Mooney M20V N576CM accident near Phoenix, Arizona

Probable cause

The partial loss of engine power during cruise flight for reasons that could not be determined with the available evidence.

NTSB analysis

During a personal flight, the pilot notified air traffic control that he had a rough-running engine, and the pilot declared an emergency. The controller advised the pilot of two diversion airports; the first was located near the airplane’s position at the time, and the second was located about 12 miles south of the airplane’s position. The pilot elected to divert to the second airport. The pilot advised the controller a few minutes later that the airplane would be unable to reach that airport, and the radar track showed a right turn toward the other airport, which was about 8 miles east from the airplane’s position. No further communication from the pilot was received. A witness located near the accident site reported that the airplane maneuvered to avoid power lines and struck light poles before it impacted the ground. A postimpact fire ensued.

Postaccident examination of the wreckage revealed that engine control continuity was established from all the engine controls to their respective engine components. The engine exhibited extensive thermal damage. To prepare the engine for test runs performed by the manufacturer, several components and accessories were replaced due to thermal damage. The engine was successfully run at various power settings. No mechanical anomalies were noted with the recovered parts of the engine and airframe that would have precluded normal operation. As a result, the reason for the partial loss of engine power was not determined.

Text from the NTSB. Open the NTSB docket for WPR19LA167 for the full record.