Accident Sequence
The pilot began a takeoff with 10 jumpers on board. At the rotation speed of 100 knots, he used elevator trim to rotate the airplane, but it failed to lift off the runway. As the aircraft continued down the runway, he moved the trim wheel violently in an attempt to pitch the nose up and also pulled back on the yoke. Despite these efforts, the airplane did not become airborne and collided with rising terrain off the end of the runway.
Observations and Witness Report
A witness who observed the preflight inspection did not see any of the flight controls move during that time. During the takeoff roll, the witness also did not observe the nose of the airplane rotate upward. The pilot reported that during preflight he removed a single pin control lock from the yoke. The Beech control lock consisted of two pins, two chains, and a U-shaped engine control lock.
Post-Accident Examination
The pilot walked away from the wreckage after the accident. No control locks were found in the wreckage. However, the control column shaft exhibited distress signatures on the periphery of the hole where the control lock is installed. No other evidence was found of any other form of mechanical jamming, interference, or discontinuity with the flight controls. Investigators were unable to identify any potential source of interference, other than a control lock, that could have simultaneously jammed both pitch and roll control.
Aircraft Performance Context
According to the airplane's manufacturer, about 3 to 6 degrees of trim would have been normal for the airplane's takeoff conditions.