Incident Overview
During a level cruise flight at 12,500 feet, the pilot reported a sudden loss of engine power. In an attempt to restore power, the pilot switched fuel tanks and turned on the boost pump, but the engine did not respond. The pilot then initiated a glide toward the Salida, Colorado, Airport.
Forced Landing
The aircraft touched down short of the runway and struck a fence post during the landing roll. The pilot was able to bring the aircraft to a stop after the impact.
Postaccident Examination
A postaccident examination of the engine revealed the cause of the power loss. The bolt that secured the alternate air valve to its actuating shaft had failed. This failure allowed the alternate air valve to close, thereby blocking the engine's air supply and causing it to starve for air. The other half of the failed bolt was found ingested in the No. 6 cylinder.
Investigation Findings
The investigation determined that the engine power loss was directly caused by the failure of the bolt on the alternate air valve assembly. No other contributing factors were identified.