Incident Overview
During a descent following a mountain ridge crossing, the pilot reported that the engine began running rough and subsequently quit completely. The failure occurred over unsuitable terrain, but the pilot located a narrow gravel road and executed a forced landing.
Landing and Loss of Control
The landing was conducted with a 13 to 16 knot tail wind. During the landing roll, the pilot lost control, the airplane veered left, and nosed over.
Engine Examination
Post-incident examination found no evidence of mechanical failure or malfunction on the engine.
Pilot's Report
In an initial interview, the pilot stated that he suspected carburetor ice as the cause of the engine failure.
Icing Probability Assessment
A review of icing probability charts indicated that, for the atmospheric conditions at the time, there was a threat of visible carburetor ice at both rated engine power and glide power settings. The temperature and dew point were 77 degrees and 64 degrees, respectively.