Cessna 150F N8879S accident near Bullard, Texas

Probable cause

The partial loss of engine power due to carburetor icing and the pilot's inability to maintain adequate airspeed during the soft-field takeoff, which resulted in an exceedance of the airplane's critical angle-of-attack and an aerodynamic stall.

NTSB analysis

Following a full-stop landing and a back taxi to the runway, the flight instructor and a student pilot planned to conduct a soft-field takeoff to prepare the student for his private pilot test flight. Although there were no witnesses to the takeoff, an automobile dash camera video showed the airplane flying just above tree tops and then entering a right turn. During the turn, the left wing and the nose of the airplane dropped, which was consistent with a stall and an initial spin. The airplane then descended and impacted the ground. The available evidence did not indicate which pilot was flying the airplane at the time of the accident, but it is likely that the student pilot was flying at the time.

Postaccident examination of the airplane and engine revealed no anomalies that would have precluded normal operation. The carburetor heat control was found in the off position, which was the correct position for takeoff. The temperature and dew point at the time of the accident were in a range of susceptibility for moderate icing at cruise power settings and serious icing at descent power settings. Although the airplane was at takeoff power when the accident occurred, a partial loss of engine power likely occurred due to carburetor icing, which might have accumulated while the airplane was operating at a lower power setting on the ground before the accident takeoff. The partial loss of engine power resulted in reduced airplane performance and the pilot's inability to maintain adequate airspeed, which then resulted in an exceedance of the airplane's critical angle-of-attack and a subsequent aerodynamic stall.

Text from the NTSB. Open the NTSB docket for CEN17LA298 for the full record.