Cessna 150 N7948F accident near Stockbridge, Georgia

Probable cause

A partial loss of engine power due to a stuck exhaust valve and the pilot's exceedance of the airplane’s critical angle of attack, which resulted in an aerodynamic stall.

NTSB analysis

The private pilot completed an engine run-up before the personal flight with no anomalies noted. The pilot rotated the airplane about halfway down the runway. He stated that the airplane was not climbing normally during the takeoff, and a ground witness heard the engine making "popping" noises. The pilot attempted to clear trees off the end of the runway in order to make a controlled landing in the field on the other side, but the airplane impacted the field; the pilot was unable to recall any events that happened after passing over a tree. Examination of the wreckage revealed that the airplane displayed impact damage that included aftward crushing of the airplane's nose and the leading edges of both wings, which was consistent with an aerodynamic stall and impact with the ground in a nose-low attitude. Examination of the engine revealed the No. 4 cylinder's exhaust valve was stuck in the fully open position and coated in a carbon-like material. The stuck valve likely reduced engine power and airplane performance during the takeoff, which resulted in an aerodynamic stall.

Text from the NTSB. Open the NTSB docket for ERA17LA015 for the full record.