Aeronca O-58C N47503 accident near San Luis Obispo, California

Probable cause

The pilot’s delay in using carburetor heat, which resulted in a loss of engine power due to an encounter with carburetor icing conditions.

NTSB analysis

The airplane was in cruise flight at 3,500 feet mean sea level when the engine lost power. The pilot restarted the engine, and it ran for about 20 seconds before again losing power. He applied carburetor heat, but the cycle of losing power and restarting for a few seconds occurred several times. The pilot attempted to land in a field, but collided with trees at the edge of the field. There was no evidence of preimpact mechanical malfunction found during a postaccident examination of the airframe and engine. The meteorological conditions at the time of the accident were conductive to serious carburetor icing at cruise power. Although the pilot applied carburetor heat after the initial power loss, the engine likely did not run long enough to melt the ice and restore power.

Text from the NTSB. Open the NTSB docket for WPR11FA120 for the full record.