Background
The aircraft was on a test flight following the completion of a top-overhaul. Mechanics reported that prior to the flight, the engine had been properly rigged and operated normally during the run-up.
Accident Sequence
During the initial climb after takeoff, witnesses observed that the engine lost power. The pilot then initiated a steep turn, estimated at 70 to 75 degrees of bank, back toward the airport reference point. While turning, the nose dropped and the aircraft impacted the ground in a left-wing-low, nose-down attitude. The impact and subsequent ground fire extensively damaged the aircraft.
Post-Accident Investigation
A teardown examination of the engine revealed internal mechanical continuity, evidence of oil pump operation, and normal lubrication. The dual magneto exhibited extensive fire damage. The fuel pump was charred, and investigators were unable to rotate its driveshaft. The teardown did not confirm the reason for the power loss.