ERA20LA047 · Cessna 172 L

The pilot was conducting a flight at night when, about 20 minutes after departure, there was a total loss of engine power. He declared an emergency with air traffic control and was given radar vectors by the controller to a nearby airport, which was directly ahead of the airplane and 17 miles away. After the pilot established best glide speed and performed the emergency checklist, which included activating carburetor heat, the engine briefly restarted but lost total power a second time. The pilot then maneuvered the airplane for a forced landing on a highway. During touchdown, the airplane bounced, flipped over, and came to rest inverted, which resulted in the pilot’s serious injuries and substantial damage to the airplane. Postaccident examination of the engine and associated components revealed no mechanical malfunctions or failures that would have precluded normal operation; adequate fuel was onboard, and no contamination was discovered. The carburetor heat control was found in the ON position. The weather conditions at the time of the accident were conducive to the accumulation of serious carburetor icing at cruise power. Although the pilot reported performing the emergency checklist, which included applying carburetor heat, it was applied sometime after the initial loss of power. The accumulation of ice in the carburetor was likely sufficient to prevent the continued operation of the engine. The loss of engine power may have been prevented had the pilot preemptively activated carburetor heat.

Verbatim NTSB analysis and probable cause from the NTSB dataset