Incident
While cruising under instrument flight rules (IFR), the aircraft experienced a loss of power. The pilot executed emergency procedures for the power loss but lost control of the aircraft when reaching down to switch the fuel tank selector. The aircraft entered a nose-down unusual attitude, descending at a rate of approximately 2,500 feet per minute.
During the recovery effort, the aircraft broke out of cloud cover at an altitude of 1,200 feet above ground level (AGL). The pilot then attempted to land on a curving road. During the approach, the pilot had to maneuver to avoid power lines. The subsequent landing was hard.
Investigation
Post-incident investigation found that a loose carburetor heat housing clamp restricted the travel of the carburetor heat control. Additionally, the investigation revealed that the aircraft was being operated with automotive fuel or a mixture of automotive and aviation fuel.