Cessna 172 N1727V accident near New Milford, Connecticut

Probable cause

The flight instructor's failure to ensure that the wing flaps were properly configured for takeoff, which resulted in an aerodynamic stall and loss of control during the initial climb.

NTSB analysis

The student pilot, who had 15 hours of flight experience, was performing an instructional flight with her flight instructor and a passenger. According to GPS data, the airplane landed on and then took off from a grass airstrip, climbed about 150 ft, then collided with terrain about 1,000 ft past the end of the runway. There were no known eyewitnesses, and the student pilot and passenger did not recall the accident due to their injuries. The flight instructor was fatally injured.

An examination of the wreckage did not reveal any evidence of a preaccident mechanical malfunction or anomaly. An examination of the flight controls revealed that the wing flaps were in the fully extended (40º) position at impact. The airplane's operating checklist stated that normal and obstacle clearance takeoffs are performed with wing flaps up, and flap settings greater than 10º are not recommended at any time for takeoff. Upon landing on the grass runway, the flaps should have been retracted as part of the after-landing checklist, then confirmed up as part of the before takeoff and takeoff checklists. It is likely that the flap setting at the time of takeoff resulted in an aerodynamic stall and loss of control during the initial climb.

It could not be determined who was at the controls at the time of the takeoff and loss of airplane control; however, the flight instructor, as pilot-in-command, was responsible for the operation and safety of the flight and should have ensured that the flaps were retracted before takeoff. He also should have anticipated and corrected any significant errors made by the student.

Text from the NTSB. Open the NTSB docket for ERA17FA272 for the full record.