Cessna 182P N6525M accident near Brevard, North Carolina

Probable cause

The cylinder manufacturer's misalignment of the exhaust valve guides in the No. 2 cylinder during manufacture, which resulted in the exhaust valve sticking and the pushrod breaking and the subsequent total loss of engine power.

NTSB analysis

The pilot reported that the airplane was in cruise flight at 9,500 feet mean sea level when he heard a loud noise and then popping sounds coming from the engine. He then smelled smoke and saw oil trailing from the engine compartment down the outside of the airplane. As the pilot maneuvered for a forced landing at a nearby airport, the engine produced intermittent power and then lost power completely. The pilot maneuvered the airplane for landing, but the runway was obstructed by cars and farm equipment, so he landed the airplane long. After touchdown, the pilot maneuvered the airplane into a small knoll between the airport and an elementary school where it struck a berm and came to rest.

Postaccident examination of the engine revealed that the No. 2 cylinder exhaust valve was stuck and that its associated pushrod was bent, worn through, and fractured as a result of compression loading near its midpoint due to the stuck exhaust valve. Examination of the cylinder and its associated parts revealed that the exhaust valve guides were misaligned during manufacture, which subsequently resulted in the valve guide wearing unevenly, the valve sticking, the pushrod breaking, and the subsequent total loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA13LA262 for the full record.