Incident Overview
During a flight, the engine lost power, prompting the pilot to attempt a forced landing in an open field. During the landing, the aircraft collided with a power pole and subsequently came to rest on top of a pile of railroad ties. The specific aircraft type, registration, operator, and location were not disclosed in the report.
Postcrash Examination
A postcrash examination of the engine revealed significant damage to the number 1 cylinder exhaust valve assembly. The valve guide and valve stem were eroded. Further inspection showed that the valve guide had partially separated due to progressive cracking, and the valve head had separated from the stem. The reason for the erosion of the valve stem and guide could not be determined from the examination.
Engine Maintenance History
The engine had accumulated 2,225 flight hours since its last major overhaul. During that overhaul, the valves and valve guides were replaced with new parts. The manufacturer's recommended time between overhauls for this engine model is 2,400 flight hours, meaning the engine was still within the recommended service interval at the time of the incident.