What happened
During the initial takeoff roll, as the aircraft accelerated to 20 mph, the pilot's seat assembly collapsed. This mechanical failure caused the pilot to be displaced aft from his station. Due to this displacement, the pilot was unable to reach the flight or throttle controls and could not reduce the engine power.
The uncontrolled aircraft subsequently veered left and entered a ground loop. After the pilot successfully exited the aircraft, the plane burst into flames. The resulting fire destroyed the entire aircraft and the seat assembly. The pilot was not injured.
The investigation
The investigation focused on the failure of the seat assembly. In his initial report, the pilot stated that the seat failed to remain locked. However, in a subsequent telephone conversation, the pilot noted that it appeared the right rear portion of the seat had collapsed, though he did not recall the entire seat assembly moving.