Cessna 180A N9699B accident near Polson, Montana

Probable cause

A total loss of engine power during approach for reasons that could not be determined because postaccident examination revealed no anomalies that would have precluded normal operation.

NTSB analysis

The pilot reported that, while the airplane was on approach and about 3 miles from the airport, the engine lost all power. The pilot continued the descent while maintaining the best glide airspeed and performing the engine restart procedures, which included applying carburetor heat. Despite the pilot's efforts, the engine would not restart, and he initiated a forced landing to a small field. During the landing, the landing gear collapsed, and the right wing impacted terrain. Postaccident examination of the engine and airframe revealed no mechanical anomalies that would have precluded normal operation.

About the time of the accident, a weather reporting facility located 37 nautical miles north of the accident site recorded a temperature and dew point that were conducive to the accumulation of carburetor icing at glide power. However, it could not be determined whether carburetor ice caused the power loss.

Text from the NTSB. Open the NTSB docket for WPR15LA191 for the full record.