Cessna 177RG N2016Q accident near Marietta, Ohio

Probable cause

The total loss of engine power due to the fatigue failure of the No. 2 cylinder attachment fasteners as a result of improper engine overhaul practices.

NTSB analysis

While on a cross-country flight, the airplane experienced a total loss of engine power when the No. 2 cylinder, piston, and connecting rod separated from the engine. The pilot reported that the airplane had insufficient altitude to reach the nearest airport, and a forced landing was made into an agricultural field. A postaccident metallurgical examination revealed multiple fatigue fractures of the attachment fasteners used to secure the No. 2 cylinder to the crankcase. The observed fatigue was the result of an insufficient fastener preload. The engine had accumulated 519 hours since the last major overhaul. Review of the engine logbook established that there were no maintenance actions completed to the No. 2 cylinder, piston, or connecting rod since the last overhaul. Therefore, the insufficient fastener preload was likely due to improper overhaul practices during the last engine overhaul.

Text from the NTSB. Open the NTSB docket for CEN10LA306 for the full record.