1. Office of Aviation Safety American Airlines Flight 1400 St. Louis, Missouri Harald Reichel Powerplants

2. Left Nacelle Findings Significant fire occurred Fire confined to nacelle cavity No engine core problems Combustible fluid source could not be determined The ignition source of the fire was the start system failure

3. Engine Start System Overview ATSV air filter Pneumatic supply line Air turbine start valve (ATSV) Air turbine starter (ATS)

4. Air Turbine Starter Findings Does not normally operate during flight Uncommanded operation during takeoff and climb Failed, acting as ignition source Event air turbine starter

5. ATSV Air Filter Findings New ATSV air filter AA1400 ATSV air filter Loose end cap Air flow Filter element Fitting End cap Filter element missing

6. Air Turbine Start Valve- Normal Operation Armature Pin Cut-away Illustrating butterfly valve To Air Turbine Starter Manual O/R Button To Air Turbine Starter Ball Valve Solenoid Piston

7. AA1400 Event No-Start History Solenoid operates Manual O/R button No air flow Cap blocks air flow No air flow

8. Manual Override Pin and Ball Valve Ball valve Manual override pin bent

9. AA1400 Event Takeoff and Climb Ball valve partially open Pin bent Cap vibrates and allows air flow

10. Summary Disintegrated ATSV-air filter caused intermittent no-starts ATSV manual override pin was found bent Bent pin caused uncommanded ATS activation at takeoff Catastrophic failure of the ATS ignited combustible fluid present in the nacelle