What happened
During an approach following the visual approach slope indicator, the pilot of the aircraft performed a landing with the landing gear extended and flaps at full position. The aircraft touched down slightly beyond the runway threshold and the pilot initiated deceleration by engaging reverse thrust on both engines. During this process, the aircraft veered left and departed the runway because the right engine failed to enter reverse thrust mode.
After disengaging reverse thrust, the pilot managed to realign the aircraft with the runway centerline. However, due to the high speed maintained during the aborted landing, the pilot decided to attempt a takeoff. As the aircraft reached the end of the runway, it transitioned onto a smooth grass area. The pilot initiated rotation, but the aircraft subsequently struck an airport boundary fence before coming to a stop in a nearby field. There were no fatalities or injuries reported in this incident.
Findings
Post-accident inspections of the engine controls revealed significant discrepancies between the left and right sides. When the power levers were moved to the full reverse position, the left fuel control measured 4° while the right measured 0°. Additionally, the left pitch control showed a 10° measurement compared to 0° on the right, despite the requirement for both to read 0°.
An investigation by a controls engineer concluded that a propeller pitch control mismatch of 10° existed during the landing phase. This discrepancy resulted in a difference of approximately 2.5° in the BETA angle. The findings indicate that if both propellers had successfully entered reverse thrust, the resulting asymmetric thrust—with the left engine producing lower torque—would have caused the aircraft to veer toward the left.