Cirrus Design Corp SR22 N754AP accident near Ogden, Utah

Probable cause

The failure of the No. 4 cylinder exhaust valve head, which resulted in a total loss of engine power due to oil starvation.

NTSB analysis

According to the pilot, the personal cross-country flight was uneventful until he was established on the final approach about 7 miles from the destination airport. At that point, he heard a bang, felt a shudder from the engine, and noticed the airplane’s oil pressure decreasing. Shortly thereafter, the oil pressure indicated zero and the engine shut down. Unable to maintain altitude and too low to deploy the airplane’s parachute, the pilot decided to land on a nearby open field. During the landing sequence, the airplane’s left wing struck two wood posts, incurring substantial damage.

Postaccident examination of the airplane’s engine revealed that the No. 4 cylinder exhaust valve head was separated from the valve stem, which destroyed the No. 4 piston causing oil to dump through the No. 4 cylinder’s exhaust valve area. The resulting oil starvation led to catastrophic engine failure. The reason for the failure of the No. 4 cylinder exhaust valve head could not be determined.

Text from the NTSB. Open the NTSB docket for WPR17LA157 for the full record.