Cessna 177 N9058F accident near Fort Wayne, Indiana

Probable cause

The failure of the oil cooler due to a defect in the brazed joint, which resulted in a loss of engine power due to oil starvation.

NTSB analysis

The pilot reported that he had departed on a local flight and leveled the airplane at 2,600 ft mean sea level when he observed a drop in engine rpm and heard a "thumping" sound from the engine. The pilot reversed course to return to the airport; the noise increased, he smelled burning oil, and the engine subsequently quit. The pilot conducted a forced landing to a field, during which the nose landing gear collapsed and the wings sustained substantial damage.

An examination of the airplane revealed no oil on the engine dipstick; however, oil was coming out of the oil cooler, and oil was visible on the right side of the cowling. Maintenance records indicated that the engine, including the oil cooler, was new and had been installed about 8 hours before the accident flight. An examination of the oil cooler revealed that the leak came from between the plates forming the oil circuit; it was likely due to a defect in the brazed joint between the plates. The engine lost power due to oil starvation.

Text from the NTSB. Open the NTSB docket for CEN18LA174 for the full record.