What happened
While the aircraft was operating in the cruise phase of flight, the engine began to misfire and subsequently lost power on one cylinder, continuing to operate on only three cylinders. Due to the presence of rough terrain between the pilot's current position and a known suitable airport, the pilot elected to execute a precautionary landing at a small airstrip covered with snow.
During the landing roll, the aircraft encountered approximately four feet of snow. The nose gear collapsed under these conditions, causing the aircraft to nosed over.
The investigation
A post-accident inspection of the engine revealed that the exhaust valve for cylinder number three had failed. This mechanical failure was identified as the primary reason for the engine's reduced performance and subsequent misfiring during cruise flight.
Findings
The aircraft sustained significant damage due to the nosed-over landing in deep snow. The pilot made a prudent decision to land at an unprepared strip rather than attempt to reach a distant airport over difficult terrain, though the surface conditions contributed to the final impact dynamics.