What happened
The accident occurred shortly after the aircraft began its takeoff roll. According to the pilot's account, moments after takeoff power was applied, the structural integrity of the pilot's seating assembly failed. The seat retaining pins broke simultaneously, causing the seat to slide aft. This movement snapped the rear retainer, leaving the pilot in a position where he could not reach the control yoke.
With no ability to manipulate the flight controls, the aircraft swerved off the runway and collided with trees. The pilot later reported that both the seat retainer and the pin had been replaced during a major overhaul of the aircraft in March 1981.
The investigation
The investigation focused on the mechanical failure of the seat assembly. Evidence indicated that the retaining pins had failed under load, allowing the seat to move rearward. This displacement broke the rear retainer mechanism, effectively isolating the pilot from the control inputs necessary to maintain or recover flight.