Cessna 182A N6077B accident near Safford, Arizona

Probable cause

The total loss of engine power due to the failure of the No. 5 piston, piston pin, or connecting rod assembly for reasons that could not be determined due to the severity of the post fracture damage.

NTSB analysis

The commercial pilot reported that, during cruise flight, he noticed the oil pressure begin to fluctuate and he decided to return to the departure airport. As the airplane neared the airport, the engine experienced a total loss of power, and the pilot initiated an off-airport forced landing. During the landing roll, the airplane struck two dirt berms and the nose landing gear collapsed. Postaccident examination of the engine revealed that the connecting rods, pistons, piston pins, bearings, and bushings in cylinder Nos. 5 and 6 exhibited numerous fractures and severe deformation. Due to the widespread postfracture damage to many of the fracture surfaces, it was not possible to determine which component fractured first. The No. 5 cylinder connecting rod and cap were severely deformed and battered. The piston pin had fractured in multiple places, and the underside of the piston exhibited gouging consistent with impact from adjacent components. In addition, the skirt and pin boss of the piston had fractured in multiple locations. The features on these fracture surfaces were generally consistent with having fractured in and around the pin boss; therefore, the likely initial point of failure in cylinder No. 5 was either the piston pin boss, the piston pin, or the pin side of the connecting rod. Based on the degree of damage observed, the components in the No. 5 cylinder likely began to fracture first, followed by fractures in the No. 6 cylinder.

Text from the NTSB. Open the NTSB docket for WPR17LA038 for the full record.