Piper PA 25-235 N4652Y accident near Harvey, North Dakota

Probable cause

The partial loss of engine power due to a failed magneto and two cylinders with low compression. Contributing to the accident was the pilot/owner’s decision to operate the airplane with an ongoing engine issue.

NTSB analysis

The commercial pilot/owner noted that, during previous flights in the agricultural application airplane, he had heard a "wheezing" sound coming from the engine. During a conversation with a mechanic about the issue, the mechanic stated that the abnormal engine sound could have been due to an issue with an engine valve. Although an annual inspection was completed after the pilot first noted the issue, no maintenance was conducted to resolve the issue. Despite this, the pilot chose to continue flying the airplane.

The pilot reported that, while en route to the destination field during the accident flight, he heard a noise come from the engine, followed by a partial loss of power as the engine shuddered. He subsequently made a forced landing to a wheat field.

A postaccident engine examination revealed that the right magneto was not functioning, and two of the cylinders did not pass compression checks. The loss of engine power is consistent with a failed magneto and two cylinders with low compression.

Text from the NTSB. Open the NTSB docket for CEN15LA383 for the full record.