Incident Overview
Approximately four hours into the flight, while on a long descent to the destination airport, the pilot noticed a reduction in engine power. The power reduction continued over a period of eight minutes and eventually resulted in a complete loss of engine power.
Pilot Actions and Emergency Landing
Following the loss of power, the pilot attempted to restore full engine power, including the application of carburetor heat, but these efforts were unsuccessful. The pilot selected a nearby paved road for an emergency landing. During the landing rollout, the right wing collided with a road sign, causing the airplane to swerve into an adjacent ditch and nose over.
Post-Accident Examination
Examination of the airplane did not disclose any mechanical problems. Fuel was recovered from the fuel system. During a functional test, the engine operated normally through all power ranges.
Weather Conditions
A review of current weather information revealed that weather conditions were favorable for the formation of carburetor icing.