SCIENTIFIC UNDERSTANDING IN 2003 vs. 1999

Green bars are updated values, with arrows updated uncertainty.

© 2003 Waitz 32

RADIATIVE IMBALANCE AT TROPOSPHERE DUETO AIRCRAFT

(IPCC Special Report on Aviation, 1999)© 2003 Waitz 35

NOTES ON CLIMATE CHANGE IMPACTS

• Burning a gallon of fuel at 11km has about double the radiative impact of burning a gallon of fuel at sea-level

• Burning a gallon of fuel at 19km has about 5 times the impact at sea-level

• CO2 is not the biggest global concern (potential impacts from contrails and cirrus clouds are greater).

• Large imbalance between northern and southern hemisphere

• Improving engine efficiency tends to make NOx and contrails worse

• High uncertainty

© 2003 Waitz 36

THE ROLE OF TECHNOLOGY:CHARACTERISTICS OF AVIATION SYSTEMS

• Safety critical

• Weight and volume limited

• Complex

• 10-20 year development times

• $30M to $1B per unit capital costs

• 25 to 100 year usage in fleet

• Slow technology development and uptake

© 2003 Waitz 37

COMMERCIAL vs. MILITARY FLEET TRENDS

• Demand growth for civil aviation (3.8%/year in US) • Military fleet contraction • Ops tempo (4.3/day commercial, 0.35/day military)

Number of Aircraft Flights/day

© 2003 Waitz 40

FUEL CONSUMPTION TRENDS

Aircraft responsible for 2%-3% of U.S fossil fuel use

© 2003 Waitz 41

COMMERCIAL AIRCRAFT EFFICIENCY

Average Age = 13 yrs

© 2003 Waitz 42

MILITARY AIRCRAFT FUEL BURN

Average Age 21 yrs

© 2003 Waitz 43

ENERGY EFFICIENCY

• Function of performance of entire system

– Aircraft technology (structures, aerodynamics, engines)

– Aircraft operations (stage length, fuel load, taxi/take-off/landing time, flight altitude, delays, etc.)

– Airline operations (load factor)

• Each component of system can be examined independently for reduced fuel burn and impacts on local air quality and regional/global atmospheric effects

© 2003 Waitz 44

⋅⋅

⋅⋅

RANGE EQUATIONTechnology and Operations

Stage Length V L D

g SFC W

W W W fuel

payload structure reserve

=( ) ⋅

+ + +

ln 1

= Technology = Operations

Efficiency W StageLength

W

ASK kg

Stagelength seats

payload

fuel

fuel W

g f

∝∝

==

,

#

Use data to separate effects and understand influences of technology

© 2003 Waitz 45

TRENDS IN LOAD FACTOR

Load

Fac

tor

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Regional Jets

Turboprops

Large Aircraft

1965 1970 1975 1980 1985 1990 1995 2000 Year

Babikian, Raffi, The Historical Fuel Efficiency Characteristics of Regional Aircraft From Technological, Operational, and Cost Perspectives, SM Thesis, Massachusetts Institute of Technology, June 2001

© 2003 Waitz 46

FLIGHT AND GROUND DELAYSR

atio

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

Airborne to Block Hours Minimum Flight to Airborne Hours Mininum Flight to Block Hours

1965 1970 1975 1980 1985 1990 1995 2000

Year

© 2003 Waitz 47

HISTORICAL TRENDSAerodynamic Efficiency

L/D

max

25

20

15

10

5

0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

abikian et al. (2002) Data Unavailable For: EMB-145 FH-227

BAE RJ85 SA-226

CV-600 DHC-7

Turboprops CV-880 Nihon YS-11

Regional Jets Beech 1900 DHC-8-100 Large Aircraft CV-580 L-188

DHC8-300

D328

J41

ATR42 BAE-ATP

ATR72F27 BAC111-200/400 B767-200/ER

S360

J31

SA227

S340A

F28-1000 F28-4000/6000

BAE146-100/200/RJ70 B727-200/231A BAE-146-300

B757-200 F100 B747-400 RJ200/ER B777

B707-100B/300 B707-300B B737-100/200 L1011-1/100/200

A300-600

DC9-30 B737-300

DC10-40

MD11

B737-400

A320-100/200A310-300

DC10-30 L1011-500 B767-300/ER

B747-100/200/300

DC10-10 MD80 & DC9-80 EMB120 B737-500/600

B

Year © 2003 Waitz 48

HISTORICAL TRENDSEngine Efficiency

TSFC

(mg/

Ns)

30

25

20

15

10

5

0

B707-300

B720-000

B727-200/231A

F28-4000/6000BAC111-400 DC9-40 BAE146-100/200/RJ70

CV880 F28-1000

BAE-146-300

F100 RJ85

B737-100/200DC9-30

DC9-10 DC9-50

MD80 & DC9-80

B737-300

D328 EM170

RJ200/ERF27

CV600

DC10-30

DC10-40

L1011-500

B767-200/ER MD11 B747-400

B737-400 B737-500/600

A300-600

B767-300/ER B757-200

L1011-1/100/200 B747-100

B747-200/300

DC10-10

EMB145

EMB135 RJ700

J31L188A-08/188C A320-100/200A310-300 B777

D328

J41

ATR72

DHC7 S360

B1900

CV580

SA226 SA227

EMB120 ATR42

DHC8-300BAE-ATP DHC8-100

DHC8-400

Turboprops

S340A

bikian et al. (2002)Ba

Regional Jets Large Jets New Regional Jet Engines New Turboprop Engines

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year

© 2003 Waitz 49

HISTORICAL TRENDSStructural Efficiency

OEW

/MTO

W

0.70

0.60

0.50

0.40

0.30

0.20

0.10

0.00

DC9-40

B737-100/200

B727-200/231A

DC9-10 DC10-10

BAC111-200 F28-1000

BAC111-400

F27 FH227

CV600

L188A-08/188C DC10-40

DC9-50

MD80 & DC9-80

B767-200/ER

B777B747-400

B737-400

B737-500/600

A320-100/200

A300-600 A310-300

B767-300/ER

B737-300 B757-200

L1011-1/100/200

B747-200/300

F28-4000/6000

BAE146-100/RJ70

BAE146-200

BAE-146-300 F100

RJ85

RJ200/ER

EMB145

DHC8-300D328

J41BAE-ATP

ATR72DHC7 S360

B1900

J31

DHC8-100

SA226

SA227 EMB120 S340A

ATR42

DC9-30CV880 L1011-500 DC10-30 MD11

B747-100

Turboprops

B707-300B

bikian et al. (2002)Ba

Regional Jets Large Aircraft

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year

© 2003 Waitz 50

EFFICIENCYRegional Jets Versus Turboprops

6En

ergy

Usa

ge (M

J/A

SK)

5 Regional

BAC111-400 Jet Fleet Regional

4 CV880 Aircraft Fleet

BAC111-200

CV600

3 RJ200/ERB1900F28-1000 L188A-08/188C

BAE146-100 RJ85F28-4000/6000

F27 J31 DHC7

SA226 S360 SA227 BAE-146-300

F100 EMB1452 J41 D328Turboprop BAE146-200 DHC8-300Fleet

DHC8-100 ATR72S340ABabikian et al. (2002)

EMB120

1 ATR42 BAE-ATP

Turboprops Regional Jets

0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005

Year © 2003 Waitz 51

ENERGY USAGETotal Versus Cruise

0

1

2

3

4

5 M

J/A

SK

EU,CR Large Aircraft Total EU Large Aircraft EU,CR Regional Aircraft Total EU Regional Aircraft

Babikian (2001)

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

Year 52© 2003 Waitz

COMMERCIAL AIRCRAFT ENERGY INTENSITY TRENDS

• New technology energy intensity has been reduced 60% over last 40 years (jet age)

– 57% due to increases in engine efficiency

– 22% due to increases aerodynamic performance

– 17% due to load factor

– 4% due to other (structures, flight time efficiency, etc.)

– Structural efficiency constant (but traded for aero, passenger comfort, noise and SFC)

– Flight time efficiency constant (balance of capacity constraints and improved ATM)

• Fleet average energy intensity has been reduced 60% since 1968

– Lags new technology by 10-15 years

© 2003 Waitz 53

COMPARISON TO OTHER TRANSPORT MODES

(Mark Janes, Boeing, in ICAO CAEP/5, 2002) © 2003 Waitz 54

SHORT HAUL AIRCRAFTFacing Increasing Scrutiny

E U (M

J/A

SK)

3.5

3.0

2.5

2.0

1.5

1.0

0.5

0

Jets Turboprops

Aircraft introduced during or after 1980 only

(Babikian, 2002)

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Stage Length (km)

Royal Commission on the Environment (2002)

the prospect of continuing rapid increases in air transport, particularly an increase in short haul flights…”

government should divert resources...encouraging and facilitating a modal shift from air to high-

“…deeply concerned at

“It is essential that the

speed rail.”

© 2003 Waitz 55

IMPACT OF NASA TECHNOLOGY SCENARIOSG

lob

al C

O2

Em

itte

d p

er Y

ear

Billion Kg Effect of Proposed Environmental CO2 Goals2000

1750

1500

1250

1000

750

500

250

0

1990 2000 2010 2020 2030 2040 2050

No Improvement Beyond 1997 Technology 25% Reduction Introduced in 2007 50% Reduction Introduced in 2022 Zero CO2 Emission A/C Introduced in 2027 Zero CO2 Emission A/C Introduced in 2037

+340%

+140%

+230%

+40%

Change Relative to 1990:

Emission inventories

U.S. DOE reported fuel use

1990-5% Level

-20%

( - GA and Military Emissions based on Boeing forecast

- IPCC IS92a based ICAO demand model - No retrofit of technologies)

Kyoto Protocol Timing For Reductions

Year

J. E. Rohde, NASA 1999© 2003 Waitz 56

IMPACTS OF MISSION REQUIREMENTS (NOx & Noise)

• Range/payload ~ fuel efficiency (commercial and military) High pressures and– Thermal efficiency temperatures High NOx

– Propulsive efficiency velocity change Large mass flow with small

Low Noise

• Maneuverability (military) High energy conversion per

– High thrust-per-weight, unit volume (high small compact engine temperatures and

pressures) High NOx

• Supersonic flight (military) velocity change– Low drag, small compact

engine

Small mass flow with large High Noise

© 2003 Waitz 57

NOx EMISSIONS TECHNOLOGY TRENDS

© 2003 Waitz 58

NOx EMISSIONS TRENDS

© 2003 Waitz 59

HISTORICAL FLEET CRUISE EMISSIONS PERPASSENGER PER KILOMETER

1.0

Rel

ativ

e Em

issi

on /

Pass

-km

0.5

0

1975 1980 1985 1990 1995

NOx

CO2, H2O

CO

HC

Year (DuBois, Boeing)© 2003 Waitz 60

TECHNOLOGY AND EMISSIONS

• Improvements will not keep up with growth

• Aircraft typically have greater impact per unit of fuel burned

• “Solutions” for global climate will require unprecedented action (demand management/regulations, electric vehicles, contrail avoidance, etc.)

• Current understanding is that hydrogen makes problem worse

• High uncertainty relative to global impacts

• Engine efficiency improvements exacerbate NOx and contrails

• Significant improvements in structural efficiency, aero and operations are possible

– Improvements in these areas do not exacerbate other problems

© 2003 Waitz 61

SUMMARY

• Broad range of environmental impacts from aircraft

– Social costs of same order as industry profits

– Currently not internalized

– Current technology path and regulations not aligned with social costs

• Strong growth in demand

• Increasing public concern/regulatory stringency

• High uncertainty

• Many competing trades

– Environmental impacts

– Design, operations © 2003 Waitz 62

SELECTED REFERENCES

• Babikian, R., Lukachko, S. P. and Waitz, I. A. "Historical Fuel Efficiency Characteristics of Regional Aircraft from Technological, Operational, and Cost Perspectives,” Journal of Air Transport Management, Volume 8, No. 6, pp. 389-400, Nov. 2002

• Lee, J. J., Lukachko, S. P., Waitz, I. A., and Schafer, A., “Historical and Future Trends inAircraft Performance, Cost and Emissions,” Annual Review of Energy and theEnvironment, Volume 26, 2001.

• Waitz, I. A., Lukachko, S. P., and J. J. Lee, "Military Aviation and the Environment: Historical Trends and Comparison to Civil Aviation," AIAA-2003-2620, invited contribution to AIAA/ICAS International Air and Space Symposium and Exposition, Dayton, Ohio, July 14-17, 2003.

• Marks, D. H., et al., "Mobility 2001", World Business Council for Sustainable Development, Switzerland, 2001.

• Miake-Lye, R.C., Waitz, I.A., Fahey, D.W., Kolb, C.E., Wesoky, H.L., and Wey, C.C., “Aviation and Climate Change,” Aerospace America, September, 2000.

• Penner et al., United Nations Environment Programme, Intergovernmental Panel onClimate Change (IPCC), Special Report on Aviation and the Global Atmosphere, 1999.

• RCEP, “The Environmental Effects of Civil Aircraft In Flight,” Royal Commission onEnvironmental Pollution (RCEP), England, December, 2003

© 2003 Waitz 63