Cessna 172S N612SP accident near Big Bear, California

Probable cause

A partial loss of engine power for reasons that could not be determined because postaccident examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation.

NTSB analysis

The commercial pilot was conducting a personal cross-country flight during daytime visual meteorological conditions over mountainous terrain. He reported that, about 30 minutes into the flight, the engine began to lose power. The airplane descended into a box canyon, and the pilot then attempted to maneuver the airplane to initiate a 180-degree turn out of the canyon toward lower terrain. The airplane continued to descend, and the stall warning horn sounded, so the pilot decided to land in trees.

First responders reported that the wing fuel tanks were breached and that fuel had drained out through holes in the wings. A postaccident examination of the airframe and engine revealed no evidence of any preexisting mechanical malfunctions or failures that would have precluded normal operation. The reason for the partial loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for WPR15LA014 for the full record.