Cessna 172M N4428Q accident near Velma, Oklahoma

Probable cause

The pilot’s failure to maintain control of the airplane while maneuvering, which resulted in an inadvertent stall and subsequent impact with terrain. Contributing to the accident was the pilot's relative inexperience in pipeline patrols.

NTSB analysis

The pilot had been flying pipeline patrol for approximately 4 months and had no previous pipeline patrol experience. According to witnesses, the pilot was circling and attempting to guide a ground crew to a pipeline leak. He made four complete circles around the leak and, on the fifth circle, the airplane rolled into a hard left turn. The nose of the airplane dropped, and the airplane struck power lines during the ensuing uncontrolled descent. An examination of the airplane’s structure, engine, and systems revealed no anomalies. Recorded weather observations and witness reports indicated gusting wind in the area of the accident site.

Text from the NTSB. Open the NTSB docket for CEN11LA082 for the full record.