NTSB Identification: FTW98IA130.
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Scheduled 14 CFR operation of SIMMONS AIRLINES (D.B.A. AMERICAN EAGLE )
Incident occurred Sunday, February 22, 1998 in LAWTON, OK
Probable Cause Approval Date: 05/17/2001
Aircraft: Saab-Scania AB (Saab) 340B, registration: N396AE
Injuries: 6 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
During cruise flight, the flight crew reported smelling an odor similar to burning/smoldering electrical equipment and noticed that the landing gear control circuit breaker had popped. The flight crew consulted the company's Quick Reference Handbook (QRH). The QRH addressed hydraulic problems and failed to discuss possible electrical problems related to the operation of the landing gear. The company's maintenance facility was appraised of the situation; however, the maintenance person on duty was not able to assist the flight crew. Three tower fly-bys were made. The flight attendant and tower personnel reported that the landing gear appeared to be down and the gear doors were closed. The flight crew elected to land with the light on the gear handle indicating an 'in-transit' condition and the two main landing gear indicators in the 'unsafe' condition. The left main landing gear on the twin-engine transport category airplane collapsed during the landing roll. Examination revealed that the weight-on-wheels relay, which is located in the avionics bay directly under the captain's station, shorted, and as a result, the landing gear control circuit breaker popped. The electrical short was attributed to the spill of a soda can on the flight deck on a previous flight. The investigation revealed that the cockpit floor was not carpeted or sealed to prevent fluids/moisture from seeping into the electrical compartment beneath the cockpit floor. A review of the emergency extension system for the airplane revealed that the landing gear could have been extended if the fight crew had pulled the emergency extension handle.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: the collapse of the left main landing gear during landing roll as result of a shorted weight-on-wheels relay. Contributing factors were the insufficient information available to the flight crew in the company's quick reference handbook (QRH), and the manufacturer's inadequate protection of the weight-on-wheels relay from moisture. Full narrative available
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