Accident Overview
The airline transport certificated pilot was landing a tailwheel equipped airplane on an airstrip near a remote cabin as part of an on-demand air taxi flight. The airstrip had been used previously by the pilot. 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, causing the airplane to nose over. Damage was sustained to the right wing, propeller, vertical stabilizer, and rudder.
Examination Findings
The lower end of the gear strut had four holes drilled through the metal for installation of the wheel axle and brake assembly. 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 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 corrosion.
Inspection Practices
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.