MD82, vicinity Lambert St Louis MO USA, 2007

MD82, vicinity Lambert St Louis MO USA, 2007


On September 28, 2007 the left engine of a McDonnell Douglas MD82 caught fire during the departure climb from Lambert St. Louis and an air turn back was initiated. When the landing gear failed to fully extend, a go around was made to allow time for an emergency gear extension to be accomplished after which a successful landing and emergency evacuation from the fire-damaged aircraft followed. The Investigation concluded that the engine fire was directly consequential on an unapproved maintenance practice and that the fire was prolonged by flight crew interruption of an emergency checklist to perform non-essential tasks.

Event Details
Event Type
Flight Conditions
Flight Details
Type of Flight
Public Transport (Passenger)
Take-off Commenced
Flight Airborne
Flight Completed
Phase of Flight
Location - Airport
Fire-Power Plant origin
Distraction, Flight / Cabin Crew Co-operation, Inappropriate crew response (technical fault), Manual Handling, Procedural non compliance
Emergency Evacuation, “Emergency” declaration, RFFS Procedures
Engine Fuel and Control
Maintenance Error (valid guidance available), Component Fault in service
Damage or injury
Aircraft damage
Non-aircraft damage
Non-occupant Casualties
Off Airport Landing
Causal Factor Group(s)
Aircraft Operation
Aircraft Technical
Safety Recommendation(s)
Aircraft Operation
Aircraft Airworthiness
Investigation Type


On September 28, 2007 a McDonnell Douglas MD82 being operated by American Airlines on a scheduled passenger flight in day Visual Meteorological Conditions (VMC) experienced an in flight left engine fire during departure climb from Lambert St. Louis International Airport (STL), St. Louis, Missouri. A return to land was made but when the nose landing gear failed to extend, a go around was made to allow emergency gear extension to be accomplished prior to making a second approach which culminated in a successful landing. All occupants evacuated the aircraft on the runway without injury but the aircraft sustained substantial damage due to the fire.


An Investigation was carried out by the National Transportation Safety Board (USA) (NTSB) which examined both the cause of and crew response to the engine fire. The Findings of the Investigation included that:

  • American Airlines’ maintenance personnel’s troubleshooting efforts for the engine no-start condition incorrectly focused on the air turbine starter valve (ATSV) and engine start system wiring because of the intermittent nature of the condition, the history of ATSV electrical circuit problems, and the lack of a history of ATSV-air filter failures for which no troubleshooting guidance existed.
  • American Airlines’ maintenance personnel repeatedly used an unapproved maintenance procedure, which included using a prying device to push the air turbine starter valve manual override button, to manually start the accident engine, which resulted in bending the internal pin in the override button.
  • The internal pin in the left engine air turbine starter valve (ATSV) override button was bent, which resulted in the uncommanded opening of the ATSV during high-power engine conditions at the beginning of the takeoff roll and caused the air turbine starter to freewheel until it sustained a catastrophic internal failure.
  • The open air turbine starter valve and resulting failed air turbine starter allowed a hotter than typical airstream and/or incandescent particles to flow into the engine nacelle area and likely provided the ignition source for the in-flight fire.
  • A combustible fluid, such as oil, hydraulic fluid, or fuel, was available in the engine; however, fire damage precluded the determination of the specific source of the combustible fluid.
  • The pilots failed to properly allocate tasks, including checklist execution and radio communications, and they did not effectively manage their workload; this adversely affected their ability to conduct essential cockpit tasks, such as completing appropriate checklists.
  • No preexisting indicators in the pilots’ training or performance histories were found that could explain their poor performance during the accident flight.
  • American Airlines’ maintenance personnel were using maintenance procedures that were not in accordance with written manuals and guidelines, and it’s Continuing Analysis and Surveillance System program did not adequately detect and correct these performance deficiencies before they contributed to an accident.

Probable Cause

The National Transportation Safety Board determines that the probable cause of this accident was American Airlines’ maintenance personnel’s use of an inappropriate manual engine-start procedure, which led to the uncommanded opening of the left engine air turbine starter valve, and a subsequent left engine fire, which was prolonged by the flight crew’s interruption of an emergency checklist to perform nonessential tasks. Contributing to the accident were deficiencies in American Airlines’ Continuing Analysis and Surveillance System program.

Safety Recommendations

As a result of the investigation of this accident, the National Transportation Safety Board makes the following recommendations.

To the Federal Aviation Administration:

  • Evaluate the history of uncommanded air turbine starter valve (ATSV) open events in the MD-80 fleet and the effectiveness of coupling the ATSV-Open light to the Master Caution system to determine whether all MD-80 airplanes need to be modified to couple the ATSV-Open light to the Master Caution system. Once the evaluation is completed, require any necessary modifications. (A-09-21)
  • Require principal operations inspectors to review their operators’ pilot guidance and training on task allocation and workload management during emergency situations to verify that they state that, to the extent practicable, the pilot running the checklists should not engage in nonessential operational tasks, such as radio communications. (A-09-22)
  • Require MD-80 series airplane operators to incorporate information about the relationship between the pneumatic crossfeed valve and the engine fire handle into their training programs and written guidance. (A-09-23)
  • Establish best practices for conducting both single and multiple emergency and abnormal situations training. (A-09-24)
  • Once the best practices for both single and multiple emergency and abnormal situations training asked for in Safety Recommendation A-09-24 have been established, require that these best practices be incorporated into all operators’ approved training programs. (A-09-25)
  • Require that operators provide pilots with guidance requiring that pilots and flight attendants actively monitor exit availability and configure the airplane and cabin for an evacuation when the airplane is stopped away from the gate after a significant event to help expedite an emergency evacuation if one becomes necessary. (A-09-26)
  • Revise Advisory Circular 120-48, “Communication and Coordination Between Flight Crewmembers and Flight Attendants,” to update guidance and training provided to flight and cabin crews regarding communications during emergency and unusual situations to reflect current industry knowledge based on research and lessons learned from relevant accidents and incidents over the last 20 years. (A-09-27)
  • Require Boeing to establish an appropriate replacement interval for air turbine starter valve-air filters installed on all MD-80 series aircraft. (A-09-28)

To American Airlines:

  • Evaluate your Continuing Analysis and Surveillance System program to determine why it failed to (1) identify deficiencies in its maintenance program associated with the MD-80 engine no-start failure and (2) discover the lack of compliance with company procedures. Then, make necessary modifications to the program to correct these shortcomings. (A-09-29)

The Final Report of the Investigation was adopted on 7 April 2009

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