Incident Overview
During a cross-country flight, while the airplane was in cruise flight, the engine suddenly began to run rough. The engine RPM dropped, and the airplane was unable to maintain altitude. In response, the pilot initiated a forced landing to an open field. During the landing roll, the airplane collided with the rough terrain.
Post-Crash Inspection
After the accident, an inspection of the engine was conducted. It was found that the number one exhaust valve head had broken away at the neck. No other mechanical anomalies were noted in the source.
Sequence of Events
The engine roughness and RPM drop occurred without warning during cruise. The pilot executed a forced landing to the nearest suitable open field. The rough terrain during the landing roll resulted in a collision, ending the roll.