATEGORY

Figure AppI.1 shows the distribution of global NOx by FESG aircraft seat category for the base case during

the landing and take-off cycle. It shows the results of the EDMS base case NOx emissions from 2002 to 2020

for FESG fleet forecast years. Figure AppI.2 shows FESG fleet forecast aircraft departures used in EDMS

for both the base case and options modelling.
CAEP/6-IP/13

Appendix H H-2

— — — — — — — —
-

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

2002 2006 2008 2012 2016 2020

Years

Tonnes of NOx Saved

CAEP/4 Minus 5%

CAEP/4 Minus 10%

CAEP/4 Minus 15%

CAEP/4 Minus 20%

CAEP/4 Minus 25%

CAEP/4 Minus 30%

Figure AppJ.1. Total NOx reduction by option: 2008 effectivity

-

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

45,000

50,000

2002 2006 2008 2012 2016 2020

Years

Tonnes of NOx Saved

CAEP/4 Minus 5%

CAEP/4 Minus 10%

CAEP/4 Minus 15%

CAEP/4 Minus 20%

CAEP/4 Minus 25%

CAEP/4 Minus 30%

Figure AppJ.2. Total NOx reduction by option: 2012 effectivity

CAEP/6-IP/13

Appendix I

APPENDIX I

TOTAL NOX REDUCTION BY OPTION

Projected NOx saved for each stringency option for 2008 implementation is illustrated in Figure AppJ.1, and

for 2012 implementation in Figure AppJ.2. The benefits start accruing from the time the stringency options

become effective as aircraft meeting the new standard enter into service.
CAEP/6-IP/13

Appendix I I-2

— — — — — — — —
Appendix J

CAEP/6-IP/13

APPENDIX J

TL ASSIGNMENT TO INDIVIDUAL ENGINES BY ENGINE FAMILY

Discount Rate applied to Cost Data 0%

For Present Value Analysis

Operator

Cost

Stringency 

Option

Engine 

Production

Aircraft 

Production 

Incremental 

MTOGW

Engine 

Maintenance FuelLanding 

Fees

Spares 

Inventory

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 120 $ 120 $ 83 $ - $ 74 $ - $ - $ 1,175 $ 177 $ 1,452 $ 1,452 $ 1,629 $ 1,629

10% $ 360 $ 360 $ 284 $ - $ 283 $ - $ - $ 2,040 $ 651 $ 2,967 $ 2,967 $ 3,618 $ 3,618

15% $ 1,000 $ 1,800 $ 904 $ 1,264 $ 605 $ 667 $ 222 $ 3,379 $ 1,403 $ 8,041 $ 8,841 $ 9,444 $ 10,244

20% $ 2,530 $ 4,830 $ 1,128 $ 2,227 $ 742 $ 1,063 $ 385 $ 4,830 $ 1,680 $ 12,906 $ 15,206 $ 14,586 $ 16,886

25% $ 7,185 $ 14,260 $ 3,085 $ 12,347 $ 1,826 $ 5,833 $ 1,879 $ 6,628 $ 3,881 $ 38,783 $ 45,858 $ 42,664 $ 49,739

30% $ 10,500 $ 21,000 $ 3,909 $ 16,846 $ 2,314 $ 8,296 $ 2,519 $ 7,416 $ 4,725 $ 51,799 $ 62,299 $ 56,523 $ 67,023

Stringency Year = 2012

5% $ 120 $ 120 $ 60 $ - $ 40 $ - $ - $ 1,052 $ 464 $ 1,272 $ 1,272 $ 1,736 $ 1,736

10% $ 360 $ 360 $ 204 $ - $ 152 $ - $ - $ 2,138 $ 1,652 $ 2,854 $ 2,854 $ 4,506 $ 4,506

15% $ 1,000 $ 1,800 $ 653 $ 915 $ 326 $ 356 $ 119 $ 3,563 $ 3,608 $ 6,933 $ 7,733 $ 10,540 $ 11,340

20% $ 2,530 $ 4,830 $ 816 $ 1,596 $ 400 $ 571 $ 205 $ 4,704 $ 4,323 $ 10,822 $ 13,122 $ 15,145 $ 17,445

25% $ 7,185 $ 14,260 $ 2,231 $ 9,011 $ 983 $ 3,152 $ 1,023 $ 7,096 $ 9,723 $ 30,680 $ 37,755 $ 40,404 $ 47,479

30% $ 10,500 $ 21,000 $ 2,830 $ 12,257 $ 1,255 $ 4,528 $ 1,374 $ 8,106 $ 11,915 $ 40,849 $ 51,349 $ 52,764 $ 63,264

Fleet Value

Engineering & 

Development

Manufacturer Costs Manufacturer Costs Operator Costs Fleet Value

Non-recurring Costs Recurring Costs Without Loss With Loss

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs over Forecast Period to 2020

Totals

Table J.1. Forecast to 2020, discount rate = 0%
Appendix J

CAEP/6-IP/13

J-2

Discount Rate applied to Cost Data 3%

For Present Value Analysis

Operator

Cost

Stringency 

Option

Engine 

Production

Aircraft 

Production 

Incremental 

MTOGW

Engine 

Maintenance FuelLanding 

Fees

Spares 

Inventory

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 107 $ 107 $ 58 $ - $ 49 $ - $ - $ 879 $ 149 $ 1,093 $ 1,093 $ 1,242 $ 1,242

10% $ 324 $ 324 $ 199 $ - $ 187 $ - $ - $ 1,577 $ 545 $ 2,287 $ 2,287 $ 2,832 $ 2,832

15% $ 902 $ 1,624 $ 632 $ 883 $ 399 $ 441 $ 147 $ 2,614 $ 1,175 $ 6,019 $ 6,741 $ 7,194 $ 7,916

20% $ 2,281 $ 4,356 $ 789 $ 1,560 $ 490 $ 702 $ 255 $ 3,674 $ 1,407 $ 9,752 $ 11,827 $ 11,159 $ 13,234

25% $ 6,482 $ 12,865 $ 2,156 $ 8,608 $ 1,206 $ 3,850 $ 1,240 $ 5,097 $ 3,250 $ 28,639 $ 35,022 $ 31,890 $ 38,273

30% $ 9,473 $ 18,946 $ 2,731 $ 11,754 $ 1,527 $ 5,473 $ 1,662 $ 5,732 $ 3,957 $ 38,352 $ 47,825 $ 42,309 $ 51,782

Stringency Year = 2012

5% $ 95 $ 95 $ 40 $ - $ 25 $ - $ - $ 726 $ 346 $ 887 $ 887 $ 1,232 $ 1,232

10% $ 288 $ 288 $ 135 $ - $ 97 $ - $ - $ 1,496 $ 1,230 $ 2,016 $ 2,016 $ 3,245 $ 3,245

15% $ 827 $ 1,493 $ 431 $ 604 $ 207 $ 227 $ 76 $ 2,494 $ 2,685 $ 4,865 $ 5,531 $ 7,550 $ 8,216

20% $ 2,128 $ 4,072 $ 539 $ 1,055 $ 254 $ 363 $ 130 $ 3,274 $ 3,216 $ 7,743 $ 9,687 $ 10,959 $ 12,903

25% $ 6,111 $ 12,135 $ 1,472 $ 5,937 $ 624 $ 2,001 $ 649 $ 4,956 $ 7,235 $ 21,750 $ 27,773 $ 28,985 $ 35,008

30% $ 8,945 $ 17,890 $ 1,867 $ 8,079 $ 797 $ 2,874 $ 872 $ 5,669 $ 8,866 $ 29,102 $ 38,047 $ 37,968 $ 46,913

Fleet Value

Engineering & 

Development

Manufacturer Costs Manufacturer Costs Operator Costs Fleet Value

Non-recurring Costs Recurring Costs Without Loss With Loss

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs over Forecast Period to 2020

Totals

Table J.2. Forecast to 2020, discount rate = 3%
CAEP/6-IP/13

J-3 Appendix J

Discount Rate applied to Cost Data 7%

For Present Value Analysis

Operator

Cost

Stringency 

Option

Engine 

Production

Aircraft 

Production 

Incremental 

MTOGW

Engine 

Maintenance FuelLanding 

Fees

Spares 

Inventory

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 93 $ 93 $ 37 $ - $ 29 $ - $ - $ 615 $ 118 $ 775 $ 775 $ 893 $ 893

10% $ 284 $ 284 $ 128 $ - $ 111 $ - $ - $ 1,147 $ 434 $ 1,670 $ 1,670 $ 2,104 $ 2,104

15% $ 791 $ 1,425 $ 406 $ 567 $ 237 $ 262 $ 87 $ 1,902 $ 935 $ 4,253 $ 4,886 $ 5,188 $ 5,821

20% $ 2,000 $ 3,820 $ 506 $ 1,004 $ 291 $ 417 $ 151 $ 2,623 $ 1,120 $ 6,993 $ 8,813 $ 8,113 $ 9,933

25% $ 5,685 $ 11,285 $ 1,383 $ 5,506 $ 716 $ 2,284 $ 735 $ 3,686 $ 2,586 $ 19,996 $ 25,595 $ 22,582 $ 28,181

30% $ 8,310 $ 16,619 $ 1,752 $ 7,525 $ 906 $ 3,245 $ 985 $ 4,168 $ 3,148 $ 26,891 $ 35,201 $ 30,039 $ 38,349

Stringency Year = 2012

5% $ 71 $ 71 $ 24 $ - $ 14 $ - $ - $ 454 $ 236 $ 563 $ 563 $ 799 $ 799

10% $ 217 $ 217 $ 80 $ - $ 54 $ - $ - $ 951 $ 840 $ 1,302 $ 1,302 $ 2,142 $ 2,142

15% $ 651 $ 1,181 $ 255 $ 357 $ 116 $ 127 $ 43 $ 1,585 $ 1,834 $ 3,133 $ 3,663 $ 4,967 $ 5,497

20% $ 1,713 $ 3,290 $ 318 $ 624 $ 143 $ 203 $ 73 $ 2,068 $ 2,197 $ 5,143 $ 6,719 $ 7,340 $ 8,916

25% $ 4,994 $ 9,923 $ 869 $ 3,498 $ 350 $ 1,121 $ 364 $ 3,143 $ 4,943 $ 14,337 $ 19,266 $ 19,280 $ 24,208

30% $ 7,325 $ 14,649 $ 1,102 $ 4,762 $ 446 $ 1,609 $ 488 $ 3,601 $ 6,057 $ 19,334 $ 26,658 $ 25,391 $ 32,715

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs over Forecast Period to 2020

Totals

Non-recurring Costs Recurring Costs Without Loss With Loss

Fleet Value

Engineering & 

Development

Manufacturer Costs Manufacturer Costs Operator Costs Fleet Value

Table J.3. Forecast to 2020, discount rate = 7%
Appendix J

CAEP/6-IP/13

J-4

Discount Rate applied to Cost Data 9%

For Present Value Analysis

Operator

Cost

Stringency 

Option

Engine 

Production

Aircraft 

Production 

Incremental 

MTOGW

Engine 

Maintenance FuelLanding 

Fees

Spares 

Inventory

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 87 $ 87 $ 30 $ - $ 23 $ - $ - $ 520 $ 106 $ 661 $ 661 $ 766 $ 766

10% $ 267 $ 267 $ 104 $ - $ 86 $ - $ - $ 987 $ 388 $ 1,445 $ 1,445 $ 1,833 $ 1,833

15% $ 743 $ 1,337 $ 330 $ 460 $ 185 $ 205 $ 68 $ 1,638 $ 837 $ 3,628 $ 4,223 $ 4,465 $ 5,059

20% $ 1,877 $ 3,586 $ 411 $ 816 $ 227 $ 325 $ 118 $ 2,240 $ 1,002 $ 6,015 $ 7,724 $ 7,017 $ 8,726

25% $ 5,338 $ 10,595 $ 1,123 $ 4,464 $ 559 $ 1,782 $ 573 $ 3,165 $ 2,314 $ 17,003 $ 22,260 $ 19,317 $ 24,575

30% $ 7,802 $ 15,604 $ 1,422 $ 6,104 $ 707 $ 2,531 $ 769 $ 3,587 $ 2,817 $ 22,921 $ 30,723 $ 25,738 $ 33,540

Stringency Year = 2012

5% $ 62 $ 62 $ 18 $ - $ 11 $ - $ - $ 363 $ 196 $ 454 $ 454 $ 650 $ 650

10% $ 189 $ 189 $ 62 $ - $ 41 $ - $ - $ 765 $ 698 $ 1,057 $ 1,057 $ 1,755 $ 1,755

15% $ 581 $ 1,056 $ 198 $ 277 $ 88 $ 96 $ 32 $ 1,276 $ 1,524 $ 2,547 $ 3,023 $ 4,071 $ 4,547

20% $ 1,546 $ 2,974 $ 247 $ 485 $ 108 $ 154 $ 55 $ 1,659 $ 1,826 $ 4,255 $ 5,682 $ 6,081 $ 7,508

25% $ 4,540 $ 9,022 $ 674 $ 2,714 $ 265 $ 848 $ 275 $ 2,526 $ 4,107 $ 11,841 $ 16,324 $ 15,949 $ 20,431

30% $ 6,665 $ 13,329 $ 855 $ 3,695 $ 338 $ 1,217 $ 370 $ 2,897 $ 5,033 $ 16,037 $ 22,701 $ 21,070 $ 27,735

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs over Forecast Period to 2020

Totals

Non-recurring Costs Recurring Costs Without Loss With Loss

Fleet Value

Engineering & 

Development

Manufacturer Costs Manufacturer Costs Operator Costs Fleet Value

Table J.4. Forecast to 2020, discount rate = 9%
CAEP/6-IP/13

J-5 Appendix J

Discount Rate applied to Cost Data 0%

For Present Value Analysis

Operator

Cost

Stringency 

Option Total to 2020

Estimated Total 

to 2030

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 120 $ 120 $ 1,332 $ 1,981 $ 177 $ 2,101 $ 2,101 $ 2,278 $ 2,278

10% $ 360 $ 360 $ 2,607 $ 3,698 $ 651 $ 4,058 $ 4,058 $ 4,709 $ 4,709

15% $ 1,000 $ 1,800 $ 7,041 $ 12,975 $ 1,403 $ 13,975 $ 14,775 $ 15,378 $ 16,178

20% $ 2,530 $ 4,830 $ 10,376 $ 19,834 $ 1,680 $ 22,364 $ 24,664 $ 24,044 $ 26,344

25% $ 7,185 $ 14,260 $ 31,598 $ 76,274 $ 3,881 $ 83,459 $ 90,534 $ 87,340 $ 94,415

30% $ 10,500 $ 21,000 $ 41,299 $ 101,297 $ 4,724 $ 111,797 $ 122,297 $ 116,521 $ 127,021

Stringency Year = 2012

5% $ 120 $ 120 $ 1,152 $ 1,740 $ 464 $ 1,860 $ 1,860 $ 2,324 $ 2,324

10% $ 360 $ 360 $ 2,494 $ 3,499 $ 1,652 $ 3,859 $ 3,859 $ 5,511 $ 5,511

15% $ 1,000 $ 1,800 $ 5,933 $ 10,831 $ 3,608 $ 11,831 $ 12,631 $ 15,439 $ 16,239

20% $ 2,530 $ 4,830 $ 8,292 $ 16,150 $ 4,323 $ 18,680 $ 20,980 $ 23,003 $ 25,303

25% $ 7,185 $ 14,260 $ 23,495 $ 62,612 $ 9,723 $ 69,797 $ 76,872 $ 79,520 $ 86,595

30% $ 10,500 $ 21,000 $ 30,349 $ 83,262 $ 11,915 $ 93,762 $ 104,262 $ 105,677 $ 116,177

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs Estimated to 2030

Totals Estimated to 2030

Non-recurring Costs Recurring Costs Without Loss With Loss

Fleet Value

Engineering & 

Development

Manufacturer Costs Mfg + Operator Costs Fleet Value

Table J.5. Forecast to 2020, discount rate = 0%
Appendix J

CAEP/6-IP/13

J-6

Discount Rate applied to Cost Data 3%

For Present Value Analysis

Operator

Cost

Stringency 

Option Total to 2020

Estimated Total 

to 2030

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 107 $ 107 $ 986 $ 1,367 $ 149 $ 1,474 $ 1,474 $ 1,623 $ 1,623

10% $ 324 $ 324 $ 1,963 $ 2,605 $ 545 $ 2,929 $ 2,929 $ 3,474 $ 3,474

15% $ 902 $ 1,624 $ 5,117 $ 8,602 $ 1,175 $ 9,504 $ 10,226 $ 10,679 $ 11,401

20% $ 2,281 $ 4,356 $ 7,470 $ 13,027 $ 1,407 $ 15,308 $ 17,383 $ 16,715 $ 18,790

25% $ 6,482 $ 12,865 $ 22,157 $ 48,400 $ 3,250 $ 54,882 $ 61,265 $ 58,132 $ 64,515

30% $ 9,473 $ 18,946 $ 28,879 $ 64,122 $ 3,957 $ 73,595 $ 83,068 $ 77,552 $ 87,025

Stringency Year = 2012

5% $ 95 $ 95 $ 791 $ 1,137 $ 346 $ 1,232 $ 1,232 $ 1,578 $ 1,578

10% $ 288 $ 288 $ 1,727 $ 2,317 $ 1,230 $ 2,605 $ 2,605 $ 3,835 $ 3,835

15% $ 827 $ 1,493 $ 4,038 $ 6,915 $ 2,685 $ 7,742 $ 8,408 $ 10,427 $ 11,093

20% $ 2,128 $ 4,072 $ 5,615 $ 10,231 $ 3,216 $ 12,359 $ 14,303 $ 15,575 $ 17,519

25% $ 6,111 $ 12,135 $ 15,638 $ 38,615 $ 7,235 $ 44,726 $ 50,750 $ 51,961 $ 57,985

30% $ 8,945 $ 17,890 $ 20,157 $ 51,238 $ 8,866 $ 60,183 $ 69,128 $ 69,049 $ 77,994

Fleet Value

Engineering & 

Development

Manufacturer Costs Mfg + Operator Costs Fleet Value

Non-recurring Costs Recurring Costs Without Loss With Loss

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs Estimated to 2030

Totals Estimated to 2030

Table J.6. Forecast to 2030, discount rate = 3%
CAEP/6-IP/13

J-7 Appendix J

Discount Rate applied to Cost Data 7%

For Present Value Analysis

Operator

Cost

Stringency 

Option Total to 2020

Estimated Total 

to 2030

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 93 $ 93 $ 681 $ 874 $ 118 $ 967 $ 967 $ 1,085 $ 1,085

10% $ 284 $ 284 $ 1,386 $ 1,709 $ 434 $ 1,993 $ 1,993 $ 2,427 $ 2,427

15% $ 791 $ 1,425 $ 3,461 $ 5,216 $ 935 $ 6,007 $ 6,641 $ 6,942 $ 7,576

20% $ 2,000 $ 3,820 $ 4,993 $ 7,791 $ 1,120 $ 9,791 $ 11,611 $ 10,911 $ 12,731

25% $ 5,685 $ 11,285 $ 14,310 $ 27,528 $ 2,586 $ 33,213 $ 38,813 $ 35,799 $ 41,399

30% $ 8,310 $ 16,619 $ 18,581 $ 36,333 $ 3,148 $ 44,643 $ 52,952 $ 47,791 $ 56,100

Stringency Year = 2012

5% $ 71 $ 71 $ 492 $ 666 $ 236 $ 737 $ 737 $ 973 $ 973

10% $ 217 $ 217 $ 1,085 $ 1,382 $ 840 $ 1,599 $ 1,599 $ 2,439 $ 2,439

15% $ 651 $ 1,181 $ 2,482 $ 3,931 $ 1,834 $ 4,582 $ 5,112 $ 6,416 $ 6,946

20% $ 1,713 $ 3,290 $ 3,429 $ 5,754 $ 2,197 $ 7,467 $ 9,044 $ 9,664 $ 11,241

25% $ 4,994 $ 9,923 $ 9,343 $ 20,916 $ 4,943 $ 25,910 $ 30,839 $ 30,853 $ 35,782

30% $ 7,325 $ 14,649 $ 12,009 $ 27,664 $ 6,057 $ 34,989 $ 42,313 $ 41,046 $ 48,370

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs Estimated to 2030

Totals Estimated to 2030

Non-recurring Costs Recurring Costs Without Loss With Loss

Fleet Value

Engineering & 

Development

Manufacturer Costs Mfg + Operator Costs Fleet Value

Table J.7. Forecast to 2030, discount rate = 7%
Appendix J

CAEP/6-IP/13

J-8

— — — — — — — —

Discount Rate applied to Cost Data 9%

For Present Value Analysis

Operator

Cost

Stringency 

Option Total to 2020

Estimated Total 

to 2030

Lost Fleet 

Value

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

CAEP/4 Minus Low Est High Est

Stringency Year = 2008

5% $ 87 $ 87 $ 573 $ 711 $ 106 $ 798 $ 798 $ 904 $ 904

10% $ 267 $ 267 $ 1,178 $ 1,409 $ 388 $ 1,676 $ 1,676 $ 2,064 $ 2,064

15% $ 743 $ 1,337 $ 2,885 $ 4,143 $ 837 $ 4,886 $ 5,480 $ 5,723 $ 6,317

20% $ 1,877 $ 3,586 $ 4,138 $ 6,143 $ 1,002 $ 8,020 $ 9,729 $ 9,022 $ 10,731

25% $ 5,338 $ 10,595 $ 11,665 $ 21,137 $ 2,314 $ 26,475 $ 31,732 $ 28,789 $ 34,046

30% $ 7,802 $ 15,604 $ 15,119 $ 27,838 $ 2,817 $ 35,640 $ 43,442 $ 38,457 $ 46,259

Stringency Year = 2012

5% $ 62 $ 62 $ 392 $ 516 $ 196 $ 578 $ 578 $ 774 $ 774

10% $ 189 $ 189 $ 868 $ 1,081 $ 698 $ 1,270 $ 1,270 $ 1,968 $ 1,968

15% $ 581 $ 1,056 $ 1,967 $ 3,005 $ 1,524 $ 3,586 $ 4,061 $ 5,110 $ 5,585

20% $ 1,546 $ 2,974 $ 2,709 $ 4,374 $ 1,826 $ 5,920 $ 7,348 $ 7,746 $ 9,174

25% $ 4,540 $ 9,022 $ 7,302 $ 15,595 $ 4,107 $ 20,134 $ 24,617 $ 24,242 $ 28,724

30% $ 6,665 $ 13,329 $ 9,372 $ 20,590 $ 5,033 $ 27,255 $ 33,919 $ 32,288 $ 38,952

Fleet Value

Engineering & 

Development

Manufacturer Costs Mfg + Operator Costs Fleet Value

Non-recurring Costs Recurring Costs Without Loss With Loss

Summary of NOx Cost Impact

Expressed as Millions of Constant 2002 U.S. Dollars

Costs Estimated to 2030

Totals Estimated to 2030

Table J.8. Forecast to 2030, discount rate = 9%
Appendix K

CAEP/6-IP/13

APPENDIX K

COMPARISON OF COST-BENEFIT DATA

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2020 Discount Rate = 0%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 1,452 $ 1,452 $ 1,629 $ 1,629 49,340 $ 29,426 $ 29,426 $ 33,021 $ 33,021

10% $ 2,967 $ 2,967 $ 3,618 $ 3,618 146,413 $ 20,265 $ 20,265 $ 24,709 $ 24,709

15% $ 8,041 $ 8,841 $ 9,444 $ 10,244 196,900 $ 40,838 $ 44,901 $ 47,966 $ 52,029

20% $ 12,906 $ 15,206 $ 14,586 $ 16,886 217,229 $ 59,410 $ 69,998 $ 67,145 $ 77,733

25% $ 38,783 $ 45,858 $ 42,664 $ 49,739 292,002 $ 132,817 $ 157,046 $ 146,108 $ 170,337

30% $ 51,799 $ 62,299 $ 56,523 $ 67,023 320,921 $ 161,406 $ 194,125 $ 176,128 $ 208,847

Stringency Year = 2012

5% $ 1,272 $ 1,272 $ 1,736 $ 1,736 26,418 $ 48,131 $ 48,131 $ 65,708 $ 65,708

10% $ 2,854 $ 2,854 $ 4,506 $ 4,506 78,384 $ 36,411 $ 36,411 $ 57,492 $ 57,492

15% $ 6,933 $ 7,733 $ 10,540 $ 11,340 105,488 $ 65,719 $ 73,302 $ 99,921 $ 107,505

20% $ 10,822 $ 13,122 $ 15,145 $ 17,445 116,402 $ 92,973 $ 112,732 $ 130,108 $ 149,867

25% $ 30,680 $ 37,755 $ 40,404 $ 47,479 156,880 $ 195,565 $ 240,663 $ 257,545 $ 302,643

30% $ 40,849 $ 51,349 $ 52,764 $ 63,264 172,813 $ 236,378 $ 297,137 $ 305,327 $ 366,086

Fleet Value Fleet Value Fleet Value Fleet Value

Without Loss With Loss Without Loss With Loss

Table K.1.
Appendix K

CAEP/6-IP/13

K-2

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2020 Discount Rate = 3%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 1,093 $ 1,093 $ 1,242 $ 1,242 32,605 $ 33,524 $ 33,524 $ 38,081 $ 38,081

10% $ 2,287 $ 2,287 $ 2,832 $ 2,832 96,750 $ 23,643 $ 23,643 $ 29,276 $ 29,276

15% $ 6,019 $ 6,741 $ 7,194 $ 7,916 130,107 $ 46,261 $ 51,809 $ 55,295 $ 60,842

20% $ 9,752 $ 11,827 $ 11,159 $ 13,234 143,538 $ 67,937 $ 82,394 $ 77,741 $ 92,197

25% $ 28,639 $ 35,022 $ 31,890 $ 38,273 192,892 $ 148,473 $ 181,565 $ 165,323 $ 198,415

30% $ 38,352 $ 47,825 $ 42,309 $ 51,782 211,966 $ 180,936 $ 225,628 $ 199,603 $ 244,295

Stringency Year = 2012

5% $ 887 $ 887 $ 1,232 $ 1,232 16,787 $ 52,815 $ 52,815 $ 73,398 $ 73,398

10% $ 2,016 $ 2,016 $ 3,245 $ 3,245 49,800 $ 40,475 $ 40,475 $ 65,165 $ 65,165

15% $ 4,865 $ 5,531 $ 7,550 $ 8,216 67,020 $ 72,588 $ 82,532 $ 112,646 $ 122,590

20% $ 7,743 $ 9,687 $ 10,959 $ 12,903 73,953 $ 104,698 $ 130,989 $ 148,191 $ 174,482

25% $ 21,750 $ 27,773 $ 28,985 $ 35,008 99,644 $ 218,275 $ 278,725 $ 290,885 $ 351,335

30% $ 29,102 $ 38,047 $ 37,968 $ 46,913 109,756 $ 265,154 $ 346,652 $ 345,933 $ 427,432

Without Loss With Loss Without Loss With Loss

Fleet Value Fleet Value Fleet Value Fleet Value

Table K.2.
CAEP/6-IP/13

K-3 Appendix K

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2020 Discount Rate = 7%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 775 $ 775 $ 893 $ 893 19,369 $ 39,992 $ 39,992 $ 46,095 $ 46,095

10% $ 1,670 $ 1,670 $ 2,104 $ 2,104 57,473 $ 29,061 $ 29,061 $ 36,606 $ 36,606

15% $ 4,253 $ 4,886 $ 5,188 $ 5,821 77,284 $ 55,026 $ 63,218 $ 67,127 $ 75,319

20% $ 6,993 $ 8,813 $ 8,113 $ 9,933 85,261 $ 82,020 $ 103,369 $ 95,152 $ 116,501

25% $ 19,996 $ 25,595 $ 22,582 $ 28,181 114,534 $ 174,584 $ 223,471 $ 197,163 $ 246,050

30% $ 26,891 $ 35,201 $ 30,039 $ 38,349 125,836 $ 213,699 $ 279,736 $ 238,718 $ 304,754

Stringency Year = 2012

5% $ 563 $ 563 $ 799 $ 799 9,417 $ 59,798 $ 59,798 $ 84,865 $ 84,865

10% $ 1,302 $ 1,302 $ 2,142 $ 2,142 27,930 $ 46,602 $ 46,602 $ 76,677 $ 76,677

15% $ 3,133 $ 3,663 $ 4,967 $ 5,497 37,587 $ 83,357 $ 97,456 $ 132,153 $ 146,252

20% $ 5,143 $ 6,719 $ 7,340 $ 8,916 41,475 $ 123,998 $ 162,004 $ 176,980 $ 214,986

25% $ 14,337 $ 19,266 $ 19,280 $ 24,208 55,865 $ 256,641 $ 344,861 $ 345,121 $ 433,340

30% $ 19,334 $ 26,658 $ 25,391 $ 32,715 61,528 $ 314,226 $ 433,272 $ 412,671 $ 531,716

Fleet Value Fleet Value Fleet Value Fleet Value

Without Loss With Loss Without Loss With Loss

Table K.3.
Appendix K

CAEP/6-IP/13

K-4

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2020 Discount Rate = 9%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 661 $ 661 $ 766 $ 766 15,122 $ 43,683 $ 43,683 $ 50,678 $ 50,678

10% $ 1,445 $ 1,445 $ 1,833 $ 1,833 44,871 $ 32,193 $ 32,193 $ 40,841 $ 40,841

15% $ 3,628 $ 4,223 $ 4,465 $ 5,059 60,337 $ 60,130 $ 69,982 $ 74,000 $ 83,852

20% $ 6,015 $ 7,724 $ 7,017 $ 8,726 66,564 $ 90,371 $ 116,046 $ 105,423 $ 131,098

25% $ 17,003 $ 22,260 $ 19,317 $ 24,575 89,401 $ 190,193 $ 248,997 $ 216,077 $ 274,881

30% $ 22,921 $ 30,723 $ 25,738 $ 33,540 98,214 $ 233,377 $ 312,817 $ 262,060 $ 341,500

Stringency Year = 2012

5% $ 454 $ 454 $ 650 $ 650 7,129 $ 63,619 $ 63,619 $ 91,132 $ 91,132

10% $ 1,057 $ 1,057 $ 1,755 $ 1,755 21,142 $ 49,988 $ 49,988 $ 83,003 $ 83,003

15% $ 2,547 $ 3,023 $ 4,071 $ 4,547 28,453 $ 89,529 $ 106,234 $ 143,093 $ 159,798

20% $ 4,255 $ 5,682 $ 6,081 $ 7,508 31,395 $ 135,531 $ 180,996 $ 193,691 $ 239,155

25% $ 11,841 $ 16,324 $ 15,949 $ 20,431 42,281 $ 280,069 $ 386,089 $ 377,213 $ 483,232

30% $ 16,037 $ 22,701 $ 21,070 $ 27,735 46,565 $ 344,395 $ 487,520 $ 452,483 $ 595,608

Without Loss With Loss Without Loss With Loss

Fleet Value Fleet Value Fleet Value Fleet Value

Table K.4.
CAEP/6-IP/13

K-5 Appendix K

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2030 Discount Rate = 0%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 2,101 $ 2,101 $ 2,278 $ 2,278 180,676 $ 11,629 $ 11,629 $ 12,608 $ 12,608

10% $ 4,058 $ 4,058 $ 4,709 $ 4,709 538,121 $ 7,541 $ 7,541 $ 8,751 $ 8,751

15% $ 13,975 $ 14,775 $ 15,378 $ 16,178 723,452 $ 19,317 $ 20,423 $ 21,256 $ 22,362

20% $ 22,364 $ 24,664 $ 24,044 $ 26,344 798,214 $ 28,018 $ 30,899 $ 30,122 $ 33,004

25% $ 83,459 $ 90,534 $ 87,340 $ 94,415 1,081,634 $ 77,160 $ 83,701 $ 80,748 $ 87,289

30% $ 111,797 $ 122,297 $ 116,521 $ 127,021 1,191,316 $ 93,843 $ 102,657 $ 97,809 $ 106,622

Stringency Year = 2012

5% $ 1,860 $ 1,860 $ 2,324 $ 2,324 140,112 $ 13,275 $ 13,275 $ 16,587 $ 16,587

10% $ 3,859 $ 3,859 $ 5,511 $ 5,511 417,359 $ 9,246 $ 9,246 $ 13,204 $ 13,204

15% $ 11,831 $ 12,631 $ 15,439 $ 16,239 560,906 $ 21,093 $ 22,519 $ 27,525 $ 28,951

20% $ 18,680 $ 20,980 $ 23,003 $ 25,303 618,806 $ 30,187 $ 33,904 $ 37,173 $ 40,890

25% $ 69,797 $ 76,872 $ 79,520 $ 86,595 840,491 $ 83,043 $ 91,460 $ 94,612 $ 103,029

30% $ 93,762 $ 104,262 $ 105,677 $ 116,177 926,720 $ 101,176 $ 112,506 $ 114,034 $ 125,364

Fleet Value Fleet Value Fleet Value Fleet Value

Without Loss With Loss Without Loss With Loss

Table K.5.
Appendix K

CAEP/6-IP/13

K-6

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2030 Discount Rate = 3%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 1,474 $ 1,474 $ 1,623 $ 1,623 96,966 $ 15,201 $ 15,201 $ 16,738 $ 16,738

10% $ 2,929 $ 2,929 $ 3,474 $ 3,474 288,690 $ 10,146 $ 10,146 $ 12,034 $ 12,034

15% $ 9,504 $ 10,226 $ 10,679 $ 11,401 388,131 $ 24,488 $ 26,347 $ 27,515 $ 29,374

20% $ 15,308 $ 17,383 $ 16,715 $ 18,790 428,237 $ 35,747 $ 40,592 $ 39,032 $ 43,878

25% $ 54,882 $ 61,265 $ 58,132 $ 64,515 579,769 $ 94,661 $ 105,671 $ 100,267 $ 111,277

30% $ 73,595 $ 83,068 $ 77,552 $ 87,025 638,400 $ 115,280 $ 130,119 $ 121,479 $ 136,317

Stringency Year = 2012

5% $ 1,232 $ 1,232 $ 1,578 $ 1,578 72,231 $ 17,062 $ 17,062 $ 21,847 $ 21,847

10% $ 2,605 $ 2,605 $ 3,835 $ 3,835 215,103 $ 12,110 $ 12,110 $ 17,829 $ 17,829

15% $ 7,742 $ 8,408 $ 10,427 $ 11,093 289,122 $ 26,779 $ 29,082 $ 36,064 $ 38,368

20% $ 12,359 $ 14,303 $ 15,575 $ 17,519 318,975 $ 38,746 $ 44,841 $ 48,828 $ 54,923

25% $ 44,726 $ 50,750 $ 51,961 $ 57,985 433,013 $ 103,291 $ 117,202 $ 120,000 $ 133,910

30% $ 60,183 $ 69,128 $ 69,049 $ 77,994 477,410 $ 126,061 $ 144,798 $ 144,632 $ 163,369

Without Loss With Loss Without Loss With Loss

Fleet Value Fleet Value Fleet Value Fleet Value

Table K.6.
CAEP/6-IP/13

K-7 Appendix K

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2030 Discount Rate = 7%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 967 $ 967 $ 1,085 $ 1,085 45,303 $ 21,345 $ 21,345 $ 23,950 $ 23,950

10% $ 1,993 $ 1,993 $ 2,427 $ 2,427 134,807 $ 14,787 $ 14,787 $ 18,003 $ 18,003

15% $ 6,007 $ 6,641 $ 6,942 $ 7,576 181,249 $ 33,142 $ 36,638 $ 38,303 $ 41,799

20% $ 9,791 $ 11,611 $ 10,911 $ 12,731 199,975 $ 48,961 $ 58,064 $ 54,560 $ 63,663

25% $ 33,213 $ 38,813 $ 35,799 $ 41,399 270,383 $ 122,838 $ 143,548 $ 132,402 $ 153,112

30% $ 44,643 $ 52,952 $ 47,791 $ 56,100 297,614 $ 150,003 $ 177,922 $ 160,580 $ 188,499

Stringency Year = 2012

5% $ 737 $ 737 $ 973 $ 973 31,612 $ 23,314 $ 23,314 $ 30,779 $ 30,779

10% $ 1,599 $ 1,599 $ 2,439 $ 2,439 94,105 $ 16,992 $ 16,992 $ 25,918 $ 25,918

15% $ 4,582 $ 5,112 $ 6,416 $ 6,946 126,508 $ 36,219 $ 40,408 $ 50,716 $ 54,906

20% $ 7,467 $ 9,044 $ 9,664 $ 11,241 139,575 $ 53,498 $ 64,797 $ 69,239 $ 80,538

25% $ 25,910 $ 30,839 $ 30,853 $ 35,782 189,321 $ 136,858 $ 162,893 $ 162,967 $ 189,002

30% $ 34,989 $ 42,313 $ 41,046 $ 48,370 208,711 $ 167,643 $ 202,735 $ 196,664 $ 231,756

Fleet Value Fleet Value Fleet Value Fleet Value

Without Loss With Loss Without Loss With Loss

Table K.7.
Appendix K

CAEP/6-IP/13

K-8

— — — — — — — —

Costs Compared to Benefits - Cost per Tonne of NOx Saved

Forecast Horizon : 2002 - 2030 Discount Rate = 9%

Costs Benefits Costs / Benefit Results

 Millions of 2002 U.S. Dollars U.S. Dollars per Tonne of NOx

Stringency

Option

CAEP/4 Minus

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Tonnes of 

NOx Saved

Low E&D 

Estimate

High E&D 

Estimate

Low E&D 

Estimate

High E&D 

Estimate

Stringency Year = 2008

5% $ 798 $ 798 $ 904 $ 904 31,866 $ 25,042 $ 25,042 $ 28,369 $ 28,369

10% $ 1,676 $ 1,676 $ 2,064 $ 2,064 94,798 $ 17,680 $ 17,680 $ 21,773 $ 21,773

15% $ 4,886 $ 5,480 $ 5,723 $ 6,317 127,457 $ 38,331 $ 42,995 $ 44,898 $ 49,562

20% $ 8,020 $ 9,729 $ 9,022 $ 10,731 140,624 $ 57,031 $ 69,184 $ 64,157 $ 76,310

25% $ 26,475 $ 31,732 $ 28,789 $ 34,046 190,008 $ 139,336 $ 167,003 $ 151,514 $ 179,182

30% $ 35,640 $ 43,442 $ 38,457 $ 46,259 209,101 $ 170,444 $ 207,756 $ 183,915 $ 221,228

Stringency Year = 2012

5% $ 578 $ 578 $ 774 $ 774 21,413 $ 26,993 $ 26,993 $ 36,146 $ 36,146

10% $ 1,270 $ 1,270 $ 1,968 $ 1,968 63,729 $ 19,928 $ 19,928 $ 30,881 $ 30,881

15% $ 3,586 $ 4,061 $ 5,110 $ 5,585 85,680 $ 41,849 $ 47,398 $ 59,636 $ 65,185

20% $ 5,920 $ 7,348 $ 7,746 $ 9,174 94,530 $ 62,630 $ 77,732 $ 81,946 $ 97,048

25% $ 20,134 $ 24,617 $ 24,242 $ 28,724 128,166 $ 157,095 $ 192,069 $ 189,143 $ 224,116

30% $ 27,255 $ 33,919 $ 32,288 $ 38,952 141,284 $ 192,907 $ 240,077 $ 228,530 $ 275,700

Without Loss With Loss Without Loss With Loss

Fleet Value Fleet Value Fleet Value Fleet Value

Table K.8.
CAEP/6-IP/13

Appendix L

APPENDIX L

FESG ANALYSIS OF ICAO TIMES IN MODE

& AIRCRAFT PERFORMANCE

ICAO Committee on Aviation Environmental Protection

Forecasting and Economic Analysis Support Group, Eighth Meeting

NOx Emissions Modeling Task Group (NEMTG) Meeting

Washington, D.C. - 7 October 2003

EFFECT OF TIMES IN MODE AND POWER SETTING CALCULATIONS ON

EMISSIONS DISPERSION MODELING SYSTEM RESULTS

Presented by: Howard Aylesworth, NEMTG Chair (ICCAIA)

The Emissions Dispersion Modeling System (EDMS) is designed to model aircraft emissions produced over

the landing-takeoff (LTO) cycle. EDMS defaults to ICAO times in mode. ICAO times in mode have been

used in the FESG economic analysis of NOx stringency options. Other times in mode are calculated using the

aircraft weight or the corresponding stage length. ICAO times in mode are shown in the first two columns

of Table L.1. 

Table L.1 FAA EDMS landing-takeoff mission times in mode & fuel calculations

Mode Minutes Power

Setting

(% Rated

Thrust)

Fuel Use

Takeoff 0.7 100% Standard aircraft weight, Calculated from engine fuel flow.

Climb Out 2.2 80% Standard aircraft weight, Calculated from engine fuel flow.

Approach 4.0 30% Standard aircraft weight, Calculated from engine fuel flow.

Idle 26.0 7% Standard aircraft weight, Calculated from engine fuel flow.

Comparison of GEM and ICAO times in mode 

Airplane performance data used in the Boeing Global Emissions Model (GEM) emissions inventories are

calculated using the standard set of rules shown in Table L.2 (next page). GEM times in mode (TIM) are

constructed to calculate emissions produced over all stages of flight with specific emphasis on the climb and

cruise phases. GEM output of emissions inventory calculations provides a “map” of aircraft fuel burned and

engine emissions for the global fleet on a three dimensional grid of 1 degree latitude by 1 degree longitude by

1 kilometer altitude cells up to an altitude of 13 kilometers. Altitude is recorded as flight (barometric) pressure.

The first altitude cell in the inventory calculation is one kilometer high (3281 feet), a value 9.4% higher than

the EDMS altitude value of 3,000 feet at sea level. EDMS altitudes are 3,000 feet above ground level. Thus,
CAEP/6-IP/13

Appendix L L-2

there is not a one-to-one correspondence between GEM altitude cells and EDMS altitudes although a majority

of the world’s airports are captured within the first GEM altitude cell.

Comparison of LTO base case NOx emissions and fuel burn were calculated by GEM using ICAO and GEM

times in mode. The results are presented in Figures L.1 through L.4 (page 96). The GEM method allows 14

minutes at idle taxi power (9 minutes out + 5 minutes returning) whereas EDMS is set according to the value

specified by the ICAO standard times in mode. Using the ICAO LTO idle segment a relatively large portion

of fuel (~35 -to 45%) is burned as shown in Figure L.1, but only a minor portion of total LTO NOx (10 - 20%)

occurs under this mode as shown in Figure L.2. Takeoff plus climb out to 3,000 feet is roughly a half-minute

longer in EDMS than is generally calculated by GEM for twin-engine airplanes. Using GEM rather than

ICAO times in mode reduces LTO fuel burned by about 26% and NOx by 20% as shown in Figures L.3 and

L.4 respectively.

Table L.2. Boeing GEM mission segment time-in-mode & fuel calculations (NOTE)

Segment Time Fuel Comment

Taxi out 9 minutes Allowance Constant allowance all missions

Takeoff to 35 feet. Calculated Calculated

Climb to 1500 feet. Calculated Calculated

Accelerate to 250 knots Calculated Calculated Constant 1500 ft. altitude

Climb to 10,000 feet Calculated Calculated Constant 250 knots

Accelerate to climb speed Calculated Calculated Constant 10,000 ft. altitude

Climb to cruise altitude Calculated Calculated

Cruise Calculated Calculated Includes step-climbs 

Descent to 10,000 feet Calculated Calculated Descent speed schedule

Decelerate to 250 knots Calculated Calculated Constant 10,000 ft. altitude

Descend to 1500 feet Calculated Calculated Constant 250 knots

Approach and land Allowance Allowance Constant allowance all missions of same aircraft

but varies with type

Taxi in 5 minutes Allowance Constant allowance all missions

NOTE: GEM mission segments, in whole or in part, included in the ICAO landing-takeoff (LTO) cycle are

shown in green italic. Segments containing a portion of the flight falling within the ICAO LTO cycle are

shown in black italic. Segments not included in ICAO LTO appear in red. 

Impact of varying EDMS times in mode

Of the four modes the taxi/idle mode is the most variable due to its airport specific nature. The taxi/idle time

in mode has three components: landing roll time, taxi time, and queue time. Landing roll time is the time spent

at idle power after touchdown and is dependent on aircraft performance. The taxi and queue time is the time

spent in taxi and queue between gates and runways. The approach and climb out time will vary depending

on the aircraft performance and mixing height.

EDMS treats each aircraft type as a specific airframe and engine combination by type and by model. In each

of the four modes the engines operate at correspondingly different power settings as show in column 3 of
CAEP/6-IP/13

L-3 Appendix L

1

In both the assigned stage length and the WYLE calculations aircraft weights were assigned on the bases of stage length from which

times in mode were determined. The modeling differences reflect different methods of determining stage length.

Figure L.5.

Table L.1. The power settings determine the rate at which fuel is burned which in turn determines the quantity

of emissions generated from an aircraft in a specific mode. Aircraft emissions are calculated as:

Eij = S (TIMjk * FFjk/1000 * EIijk * NEj)

where: Eij Total pounds of pollutant i produced by aircraft type j over one LTO cycle.

TIMjk Time in mode for mode k, inn minutes, for aircraft type j.

FFjk Fuel flow for mode k, in pounds per minute, for each engine used on the aircraft type j.

EIijk Emission index for pollutant i, in pounds of pollutant per thousand pounds of fuel, in mode k

for aircraft type j.

NEj Number of engines used on aircraft type j.

Using the FESG CAEP/5 fleet forecast and the CAEP/5 Magenta detailed data base of CAEP/5 Jet-9

aircraft by seat category, FAA produced an EDMS demonstration based on worldwide flight operations for

the years 1998, 2005, 2010, 2015, and 2020. Three different times in mode were presented: (1) the base case

using ICAO times in mode; (2) a base case using times in mode assigned on the basis of stage length selected

from the EDMS matrix of seven options; and, (3) a WYLE Laboratories times in mode base case using

maximum stage length where intermediary stops during transoceanic flights were eliminated1. 2020 calculated

NOx using the EDMS assigned stage length is about 12% lower than using ICAO times in mode. The WYLE

value is nearly 26% lower than the base case value based on ICAO times in mode. These results are shown

in Figure L.5. These results are consistent with those produced by GEM.
CAEP/6-IP/13

Appendix L L-4

Figure L.6.

Findings

The base case results reported in Section 5.2 (EDMS SG4), and the GEM and FAA Demonstration base

cases are shown in Figure L.6 (next page). The FAA Demonstration and EDMS SG4 base cases are not

representative of actual times in mode and thrust settings used in service, whereas the GEM base case values

more closely approximate actual times in mode. It can be concluded with a very high degree of certainty the

SG4 base case values would be meaningfully lower if other than ICAO times in mode were used. If all other

aspects of such a modeling exercise remained the same, these values would be expected to be 10% to 15%

below current SG4 base case values if EDMS assigned times in mode were conservatively assigned. In this

instance, the 2020 annual tons of NOx would be expected to fall between 693,214 and 654,702 tons annually.

If GEM times in mode and power settings were modeled in EDMS, with a comfortable degree of certainty

the new base case values would be expected to be approximately 20% lower regardless of any differences

in how much NOx the two models capture in their respective altitude cells. For 2020 616,190 tons LTO NOx

would be the expected lower limit.

Implications for analysis of benefits 

At CAEP/3 the question was raised that the benefits represented in the cost-benefit analysis were

understated due to the short time horizon considered in relation to the rate of entry of new aircraft into the

fleet and the rate of retirement of older aircraft. GEM estimates baseline and NOx stringency option emissions

to 2030. The potential exists to estimate EDMS results for 2030 with a satisfactory degree of certainty. 
CAEP/6-IP/13

L-5 Appendix L

— — — — — — — —

Figure L.1 Figure L.2

Figure L.3 Figure L.4

PERCENTAGE OF NOx EMISSIONS IN ICAO LTO CYCLE SEGMENTS

(PRESENT PRODUCTION ENGINES)

0%

10%

20%

30%

40%

50%

60%

0 50 100 150 200 250 300 350 400 450 500

RATED OUTPUT - KN

PERCENT OF NOx EMISSIONS IN LTO CYCLE

T/O

C/O

App

Idle

LTO CYCLE FUEL BURNED - PRESENT PRODUCTION ENGINES

0

200

400

600

800

1000

1200

1400

1600

0 50 100 150 200 250 300 350 400 450 500

RATED OUTPUT - KN

FUEL BURNED IN LTO CYCLE - KG

ICAO TiM

BOEING TiM

LTO CYCLE NOx PRODUCED - PRESENT PRODUCTION ENGINES

05

10

15

20

25

30

35

0 50 100 150 200 250 300 350 400 450 500

RATED OUTPUT - KN

MASS OF NOx PRODUCED IN LTO CYCLE - KG

NOx MASS - ICAO TiM

NOx MASS - BOEING TiM

PERCENTAGE OF FUEL BURNED IN ICAO LTO CYCLE SEGMENTS

(PRESENT PRODUCTION ENGINES)

0%

0%

0%

0%

0%

0%

0%

0 50 100 150 200 250 300 350 400 450 500

ENGINE RATED OUTPUT - KN

T/O

C/O

App

Idle
Appendix L

CAEP/6-IP/13

L-6

Appendix AAN-WP/
CAEP/6-IP/13

Appendix M

APPENDIX M

FESG ANALYSIS OF NO FURTHER STRINGENCY ASSUMPTION

The statement “benefits are underestimated because they do not extend for long enough a period; i.e., costs

are front-end, and benefits back-end loaded.” This is totally dependent on the assumption that there will be

no further NOx stringency increase.

Figure 3.1 (page 7) shows that over an 18 year period 70% of the 2020 fleet is comprised of aircraft

purchased since 2002 (call this “New”), and 30% of aircraft in the end year are those that were there at the

beginning of the period (call this “Old”). This is just a function of the retirement curves applied to individual

aircraft/engine combinations; albeit their growth rates vary according to growth in demand and a manner in

which operators meet this demand (operator response). These fleet proportionality relationships should remain

the same regardless of the date they are initially applied (i.e., 2008 to 2026).

Examples of the effect of the assumed no further increase in NOx stringency are provided below:

Case 1

An X% reduction in 2008 will yield a 2016 fleet, of which 42% have been purchased since 2008 (new) and

comply with the new standard and 58% were purchased prior to 2008 (old) and are not subject to that

standard. By 2026 the composition of the fleet is 70% new and 30% old aircraft; call these a1 and ß

respectively. The 30% old aircraft show the benefits of prior NOx standards, and not all airframe/engine

combinations in this category necessarily fall below the new standard. As these old aircraft are the result of

prior standards they do not appear in the benefits resulting from the new standard. This is also true of the

benefits for existing aircraft meeting the new standard amongst the aircraft in the new 70% category (a1U).

In the a1 category, only the benefits from engines that were not compliant with the new standard and have

been made so (a1A) are counted. These are the direct benefits of the new standard.

The proportion of aircraft affected by the new standard depends on the amount of the stringency increase,

the number of affected aircraft entering the fleet and the retirement curves that apply to them. Based on the

results of the CAEP/6 cost-benefit analysis, the long-term benefits of an X% reduction in 2008 are:

Table M.1. 2008 stringency increase only

X = -10% X = -20%

Percent 2008 Fleet Affected 33% 56%

Total NOx Reduction through 2015 -16,455 -24,427

Total NOx Reduction through 2016 -24,887 -36,949

Total NOx Reduction through 2026 -235,154 -349,960

Total NOx Reduction through 2030 -417,359 -618,806
CAEP/6-IP/13

Appendix M M-2

Case 2

An X% reduction to the NOx stringency standard in 2008 and a Y% reduction in 2016 will yield a 2026 fleet

of 70% aircraft purchased since 2007 (a2) and 30% aircraft purchased before 2008 (ß). The composition of

the 2026 fleet new aircraft category is:

a) those aircraft in the 2008 a1 portion of the fleet that meet both X and Y (a1Ua);

b) those aircraft in the 2008 a1 portion of the fleet that meet X but not Y (a1Uß);

c) those aircraft in the 2008 a1 portion of the fleet made compliant with X that meet Y

(a1Aa); and

d) those aircraft in the 2008 a1 portion of the fleet made compliant with X that do not meet

Y (a1Aß).

Such that:

2016 aircraft made compliant to Y a2ß = a1Uß + a1Aß;

2016 aircraft meeting standard Y a2a = a1Ua + a1Aa; and

2026 new aircraft since 2008 a2 = a2a + a2ß

As of the date Y% NOx stringency becomes effective, a1 has achieved a total NOx reduction of 16,445

tonnes for X = -10% and 24,427 tonnes for X = -20%. Based on the CAEP/6 cost-benefit analysis, the long

term benefits are:

Table M.2. 2008 and 2016 stringency increases

2008 -15% 2016 - Z%

Percent Initial Year Fleet Affected 44% n.a.

Total NOx Reduction through 2015 -22,142 n.a.

Total NOx Reduction through 2016 -33,492 - a1Aß benefits1, 2 a2ß benefits1

Total NOx Reduction through 2026 -317,154 - a1Aß benefits1, 2 a2ß benefits1

Total NOx Reduction through 2030 -560,906 - a1Aß benefits1, 2 a2ß benefits1

1

 Denotes total benefits accruing over the 2016 to 2026 time period.

2

 This is equivalent to: -22,142 + a1Aa

In 2024 new aircraft purchased since stringency Y became effective are 42% of the fleet. The portion of the

new fleet attributable to stringency X a1Aa and those attributable to Y is a1Uß + a1Aß, such that benefits

accruing to stringency X had the new standard not come into effect have been reduced by a1Aß. Carrying

this forward to 2026 where 70% of the fleet is new, the following relationships hold:

Total benefits accruing to stringency X = a1A

2008-16 + a1Aa = a1A2008-2026

 - a1Aß

Total benefits accruing to stringency Y = a2ß

Assuming approximately 45% of the 2026 fleet has been purchased since 2016:
CAEP/6-IP/13

M-3 Appendix M

If a1Aa = 0, then approximately 64% of the 2026 new fleet is a2ß and 36% a1A

2008-16; 

If a1Aß = 0, then a1A remains unchanged and a2ß = a1Uß.

Conclusions

The assumption of no further stringency increase is the primary factor influencing the quantity of long term

benefits resulting from the original stringency increase. From the examples above the following conclusions

may be drawn:

1. In the case of no further NOx stringency the rate of increase in total benefits increases over

time unencumbered until the entire fleet complies with the new standard and all originally

purchased a 1A aircraft have been retired. At that point there are no additional benefits.

Between the time that all new purchases are a1A aircraft and all a1A aircraft have been

retired, the rate at which benefits accrue decelerates.

2. The influence of the retirement curves on the accrual rate of total benefits resulting from a

given stringency increase is due primarily to the “S” shape of the retirement curves and the

time horizon over which the steeply vertical part of the curve exercises its influence; and

only secondarily to the number of individual curves, and the time span for, and number of

aircraft falling under each curve.

3. If an initial stringency increase is followed by further stringency increase(s), starting the year

the later standard(s) becomes effective, benefits attributable to the original standard are

adjusted downward. The magnitude by which benefits of the initial change depends on the

effectivity date of the latter standard(s) relative to the effectivity date of the original

standard. This change becomes smaller the shorter the time period is between the effectivity

dates of the two stringency changes. This is due to the smaller number of aircraft subject to

the original standard entering the fleet. The proportion by which the benefits accruing to the

earlier standard are diminished depends on the amount by which later standard is reduced,

the number of airframe/engine combinations affected by each standard, and the rate at

which newly affected aircraft enter the fleet under each standard and the retirement curves

that apply to them.

4. The assumption of no further stringency increase could overstate the long term benefits

derived from the initial stringency increase. Delaying the effectivity date for a given

stringency level has a large effect on the total benefits for any given out-year. This suggests

there are two alternative approaches to achieve a given amount of total NOx reduction in the

given long term year, namely, a larger single reduction or the combination of two smaller

reductions.

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