Piper PA32 N3957X accident near Wrangell, Alaska

Probable cause

The total loss of engine power due to oil starvation after an interruption of oil circulation for reasons that could not be determined based on the available evidence.

NTSB analysis

The pilot reported that, while in level cruise flight, the engine rpm began to increase. Shortly after reducing the manifold pressure in an effort to correct for the high RPM, he noticed the engine oil pressure drop with oil visible on the airplane’s windscreen, followed by a total loss of engine power. He performed an emergency landing near the high tide line in an area of seagrass. During the emergency landing the airplane sustained substantial damage to the fuselage and left wing.

Examination of the engine revealed a large fracture hole at the Nos. 4- and 5-cylinder pads. The Nos. 4 and 5 connecting rods were fragmented, and pieces of the connecting rods and a large amount of metal debris was located within the engine. A large amount of metal contamination was present in the oil suction screen. The Nos. 4 and 5 connecting rods and rod bearing journals exhibited extensive mechanical damage and signatures consistent with exposure to extreme high heat.

The damage to the internal engine components, the large amount of metal contamination in the oil screen, and the significant metal debris inside the engine were all consistent with a catastrophic engine failure due to a lack of lubrication. The source of the interruption of oil circulation to the engine could not be determined after engine disassembly.

Text from the NTSB. Open the NTSB docket for ANC18LA069 for the full record.