Flight History
The pilot of N1291P reported that ice on the windshield blocked forward visibility. The aircraft diverted to Cedar Rapids (CID), which provides radar approach control. Surface temperature was 32°F, but was reported higher at 4,000 feet MSL. The flight climbed to 4,000 feet and began shedding ice, but the pilot then reported getting in worse trouble. Air traffic control at CID vectored the aircraft toward the airport. During the descent, the pilot reported that an engine had quit. The pilot stated the aircraft could not maintain altitude and reported going down. The aircraft entered a spin and crashed in an open farm field.
Weather and Icing Conditions
The pilot obtained a partial weather briefing, which included flight precautions for icing conditions, instrument flight rules, and turbulence. The aircraft was not equipped for flight in icing conditions. No propeller, windshield, or airframe deicing equipment was installed, although a windshield electrical anti-ice system was installed and turned on. The pitot heat control was found in the off position, while the carburetor heat control was in the full on position.
Aircraft Modifications
The aircraft had been modified to permit the use of auto gas. According to FAA Advisory Circular 91-33A, such a modification increases the potential for carburetor icing.