Yakovlev YAK 52 N52CY accident near Wrightsville, Georgia

Probable cause

A total loss of engine power due to the failure of the No. 5 cylinder exhaust valve, which resulted in an forced off-airport landing.

NTSB analysis

During the cruise portion of a repositioning cross-country flight, the engine experienced a catastrophic failure and a total loss of power. The flight instructor maneuvered the airplane for a forced landing in an open field, and about 500 ft above ground level, he lowered the landing gear, which significantly increased the airplane's rate of descent and reduced its airspeed. The airplane touched down in the field and nosed over, resulting in substantial damage to the fuselage, empennage, and wings. Internal examination of the engine revealed that the No. 5 cylinder's exhaust valve seat had dropped into the cylinder and likely fractured into several pieces, as metal fragments were observed in the cylinder. The failure of the exhaust valve led to the total loss of engine power.

Text from the NTSB. Open the NTSB docket for ERA20LA045 for the full record.