Incident Details
According to the pilot, the flight was proceeding above hilly terrain southeast of the airport when a loud bang was heard, immediately followed by violent vibration from the engine. The pilot reported that the engine did not suffer a total loss of power but performed poorly due to the severe vibration. Reducing the throttle caused the vibration to subside, but when the pilot attempted to add more throttle, the violent vibration returned. Deeming the flight unsafe, the pilot began searching for a suitable landing area and subsequently executed a forced landing in a pasture.
Landing and Damage
The forced landing was uneventful until one of the main landing gear contacted a "deviation" in the ground, causing the airplane to nosed over. The aircraft came to rest inverted. The extent of damage beyond the nose-over was not specified.
Examination Findings
In a phone interview with the investigator-in-charge, a mechanic who recovered the wreckage reported examining the engine. The mechanic discovered that the number 3 cylinder exhaust valve was stuck. The corresponding push rod tube was bent, and the number 3 connecting rod was intact.