SCIENTIFIC UNDERSTANDING IN 2003 vs. 1999Green bars are updated values, with arrows updated uncertainty. © 2003 Waitz 32RADIATIVE IMBALANCE AT TROPOSPHERE DUETO AIRCRAFT(IPCC Special Report on Aviation, 1999)© 2003 Waitz 35NOTES 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 36THE 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 37COMMERCIAL 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 40FUEL CONSUMPTION TRENDSAircraft responsible for 2%-3% of U.S fossil fuel use© 2003 Waitz 41COMMERCIAL AIRCRAFT EFFICIENCYAverage Age = 13 yrs © 2003 Waitz 42MILITARY AIRCRAFT FUEL BURNAverage Age 21 yrs © 2003 Waitz 43ENERGY 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 EQUATIONTechnology and Operations Stage Length VLD 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 45TRENDS IN LOAD FACTORLoad Factor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 46FLIGHT AND GROUND DELAYSRatio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 47HISTORICAL TRENDSAerodynamic Efficiency L/Dmax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 BYear © 2003 Waitz 48HISTORICAL TRENDSEngine 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)BaRegional Jets Large Jets New Regional Jet Engines New Turboprop Engines 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year © 2003 Waitz 49HISTORICAL TRENDSStructural Efficiency OEW/MTOW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 B757-200L1011-1/100/200 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)BaRegional Jets Large Aircraft 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 Year © 2003 Waitz 50EFFICIENCYRegional Jets Versus Turboprops6Energy Usage (MJ/ASK)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 DHC7SA226 S360 SA227 BAE-146-300 F100 EMB1452 J41 D328Turboprop BAE146-200 DHC8-300Fleet DHC8-100 ATR72S340ABabikian et al. (2002) EMB1201 ATR42 BAE-ATP Turboprops Regional Jets 0 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year © 2003 Waitz 51ENERGY USAGETotal Versus Cruise 0 1 2 3 4 5 MJ/ASK 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 WaitzCOMMERCIAL 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