Cost Analysis of CO2-

Reducing Technologies 

for Aircraft

 

Submitted to:

U.S. Environmental Protection 

Agency

March 17, 2015 

Submitted by:

ICF International

© 2013 1 ICF INTERNATIONAL
PREFACE

This report has been composed for the US Environmental Protection Agency (EPA) to study the 

costs of developing and implementing Carbon dioxide (CO2)-reducing technologies on new inproduction aircraft as measured by CAEP’s CO2 metric. The International Civil Aviation 

Organization’s (ICAO) Committee for Aviation Environmental Protection (CAEP) is working to 

establish an aircraft CO2 emission standard for new aircraft designs by 20161. However, further 

work is needed to support future decisions about the applicability of the CO2 standard to new inproduction aircraft. ICF’s study examines the technologies applicable to new in-production 

aircraft and the projected costs to research and apply them to existing designs. ICF gathered data 

on some 70 technologies from a combination of public sources and confidential interviews, then 

applied an expected value methodology to develop projected CO2 metric values and costs. ICF 

is grateful to its reviewers Dr. Nick Cumpsty of Imperial College, Rich Golaszewsi of GRA, 

Incorporated, Adam Klauber of ICF, Dr. Ian Poll of Cranfield University, and Fay Collier of 

NASA for their feedback. This report was prepared by Peter Zimm, Glenn McDonald, and 

Kevin Michaels of ICF, Mike Dill, and Dr. Joaquim Martins of the University of Michigan. 

© 2013 2 ICF INTERNATIONAL

 
ASSESSMENT OF CO2-REDUCING TECHNOLOGIES

1.1 INTRODUCTION

GROWTH OF AVIATION-PRODUCED CO2 AND THE INTERNATIONAL RESPONSE

In 2012, global aircraft CO2 emissions were 2% of total global aggregate CO2 output,2 (and 13% of global 

transportation CO2 emissions in 20113

, which is the most recent year that global transportation CO2

emissions data is available). Aircraft CO2 emissions are receiving increasing scrutiny because they have 

steadily increased due fleet growth and higher utilization. Globally, civil aircraft generated an estimated 

1.44 trillion pounds4 of CO2 in 2012. Commercial air transport aircraft—encompassing the Very Large 

Aircraft, Large Twin Aisle, Small Twin Aisle, Single Aisle, and Regional Jet aircraft categories—generated 

approximately 96% of this total5

. Furthermore, global commercial air transport CO2 output will increase 

at an estimated 3.5% per annum over the next 10 years.6

 ICF estimates that global air transport CO2

emissions will grow to 1.8 trillion pounds in 2021. The air transport aircraft categories will continue to 

dominate CO2 output, and the output of two categories in particular—Single Aisle and Large Twin Aisle—

will outpace the overall CO2 emissions growth.

In response to this issue, the ICAO’s CAEP has been working for over four years to establish an aircraft 

CO2 emissions standard by 20167

. (At the 8th meeting of CAEP in February 2010, CAEP agreed to a future 

work program to establish aircraft CO2 standards.) In November 2010, CAEP agreed that the standard 

would apply to subsonic jets and turboprops. More specifically, the criteria were an applicability weight 

threshold of maximum takeoff weight (MTOW) >5700kg (12,566lb) for subsonic jet aircraft and a weight 

threshold of MTOW>8618kg (19,000lb) for propeller-driven multi-engine aircraft (e.g., turboprops).8 It 

was also agreed that the scope of applicability should include “new”9 aircraft types, but not “in-service”, 

and that “new in-production”10 aircraft types should not be ruled out at this time. In February 2013, CAEP 

2 ICF International analysis.

3 Climate Data Explorer of the World Resources Institute http://cait.wri.org. Accessed October 31, 2014. International Energy 

Agency, Data Services http://data.iea.org. Accessed October 22, 2014. 4 ICF International analysis.

5 ICF International analysis.

6 ICF International analysis.

7 It is expected that aircraft CO2 standards will be adopted at the tenth meeting of CAEP in February 2016. 8 ICAO, 2013: CAEP/9 Agreed Certification Requirement for the Aeroplane CO2 Emissions Standard, Circular (Cir) 337, 

AN/192, Available at www.icao.int . 9 “New” aircraft types - If airworthiness considers an aircraft to be a “new” type, then this same perspective will be adopted by the CO2 

requirement and the latest standard will be applied. This is a same approach to the current aircraft noise requirements.

10 “In-production” aircraft types - aircraft types which have already received a Type Certificate, and appropriate Production Certificate, and for 

which manufacturers either have existing undelivered sales orders or would be willing to accept new sales orders.

© 2013 3 ICF INTERNATIONAL

 
agreed to a requirement that new aircraft be certified for their CO2 emissions using a CO2 metric system

that measures these emissions. 

The Metric Value (MV) is based on an instantaneous measure of the fuel burn per distance flown that is 

then adjusted by accounting for usable aircraft floor area. Three test points are considered in the calculation 

of the MV for each aircraft, representing flight at high, medium, and low gross weights. The fuel burn per 

unit distance of each aircraft is evaluated at these three points and then averaged to obtain the MV.11 A 

more detailed description of the MV can be found in Section 1.3. For regulation purposes, the maximum 

allowed MV increases with the maximum takeoff mass (MTOM) of the aircraft, according a stringency 

function. Currently, CAEP is expected to set a CO2 stringency standard that will go into effect in 2020 or

2023. 

This study examines the applicability of the CO2 standard to new in-production aircraft. In particular, it 

assesses the technological improvements to new in-production aircraft that are feasible, and the potential

CO2 emission reductions they could produce. The stringency function implications for 2020 and 2023 are 

also examined in light of the projected CO2 emission reductions. Finally, we project the costs of realizing 

the projected CO2 emission reductions. 

DATA SOURCES

This study was conducted over a seven month period and ICF gathered data from a wide variety of sources 

to support this analysis. In general, four types of sources were used to develop technology cost and 

performance data:

1.secondary research

2.interviews

3.domain knowledge from past work/engagements

4.internal aircraft cost and performance modeling frameworks

Secondary Research

Secondary research provided a wealth of information about individual technologies and ongoing research 

programs. This was captured in the industry press, supplier and Original Equipment Manufacturer (OEM)

press releases, conference proceedings, and news articles. University publications and websites also 

provided much information.

11 ICAO, 2013: CAEP/9 Agreed Certification Requirement for the Aeroplane CO2 Emissions Standard, Circular (Cir) 337, 

AN/192, Available at www.icao.int . 

© 2013 4 ICF INTERNATIONAL

 
Market Interviews

ICF conducted a broad and thorough market interview program to gather feedback on technology 

performance, modeling approach and methodology, and commercial feasibility. Over 40 interviews were 

conducted with a wide cross-section of key individuals from throughout the industry – airframe, engine, 

and systems manufacturers, aircraft operators, and university and research organizations provided input and 

feedback on methodology, technology performance, and costs.

Current and former employees were interviewed from the following organizations:

Exhibit 1-1. Organizations Interviewed by ICF

Organizations Interviewed

• Aerion

• Aerodynamic Solutions

• Airbus

• ATR

• Boeing

• Bombardier

• GE 

• Honeywell

• Mitsubishi

• MTU

• NASA

• Parker 

• PATS

• Pratt & Whitney 

• Rolls-Royce

• Volvo

• United Airlines

• United Technologies

Domain Knowledge and ICF Internal Cost and Performance Models

The ICF team was able to leverage knowledge gained through past consulting engagements, as well as cost 

and performance models that had been developed to support market knowledge and ongoing project work. 

In some cases, knowledge was available from in depth cost and performance models used for particular 

technologies.

Through a combination of these sources, ICF was able to create comprehensive profiles of both the fuel 

burn impact and cost of a wide variety of technologies.

KEY ASSUMPTIONS

It is also important to note that the assumptions underlying this fuel burn reduction forecast include: fuel 

prices remaining at their current levels, no wholesale business model changes by aircraft, engine, or 

component manufacturers or airlines, and the current pace of technology development is not significantly 

changed. These assumptions are critical, since the pace of technology development will strongly depend on 

degree of improvement mandated by CO2 emissions regulations, as well as programs offered to incentivize 

research and development.

© 2013 5 ICF INTERNATIONAL
Aircraft fuel consumption varies greatly depending on flight-specific operating conditions. Different 

payload weights (including passengers, cargo, and fuel) affect fuel burn metrics such as fuel burn per 

passenger mile. Air traffic control sophistication and efficiency also play an important role in driving fuel 

consumption. Excessive loitering, a “stepped” approach to climb and descent, and sub-optimal altitude or 

speed assignments all have the potential to significantly increase overall trip fuel consumption

Owing to the magnitude of analysis performed by ICF in this process, substantial sensitivity analysis was 

not performed on these assumptions. ICF expects that the final results of cost and fuel consumption impacts 

of individual technologies will be sufficiently accurate for the purposes of analyzing forecasting the cost 

and impact of CO2 stringencies on the air transport market. 

MAGNITUDE AND SOURCES OF HISTORICAL CO2 REDUCTIONS 

Since the advent of gas turbine engine powered air transport in 1958, aircraft fuel efficiency has improved 

about 1.5% per annum through a combination of major redesigns and incremental improvements. Major 

redesigns refer not only to completely redesigned aircraft, but also to significant partial redesigns –

redesigned wings (re-winging) and re-engined aircraft. Incremental improvements are less extensive 

changes to the production standard of the aircraft, such as winglets or performance improvement packages 

(PIPs) that are introduced into airframes or engines mid-life. ICF research indicates that major redesigns 

account for as much as two-thirds of historical fuel burn reduction. By implication, incremental 

improvements account for about one-third of reductions, or about 0.5% per year. Furthermore, it appears 

more of the incremental reductions in recent times are due to improvements in aerodynamics than in 

engines. In contrast, engine technology has been the primary driver of major redesign aircraft efficiency 

improvements. Secondary research and interview input point to a 0.8 to 1.0% annual improvement in 

engine efficiency from major redesign technology while incremental improvements yield about 0.2% better 

fuel burn per annum. 

THE NATURE OF TECHNOLOGY INSERTION

Major redesigns yield large fuel burn reductions – 10% to 20% over the prior generation they replace. As 

one might expect, the significant fuel burn reductions of major redesigns do not happen frequently. One of 

the best examples of this is the Boeing 737 program. Debuting in 1968 with two variants and powered by 

low bypass JT8D engines, the airplane has undergone major redesigns three times – they entered service in 

1984, 1998, and will enter in 2017, respectively, or about every 16 years. 

© 2013 6 ICF INTERNATIONAL
Exhibit 1-2. Major Redesign History of the Boeing 737

Insofar as we are going through a wave of major redesign and service entry now, prospects for further stepfunction improvements will be low in the coming 10-15 years. The outlook for major redesigns is described 

below in the Exhibit 1-3: 

Exhibit 1-3. Outlook for Major Redesigns by Aircraft Category

Photo Example Aircraft 

Category

Entry Into 

Service Major Redesign Major Redesign Outlook

Very 

Large

747-100 (1969)

A380 (2007)

747-400 (1989)

747-8 (2011)

This category is experiencing 

sluggish sales.

No other major redesign until after 

2025.

Large 

Twin 

Aisle

777-200/300 

(1995)

777-200LR (2004)

A350-900 (2015)

777-9X (2020)

777-8X (2020)

No other major redesign until after 

2030

© 2013 7 ICF INTERNATIONAL
Small 

Twin 

Aisle

767 (1982)

A330 (1994)

787-8 (2011)

767-400ER (2000)

A330neo (2017)

No other major redesign until after 

2030

Single 

Aisle

737-100 (1968)

A320 (1988)

737 Classic 

(1984)

737NG (1998)

CS100 (2015), CS300 (2016)

A320neo (2015)

737MAX (2017)

C919 (2018)

MS-21 (2018)

The decision by Boeing and Airbus 

to re-engine the 737 and A320 will 

delay introduction of a major 

redesign western single-aisle until 

well beyond 2025

Regional 

Jet

CRJ-100 (1992)

E 170 (2004)

CRJ-700 (2001)

The regional jet category was ripe 

for new major redesigns

ARJ21 (2015)

MRJ (2017)

Embraer E2 (2018)

Major redesigns can be expected in 

the 2025-2030 timeframe

Large 

Bizjet

Gulfstream 

V(1995) G550 (2004)

Contrary to all other aircraft size 

segments, business jets undergo 

frequent minor changes and 

somewhat frequent major redesigns 

Small 

Bizjet

Learjet 40/45 

(1998)

Learjet 70/75 

(2013)

Contrary to all other aircraft size 

segments, business jets undergo 

frequent minor changes and 

somewhat frequent major redesigns

© 2013 8 ICF INTERNATIONAL
Turboprop

Saab 340 (1983)

Q400 (1997)

Saab 2000 (1994)

ATR 72 (1989)

ATR 42 (1985)

Q400 Next Gen

Major redesign expected by early 

2020s, ATR 9012 turboprop 

derivative possible before then

Furthermore, increasingly, technologies developed for major redesigns eventually make their way onto 

mature aircraft – first technologies are researched to technology readiness level (TRL) 6,13 then they are 

incorporated into development programs where they are thoroughly tested and developed for applications 

on the aircraft. Lastly, they can be chosen to be incorporated into a PIP14 on an existing aircraft. Finally, 

new development cycles are very lengthy. It is not unusual for new aircraft and engine designs to take 8-

10 years to develop, from preliminary design to entry into service. 

If past trends continue into the future, we can expect:

• Overall fuel efficiency to improve by 1.5% per annum 

• Major redesign activities will contribute about two-thirds of this improvement; incremental 

technology introductions will reduce emissions by 0.5% per annum

• Engine technologies will drive major redesign aircraft improvements but aerodynamics will be a 

larger contributor of incremental improvements

• Major redesign activity will be infrequent and will not be seen for 10-15 years for most aircraft 

categories after the current redesign wave has passed

• Technologies researched and developed during the current wave of major redesign aircraft will be 

ripe for incorporation onto existing mature platforms (i.e., new in-production aircraft) 

• The coming drought of major redesigns means incremental improvements to new in-production 

aircraft will be the primary lever for CO2 reductions for the next 10-15 years. 

12 ATR 90 refers to the ATR 90-seater turboprop. 13 Technology readiness level 6 represents when the system/subsystem model or true dimensional test equipment is validated in a 

relevant environment. See the technology readiness section of the appendices for more information. 14 Occasionally, PIP’s are referred to at technology insertion packages or TI’s. 

© 2013 9 ICF INTERNATIONAL

 
1.2 TECHNOLOGY FUEL BURN IMPACT

METHODOLOGY

ICF developed a detailed methodological framework to analyze the potential impact of new technology 

introduction on aircraft fuel efficiency and CO2 emissions. This framework involved five basic steps. First, 

we identified the technologies that could reduce CO2 emissions of new in-production aircraft. Second, we 

then assessed each technology for the magnitude of potential CO2 reduction and the mechanisms by which 

reduction is achieved. Both of these were analyzed by aircraft category. Third and fourth, the technologies 

were passed through technical success probability and commercial probability success screens, 

respectively. Last, individual aircraft differences were considered within aircraft category to develop a CO2

emissions reduction forecast by technology by aircraft model. This entire methodological framework 

detailed above will be referred to henceforth as the expected value methodology.

ICF identified and evaluated some 70 engine and airframe technologies for their ability to reduce CO2

emissions15 on new, in-production aircraft. 

15 Or fuel burn. The terms are used interchangeably throughout this report.

Exhibit 1-4. ICF Technology Impact Methodology

Exhibit 1-5. ICF Airframe & Systems Technologies List 

© 2013 10 ICF INTERNATIONAL

 
16

Exhibit 1-6. ICF Engine Technologies List

Engine Technologies

16 Please refer to Appendix 2 for more information on these technologies

Airframe Technologies

Aerodynamic Structural Systems

• Adaptive Trailing Edge

• Advanced Wingtip Devices

• Variable Camber Trailing 

Edge

• Re-Wing

• Riblet Coatings

• Laminar Flow Control

− Natural and Hybrid

− Nacelle, Empennage, and 

Wing

• Advanced Configurations

• Environmental Control 

System (ECS) Inlet

• Stab Control Law

• Gap Reductions

• Aft Body Redesign

• Light Profile

• Advanced Metals

• Increased Composite 

Application

• Advanced Composites

• Re-Wing

• Advanced Configurations

• Titanium Landing Gear

• Lightweight Paint / Surface 

Treatment

• Lightweight Lightening 

Strike Protection

• More Electric Systems

• On demand Environmental 

Control Systems

• Fuel cell Auxiliary Power 

Unit (APU)

• Light interior

• Fly By Wire

• Carbon brakes

© 2013 11 ICF INTERNATIONAL

 
Materials Architecture Systems

• Titanium Aluminide (TiAl)

turbine airfoils

• TiAl compressor airfoils

• Ceramic-matrix composites 

(CMC) turbine shrouds/ 

Outer Air Seal (OAS)

• CMC High Pressure 

Turbine (HPT) blades/ 

vanes

• CMC Low Pressure (LP)

blades/ vanes

• Organic Matrix Composite 

(OMC) fan blades

• OMC case

• CMC exhaust nozzle

• Ceramic bearings

• Turbine coatings

• OMC stator

• OMC comp. cases

• Ultra High By Pass(UHBP)

engine (above 10 Bypass 

Ratio (BPR))

• UHBP (above 20 BPR)

• Open rotor

• Variable cycle

• Intercooled compressors

• Integrated propulsion 

system

• Lightweight component fab 

techniques

• Reduced hub-tip ratio fan

• Fan drive gear

• Next gen load sharing

architecture

• Bleedless engines

• Electric engine start

• High Pressure Compressor 

(HPC) mod. Clearance 

control

• Turbine mod. Clearance 

control

• Clearance control w/ 

feedback

• High Pressure (HP)/LP

power extraction sharing

• High eff. Oil/air cooler

• Recuperative exhaust

Aerodynamics Sealing Coating / Cooling

• Next gen engine airfoil 

designs

• Optimized fan root fairing

• Scalloped fan exhaust

• Low Pressure Ratio (PR) 

fan

• Low drag inlet/nacelle

• Compressor blisks

• Turbine blisks

• Compressor airfoil coating

• Turbine air cooling air 

cooling

• Next gen. turbine airfoil 

cooling design

© 2013 12 ICF INTERNATIONAL
RESULTS 

Introduction to Results

Using the modeling framework described in the preceding section, ICF was able to develop a fuel 

consumption improvement forecast by both aircraft category and aircraft model. This forecast covers the 

twenty-year period from 2013-2033. This section presents a comprehensive view of both the current state 

of the fuel efficiency of aircraft, as well as the forecast by aircraft category and by select aircraft model. 

Detailed profiles of the technologies supplying the largest contributions to fuel efficiency gains are also 

presented here. The fuel burn numbers presented here were derived from the expected value methodology, 

and thus include the impact of both the technical and commercial feasibility percentages in the final results. 

While this provides a good overall forecast of fuel burn improvement percentage per year by aircraft 

category, the contributions by individual technology must be taken in the context of this expected value 

methodology. If a technology is actually fully implemented, however, it will of course provide the full 

benefit, and not the benefit discounted by the commercial feasibility percentage. This is part of the purpose 

of the expected value methodology; it decreases the model’s reliance on the entry into service projections 

for specific technologies, and instead looks at the fuel burn forecast holistically, and thus, realistically.

Summary Results 

Impact of Technologies

Based on its analysis of the pipeline of technologies that can incrementally reduce fuel consumption of new, 

in-production aircraft, ICF projects aircraft fuel consumption will decrease 0.50-0.65% per annum over the 

next 20 years for air transport categories (Regional Jet through Very Large Aircraft), resulting in a total 

decrease of 10-13% by 2033. For air transport turboprops and business jets, fuel consumption is expected 

to decrease 0.35-0.40% per annum, resulting in a total decrease of 7-8% by 2033. 

Projected cumulative fuel burn reductions by 2020 and 2023 differ by aircraft category. A summary of the 

results is shown below in Exhibit 1-7. 

© 2013 13 ICF INTERNATIONAL
Exhibit 1-7. Cumulative Fuel Burn Reduction Forecast Summary

Aircraft Category

Cumulative Fuel Burn 

% Reduction By:

2020 2023

Very Large Aircraft 4.2% 6.3%

Large Twin Aisles 4.0% 6.0%

Small Twin Aisles 3.7% 5.5%

Single Aisles 3.1% 4.6%

Regional Jets 3.2% 4.7%

Air Transport Turboprops 2.5% 3.7%

Large B&GA 17Aircraft 3.3% 4.8%

Small B&GA Aircraft 3.0% 4.4%

Of the approximately 70 technologies evaluated, 80% of this projected improvement was generated by 

twelve airframe technologies. Because engine technologies are incorporated as a package and because no 

individual engine technology made the 80% group, they are treated as a package in the analysis. These top 

technologies are detailed in Exhibit 1-8. 

17 B&GA= Business and General Aviation

© 2013 14 ICF INTERNATIONAL

 
Exhibit 1-8. Most Impactful Fuel Burn Improvement Technologies by Aircraft Category

Technology

Cumulative Fuel Burn Reduction % by 2020 

Very 

Large

Large 

Twin

Small 

Twin

Single 

Aisle

Regional JetLarge 

Bizjet

Small 

Bizjet

Turboprop

Engine Technologies 1.4% 1.4% 1.4% 1.4% 1.4% 1.4% 1.4% 0.7%

Lighter Interiors 0.8% 0.8% 0.8% 0.6% 0.3% 0.3% 0.3% 0.3%

Advanced Wingtip Devices 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5%

Aft Body Aerodynamics 0.4% 0.4% 0.4% 0.4% 0.4% 0.4% 0.3% 0.4%

HLFC18 – Empennage 0.1% 0.1% 0.1% 0.1% <0.1% <0.1% <0.1% <0.1%

ECS Aero and On-Demand ECS 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%

Adaptive Trailing Edge 0.1% 0.1% 0.1% 0.1% <0.1% 0.1% N/A <0.1%

Titanium Landing Gear 0.1% N/A 0.1% 0.1% <0.1% <0.1% <0.1% <0.1%

Composites – Current State N/A 0.1% 0.1% 0.1% <0.1% <0.1% <0.1% <0.1%

More Electric Systems 0.1% 0.1% 0.1% 0.1% 0.1% 0.1% 0.1% 0.1%

Carbon / Ceramic Brakes N/A N/A 0.1% 0.1% 0.1% <0.1% <0.1% 0.1%

Riblet Coatings 0.1% 0.1% 0.1% <0.1% <0.1% <0.1% <0.1% <0.1%

All Other Technologies19 0.4% 0.2% N/A N/A 0.2% 0.3% 0.2% N/A

Total Average Reduction 4.2% 4.0% 3.7% 3.1% 3.2 3.3% 3.0% 3.2%

18 HLFC = Hybrid Laminar Flow Control 19 Note: totals are aircraft category averages, while not all technologies apply to every aircraft in category, thus “Other” is 

sometimes redundant, and listed technologies will have sum greater than “Total Average Reduction”

© 2013 15 ICF INTERNATIONAL

 
Results by Aircraft Category and by Aircraft

Due to the different magnitude of fuel burn reductions realized by different aircraft categories for each 

technology, meaningful differences in expected fuel burn benefit emerge for different categories. There are 

several different reasons for this scaling by aircraft category. Namely, the fuel burn benefits of many 

technologies scale with both aircraft size/weight and range. For instance, weight-saving technologies have 

a greater impact on cruise fuel efficiency for heavier/longer range aircraft, since weight (and the fuel 

required to carry that extra weight) has a compounding effect with greater distance.

Production forecasts were developed by aircraft model for the twenty year forecast period for the air 

transport aircraft, while ten year forecasts were developed for the Business and General Aviation (B&GA)

aircraft. The expected fuel burn improvement percentage per year, especially the total fuel burn percentage 

improvement possible by 2020 and 2023, will be used as input into the future stringency line determination 

recommendations. 

We profiled each of the aircraft categories, but for illustration purposes, we show the Single Aisle category 

in this report. For each of the Aircraft Categories, we profiled:

• The current in-production aircraft in the category and projected future build rates, 

• Recent technology introductions that reduced fuel burn, 

• Future fuel burn reduction forecast, and 

• The top technical contributors to fuel burn reduction

Single Aisle Aircraft

Current single aisle aircraft include the Boeing 737NG family and the Airbus A320 family. The 737 family 

first entered service in 1968 with the 737-100. This was intended to be an aircraft for short haul domestic 

routes. It was shortly followed by the 737 Advanced. A major upgrade, the 737 Classic, was introduced in 

1984. This featured new wings, high bypass engines, and new avionics. Another significant upgrade, the 

737NG, entered service in 1998. This again featured a new wing, new engines, stretched airframe variants, 

and new avionics. The A320 first entered service in 1988, followed by the shortened A319 and the stretched 

A321 in 1996 and 1994, respectively. It was developed to incorporate advanced technology for the time to 

compete with the 737 Classic, including new high bypass engines, fly-by-wire flight controls, and advanced 

avionics. 

This sector of the market will see a significant number of introductions of new or upgraded aircraft over 

the next several years. These include the 737 MAX, A320neo, Comac C919, Irkut MS-2120, and 

Bombardier CSeries. Somewhat uniquely, except for the 737 MAX and A320neo, these aircraft are all clean 

sheet designs. This aircraft category is a prime target for manufacturers aspiring to enter the air transport 

20 Comac is a division of AVIC, the state-owned Chinese aviation conglomerate, and MS-21 is manufactured by United Aircraft, 

the Russian aviation conglomerate.

© 2013 16 ICF INTERNATIONAL

 
space, due to their high production rates, strong demand, and relatively modest development costs when 

compared to new twin-aisle aircraft. The C919, MS-21, and CSeries all make use of new technologies, 

including advanced engines, varying degrees of structural composites, and advanced systems. Due to the 

introduction of the 737 MAX and the A320neo, Boeing and Airbus are unlikely to introduce clean sheet

single aisle aircraft before the end of the 2020s. 

Because the 737NG and A320 compete intensely for most of the same customers, both have had several inproduction upgrades developed. The 737NG was offered with blended winglets in 2001, first as an 

aftermarket retrofit option, then as a production option. These improved fuel burn by approximately 4-6%. 

Carbon brakes were offered on the 737NG in 2007, which saves weight and reduced fuel burn by 0.5%. In 

addition to these standalone items, a suite of fuel burn reducing technologies was introduced in 2011, called

the 737 Enhancement Package (or PIP – Performance Improvement Package). This combined several 

aerodynamic and systems improvements to provide approximately 1% in fuel burn savings, in addition to 

greater than 1% savings offered by a simultaneous engine upgrade program, the CFM56-7BE. The A320 

has also undergone numerous upgrades for fuel efficiency, as well as passenger comfort, maintenance cost 

reduction, and avionics capability.

Fuel efficiency is projected to improve 0.5% per year, on average, until 2033. By 2020, the fuel efficiency 

could be improved by 3.1%, while the projected improvement by 2023 is 4.6%.

-2.2% -3.1%

-4.6%

-7.0%

-9.5%

-20%

-18%

-16%

-14%

-12%

-10%

-8%

-6%

-4%

-2%

0%

2018 2020 2023 2028 2033

Cumulative % Reduction vs. 

Baseline

Single

Aisle Fuel

Burn

Reduction

Exhibit 1-9. Single Aisle Fuel Burn Reduction Forecast

© 2013 17 ICF INTERNATIONAL
The major technologies that contribute to this fuel consumption reduction are Engine Technology, Lighter 

Interiors, and Advanced Wingtip Devices.

Exhibit 1-10. Single Aisle Fuel Burn Reduction by Technology

Technology

2020 Reduction 

%

2023 Reduction 

%

• Engine Technology • 1.4% • 2.0%

• Advanced Wingtip Devices - • 0.5% • 0.7%

• Lighter Interiors • 0.6% • 0.8%

• Aerodynamic APU Fairing / • 0.4% • 0.5%

• ECS Aero and On Demand • 0.2% • 0.3%

• Control Surface - Optimal 

 

• 0.1% • 0.1%

• Adaptive Trailing Edge • 0.1% • 0.1%

• Riblet Coatings • <0.1% • 0.1%

• Control Surface - Optimal 

Control Laws for horizontal • 0.1% • 0.1%

• Carbon / Ceramic Brakes • 0.1% • 0.1%

© 2013 18 ICF INTERNATIONAL
1.3 TECHNOLOGY METRIC VALUE IMPACT

INTRODUCTION

The ultimate purpose of this report is to evaluate the cost of reducing aircraft CO2 emissions, which are 

proportional to fuel burn. Experts at OEMs, airlines and in academia routinely report fuel burn numbers, so 

this was a natural metric to start with. ICF began its analysis by evaluating the impact of technologies on 

relative fuel burn reductions. The reductions listed in this report are those of a representative mission for 

the particular aircraft. 

However, the CAEP certification procedure does not use fuel burn directly, but instead, defines a Metric 

Value (MV) that is related to fuel burn. 

The MV is defined based on an instantaneous measure of fuel burn per distance flown and represents an 

attempt to develop a metric that correlates with fuel burn, while being independent of aircraft type, weight 

and utilization. The MV is based on the specific air range (SAR), which is an instantaneous measure of the 

distance flown per unit weight of fuel. The MV is obtained by inverting SAR (which yields the fuel weight 

required to travel a unit distance), and then dividing it by a non-dimensionalized floor area raised to an 

exponent, resulting in the following equation:21

MMMM = 1

SSSSSS × ( FF⁄ RR)0.24

Where FF is the floor area, and RR is a reference area related to the fuselage planform. Since SAR depends 

on the instantaneous weight, which varies during flight and has a wide range depending on the mission. 

SAR can vary by as much as a factor of 2 for a given aircraft. Given this wide range of variation, the MV 

is highly dependent on the weight used in its calculation. To address this issue, CAEP defined three weight 

values over which the MV should be averaged to obtain a final value that is representative22,23. 

When converting fuel burn reductions to reductions in the MV, ICF assumed that the MV is based on SARs

at a representative set of weights. Therefore, a 1% fuel burn reduction corresponds to 1% MV reduction.

One important characteristic regarding the MV is that reductions in aircraft empty weight24 would not 

impact the MV. The rationale for this was that any reduction in empty weight would be canceled out by a 

corresponding increase in payload, fuel, or both. Thus, even though weight saving technologies and 

21 ICAO, 2013: CAEP/9 Agreed Certification Requirement for the Aeroplane CO2 Emissions Standard, Circular (Cir) 337, 

AN/192, Available at www.icao.int . 22 Ibid. 23 [ICCT2013], “International Civil Aviation Organization’s CO2 Certification Requirement for New Aircraft”, The International 

Council on Clean Transportation, Aug. 2013. http://www.theicct.org/co2-requirement-new-aircraft 24 Refers to Operating Empty Weight is the basic weight of an aircraft including the crew, all fluids necessary for operation such 

as engine oil, engine coolant, water, unusable fuel and all operator items and equipment required for flight but excluding usable 

fuel and the payload.

© 2013 19 ICF INTERNATIONAL

 
improvements increase the aircraft efficiency, this is not reflected in the MV. Therefore, ICF post-processed 

all the fuel burn reductions to remove the reductions due to weight. Across technologies, about 2/3 of the 

fuel burn impact is reflected in the MV, although this varies depending on the technology and the aircraft 

category. 

RESULTS SUMMARY

Based on its analysis, ICF projects MVs for new, in-production aircraft will decrease 0.4-0.5% per annum 

over the next 20 years for air transport categories (Regional Jet through Very Large Aircraft), resulting in 

a total decrease of 8-10% by 2033. For air transport turboprops and business jets, fuel consumption is 

expected to decrease 0.3-0.4% per annum, resulting in a total decrease of 6-8% by 2033. Projected 

cumulative MV reductions by 2020 and 2023 differ by aircraft category. A summary of the results is shown 

below in Exhibit 1-11. 

Exhibit 1-11. Metric Value Reduction Summary

Aircraft Category

Cumulative Metric Value

% Reduction By:

2020 2023

Very Large Aircraft 3.0% 4.5%

Large Twin Aisles 2.8% 4.3%

Small Twin Aisles 2.6% 4.0%

Single Aisles 2.5% 3.6%

Regional Jets 2.7% 3.9%

Air Transport Turboprops 2.0% 2.9%

Large B&GA Aircraft 2.7% 4.0%

Small B&GA Aircraft 2.5% 3.6%

Technologies with the most beneficial impact on Metric Values are summarized in Exhibit 1-12. 

Exhibit 1-12. Technologies Having Highest Impact on Metric Value Improvement by 

Aircraft Category

Technology

Cumulative Metric Value % Reduction by 2020 

Very 

Large

Large 

Twin

Small 

Twin

Single 

Aisle

Regional JetLarge 

Bizjet

Small 

Bizjet

Turboprop

© 2013 20 ICF INTERNATIONAL
Engine Technologies 1.4% 1.4% 1.4% 1.4% 1.4% 1.4% 1.4% 0.7%

Lighter Interiors N/A N/A N/A N/A N/A N/A N/A N/A

Advanced Wingtip Devices 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5%

Aft Body Aerodynamics 0.4% 0.4% 0.4% 0.4% 0.4% 0.4% 0.3% 0.4%

HLFC25 – Empennage 0.1% 0.1% 0.1% 0.1% <0.1% <0.1% <0.1% <0.1%

ECS Aero and On-Demand ECS 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%

Adaptive Trailing Edge 0.1% 0.1% 0.1% 0.1% <0.1% 0.1% N/A <0.1%

Titanium Landing Gear N/A N/A N/A N/A N/A N/A N/A N/A

Increased use of composite parts N/A N/A N/A N/A N/A N/A N/A N/A

More Electric Systems N/A N/A N/A N/A N/A N/A N/A N/A

Carbon / Ceramic Brakes N/A N/A N/A N/A N/A N/A N/A N/A

Riblet Coatings 0.1% 0.1% 0.1% <0.1% <0.1% <0.1% <0.1% <0.1%

All Other Technologies N/A N/A N/A N/A N/A N/A N/A N/A

Total Reduction 3.0% 2.8% 2.61% 2.5% 2.7% 2.7% 2.5% 2.0%

25 HLFC = Hybrid Laminar Flow Control

© 2013 21 ICF INTERNATIONAL

 
RESULTS BY AIRCRAFT CATEGORY

Single Aisle Aircraft 

Single Aisle aircraft MVs are projected to decrease at 0.38% per year, or 2.40% by 2020 and 3.59% by 

2023. 

-1.7% -2.4% -3.6%

-5.5%

-7.5%

-20%

-18%

-16%

-14%

-12%

-10%

-8%

-6%

-4%

-2%

0%

2018 2020 2023 2028 2033

Cumulative % Metric Value 

Reduction vs. Baseline

SA Metric

Value

Reduction

Exhibit 1-13. Single Aisle Metric Value Reduction Forecast

© 2013 22 ICF INTERNATIONAL
Engine Technologies, Advanced Wingtip Devices, and Aft Body Aerodynamics contribute most to Single 

Aisle Metric Value reductions. 

Exhibit 1-14. Single Aisle Metric Value Reduction Forecast by Technology

Technology

Cumulative Metric Value 

Reduction %

2020 2023

Engine Technologies 1.4% 2.0%

Advanced Wingtip Devices 0.5% 0.7%

Aft Body Aerodynamics 0.4% 0.5%

ECS Aero and On-Demand Schd. 0.2% 0.3%

All Other Technologies <0.1% 0.1%

Total 2.4% 3.6%

© 2013 23 ICF INTERNATIONAL
DEVELOPMENT COSTS OF CO2-REDUCING TECHNOLOGIES

1.4 TECHNOLOGY DEVELOPMENT COST 

INTRODUCTION

High fuel prices are the primary driver of current fuel burn reduction efforts

Despite the slow recovery from the global downturn, oil prices have risen to over $100/barrel26. Jet fuel 

prices now exceed 30% of airline total cost and exceed 50% of airline operating cost. Consequently, fuel 

burn reducing technologies are much more valuable now than they were when fuel prices were much lower. 

The result of high fuel costs has been a flurry of recent and upcoming new program launches as well as

incremental upgrades. New program launches include completely new “Major redesigns” such as the 787 

and A350XWB to re-winged aircraft (with new engines as well) such as the 777-X and EMB-175/190 E2

to re-engine programs such as the A320 Neo and 737 MAX. These major redesign and significant redesign 

program launches are delivering sizable fuel burn improvements on the order of 10-20%+ per seat-mile. 

As has been discussed earlier in this paper, incremental technology insertions have also been made. Typical 

incremental upgrades include PIPs such as those released for the 737NG and the 777. As shown below, 

these PIPs include such discrete items as engine upgrades, weight reductions, and minor aerodynamic 

changes.

26 Since this report was completed, oil has fallen to $55/barrel. However, it's too early to tell if this condition will be long-lived. 

For the time being, airlines are holding to their fleet renewal plans (indeed, due to hedging, airlines will not begin to realize 

substantial benefits from this reduction for another 18 months). Should these low prices endure, fuel would remain a 

substantial airline operating cost, but older airplanes would likely be flown longer (as before) and fleet renewal would slow. 

© 2013 24 ICF INTERNATIONAL

 
Exhibit 1-15. Example of Incremental Technology Insertion – 737NG

Source ICF analysis, Boeing

Changes included in performance improvement packages offered in the aftermarket are typically adopted 

in the new production standard. Improvements in fuel burn from these incremental upgrades typically range 

from 0.5-4.0%. In some instances, a series of improvements or PIPs are grouped together into larger 

changes that yield up to 8-10% fuel burn reduction on a particular aircraft family.

© 2013 25 ICF INTERNATIONAL
Aircraft development activity is expensive

Aircraft development programs are expensive. Analysts estimate a new single aisle would have cost $10-

12B to develop. The A380 and 787 are estimated to each have cost around $20B to develop; the A350 is 

estimated to have cost $15B, excluding engine development. Due to the large development cost of a totally 

new aircraft design, manufacturers are opting to re-wing or just re-engine their aircraft. Boeing is said to 

have budgeted $5B for the re-wing of the 777 and Airbus and Boeing have budgeted $1-2B each for the reengine of the A320 and the 737, respectively (excluding engine development costs). Embraer has publically 

stated they will need to spend $1-2B to re-wing the EMB-175 and variants. 

Large fuel burn reductions require large investments; a 15-25% improvement is required 

to trigger a brand new aircraft design

The obverse of expensive development programs is also true: Given the time, expense and risk of new 

technology development, a high level of potential improvement is required to trigger such significant 

investment. Thus, a pipeline of technologies has to be likely to deliver fuel burn reductions commensurate 

with the level of research and development (R&D) expense required to commercialize them. In total, 

airframe and engine manufacturers spent over $8.6B in 2012 year on R&D, $4.5B by the top 4 airframe 

manufacturers and $4.1B by the top 4 engine manufacturers. Some industry analysts have noted that the 

cost to develop new aircraft and engines may be rising.

METHODOLOGY

Introduction

ICF developed an independent bottom-up cost curve especially focused on categorizing the non-recurring 

cost of implementing minor (0-10% metric value) improvement on existing aircraft platforms. This area is 

of particular importance for determining the costs of compliance with a number of proposed stringency 

options, and was also an area neglected by previous non-recurring cost (NRC) methodologies. The results 

of the ICF curve were a supply-curve of available technology options and associated non-recurring costs 

for each aircraft platform. For most aircraft, this methodology was limited to predicting improvements in 

the 0-10% range. Also, ICF’s research indicated that, given the lack of verifiable publically available cost 

data for small metric value improvements, it would be most effective to create bottom-up technology 

applicability and cost analyses by aircraft model, and then validate these through case studies, secondary 

research, and targeted interviews. 

Metholodogy Overview 

ICF developed the following methodology to estimate the non-recurring costs (NRC) by aircraft:

1.Categorize incremental technologies into groupings by impactful-ness – either Minor PIP or Large 

Incremental Update

© 2013 26 ICF INTERNATIONAL
2.Identify the elements of non-recurring cost 

3.Develop baseline NRC element proportions by incremental technology category for single-aisle 

aircraft

4.Scale the baseline NRC elements to the other aircraft categories

5.Determined the NRC costs for single aisle aircraft and applied the scaled costs to the other aircraft 

categories

6.Compiled technology supply curves by aircraft model

Categorizing Incremental Technologies

Incremental technologies fall into two categories: minor PIPs and large incremental updates. Minor PIPs 

are aerodynamic cleanups (e.g., redesigned fairings, APU inlets, ECS exhausts, etc.) and other 

improvements that often can be certified by analysis without dedicated flight test aircraft, and with only 

minor ground, wind tunnel, and flight tests. Minor PIP costs scale only incrementally with aircraft size. 

Most of the technologies ICF researched were minor PIPs, providing in the range of 0-2% fuel burn 

improvement.

Large incremental updates are significant aerodynamic or structural improvements (e.g., winglets) that 

require flight test programs – usually with production aircraft. These types of improvements, singly or 

grouped into a large package, can provide from 2-10% fuel burn reduction. Tooling and facilities costs are 

not driving factors for these improvements. Large incremental upgrades scale highly with aircraft size. 

Elements of Non-Recurring Cost

Non-recurring cost is fundamentally driven by three elements: engineering and integration, testing (flight 

and ground) and tooling, capital equipment, and infrastructure. Engineering and Integration (Engrg) 

includes the engineering and Research & Development (R&D) required to progress a given technology 

from its current TRL so it can be integrated onto a production airframe. It also includes all airframe and 

technology integration costs. 

Flight and Ground Testing (Testing) includes fixed costs for test instrumentation, infrastructure, and 

program management and variable costs27 related to the degree of flight and ground testing required. 

Tooling, Capital Equipment, and Infrastructure (Capital) includes tooling required to modify the production 

line to support the PIP, incorporates any capitalized changes to plant, property, and equipment, and includes 

other miscellaneous costs such as Information Technology (IT) system, supply chain system, and other

costs associated with a particular design change. 

Baseline Non-Recurring Cost Element Proportions 

27 Variable costs refer to the costs of flight and ground testing that scale with the amount of time spent testing. For instance, fuel 

costs and crew/test engineer salaries directly scale with the amount of time spent in flight and ground test.

© 2013 27 ICF INTERNATIONAL

 
For incremental technologies applicable to single aisle aircraft, the proportion of engineering and 

integration, flight and ground testing, and tooling, capital equipment, and infrastructure varies depending 

on whether it is an airframe or an engine technology and, for airframe technologies, whether the technology 

is a minor PIP or a large incremental update. Exhibit 1-16 illustrates the cost element proportions for single 

aisle aircraft. In general, engine PIP development costs are heavily driven by both flight and ground testing. 

This includes the cost of test hardware, recurring flight and ground test costs, test engineering and analysis, 

and the like. Small airframe PIPs, on the other hand, are dominated by engineering costs. This is because 

small airframe PIPs generally do not require a dedicated flight testing program. Therefore, costs are 

concentrated on the engineering design and analysis required to analytically verify the safety and 

performance of the PIP. Large airframe PIPs do require a flight test program, and therefore have a large 

portion of their total costs allocated to the testing effort.

Non-Recurring Cost Scaling Factors

Non-recurring costs exhibit different scaling behavior with aircraft size. Engineering and integration cost 

for a given technology and metric value improvement is not strongly correlated with aircraft size; rather, it 

scales with a 5% differential of aircraft complexity. ICF used aircraft realized sale price to scale this 

element. Flight and ground testing scales with aircraft operating costs. ICF used direct block hour average 

operating costs to scale this element. Lastly, for Minor PIPs, tooling, capital equipment, and infrastructure 

costs are not strongly correlated with aircraft size. As with engineering, average realized aircraft sale price 

was used to scale this element. 

Exhibit 1-16. Single Aisle NRC Cost Element Proportions

© 2013 28 ICF INTERNATIONAL
ICF used independently verifiable data to calculate the NRC scaling factors, shown in Exhibit 1-17. 

Average realized sale price is the scaling parameter used for Engineering, as well as for Capital NRC. 

Average operating cost was used as the scaling parameter for Testing NRC. Testing scales with 100% of 

the operating cost differential, using single aisle as the baseline. Engineering and Capital scale by 15% of 

the differential in average realized sale price, using single aisle as the baseline. 

Source: Block hour operating cost and averaged realized price data from The Airline Monitor

The end result was factors that were used to scale the cost elements in reference to the baseline single aisle 

aircraft to every aircraft category, illustrated in Exhibit 1-18. 

Exhibit 1-17. Aircraft Cost Element Scaling Factor Sources

Exhibit 1-18. Non-Recurring Cost Element Scaling Factors

© 2013 29 ICF INTERNATIONAL
© 2013 30 ICF INTERNATIONAL
Cost Calculations

Applying the scaling factors, NRC was calculated for every technology across every aircraft category. An 

example is provided below. 

Example: Large Incremental Update NRC (Wingtip Devices)

Wingtip devices are a “Large Incremental Update” –level technology. For the baseline single aisle aircraft, 

total cost is composed of 3% baseline fixed costs, 52% engineering & integration, 40% testing, and 5% 

capital equipment. The calculation assumes a minimum $5M fixed cost. (We used this amount for all of 

the incremental upgrades. It does not vary by technology or aircraft category.) This fixed cost is an 

allowance for basic program management overhead that accompanies any level of design change at an 

aircraft OEM. An example of this approach in practice is shown below in Exhibit 1-19, which in this case 

represents winglets. For this technology, interview input and secondary research indicated a total nonrecurring cost for winglet implementation of $173M for single aisle aircraft. Given this known data point, 

ICF used the cost element breakdown shown in Exhibit 1-18 above to split the total NRC into the constituent 

elements. Note in Exhibit 1-19 below that Engineering and Capital NRCs exhibit only minor scaling 

factors. 

© 2013 31 ICF INTERNATIONAL
Exhibit 1-19. Large Incremental Update Cost Scaling by Aircraft Category

© 2013 32 ICF INTERNATIONAL
RESULTS

Introduction

ICF calculated cost curves for individual aircraft, taking into account the costs of each technology 

applicable to that category of aircraft. The cost curve depictions are not intended to state that all these 

insertions will happen; rather, they are a menu of potential technology insertions organized from most cost 

effective to least based on our analysis. Note also that ICF’s results are valid from 0-10% for most aircraft 

types. Technology improvements above 10% tend to take the form of significant redesigns such as reengines or re-wings, often in combination with additional incremental technology insertion. 

We use the A330 program to illustrate the presentation of the results of ICF’s cost analysis for key aircraft 

platforms. The cost curve shown here are comprised of the costs and metric value improvement benefits 

for individual technologies. As discussed earlier in the technology evaluation methodology, each aircraft 

has a certain set of airframe and engine technologies that can be applied to it. This technology applicability 

matrix drives the cost curves and other results. Using the methodology described above, the cost of every 

technology is scaled to each aircraft size category. These costs are then applied to each aircraft as 

appropriate to develop the cost curves. In addition to using these curves to calculate an individualized cost 

curve for each aircraft model, these analyses can be used to generate a series of data points that can be used 

to generate a cost curve in the 0-10% metric value range.

© 2013 33 ICF INTERNATIONAL
Cost Results for Selected Aircraft Models

EMB 170/190 Family

The EMB-170/190 is a family of large regional jets manufactured by Embraer. The family has four inproduction models of different sizes, the E-170, E-175, E-190, and E-195. The smaller E-170 and E-175 

models have the GE CF34-8 engine, while the larger E-190 and E-195 models have the GE CF34-10 

engine. ICF analyzed the current state of technology on the in-production EJet family, and then 

determined that nearly a dozen technologies could be incrementally applied to the current aircraft. The 

most cost-effective upgrades include advanced wingtip devices, engine technology insertion, and other 

aerodynamic and systems improvements. As a validation of the ICF analysis, Embraer announced in early 

2013 that they would proceed with an EJet “enhanced” series of upgrades covering maintenance costs, 

passenger comfort, and fuel burn. Among the fuel burn-reducing devices proposed were advanced 

wingtip devices, gap reductions, ECS and APU optimization, and others systems and aerodynamics 

modifications. In total, these will yield between 3.5-5.5% fuel burn savings depending on the specific 

family model. ICF estimates that, in total, it would be economically feasible to improve the EJets ~10% 

~$700M using only incremental technology. If a greater level of improvement was desired, it would be 

more economical to simply re-wing and re-engine the aircraft, instead of relying on incremental 

improvements. Indeed, this is what Embraer has decided to do with the EJet family, with a re-engined 

model planned for a 2018 EIS. 

© 2013 34 ICF INTERNATIONAL
Exhibit 1-20. EJets Incremental Improvement Supply Curve

© 2013 35 ICF INTERNATIONAL
767 Family

The Boeing 767 family was introduced in the early 1980s and included a variety of models. Current inproduction models include the 767-300ER passenger and freighter variants. While future production of the 

767 will be focused on military tanker transport variants, the commercial versions are still available for 

sale. There are several available technologies that could make an immediate impact, including advanced 

wingtip devices, engine upgrades, reduced light profiles, ECS aerodynamics, and an adaptive trailing edge. 

These technology insertions could improve the 767 family’s metric value by approximately 10% for an 

NRC of $1.3B. Some of the technologies listed here, such as winglets and engine upgrades, have been 

tested successfully but are not part of the current production standard. With the relatively slow sales of the 

commercial 767, it is understandable that these upgrades are not being undertaken.

Exhibit 1-21. 767 Incremental Improvement Supply Curve

© 2013 36 ICF INTERNATIONAL
A330

The Airbus A330 has been in service since the early 1990s. Many different incremental improvements have 

been introduced over the years, namely increased maximum takeoff weights. ICF estimated that a variety 

of incremental improvements could be applied to the A330, yielding an estimated 8-10% improvement for 

approximately $1.4B in NRC. ICF estimated that achieving improvements above this level would require 

a more substantial re-engining program. In July 2014, Airbus announced that they were proceeding with a 

re-engined version of the aircraft, the A330neo. It will achieve 12%-14% fuel burn reductions with an 

Airbus initial cost estimate of “between $1B-$2B Euros” ($1.4-2.7B). This subsequent Airbus 

announcement validates ICF cost projections .

Exhibit 1-22. A330 Incremental Improvement Supply Curve

© 2013 37 ICF International
Cost Results Data Points

By running cost curve analysis for many aircraft platforms, ICF was able to develop a comprehensive set 

of data points to better inform the non-recurring cost curve for metric value improvements in the 0-10%

range. Eight aircraft were analyzed, yielding fifty-six discrete data points28. These are shown below in 

Exhibit 1-23

Exhibit 1-23. ICF Metric Value and NRC Data Points

E-175 CSeries A320 767 787-8 A330 777-300ER A380

MV% NRC

($B)

MV% NRC

($B)

MV% NRC

($B)

MV% NRC

($B)

MV% NRC

($B)

MV% NRC

($B)

MV% NRC

($B)

MV% NRC

($B)

<0.1% <$01 <0.1% <$0.1 <0.1% <$0.1 <0.1% <$0.1 <0.1% <$0.1 <0.1% <$0.1 <0.1% <$0.1 <0.1% <$0.1

3.5% $0.1 3.5% $0.2 3.5% $0.2 3.5% $0.2 3.5% $0.2 3.5% $0.3 3.5% $0.3 3.5% $0.3

5.5% $0.2 5.5% $0.3 5.5% $0.3 5.5% $0.5 5.5% $0.5 5.5% $0.6 5.5% $0.6 5.5% $0.7

5.7% $0.2 5.7% $0.3 5.7% $0.3 5.7% $0.5 8.5% $0.9 5.7% $0.6 5.7% $0.6 5.7% $0.7

7.2% $0.3 6.3% $0.4 6.3% $0.4 6.3% $0.6 10.0% $1.2 6.3% $0.7 8.7% $1.1 6.3% $0.8

7.8% $0.4 8.0% $0.7 8.0% $0.7 9.3% $1.0 - - 9.3% $1.2 10.7% $1.5 9.3% $1.4

8.8% $0.5 9.3% $0.9 9.3% $0.9 11.3% $1.3 - - 11.3% $1.6 - - 11.3% $1.9

10.0% $0.7 10.3% $1.1 10.5% $1.2 - - - - - - - - - -

28 The number of data points for each aircraft depends on the maximum potential for improvement and the specific mix of 

available technologies.

© 2013 38 ICF International

 
CONCLUSIONS

EFFECTIVENESS OF INCREMENTAL TECHNOLOGY INSERTIONS ON FUEL BURN

• ICF analyzed over 70 incremental technologies that can incrementally reduce fuel consumption of 

new, in-production aircraft.

• For the air transport categories (Regional Jet through Very Large Aircraft), ICF projects 

incremental technologies will decrease aircraft fuel consumption 0.50-0.65% per annum 

(depending on the aircraft category) over the next 20 years, resulting in a total decrease of 10-13% 

by 2033.

• For air transport turboprops and business jets, incremental technologies are expected to reduce fuel 

consumption 0.35-0.40% per annum, resulting in a total decrease of 7-8% by 2033. 

• Of the approximately 70 technologies evaluated, 80% of the projected improvement was generated 

by twelve airframe technologies plus the engine technologies (they are treated as a package in the 

analysis): 

o Engine Technologies

o Lighter Interiors

o Advanced Wingtip Devices

o Aft Body Aerodynamics

o HLFC – Empennage

o ECS Aero and On-Demand ECS

o Adaptive Trailing Edge

o Titanium Landing Gear

o Composites – Current State

o More Electric Systems

o Carbon / Ceramic Brakes

o Riblet Coatings

© 2013 39 ICF International
EFFECTIVENESS OF INCREMENTAL TECHNOLOGY INSERTIONS ON METRIC 

VALUE

• For the air transport categories (Regional Jet through Very Large Aircraft), ICF projects 

incremental technologies will decrease aircraft metric value 0.4-0.5% per annum (depending on the 

aircraft category) over the next 20 years, resulting in a total decrease of 8-10% by 2033.

• For air transport turboprops and business jets, incremental technologies are expected to reduce fuel 

consumption 0.3-0.4% per annum, resulting in a total decrease of 6-8% by 2033. 

• Six technologies accounted for the metric value improvements: 

o Engine Technologies

o Advanced Wingtip Devices

o Aft Body Aerodynamics

o HLFC – Empennage

o ECS Aero and On-Demand ECS

o Adaptive Trailing Edge

o Riblet Coatings

COST TO DEVELOP AND IMPLEMENT TECHNOLOGIES

• The cost to develop and incorporate new technologies varies depending on aircraft size category 

and the particular technology employed

• For regional jets, we estimate development costs to be $30-70M per 1% reduction in metric value

• For Single Aisle and Small Twin Aisle aircraft, we estimate development costs to be $60-120M 

per 1% reduction in metric value

• For Large Twin Aisle and Large Quad aircraft, we estimate development costs to be $90-170M per 

1% reduction in metric value29

29 ICF expects that the cost per 1% metric value improvement would increase substantially above 10% total improvement, as 

more extensive changes to the airframe or engine would be required.

© 2013 40 ICF International

 
2 APPENDIX

2.1 TECHNOLOGY READINESS LEVELS 

30

30 “Definition Of Technological Feasibility In The Context Of Considering Revised Engine Exhaust Emissions Standards And 

Transition Goals To Standards”, CAEP/7-WP/09, November 10, 2006

© 2013 41 ICF International

 
2.2 COMPLETE TECHNOLOGY PROFILES 

Engine Technologies

Major engine OEMs are continually adding to their technology portfolio. Big Four OEMs are spending between $800M and $1.2B on R&D, so these types 

of upgrades are part of the ongoing business model to keep competitive in the aero-engine market. Engine technology insertion is targeted to address 

TSFC (Thrust Specific Fuel Consumption), Propulsion System Weight Reduction, Maintenance Cost reduction, Performance Improvement, or System 

Reliability. Engine technologies embody a range of innovations, including materials (e.g., ceramic matrix composite parts), architecture (e.g., optimizing 

thermal efficiency versus propulsive efficiency), airfoil aerodynamics, sealing (e.g., blade tip clearances), cooling (i.e., blade cooling to enable higher 

operating temperatures), and systems technologies (e.g., electric engine start). In practice, however, it is airfoil aerodynamics and sealing technologies that 

are applied to new in-production aircraft. The engine is a highly integrated set of systems that leaves little room for modifications post-entry into service 

(EIS). 

Exhibit 2-1. Representative Engine "Tech Insertion" Packages

© 2013 42 ICF International
Furthermore, engine technologies rarely buy their way on individually; rather, engine OEM’s create technology insertion (TI) “packages” that improve 

fuel burn, reduce maintenance cost, and/or improve performance (representative TI packages are illustrated in Exhibit 2-1). If fuel burn is the competitive 

requirement, a minimum of 0.5 to 1.0% fuel burn improvement is necessary to justify the development and certification costs in order to be marketable to 

airline customers. Integration of a suite of TRL-6 technologies into a propulsion system can cost the OEM in the ballpark of $100M per 1% fuel burn 

reduced, excluding any potential additional certification costs. Lower TRL technologies can add another $100 to $150M, and require additional years in 

development. These TI packages normally become the new production standard, and are sold for incorporation during normal engine maintenance 

activities. As stated by a major engine OEM executive “....there is 2 to 4 year financial return requirement (for technology insertion 

packages).....anything that gets repaired or replaced (during normal maintenance) buys its way in....”. Another consideration, especially for lessors, is 

residual value. Technology insertion is not only a short term cost/benefit analysis, but a consideration in future residual value of the aircraft and/or engine 

at future sale.

Traditionally, technology development generally revealed itself in mid-life upgrades to engine programs. With the plethora of new engine development 

going on, technologies developed for new engines (such as LEAP-X and Trent XWB) are being migrated back to prior versions of existing engines (e.g., 

technology developed for the Trent 1000 and 700EP were incorporated into a TI package for the Trent 90031). While TI packages will vary from engine to 

engine, technologies developed and tested in recent new engine programs (e.g., GEnx, Trent 1000/XWB, GTF, LEAP-X, etc.) will be incorporated into 

current engines. ICF projects engine upgrade packages will continue to be developed throughout the forecast period regardless of the source of technology 

development. While ICF forecasted 0.2% improvement per annum, some sources indicate that there is substantial upside to this number, with Pratt and 

Whitney claiming an average fuel burn improvement of 0.5%-1% for the geared turbofan (Warwick, Pratt and Whitney's Geared Turbofan).

31 “Rolls-Royce Reveals Trent 900 Enhancement Package”, Aviation Week & Space Technology, September 28, 2009, p. 41.

© 2013 43 ICF International

 
Sources

Small 

BGA

Large 

BGA

Turbo

-prop

Region

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Fuel Burn

• Primary reduction mechanisms are Airfoil Aerodynamics 

and Sealing

• Engine OEMs typically do not charge a premium for 

engine technology improvements 

• Based on interview feedback, ICF modeled this as a 

fixed percentage per year, rather than using commercial 

or technical probability built up from individual 

technologies

=32 = - = = = = =

0.2% 

/yr

0.2% 

/yr

0.1% 

/yr

0.2% 

/yr

0.2% 

/yr

0.2% 

/yr

0.2% 

/yr

0.2% 

/yr

2013 2018 2020 2023 2033

Commercial 

Feasibility N/A N/A N/A N/A N/A

Technical 

Feasibility N/A N/A N/A N/A N/A

Cost Impact

• Engine OEMs typically do not charge a premium for 

engine technology improvements 

• Interviews indicated $100M of Non-Recurring 

Engineering Cost (NRE) for every 1% improvement (on 

single aisle-sized engines) for TRL 6+ 

• This was scaled by ICF (as described in the 

“methodology” section) to estimate the NRE required 

for other engine sizes

Estimated Unit Cost Increase ($M) by Aircraft Category

$0 $0 $0 $0 $0 $0 $0 $0

Estimated Total NRE ($M) by Aircraft Category

$21 $86 $20 $71 $141 $277 $396 $440

32 =: Technology has maximum benefit of average of minimum and maximum for that category

 -: Technology has maximum benefit of 100% of minimum for that category

© 2013 44 ICF International

 
Variable Camber Trailing Edge 

The idea of the variable camber trailing edge is to tailor the aerodynamics of the wing in flight to improve the performance over a range of flight conditions. 

Ideally aircraft would fly mostly at the nominal cruise flight condition for which the wing was designed for, but in practice, aircraft end up flying at a range 

of conditions dictated by operations. The air traffic control restriction that requires flight at a constant altitude in 2,000 ft. increments is particularly limiting. 

The drag penalty due to this restriction over the complete cruise segment can be as high as 7%. If these restrictions were to be reduced or eliminated in the 

future, as planned under Federal Aviation Administration (FAA)’s NextGen program, the penalties could reduce dramatically, and this technology might no 

longer be worthwhile.

Variable camber trailing edge technology is currently implemented in the Boeing 787 and the Airbus A350. In these implementations, both ailerons and flap 

positions are optimized for each flight condition to minimize the drag ( (Norris, Boeing Unveils Plans for Trailing Edge Variable Camber on 787 to Reduce 

Drag, Save Weight)). The aileron mechanisms are similar to conventional ones, but the flap mechanisms had to be adapted to enable the required adjustments. 

This includes the ability of the spoilers to deflect downwards to close gaps opened when the flaps are slightly drooped. There is also the possibility of 

morphing the trailing edge without resorting to hinged surfaces, which we cover in the “Adaptive Morphing Trailing Edge” section.

© 2013 45 ICF International
33 X: Technology doesn’t apply to category for technical or economic reasons

 +: Technology has maximum benefit of maximum for that category

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Fuel Burn

• In service on 787, could be improved to provide further 

benefit on other aircraft

• Greatest applicability to large/long-range aircraft

• Fuel burn benefit determined from interview input from 

airframe OEMs

• Fuel burn reduction mechanism: drag reduction

X33 + - - = + + +

0.0% 2.0% 0.5% 0.5% 1.3% 2.0% 2.0% 2.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 0% 4% 10% 20%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Used initial costs from ICF intellectual property (IP)

(Aircraft Value Database), and assumed 20% additional 

unit cost to actuation and flight control system

• 20% figure gained from interview input and ICF team 

consensus

• NRE estimates scaled relatively from known data points 

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.2 $0.1 $0.2 $0.2 $0.6 $0.8 $1.2 

Estimated Total NRE ($M) by Aircraft Category

$135 $180 $180 $180 $230 $270 $270 $270 

© 2013 46 ICF International

 
Advanced Wingtip Devices

Wingtips devices are an effective way of increasing the lift-to-drag ratio of an aircraft. These can be winglets (single or split), or span extensions. Increasing 

the span or the vertical extent of the wing reduces the lift-induced drag by spreading the vorticity, weakening the adverse effect that this vorticity has on the 

rest of the wing. At the global level, this is expressed as a reduction in the kinetic energy associated with the vortex system. Adding wing tip devices also 

increases the lift, which improves field and climb performance. The penalty for adding a wing tip device is added viscous drag and weight. The degree to 

how much weight is added is highly dependent on how much margin there is in the structural design of the original wing. For an over-designed wing, it is 

possible to add wingtip devices with no structural reinforcement, but usually reinforcements are required in the rest of the wing.

The tradeoffs between extending the wing horizontally versus adding a winglet involve a careful multidisciplinary analysis. Aerodynamically, a wing 

horizontal extension is more effective in reducing the induced drag than an equivalent increase in the vertical extent of the wing. The fact that the equivalent 

horizontal extension can be made smaller for the same induced drag reduction further decreases the viscous drag penalty. However, the horizontal extension 

induces larger bending moments on the wing and thus leads to a heavier wing. This makes it more challenging to incorporate in a wing that has already been 

designed.

Given the trend to retrofit in-production aircraft with winglets, one must question why this was not done in the original design. After all, winglets are 

relatively mature technology. The reason has to do with the tradeoff between fuel burn and aircraft cost. Fuel burn depends on both weight and drag, but it 

is more sensitive to drag, while aircraft cost depends primarily on the weight and has no dependence on drag. Hence, as fuel prices increase, there is more 

incentive to decrease the fuel burn at the cost of a more expensive aircraft. This is a major factor when determining the optimal span and wingtip devices of 

an aircraft. 

This trend can be seen in two of the most recent aircraft, the Boeing 787 and the Airbus 350, which exhibit significantly higher spans when compared to 

aircraft of the same weight. Further, the 777X is rumored to feature higher span wings, and Embraer just announced that they would extend the span of the 

E-175 (Caldas)

Gate code constraints play a major role in the decision of span and wingtip devices. It is no coincidence that the Airbus A350 has winglets while the Boeing 

787 does not: the A350’span is just under the ICAO gate code E constraint, while the Boeing 787 is well under this constraint. An interesting note on this is 

© 2013 47 ICF International
that the 777X is rumored to feature folding wingtips in order to increase its span while fitting in code E gates, further reinforcing the fact that we are now 

willing to trade higher penalties in weight and cost for lower drag and hence lower fuel burn. 

The design of wing tip extensions is still progressing, as evidenced by the novel shape of the split winglets introduced by Boeing on the 737 MAX. Raked 

wingtip are also becoming more common and their shape is changing, as can be seen in the evolution of the original 777-200LR/300ER tips to the shape in 

the 787. Thus, further gains are expected from the shaping of wingtip devices.

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Fuel Burn

• According to OEM statements, blended winglets realize 

3-5% fuel burn improvements over non-winglet aircraft

• New winglet technologies, such as split wingtips and 

Aviation Partners Boeing “Scimitar” winglets can yield 

1-3% improvement compared to current generation 

winglet technologies

• Winglets on 737MAX will offer 1-1.5% better fuel burn 

than 737NG blended winglets, depending on results of 

investigations into natural laminar flow

= = = = = = = =

3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5% 3.5%

2013 2018 2020 2023 2033

Commercial 

Feasibility 1% 10% 14% 20% 50%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Used publically available pricing and interview input to 

determine price of current technology winglets

• Assumed next-generation winglets will have 10% 

increased price

• NRE estimated based on interview input and some 

scaling relative to aircraft size

• Advanced wingtip device NRE was used as a data point 

to scale other technology NREs

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.2 $0.1 $0.2 $0.2 $0.6 $0.8 $1.2 

Estimated Total NRE ($M) by Aircraft Category

$105 $135 $135 $135 $175 $205 $205 $205 

© 2013 48 ICF International
Adaptive Trailing Edge

The motivation for this technology is exactly the same as the one for the variable camber trailing edge described previously: to tailor the wing so as to 

minimize the drag at the various flight conditions. Instead of relying on hinged surfaces to alter the shape of the wing, morphing changes the shape of the 

structure continuously by using piezoelectric materials or by internal mechanisms. The result is a smooth variation in the shape with no need for gaps that 

would otherwise contribute to the overall drag. On the other hand, gaps are a desirable feature in the high-lift system (slats and flaps), since they enable 

higher maximum lift. This technology has been tested in the Boeing 737 ecoDemonstrator (Wilsey and Stoker). 

The main tradeoff to be considered when employing morphing is whether the performance improvement is worth the added weight, cost, complexity and 

actuation energy. Morphing technology has been progressing in all these fronts and it is expected that this trade will become favorable at some point in the 

next 10 years. There are two possibilities to deploy the morphing trailing edge: one could have local morphing on the trailing edge or conventional moving 

surfaces to augment or replace the conventional adaptive trailing edge technology, or one could replace all control surfaces with morphing. The latter would 

have the advantage of eliminating the drag due to gaps, and it also allows for a finer control of the spanwise distribution of the trailing edge camber, which 

is very limited when using a conventional adaptive trailing edge.

© 2013 49 ICF International
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Fuel Burn 

Applicability 

• A full variable camber trailing edge would allow reduced 

structural weight due to load alleviation, as well as 

reduced control sizing and more efficient cruise 

configurations

• Scaled benefit from adaptive trailing edge given aircraft 

OEM input and ICF team analysis

• Fuel burn reduction mechanism: induced drag reduction

X + - - = + + +

0.0% 3.0% 0.5% 0.5% 1.8% 3.0% 3.0% 3.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 0% 2% 3% 8%

Technical 

Feasibility 0% 0% 50% 100% 100%

Cost Impact

• Used initial costs from ICF IP (Aircraft Value Database), 

and assumed 50% additional unit cost to actuation and 

flight control system

• 50% figure gained from ICF team consensus, and 

assumption of greater material and component costs in 

actuation system

• Relative scaling “check” to reflect value of increased fuel 

savings

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.2 $0.1 $0.2 $0.5 $1.5 $1.9 $3.0 

Estimated Total NRE ($M) by Aircraft Category

$135 $180 $180 $225 $280 $340 $340 $340 

© 2013 50 ICF International
Riblet Coatings

Riblets are a pattern of tiny ridges that are aligned in the direction of the flow. They have been shown to reduce the skin friction due to a turbulent boundary 

layer by about 6.5% for the flight regime that is typical of commercial transport aircraft. Riblets work by reducing the turbulence at the surface in the 

direction perpendicular to the flow, reducing the skin friction drag. Although this is a well understood way of reducing skin friction drag, the issue with the 

use of this technology hinges on the cost of manufacturing, the curability in service and maintenance issues. Lufthansa Technik is currently researching 

riblet paint coatings (Gubisch). Given the increasing value of decreasing drag, there is a chance that this technology is deployed within the next 10 years.

© 2013 51 ICF International
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Applicability 

• Not currently in production, but has had concept 

validated

• Potential issues with increased maintenance and cleaning 

costs, and practicality in field

• Sources for information included publically available 

documents, secondary research, and confirmation from 

airframe OEM interview sources (Gubisch)

• Fuel burn reduction mechanism: skin friction drag 

reduction

- - - - = + + +

0.5% 0.5% 0.5% 0.5% 1.0% 1.5% 1.5% 1.5%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 0% 5% 10% 20%

Technical 

Feasibility 0% 25% 80% 100% 100%

Cost Impact

• Riblet coatings would primarily affect manufacturing 

costs, after initial design NRE is performed to validate 

concept

• Estimates from interviews/ICF team consensus

• Unknown impact on maintenance costs

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.2 $0.1 $0.2 $0.2 $0.6 $0.8 $1.2 

Estimated Total NRE ($M) by Aircraft Category

$135 $180 $180 $180 $230 $270 $270 $270 

© 2013 52 ICF International
Natural Laminar Flow Control - Nacelle

Skin-friction drag is one of the primary sources of drag on an aircraft, usually accounting for just over 50% of the total drag at cruise. As mentioned 

previously, this drag is due to the friction caused by the boundary layer. Boundary layers can be either laminar or turbulent, and the former generate less 

friction, and thus lower drag. Laminar boundary layers are also thinner, contributing to a decrease in pressure drag as well. Due to the combination of high 

speed and scale of the aircraft, the boundary layers on transport aircraft all almost completely turbulent. It is particularly difficult to achieve a laminar 

boundary layer in this flow regime through passive means, especially in lifting surfaces that are swept. Although they start as laminar at the leading edges, 

they will quickly transition to turbulent unless the right technology is used.

Natural laminar flow (NLF) relies solely on the careful design of the aerodynamic shape so as to delay the transition of the boundary layer from laminar to 

turbulent as much as possible. This technology has been used in high-performance sailplanes for several decades, but the higher the speed and the longer the 

dimensions, the more difficult it is to achieve. Furthermore, wing sweep has an adverse effect. As a result, NLF is currently not feasible on wings of 

commercial transports flying at high subsonic speeds.

However, recent progress has made it possible to achieve NLF for a significant portion of engine nacelles, as is the case in the Boeing 787. NLF requires 

especially tight manufacturing tolerances as well as attention to the paint material and thickness. The 777X will also feature nacelles with NLF. (CITE 

Boeing PAS Widebody presentation).

© 2013 53 ICF International
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Fuel Burn 

Applicability 

• Portion of 787 nacelle was designed for natural laminar 

flow, but full potential benefit is not currently being 

realized (Norris, Boeing Plans Plain Grey Natural 

Laminar Flow Nacelles for 787s in Bid to Reduce Fuel 

Burn)

• Natural laminar flow easier to design into lower speed 

aircraft (regional jets, turboprops)

• Interviews indicated <0.5% fuel burn benefit realized on 

787, estimates scaled from that data point and internal 

team analysis

• Fuel burn reduction mechanism: skin friction drag 

reduction

- - + + = = = =

0.1% 0.1% 1.0% 1.0% 0.6% 0.6% 0.6% 0.6%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 0% 1% 3% 8%

Technical 

Feasibility

80% 100% 100% 100% 100%

Cost Impact

• Used initial costs from ICF IP (Aircraft Value Database), 

and assumed 75% additional unit cost to nacelle

• 75% estimate created from ICF team consensus, and 

assumption of greater design NRE and material 

finishing/processing costs

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Assumed much greater design/engineering NRE in the 

form of aerodynamic analysis, as well as additional 

testing to validate concept

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.2 $1.0 $0.1 $1.0 $1.1 $3.1 $3.4 $4.1 

Estimated Total NRE ($M) by Aircraft Category

$265 $355 $355 $310 $390 $470 $470 $470 

© 2013 54 ICF International
Hybrid Laminar Flow Control – Empennage

As mentioned above, it is possible to achieve a significant amount of NLF on nacelles. However, the boundary layer will eventually transition when the 

streamwise distance is long enough. To increase the extent of laminar flow beyond what is possible with the passive means of NLF, or to ensure laminar 

flow with an adverse shape or flight condition, it is possible to use hybrid laminar flow control (HLFC). 

HLFC uses suction to delay the transition from laminar to turbulent and thus create areas with a laminar boundary layer. This technology has been tested for 

the 787-9 vertical tail and will represent the first commercial application of HLFC. Usually, the suction is created by mechanical means and requires a source 

of power. The patent filed by Boeing seems to show a system that does not require mechanical power: it sucks the boundary layer in through tiny holes in 

the skin to a plenum, or hollow chamber, inside the leading edge vertical tail that is then connected to an area of lower pressure elsewhere. This reduces the 

complexity of the system and eliminates the power requirement, making it commercially more viable.

© 2013 55 ICF International
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Applicability 

• Public sources indicate implementation on very small 

portion of vertical stabilizer would yield ~0.5% fuel 

savings on 787-9, assumed that application to larger area 

of empennage would be possible

• Possible issues with practicality (HLFC requires small 

ports in aircraft skin that may become frequently clogged 

in practice)

• Fuel burn reduction mechanism: skin friction drag 

reduction

- - - - = + + +

0.3% 0.3% 0.3% 0.3% 1.4% 2.5% 2.5% 2.5%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 3% 6% 10% 20%

Technical 

Feasibility 0% 80% 100% 100% 100%

Cost Impact

• Used initial costs from ICF IP (Aircraft Value Database), 

and assumed 25% additional unit cost to empennage

• 25% estimate created from ICF team consensus, and 

assumption of greater design NRE and greater system 

costs

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.4 $1.4 $0.8 $1.2 $1.6 $6.0 $6.9 $7.6 

Estimated Total NRE ($M) by Aircraft Category

$265 $355 $355 $310 $390 $470 $470 $470 

© 2013 56 ICF International
Hybrid Laminar Flow Control – Nacelle

As mentioned above, it is possible to achieve a significant extent of NLF on nacelles. However, there might be desirable to increase the extent of laminar 

flow even further than it is possible with passive means. Given the possible application of HLFC to the empennage of the 787-9, and as this technology 

matures, it is likely that this will be applied to other components of the aircraft, including nacelles. The application to wings, however, remains a very 

challenging proposition for the reasons that were already mentioned.

© 2013 57 ICF International
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Fuel Burn 

Applicability 

• Fuel burn benefit depends on degree of implementation, 

this assumes implementation on as much of the nacelle as 

practical/cost effective

• Public sources indicate implementation on small area of 

vertical stabilizer would yield ~0.5% fuel savings on 

787-9, this data was scaled to nacelle implementation 

area and confirmed through aircraft OEM & 

aerodynamics expert interview input

• Fuel burn reduction mechanism: skin friction drag 

reduction

- - - - = + + +

0.1% 0.1% 0.1% 0.1% 0.7% 1.3% 1.3% 1.3%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 3% 6% 10% 20%

Technical 

Feasibility 0% 80% 100% 100% 100%

Cost Impact

• Used initial costs from ICF IP (Aircraft Value Database), 

and assumed 75% additional unit cost to nacelle

• 75% estimate created from ICF team consensus, and 

assumption of greater design NRE and greater system 

costs

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Assumed much greater design/engineering NRE in the 

form of aerodynamic analysis, as well as additional 

testing to validate concept

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.3 $0.1 $0.3 $0.4 $1.0 $1.2 $1.4 

Estimated Total NRE ($M) by Aircraft Category

$265 $355 $355 $270 $335 $405 $405 $405 

© 2013 58 ICF International
Advanced Metallic Technologies – Al-Li, etc.

Although the use of carbon reinforced composite materials in primary structures has increased dramatically, and is seen as the way of the future, metal 

manufacturers have developed new metal alloys to remain competitive in the airframe material market. The most prominent of these new alloys is aluminum 

lithium (Al-Li), which is less dense than standard aluminum alloys, more durable, and less susceptible to corrosion. Alcoa claims that the use of Al-Li can 

reduce the aircraft structural weight by 10%. However, this alloy is currently much more expensive than conventional aluminum, and the manufacturing 

process is different enough from that of standard alloys that previous tooling cannot be reused. Bombardier selected Al-Li for the fuselage of the CSeries, 

and Boeing is rumored to be considering it for the fuselage of the 777X. In the future, we can also expect even more advanced metal technologies, including 

hybrid materials that combine metals with non-metallic fibers. Titanium-graphite hybrid composites, for example, promise to save weight in heavy 

attachment areas in the primary structure.

© 2013 59 ICF International
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Applicability 

• Technical challenges associated with increasing Al-Li 

raw material production, but technical feasibility will 

increase quickly with new facility investment taking 

place

• Commercial feasibility remains low due to low 

cost/benefit for direct material substitution

• Assumes direct material substitution, which gives 1-3% 

weight benefit vs. conventional Al alloys

• Sources for fuel burn benefit include interviews with raw 

material OEMs and a previous comprehensive ICF study

on the lifecycle costs and performance benefits of 

advanced metallic vs. composites

• Fuel burn reduction mechanism: weight reduction

- - - - - + + +

1.0% 1.0% 1.0% 1.0% 1.0% 2.0% 2.0% 2.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 3% 4% 5% 10%

Technical 

Feasibility 25% 100% 100% 100% 100%

Cost Impact

• Costs developed from bottom’s up model of 

aerostructures manufacturing costs by material from 

previous ICF study

• Assumed direct material substitution for density-based 

weight savings, and used estimated Al-Li per pound 

material pricing

• Assumed very little NRE required for direct material 

substitution (assuming material is qualified)

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.5 $1.9 $1.0 $1.7 $2.3 $6.0 $10.6 $13.0 

Estimated Total NRE ($M) by Aircraft Category

$50 $50 $100 $100 $200 $200 $200 $200

© 2013 60 ICF International
Titanium Landing Gear

Traditionally, commercial aircraft landing gear have been made from steel. Steel is a heavy, but strong, metal, and large steel forgings are using for landing 

gear main beams and supporting braces. Titanium is much lighter than steel (up to 45% lighter for equivalent strength). It is also more resistant to corrosion. 

These properties, however, come with a steep price penalty, as titanium can be three to four times more expensive than titanium, by weight. 

Titanium landing gear have long been found in military aircraft, but have only started to be incorporated recently in select large commercial aircraft. The 

777 was the first aircraft to incorporate Ti landing gear, followed by new-generation aircraft such as the 787 and A350. Although there are no examples yet 

of titanium landing gear being retrofitted, it is conceivable that they could be applied to other aircraft categories as part of a block upgrade package.

© 2013 61 ICF International
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Fuel Burn 

Applicability 

• Obtained current landing gear system prices from ICF

Aircraft Value Database

• Fuel burn reduction mechanism: weight reduction

- - - - = + + +

0.5% 0.5% 0.5% 0.5% 1.3% 2.0% 2.0% 2.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 5% 7% 10% 20%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Obtained current landing gear system prices from ICF 

Aircraft Value Database

• Assumed material/machining costs were 40% of total 

landing gear system price, and assumed this portion of 

total cost would increase proportionally to ratio of 

titanium/steel material prices (gives a price increase of 

3X)

• To fully take advantage of new material, redesign of 

landing gear would be required, so NRE reflects this

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.2 $0.8 $0.6 $0.6 $1.2 $3.6 $4.2 $7.2 

Estimated Total NRE ($M) by Aircraft Category

$105 $135 $135 $135 $175 $205 $205 $205 

© 2013 62 ICF International
Lightweight Lightning Strike Protection

Aircraft are struck by lightning every 1,000 to 3,000 flight hours, on average (Black). This is an average of more than once per year for air transport aircraft. 

This is Traditional aircraft with metallic primary aerostructures can easily deal with lightning strikes, since the fuselage provides a natural conduit for the 

high current caused by a lightning strike. Since composite aircraft skins are poor conductors, a lightning strike to a carbon fiber or other composite part could

result in significant structural heat damage and costly repairs, or more significant damage that could compromise the safety of the aircraft in flight. Thus, 

composite aircraft utilize several methods to account for this problem. Often, a thin metal foil or copper mesh is placed below the first layer of composite 

laminate, which provides an electrical conduit around the fuselage, and prevents any excessive heating or burn-through. These methods, however, are 

accompanied by a weight penalty, which can be quite significant. 

Because of this weight penalty, many suppliers are looking for alternative methods to increase conductivity of composite structures, including metallic fibers 

interwoven with composite weave, conductive spray coatings, and other solutions. These have the potential to take a few percent of weight out an aircraft 

with composite primary aerostructures.

© 2013 63 ICF International
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Fuel Burn 

Applicability 

• Applies only to composite aircraft

• Fuel burn reduction mechanism is weight reduction

= = = = = = = =

0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5% 0.5%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 6% 7% 10% 20%

Technical 

Feasibility 0% 80% 100% 100% 100%

Cost Impact

• Unit cost data from bespoke ICF study on advanced 

(Lightning Strike Protection) LSP concepts

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.2 $0.8 $0.6 $0.6 $1.2 $3.6 $4.2 $7.2 

Estimated Total NRE ($M) by Aircraft Category

$105 $135 $135 $135 $175 $205 $205 $205 

© 2013 64 ICF International
More Electric Systems – Weight Reductions

Many modern aircraft have begun replacing mechanical equipment with electrical systems. These design philosophies are collectively known as the “more 

electric aircraft” paradigm. Specific examples of “more electric” designs and technologies include:

• higher pressure hydraulic systems that enable reduced conveyance equipment weight

• replacement of pneumatics with electric systems, allowing the removal of ducting and tubing weight

• electric actuation, especially for secondary, utility and backup actuation systems

• utilizing electric anti-ice systems, where possible

Many new aircraft are incorporating various elements of this design philosophy, especially in the actuation system. Air transport and large business aircraft 

generally have at least three redundant actuation and hydraulic systems for safety reasons. Many large air transport aircraft incorporate electric or electrohydrostatic backup actuation systems. Electric brake actuation is becoming more common on new generation aircraft, such as the 787 and C-Series.

© 2013 65 ICF International
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Fuel Burn 

Applicability 

• Further refinements to more electric systems, including 

high pressure hydraulic systems, electric bleed air 

control, elimination of one hydraulic system, Includes 

electric ECS, electric anti-ice; electric hydraulic pumps; 

electric primary, secondary, and high lift actuation; 

electric brake actuation

• Fuel burn reduction mechanism: weight reduction

= = = = = + + +

1.2% 1.2% 1.2% 1.2% 1.2% 2.0% 2.0% 2.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 3% 6% 10% 20%

Technical 

Feasibility 0% 100% 100% 100% 100%

Cost Impact

• Assumed that using more electric systems to reduce 

weight results in substantial increases in unit costs due to 

both NRE and use of more expensive components

• Assumed resultant cost increases of approximately 2% of 

realized aircraft price

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.20 $0.80 $0.50 $0.60 $0.90 $2.60 $3.30 $3.90

Estimated Total NRE ($M) by Aircraft Category

$105 $135 $135 $135 $175 $205 $205 $205 

© 2013 66 ICF International
ECS Aerodynamic Cleanup and On-Demand ECS Scheduling

The environmental control system (ECS) of an aircraft provides air supply, thermal control and cabin pressurization for the crew and passengers. Avionics 

cooling, smoke detection and fire suppression are also commonly considered part of an aircraft’s environmental control system. The Boeing 787 and Airbus 

A350 have made both aerodynamic and power-saving improvements to the ECS system (Sinnett). The inlet and outlet ducts to the system’s compressor have 

been optimized to reduce the pressure drag. In addition, on-demand ECS scheduling now allows engines to power the system only when needed as opposed 

to an entire flight (Boeing Co.).

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Fuel Burn 

Applicability 

• Fuel burn reduction mechanism is drag reduction (

(Thomson)

= = = = = = = =

0.6% 0.6% 0.6% 0.6% 0.6% 0.6% 0.6% 0.6%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 20% 28% 40% 80%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Assumed that refining ECS system would result in minor 

charges equal to 0.25% of realized aircraft sale price

• Changes are mainly from amortized NRE and additional 

control electronics

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• NRE is aerodynamics and software design engineering

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.1 $0.1 $0.1 $0.1 $0.3 $0.4 $0.5 

Estimated Total NRE ($M) by Aircraft Category

$40 $50 $50 $50 $65 $75 $75 $75 

© 2013 67 ICF International
Lighter Aircraft Interiors

Airplane seats, bathrooms, kitchens, and cabin bins are a large portion of aircraft interiors. Companies like Rockwell Collins and Zodiac Aerospace have 

been designing lighter furnishings to help decrease aircraft takeoff weight while maintaining size. Even smaller interior components such as flight manuals 

have been replaced by more efficient Electronic Flight Bags (EFB’s). There have also been some initiatives towards replacing traditional electronic 

entertainment systems with mobile devices and using wireless streaming, which would not only reduce the weight (in both the device and the wiring), but 

reduce energy consumption as well. With a lighter plane, less fuel is burned because of a lower lift and thus lower induced drag, which translates into lower 

thrust. Alternatively, airlines can replace the saved weight with payload.

© 2013 68 ICF International
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Fuel Burn 

Applicability 

• Fuel burn reduction mechanism: weight reduction

- - - - = + + +

1.0% 1.0% 1.0% 1.0% 2.0% 3.0% 3.0% 3.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 20% 28% 40% 80%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Baseline aircraft interiors costs obtained from ICF 

aircraft value database

• Assumed that interiors were made lighter through heavy 

use of composites, resulting in over 100% increase in 

material/processing costs

• This results in 50% increase in total aircraft interiors cost

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Relatively low NRE involved in seat/galley/interiors 

design and certification

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.3 $0.5 $0.5 $1.0 $4.6 $5.5 $8.4 

Estimated Total NRE ($M) by Aircraft Category

$105 $135 $135 $95 $120 $140 $140 $140 

© 2013 69 ICF International
Fuel Cell APU Replacement

Aircraft auxiliary power units (APUs) are small gas turbine engines used to provide electrical power, air conditioning, hydraulic power, and pneumatic 

power both on the ground as a backup in flight. Several companies are conducting research to enable APUs to be replaced with fuel cells. Fuel cells take 

advantage of a chemical reaction of some hydrogen-based compounds with air to produce electricity. While this would likely not produce a direct weight 

reduction benefit, fuel cell APUs are an important element to enable further development of the “more electric aircraft” architecture discussed earlier in the 

report, as well as reducing fuel consumption and emissions for ground operations. Fuel cell APUs would have many ancillary benefits, including production 

of nitrogen as a byproduct, which could be used for the fuel tank inerting system. Fuel cells also produce water as a byproduct of the chemical reaction, 

which would allow airlines to begin a flight with less stored water for lavatories, further reducing weight (Breit). 

© 2013 70 ICF International
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Fuel Burn 

Applicability 

• Fuel burn benefit estimate from interview with Tier 134

systems supplier

• Many ancillary benefits to fuel cell APU, but probably 

will have little effect on cruise fuel burn

= = = + + - - -

0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 0% 0% 20% 45%

Technical 

Feasibility 0% 0% 0% 25% 100%

Cost Impact

• Fuel cell APU cost information obtained from interviews 

with Tier 1 aircraft system OEM involved in fuel cell 

research

• Fuel cell APUs are projected to be less expensive to 

manufacture

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00

Estimated Total NRE ($M) by Aircraft Category

$135 $180 $180 $180 $230 $270 $270 $270 

34 Tier 1 suppliers are companies that provide major systems and usually have design authority.

© 2013 71 ICF International

 
Control Surface – Optimal Control Laws for Horizontal Stabilizer Trim

Maintaining trimmed flight efficiently requires clean, accurate, and dynamic control laws. There is room for improvement with contemporary control systems 

with regards to overshoot, rise time, and steady-state error. This technology complements the adaptive trailing edge technology, since if the trailing edge 

geometry changes, the trim settings should change at the same time.

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Fuel Burn 

Applicability 

• Reduces trim drag

• Fuel burn reduction estimate from airframe OEM 

interview, and team expert input

• Fuel burn reduction mechanism: reduced induced/trim 

drag

X = = = = = = =

0.0% 0.4% 0.4% 0.4% 0.4% 0.4% 0.4% 0.4%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 10% 14% 20% 75%

Technical 

Feasibility 25% 100% 100% 100% 100%

Cost Impact

• Costs associated with new control laws are mainly in 

software development and new certification costs

• Assumed 0.25% premium in aircraft realized price

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.0 $0.1 $0.1 $0.1 $0.1 $0.3 $0.4 $0.5 

Estimated Total NRE ($M) by Aircraft Category

$105 $135 $135 $135 $175 $205 $205 $205 

© 2013 72 ICF International
Fly-By-Wire

Historically, aircraft flight controls have been actuated through a direct linkage between cockpit flight controls and the control surface actuators. This 

involves lengthy stretches of steel cable, pushrods, and linkages, which add weight to the aircraft. Fly-by-wire systems, on the other hand, use electrical 

signals to transfer inputs from the pilot’s controls to control surface actuators. This approach removes much of the cabling, but requires very expensive 

design and certification efforts.

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Fuel Burn 

Applicability 

• Fly by wire weight savings available through secondary 

research and publically available documents

• Translation from weight savings to fuel savings made 

from ICF previous project experience

• Fuel burn reduction mechanism: weight savings

X = - - = = = =

0.0% 0.4% 0.2% 0.2% 0.4% 0.4% 0.4% 0.4%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 20% 28 40% 80%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• These costs (and benefit) represent installing fly-by-wire 

in limited applications in originally non fly-by-wire 

aircraft (rudder, spoilers, partial primary control surfaces)

• Assumed 0.5% premium in aircraft realized price

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Primary NRE costs are certification, to a lesser extent 

software development costs

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.1 $0.2 $0.1 $0.2 $0.2 $0.7 $0.8 $1.0 

Estimated Total NRE ($M) by Aircraft Category

$265 $355 $355 $270 $335 $405 $405 $405 

© 2013 73 ICF International
Gap Reductions & Aerodynamic Cleanup on Slats/Spoilers/Ailerons/ etc.

Hinged control surfaces such as ailerons, elevators and rudders, leave gaps on the aerodynamic surface that need to be sealed as much as possible to reduce 

drag. While some effort has been made to minimize this type of drag, this is an area of continuous improvement.

Spoilers and slats also incur some drag if their trailing edges are not perfectly flush with the shape of the wing. By making these trailing edges thinner, this 

source of drag can be reduced, as demonstrated in a recent next-generation 737 performance improvement package (Tesch, Next-Generation 737 Fuel 

Performace Improvement). 

© 2013 74 ICF International
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Fuel Burn 

Applicability 

• Basic aerodynamic cleanup on control surfaces and 

across aircraft (Thomson)

• Fuel burn estimate from ICF team analysis

• Fuel burn reduction mechanism: drag reduction

- - = = = = = =

0.1% 0.1% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 25% 35% 50% 90%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Assumed minor changes resulted in 0.25% increase in 

aircraft realized price

• Majority of unit change costs are production related, not 

amortized NRE

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Low NRE costs, mostly related to aerodynamic analysis

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.0 $0.1 $0.1 $0.1 $0.1 $0.3 $0.4 $0.5 

Estimated Total NRE ($M) by Aircraft Category

$40 $50 $50 $50 $65 $75 $75 $75 

© 2013 75 ICF International
Reducing Profiles of Lights, Antennae, Sensors, etc.

Although the additional the lights, antennae and sensors protruding from the aircraft have relatively small dimensions, they can collectively add up to a 

significant amount of drag. It is well known that circular cross sections (such as those used in some anti-collision lights) exhibit a drag that is ten times 

higher of that of a streamlines shape with the same width. Therefore, several in-production aircraft have modified these details for in-production aircraft

(Tesch, Next-Generation 737 Fuel Performace Improvement), (Caldas). Although the drag reductions are modest, they are generally low cost modifications.

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Fuel Burn 

Applicability 

• Fuel burn estimates developed from ICF team estimates 

and checked by interview input from airframe OEM

• Fuel burn reduction mechanism: reduced excrescence 

drag

= = = = = = = =

0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 25% 35% 50% 95%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Assumed minor changes resulted in 0.25% increase in 

aircraft realized price

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Very low NRE costs, related to suppliers changing 

production standards and documentation

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.0 $0.1 $0.1 $0.1 $0.1 $0.3 $0.4 $0.5 

Estimated Total NRE ($M) by Aircraft Category

$5 $5 $5 $5 $10 $10 $10 $10 

© 2013 76 ICF International
Carbon/Ceramic Brakes

Aircraft brake friction material has historically been made out of steel. Newer carbon/ceramic brake material is much lighter, as well as more wear-resistant. 

Ceramic brakes are easily retrofitted onto new in-production aircraft, and in fact are optional for most single aisle aircraft, and standard on twin aisle and 

large aircraft. For those aircraft that do not currently offer ceramic brakes, they can be installed with minimal recertification and testing effort. 

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Fuel Burn 

Applicability 

• Fuel burn reduction mechanism is through reduced 

weight (Milller, Allen and Preston)

• Weight savings estimates available from public 

documents

- - = = = = = =

0.1% 0.1% 0.3% 0.3% 0.3% 0.3% 0.3% 0.3%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 20% 28% 40% 80%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Changing brake material results in 0.25% increase in 

aircraft realized price

• Change is due to increased material and production costs 

of carbon ceramics, compared to traditional steel brakes

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• NRE costs are related to testing and qualification of the 

new material’s strength and wear characteristics

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.0 $0.1 $0.1 $0.1 $0.1 $0.3 $0.4 $0.5 

Estimated Total NRE ($M) by Aircraft Category

$70 $95 $95 $50 $65 $75 $75 $75 

© 2013 77 ICF International
Aft Body Redesign for Aerodynamics

There is room for aerodynamic improvements on the aft body of many contemporary aircraft. Understandably, the majority of aerodynamic analysis and 

design effort targets the wings. However, with recent skyrocketing fuel prices, opportunities for drag reduction on non-lifting parts such as the fuselage have 

also become a focus of aircraft OEMs. This has been seen on the 737 MAX (Boeing Co.)

For in-production aircraft, it is not feasible to perform a major redesign of the aft body, but it is possible to make modifications on the existing shape. The 

area where the horizontal and vertical tails join the fuselage is particularly critical when it comes to interference drag, and is a good target for redesign.

© 2013 78 ICF International
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Fuel Burn 

Applicability 

• Fuel burn benefit estimated from publically 

announcements about 737MAX fuel burn reduction 

technologies ( (Boeing Co.)

• Fuel burn reduction mechanism: induced drag reduction

- = = = = = = =

1.0% 1.3% 1.3% 1.3% 1.3% 1.3% 1.3% 1.3%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 20% 28% 40% 80%

Technical 

Feasibility 50% 100% 100% 100% 100%

Cost Impact

• Significant design and production change for an aircraft 

program

• ICF estimated that this would result in a 2% increase in 

realized price

• Cost increase data scaled relatively to other known 

modification and checked through interview feedback

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

• Significant NRE related to design and changing 

production process

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.2 $0.8 $0.5 $0.6 $0.9 $2.6 $3.3 $3.9 

Estimated Total NRE ($M) by Aircraft Category

$170 $225 $225 $225 $280 $340 $340 $340 

© 2013 79 ICF International
Composites – Current State, Increased Application

Decreasing aircraft weight without compromising drag is a sure way of reducing aircraft fuel burn. Composite materials have been known for decades and 

have been used in military airplanes for a long time, and exhibit strength to weight ratios higher than those of metals. However, composites have only 

recently been used in the primary structures of commercial transport aircraft (in the Boeing 787 and the Airbus A350). In spite of the knowledge gained over 

the years in the military applications, the current generation of composite structures in these new commercial aircraft has much room for improvement. For 

both airplanes, the predicted weight advantages of composites have not been fully realized and there have been growing pains in the development of these 

structures. This is due in part to complications in the fastening of the various parts (especially when interfacing composite parts with metal ones) and also 

due to the use of conservative design procedures to mitigate the risks in using a new material. Design and manufacturing techniques that enable a more 

detailed tailoring of the composite ply angles have the potential to reduce the weight further. There is room for improvement when it comes to reducing the 

cost of manufacturing composites. In addition to the weight reduction, composites a much less susceptible to corrosion and should reduce the maintenance 

cost in the long run. Finally, composites enable more freedom in the manufacture shape, which could improve the aerodynamics of wings. 

© 2013 80 ICF International
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Fuel Burn 

Applicability 

• Fuel burn benefit information came from detailed ICF 

study on enabling technologies for both weight reduction 

and cost of composites

- - - - = + + +

0.5% 0.5% 0.5% 0.5% 1.3% 2.0% 2.0% 2.0%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 20% 28% 40% 80%

Technical 

Feasibility 50% 100% 100% 100% 100%

Cost Impact

• ICF estimated that manufacturing costs would remain the 

same, but NRE would be needed to develop and 

implement new production systems

• NRE estimated from relative scaling

Estimated Unit Cost Increase ($M) by Aircraft Category

- - - - - - - -

Estimated Total NRE ($M) by Aircraft Category

$200 $270 $270 $270 $335 $405 $405 $405

© 2013 81 ICF International
Lightweight Paint/Surface Treatments

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Applicability 

• Fuel burn reduction information from ICF team analysis 

and secondary research

• Fuel burn reduction mechanism: weight reduction

= = = = = = = =

0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 10% 14% 20% 40%

Technical 

Feasibility 0% 100% 100% 100% 100%

Cost Impact

• ICF estimated that this would not result in an increase in 

realized aircraft price

• Cost increase data scaled relatively to other known 

modification and checked through interview feedback

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00 $0.00

Estimated Total NRE ($M) by Aircraft Category

$70 $95 $95 $95 $120 $140 $140 $140 

© 2013 82 ICF International
Zonal Drying

Zonal drying systems act to remove moisture that accumulates in the aircraft insulation after a series of flights. The interior of an aircraft is usually kept at 

a very low humidity to reduce the risk of corrosion. Due to the cold exterior skin of an aircraft at cruise, remaining moisture tends to condense and accumulate 

on the interior of the aircraft skin, and then gets trapped in the adjacent insulation blankets. Over time, this accumulated water adds a significant amount of 

weight to the aircraft, which negatively affects performance and fuel burn. Zonal drying systems are targeted dehumidifiers that expel this excess water from 

the aircraft. This weight decrease is hard to quantify, since it will not change any certificated weights, such as operating empty weight or maximum takeoff 

weight. It will, however, reduce real-world fuel burn in operation, which is why ICF felt it important to include. 

© 2013 83 ICF International
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Fuel Burn 

Applicability 

• Fuel burn benefit from derived from public sources 

regarding weight savings potential, interview input from 

airlines currently using zonal dryers, and ICF analysis

• Fuel burn reduction mechanism: weight savings

= = = = = = = =

0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2% 0.2%

2013 2018 2020 2023 2033

Commercial 

Feasibility 0% 10% 14% 20% 40%

Technical 

Feasibility 80% 100% 100% 100% 100%

Cost Impact

• Significant design and production change for an aircraft 

program

• ICF estimated that this would not result in a 0.25% 

increase in realized aircraft price

• Cost increase data scaled relatively to other known 

modification and checked through interview feedback

• NRE estimates scaled relatively from known data points

on program NRE scale according to ICF team judgment

Estimated Unit Cost Increase ($M) by Aircraft Category

$0.0 $0.1 $0.1 $0.1 $0.1 $0.3 $0.4 $0.5 

Estimated Total NRE ($M) by Aircraft Category

$70 $95 $95 $95 $120 $140 $140 $140 

© 2013 84 ICF International
2.3 TECHNOLOGY DEVELOPMENT COST 

In the following subsection are examples of the types of data points and accompanying analysis that were used to validate the ICF cost curves.

© 2013 85 ICF International
As noted above, ICF relied on non-public information to develop its analysis. However, the publicly available data inputs corroborate our results. 

767-300 Winglet

Situation / Facts Assumptions

• 767-300 winglets were developed by Aviation 

Partners Boeing and entered service in 2008

• These winglets deliver 4.0-5.8% fuel burn 

improvement

• ICF estimates NRC of $250M for a 4% 

improvement 

• 767-300 winglet shipset list price is $2.35M 

(excluding installation cost)

• 767-300 fleet in 2005 was 557 AC and was 

growing by 10 per year

• A reasonable business case would 

only assume partial penetration of 

the fleet

• ICF assumed 25% penetration (139 

AC)

Results

• ICF estimates winglet per shipset 

NRC is ~$1.2M - about 50% of list 

price

© 2013 86 ICF International
757-200 Winglet

Situation / Facts Assumptions

• 757-200 winglets were developed by Aviation 

Partners Boeing and entered service in 2005

• These winglets deliver 3.5-5.2% fuel burn 

improvement

• ICF estimates $150M NRC for 3.5% 

improvement 

• 757-200 winglet shipset list price is $1.1M 

(excluding installation cost)

• 757-200 fleet in 2005 was 1,016 AC and

production had ceased in 2004

• A reasonable business case would 

only assume partial penetration of 

the fleet

• ICF assumed 25% penetration (254

AC)

Results

• ICF estimates winglet per shipset 

NRC is ~$0.6M - 50% of list price

© 2013 87 ICF International
Aviation Partners Boeing engineering employment

Situation / Facts Assumptions

• In 2008, Aviation Partners Boeing had 100 

people involved in product design and 

development activities 

• At the time, they were likely working on two 

narrowbody winglets and one widebody winglet

• Average US aerospace engineering salary was 

$100K/year in 2013

• Overhead allocation for engineering-focused 

organizations ranges from 150-300%

• Per ICF NRC analysis, engineering and 

integration is 55% of Large Incremental Update 

NRC 

• ICF estimates $150M NRC for 3.5% 

improvement

• $100K average salary at a 300% 

overhead burden rate 

(conservative)

• 3 year development period for each 

winglet design and all development 

staff 100% focused on one design 

(very conservative)

• Single Aisle Large Incremental 

Update (winglet) NRC cost 

structure – 55% Engineering, 40% 

Test, and 5% Tooling

Results

• Total design, development, and 

integration cost of $90M

• Implies total NRC of $164M

© 2013 88 ICF International
GE90-115B PIP

Situation / Facts Assumptions

• GE has steadily improved the GE90-115B from 

2004-2011

• “GE and program partners combined have spent 

average of $50M per year to improve GE90-

115B, including many improvements for 

reliability and maintenance cost”

• From simple analysis of stated improvements, 

likely that 1/3 to 1⁄2 of improvements were 

actually to improve maintainability, cost, or 

durability

• Investments yielded 3.6% improved fuel burn 

over 7 years (possibly fewer)

• ICF cost estimates indicate $506M to achieve a 

3.5% MV reduction on the 777-300ER

• 100% of stated cost was used for 

fuel burn-reducing technologies

(conservative) 

Results

• $350M total investment ($50M/yr 

over 7 years) is lower than ICF 

estimate 

© 2013 89 ICF International
737NG PIP

Situation / Facts Analysis

• 737NG PIP implemented between 2011 and 2013 

improved fuel economy ~2%

• Aerodynamic improvements (~1%)

• Redesigned ECS exhaust inlet, wheel well 

fairings, control surface aerodynamics efficiency 

improvements, and streamlined engine nozzle 

and nacelle

• CFM56-7B Evolution (>1%)

• ICF estimates $100M NRC for a 2% 

improvement to the 737NG family

• A 2% fuel savings has an net 

present value to airline operators of 

approximately +$1.4M over the 

aircraft lifetime

• Boeing’s giveaways apply to 

complete 737 PIP

Results

• Some value-creating incremental 

technologies are being given away 

for free

© 2013 90 ICF International
3 BIBLIOGRAPHY

"Analysing the options for 757 replacement." Aircraft Commerce 42 (2005): 6.

Aviation Partners Boeing. "Split Scimitar Winglets." 2013. Aviation Partners Boeing.

Document. 5 June 2013.

Black, Sara. "Lightning Strike Protection Strategies for Composite Aircraft." 1 May 2013. 

www.compositesworld.com. 1 June 2013.

Boeing Co. "Operational Efficiency and Environmental Performance." Aero Magazine (2009).

Boeing Co. "The 737 Max advantage." Technical Report. 2012.

Breit, Joe. "BCA Perspective on Fuel Cell APUs." 2010.

Caldas, Tobias. "Commercial Aviation Update." Business Overview. Embraer, 2013.

Cervenka, Michael. "The Rolls Royce Trent Engine." Presentation. Rolls Royce, 2000.

Clark, Stephen. "787 Propulsion System ." Aero Magazine (2012).

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