Cessna 152 N6469P accident near St. Augustine, Florida

Probable cause

The partial loss of engine power due to a fractured exhaust valve, which resulted in a forced landing on unsuitable terrain and a subsequent rollover.

NTSB analysis

The private pilot was conducting a personal, cross-country flight. He reported that, when the airplane was about 12 miles from the departure airport, the engine started running roughly, and the airplane was "violently shaking." He decided to conduct a forced landing in a field, during which the nose landing gear dug into the soft ground, and the airplane flipped over.

Postaccident examination of the engine revealed that the No. 4 cylinder exhaust valve was fractured, and although the head of the exhaust valve was not recovered, the fracture features on the exhaust valve stem were consistent with fatigue. A review of maintenance records revealed that the exhaust valves were installed during an overhaul of the engine about 28 years before the accident. The engine manufacturer recommended that the engine be overhauled every 12 years or 2,400 hours, whichever comes first.

Text from the NTSB. Open the NTSB docket for ERA18LA259 for the full record.