Flight Details
Airspur flight 500, operating as a domestic cargo flight, departed Kalispell, Montana, at 1903 mountain daylight time on an instrument flight rules (IFR) flight plan to Great Falls, Montana.
Sequence of Events
At 1922, the pilot notified Salt Lake Air Route Traffic Control Center (ARTCC) of an intention to return to Kalispell due to a rough running engine. Shortly thereafter, the pilot reported a complete engine failure. The pilot executed an emergency forced landing on a mountain ridge at an elevation of approximately 5,500 feet in instrument flight rules (IFR) conditions. The accident site was located about 18 nautical miles east of Kalispell. The pilot escaped with minor injuries.
Investigation Findings
Engine disassembly revealed that the #4 connecting rod had failed catastrophically. The official probable cause was determined to be the failure of the #4 connecting rod. Factors related to the accident were the adverse weather conditions and lack of suitable terrain for a forced landing.