Incident Overview
The airplane experienced a malfunction during an aborted landing, resulting in a collision with an airport boundary fence. The aircraft had made a normal approach following the visual approach slope indicator (VASI) with the landing gear down and full flaps deployed. After touching down just past the runway numbers, the pilot began decelerating and selected reverse thrust on both engines.
Sequence of Events
As the pilot added power to decelerate, the airplane suddenly veered to the left and departed the runway surface. This occurred when the right engine failed to engage reverse thrust. The pilot deselected reverse thrust and realigned the airplane with the runway. Approaching the end of the runway at high speed, the pilot elected to attempt a takeoff. The airplane continued off the end of the runway onto smooth grass. The pilot rotated the airplane, but it struck an airport boundary fence and came to rest in an adjacent field.
Post-Accident Examination
During a subsequent examination, investigators placed the power levers in the full reverse position. The left fuel control measured 4 degrees, while the right measured 0 degrees. Similarly, the left pitch control measured 10 degrees, and the right measured 0 degrees; the controls should have read 0 degrees. A controls engineer determined that during landing, this configuration would result in a 10-degree propeller pitch control (PPC) angle mismatch, corresponding to approximately 2.5 degrees of BETA angle. With matched levers, the left engine would produce lower torque, creating asymmetric reverse thrust. This asymmetry would cause the airplane to turn left if both propellers had entered reverse pitch.