Cessna 150H N23295 accident near College Place, Washington

Probable cause

The pilot’s delayed use of carburetor heat while operating the airplane in atmospheric conditions conducive to carburetor icing, which resulted in a total loss of engine power due to carburetor icing during final approach.

NTSB analysis

The pilot reported that, while on final approach, the engine rpm dropped and that the engine then lost power. He advanced the throttle, pushed in the carburetor heat control, and attempted to restart the engine, but engine power was not restored. He subsequently performed a forced landing to a road. During the landing, the airplane's right wing tip struck a sign and a mailbox, which resulted in substantial damage to the right wing spar. After the forced landing, the pilot was able to restart the engine, and he then taxied the airplane back to the airport. The pilot reported no known mechanical failures or malfunctions with the airplane, and a postaccident examination of the carburetor found no preaccident mechanical malfunctions or failures that would have precluded normal operation. Atmospheric conditions at the time of the accident were conducive to the formation of serious carburetor icing at glide power. It is likely that the pilot's delayed use of carburetor heat resulted in the total loss of engine power due to the accumulation of carburetor icing.

Text from the NTSB. Open the NTSB docket for WPR11LA210 for the full record.