Piper PA-28-235 N8535N accident near Shafter, California

Probable cause

A total loss of engine power due to carburetor ice. Contributing was the student pilot and flight instructors’ failure to utilize carburetor heat.

NTSB analysis

During a local training flight, the flight instructor directed the student pilot to return to the airport to practice touch-and-go landings. After entering the traffic pattern and completing the landing checklist while turning from base to final approach, the engine sustained a total loss of power about 400 ft above ground level. The instructor assumed control of the airplane and performed the engine restart procedures; however, the attempts were unsuccessful. Realizing the airplane could not reach the runway, the instructor executed a forced landing in an open field. During the landing rollout, the nose gear dug into the soft terrain and the airplane nosed over, resulting in substantial damage to the fuselage, vertical stabilizer, and rudder.

A postaccident examination of the airframe and engine revealed no evidence of any preimpact mechanical malfunctions or failures that would have precluded normal operation. A portable fuel tank was subsequently plumbed to each of the fuel tank ports on the selector valve and the engine operated normally in each of the fuel selector valve positions. The carburetor heat door also moved appropriately with cabin control actuation.

A review of weather data indicated atmospheric conditions conducive to the formation of serious carburetor icing at cruise-power settings. The flight instructor could not recall the position of the carburetor heat at the time of the event. Given the absence of mechanical anomalies identified during the postaccident examination, carburetor ice likely accumulated while the airplane was maneuvering in the traffic pattern before landing, resulting in the eventual loss of engine power.

Text from the NTSB. Open the NTSB docket for WPR25LA092 for the full record.