Cessna 172 N3973L accident near Houston, Texas

Probable cause

The pilot's failure to apply carburetor heat while operating in an area conducive to carburetor icing, which resulted in a total loss of engine power on approach and subsequent forced landing into a creek.

NTSB analysis

The commercial pilot reported that, as the airplane approached the runway after a short local, personal flight, the engine lost power. The pilot checked the fuel valve, mixture, and engaged the starter, but engine power was not restored. The pilot stated that the airplane was "headed directly toward a concrete revetment on the south bank" of a creek, so he banked the airplane left, and it subsequently impacted in the creek.

During recovery of the airplane, the fuel selector was found in the "both" position, and the throttle, mixture, and carburetor heat controls were found in the "forward" (off) position. Examination of the wreckage revealed no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation.

The atmospheric conditions at the time that the engine lost power were conducive to serious icing at any power, moderate icing at cruise power, and serious icing at descent power. Given the evidence, it is likely that carburetor ice accumulated during the flight and that the pilot did apply carburetor heat, which resulted in a loss of all engine power.

Text from the NTSB. Open the NTSB docket for CEN19LA015 for the full record.