NTSB Identification: ANC99LA145.
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Nonscheduled 14 CFR
Accident occurred Tuesday, September 14, 1999 in DELTA JUNCTION, AK
Probable Cause Approval Date: 08/14/2001
Aircraft: Cessna 185F, registration: N85LC
Injuries: 2 Minor,1 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 airline transport certificated pilot was landing a tailwheel equipped airplane on an airstrip near a remote cabin on an on-demand air taxi flight. The airstrip had been used by the pilot in the past. Near the end of the landing roll, the left main landing gear strut fractured above the left wheel axle. The wheel and the lower end of the gear strut separated from the airplane. The upper portion of the gear strut dug into the ground, and the airplane nosed over. The airplane received damage to the right wing, propeller, the vertical stabilizer, and the rudder. The lower end of the gear strut has four holes drilled through the metal to facilitate the installation of the wheel axle and brake assembly. An examination of the landing gear strut found areas of cracking, typical of fatigue, emanating from the inboard edge of the forward, upper bolt hole. One crack developed in an area of two small corrosion pits in the drilled hole. A second crack developed in an area of the fillet between the drilled hole, and the inboard surface of the strut. The cracks from the two areas combined to form one crack laterally across the strut and through the aft, upper bolt hole. The interior surfaces of the forward, upper bolt hole and fillet regions were pitted, consistent with the effects of corrosion. Neither the manufacturer nor the FAA, have established a life limit (hours or cycles) for the main landing gear strut. An annual inspection does not require disassembly of the axle from the gear strut. No inspection procedures, other than a general visual inspection of the landing gear, have been specified by the manufacturer, or the FAA.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: Corrosion and a fatigue failure of the lower end of the landing gear strut. Factors in the accident were the manufacturer's and the FAA's insufficient standards/requirements for life limits and inspection procedures. Full narrative available
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