1. NASA Environmental Workshop John G. Meier Vinod Nangia August 12, 1999 21-10790

2. V9485-1 21-10790 1 Environmental Impact of Small Engines Becoming Critical Turbofans for Regional and Business Aviation, APUs have significant environmental impact –Frequent takeoffs and landings –Widespread access to airports –APU ground operation Strong projected market growth, increased use –Growth in air travel –Transition from turboprop to turbofan (Regional) –Fractional ownership Greatest technology challenges –Size effects –Thermodynamic cycle trends –ETOPS requirements for APUs Technologies for noise and emission reduction in small turbine engines are unique B

3. V9485-2 21-10790 2 Regional and Business Jets and APUs Under New Environmental Scrutiny Regional and Business Aviation aircraft operate from airports in >3,500 U.S. communities Small engine environmental impact is the same as large engines Commercial Transports Business Aviation 0 3 6 9 12 15 03691215 Engine Pressure Ratio NOx Emission Index (GM/KGM Fuel) Equivalent ‘96 ICAO Ground operation of APUs creates NOx emission above the equivalent ‘96 ICAO levels Regional & General Aviation Account for 40% of All Takeoffs & Landings B 0 5 10 15 20 25 30 35 40 199119931995199719992001200320052007 HistoricalForecast Calendar Year Takeoffs & Landings, Millions Commercial Transport Military Regional General Aviation Source: FAA Air Traffic Activity

4. V9485-3 21-10790 3 Regional Jet Fleet Market Growth Turbofans replacing turboprops for customer comfort and safety –Higher Pressure Ratios and Thrust (  emissions) –Thrust and Fleet size (  Noise) Turbofan market growth drives increased noise and emissions U.S. Regional Fleet Forecast Aircraft (Units) 2,000 1,800 1,600 1,400 1,200 1,000 800 600 400 200 0 19871992199720022007 Year HistoricForecast Turbofans B Turboprops

5. V9485-4 21-10790 4 Fractional Ownership Game Changes Business Jet Market Smaller companies flying to smaller airports - more takeoffs and landings U.S.-based business aviation accounts for 75% of the overall market Fractional ownership dramatically increases takeoffs and landings Pilatus IAI Gulfstream (USA) Learjet (USA) Dassault 1998 Sales of New Turbine-Powered Aircraft to Business Aircraft Operators by Manufacturer Boeing (USA) Socata/ Aerospatiale Raytheon (USA) Canadair Cessna (USA) C

6. V9485-5 21-10790 5 Auxiliary Power Unit Dependence Increasing Future aircraft standard for twin engine use requires APUs –Extended Twin Engine Operations (ETOPS) –APU use in engine-out situation –Increased operating altitudes required Lack of facilities at small airports require APU usage for Regional and Business Jets Increased use of APUs is an added source for noise and emissions C

7. V9485-6 21-10790 6 Local Airports Driving Environmental Standards for Turbofans and APUs * Stockholm * * Denmark Zurich Federal regulation will evolve from local restrictions Proprietary 1996 ICAO Class V Class VI Aircraft landing fees based on emissions and noise APU operating time, restrictions underway A

8. V9485-7 21-10790 7 Regional Jets, Business Aviation, and APUs Face Unique Design Challenges Size Effects: –Higher % cooling air –Tolerance stacks –No space for multi-dome concepts APUs - large ignition and blowout range –Cold soak engine to sub-zero temperatures –High-altitude start Relative size comparison of Boeing 777 Combustors APU 14 Fuel Nozzle Tips Main Engine 60 Fuel Nozzle Tips Not the actual combustor Physical size forces novel solutions for emissions and noise B

9. V9485-8 21-10790 8 Technology Directions Improved operability and low emissions needed for compact combustor Fuel Staging Technology Individual Atomizer Control and Spray Advanced Flame Stabilization Single-dome, staged Altitude Flight Speed Ignition Envelope ETOPS Single-dome, not staged A

10. V9485-9 21-10790 9 Smaller Aircraft Face Stricter Noise Rules Noise abatement technology is critical to smaller engines 70 80 90 100 ApproachTakeoffSideline EPNL Stage 3 Transport (Airbus 319) Business Jet (Falcon 2000)

11. V9485-10 21-10790 10 100 110 120 130 140 1965197019751980198519901995200020052010 APU Year of Introduction Into Service Total Noise (Inlet and Exhaust) PWL re: 10^(-12) Watts [dB] 10dB APU Core Technology Commercial APU Data Trend Future Goals, Anticipated Requirements European Markets Push For Low APU Noise Current APU Operations being restricted due to noise Aircraft Manufacturers demand 5-10 dB noise reduction APU noise reduction research must intensify to support market needs Airport workers and community residents REQUIRE lower ramp noise

12. V9485-11 21-10790 11 Technology Directions A system approach is needed to globally reduce engine noise Advanced Fan Designs Advanced Nozzle Designs Advanced Suppression Measurement Technology Variable Engine Cycle A