Cessna 172B N7832X accident near Winchester, Virginia

Probable cause

The pilot’s delayed use of carburetor heat, which resulted in carburetor icing and a subsequent total loss of engine power.

NTSB analysis

After a delay while he waited for several other airplanes to land and take off, the pilot departed and was climbing to cruise altitude when the engine began to lose power. Shortly thereafter, the engine lost power completely. The pilot then attempted to restore engine power and did not activate the carburetor heat until after the power loss. He was able to briefly restart the engine, but it ultimately lost power again after a brief period of rough running. During the subsequent off-airport landing, the nose landing gear separated from the airplane and it nosed over, substantially damaging both wings and the vertical stabilizer. The engine was successfully test run following the accident, and no mechanical deficiencies were found that would have precluded normal operation. The temperature and dewpoint at the departure airport around the time of the accident were conducive to the formation of carburetor icing. It is likely that, during the delay while the pilot was waiting to depart, the carburetor began to accumulate ice, that the ice accumulation continued during the subsequent takeoff and climb, and that the engine slowly lost power throughout. Because the pilot did not activate the carburetor heat until after the engine had lost power completely, the carburetor heat was ineffective at restoring engine power.

Text from the NTSB. Open the NTSB docket for ERA21LA137 for the full record.