Accident Sequence
According to the flight instructor, during the second touch and go, she added full throttle. As the airplane began to rotate, her seat released and slid aft, causing her to lose her grip on the flight controls. The airplane then departed the runway to the left, struck the ground, and traveled 785 feet before colliding with two unoccupied airplanes located on the ramp. The accident airplane sustained substantial damage.
Post-Accident Examination
Examination of the seat rails revealed no anomalies. However, when the seat was brought to the full forward position, the inboard seat pin would not engage fully into the seat track. When force was applied, the seat would move aft. A Cessna representative observed that the outboard seat pin was installed on the outboard side of the seat handle, whereas it should be installed on the inboard side. Further examination of the remaining aircraft systems revealed no anomalies.
Service Manual Information
The Cessna Model 172 Series Service Manual provides only an illustration addressing the installation of the seat pins. There is no textual data available in the manual for the installation procedure.