Cessna 177 N2803X accident near Kinston, North Carolina

Probable cause

A partial loss of engine power due to the failure of the No. 1 cylinder exhaust valve for undetermined reasons.

NTSB analysis

During cruise flight the pilot stated that the engine suddenly and without warning began running rough with "...much vibration." He reduced power, which reduced the vibration, and the airplane began losing altitude. He proceeded to the nearest airport but after recognizing that he would be unable to land there, he maneuvered the airplane for a forced landing in a field. Examination of the engine revealed the No. 1 cylinder exhaust valve was broken and the top of the No. 1 cylinder and piston were damaged by the broken valve. Although the engine was last overhauled on August 12, 1989, the cylinders were not replaced at that time. The overhaul entry indicates that the cylinders were only inspected and honed. Further, there was no record that the No. 1 cylinder had been removed and replaced since the engine was overhauled. The engine had accumulated approximately 1,310 hours since overhaul at the time of the accident. The reason for the No. 1 exhaust valve failure was not determined.

Text from the NTSB. Open the NTSB docket for ERA09LA271 for the full record.