NTSB Identification: NYC96LA188.
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Nonscheduled 14 CFR
Accident occurred Saturday, September 28, 1996 in CHILLICOTHE, OH
Probable Cause Approval Date: 10/31/1997
Aircraft: Mitsubishi MU-2B-30, registration: N618BB
Injuries: 4 Uninjured.
NTSB investigators may not have traveled in support of this investigation and used data provided by various sources to prepare this aircraft accident report.
The Pilot (plt) said that after climbing about 500' after takeoff, at 120 kts with the gear retracted, the left engine lost power. He feathered the propeller, lowered the nose to the horizon, & began a shallow left turn back to the airport. He left the flaps at 20 deg & noted a descent of 200' to 300' per min in the turn. After clearing trees, the plt extended the landing gear, banked the aircraft (acft) to the right to align it with the runway (rwy), & lowered flaps to 40 deg. After touchdown, he applied single engine reversing. Acft went off right side of rwy & into a ditch, collapsing the right main & nose gear. Exam of the engine revealed the torque sensor housing had failed, resulting in loss of drive to the fuel pump. Metallurgical exam of the housing arm of the torque sensor revealed it had failed from fatigue. On 9/14/79, a service bulletin (SB) was issued for replacement of the torque sensor housing with an improved housing. The manufacturer overhauled the engine on 12/1179, but SB was not complied with. SB indicated a history of resonant vibration causing cracks in the housing arm of original torque sensor & gear assemblies, & that the housing should be replaced, no later than during next part exposure. Investigation revealed pilot did not comply with engine failure procedures & airspeeds. Flight manual cautioned not to use 40 deg of flaps during single engine landings.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: failure of the pilot to follow the published emergency procedures after loss of power in the left engine. Factors relating to the accident were: fatigue failure of the left torque sensor and gear assembly, which resulted in the loss of engine power, failure of the manufacturer to comply with the respective service bulletin, and the pilot's improper use of the flaps and reverse (single-engine) thrust. Full narrative available
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