Incident Overview
During a routine cruise flight, the pilot heard a distinct 'pop' emanating from the engine, followed by a noticeable vibration. The engine subsequently lost partial power, prompting the pilot to attempt troubleshooting to identify the source of the problem. Unable to resolve the issue, the pilot maneuvered the airplane toward a nearby airstrip.
Landing Attempts
The pilot made two attempts to land on the 2,950-foot-long airstrip. On both occasions, the airplane's altitude was too high to execute a proper landing. Recognizing the challenge, the pilot decided to divert to an open field, carefully maneuvering the aircraft to avoid obstructions.
Accident Sequence
During the landing in the open field, the landing gear was sheared off from the aircraft. The wings also sustained structural damage as a result of the forced landing.
Post-Crash Inspection
A post-crash examination of the engine revealed that the number three exhaust valve had broken at the neck. The head of the valve was found lodged inside the exhaust manifold.
Findings
The investigation determined that the partial power loss was caused by the failure of the number three exhaust valve. No other contributing factors were identified.