Accident Summary
A pilot concluded a series of aerobatic maneuvers and was descending toward the airport when the engine suddenly quit. Attempts to restart the engine resulted in momentary firing but it did not sustain operation. The propeller, initially windmilling after power loss, eventually stopped, and the pilot could not rotate the engine using the starter.
Forced Landing and Occurrence
The pilot executed a power-off forced landing in a nearby open field. The flare and touchdown were uneventful, but during the landing roll, the aircraft encountered two eight-inch-high berms and nosed over onto its back.
Post-Accident Inspection
A post-accident inspection of the aircraft and engine determined that the fitting attaching the oil pressure gauge line to the engine had come loose, allowing oil to escape from the area around the fitting. Further inspection revealed that the loss of oil led to extensive thermal and mechanical damage to the primary lower-end engine components, and that the engine seized as a result of that damage.
Maintenance Review
A review of the aircraft records did not reveal any recent maintenance in which the oil pressure measuring system would have been expected to have been manipulated.