What happened
The pilot was in cruise flight when the engine began running roughly. This condition was accompanied by very high oil temperature that exceeded the red line. Shortly after these symptoms appeared, the engine stopped functioning entirely.
The pilot had intended to land in a nearby bare field; however, upon noticing workers present in the planned touchdown area, the pilot was forced to execute the landing in a vineyard.
The investigation
An initial on-site examination of the aircraft revealed no discrepancies. Investigators confirmed that fuel was present in the tanks, lines, and carburetor. The engine crankshaft was found to rotate normally.
Following the on-site inspection, the aircraft was moved to a maintenance facility for further study. No particles or debris were detected in the oil strainer or the sump. Testing showed the left magneto timing was 25 degrees and the right magneto timing was 28 degrees. Using the aircraft's systems, the engine was operated for 15 minutes at idle, mid-range, and full power settings. During this ground run, the engine operation remained normal, with oil pressures and temperatures staying within their normal ranges.