Cessna 175A N7059E accident near Rio Linda, California

Probable cause

The partial loss of engine power due to detonation. Contributing to the accident was trees in the landing area.

NTSB analysis

The pilot and owner of the airplane reported that during cruise flight, the engine partially lost power followed by several backfires. The pilot was unable to maintain altitude at the reduced power setting, and initiated a forced landing to a gravel road. During the landing roll on the gravel road, the left and right wings struck trees located on the edge of the road, resulting in structural damage to both wings. The owner of the airplane reported that during disassembly of the engine, the number four cylinder exhibited "signs of detonation." The number four piston head was "eaten away" to the top ring land. No additional anomalies were noted with the engine. The underlying reason for the detonation was undetermined.

Text from the NTSB. Open the NTSB docket for LAX08LA128 for the full record.