What happened
On May 31, 2013, a BAe ATP freighter, registration PK-DGI, operated by PT. Deraya, was performing a scheduled cargo flight from Sentani Airport to Wam to Wamena Airport, Papua. During the approach to runway 15, the flight crew reported that the runway was not visible from their position. Approximately 25 seconds after the aircraft reached 500 feet, the pilot reported that the runway had come into sight, and the aircraft proceeded to land.
Upon touchdown, the aircraft was misaligned with the runway centerline. During the landing roll, the aircraft began to veer toward the left side of the runway. The crew attempted to correct the deviation by applying right rudder and asymmetric reverse thrust; however, the aircraft continued to drift left. The aircraft eventually came to a stop approximately 10 meters onto the left shoulder of the runway. The impact caused the nose landing gear to detach and resulted in broken main landing gear and bent propeller blades. There were no injuries to the two crew members on board.
The investigation
The investigation examined flight data recorder (FDR) and cockpit voice recorder (CVR) data, as well as wreckage analysis. Investigators found that the aircraft touched down with a 2-degree misalignment relative to the runway heading. Data from the FDR indicated that after touchdown, the engine torques were asymmetric, with the left engine producing greater torque than the right.
Analysis of the crew's actions revealed that the approach did not meet the stabilized approach criteria required by the company's operations manual. Furthermore, the investigation noted that the crew's recovery attempt—specifically the use of asymmetric reverse thrust—was inconsistent with established safety techniques for maintaining directional control. The CVR also indicated a lack of effective communication between the pilot flying and the pilot monitoring, particularly regarding the decision to continue the landing despite the lack of runway visibility at lower altitudes.
Findings
- The approach was unstabilized, failing to meet the required criteria for a safe landing, which should have prompted a go-around.
- The aircraft touched down with a 2-degree misalignment with the runway direction.
- The pilot's recovery technique, involving asymmetric reverse thrust, contributed to the loss of directional control.
- There was a lack of effective Crew Resource Management (CRM), characterized by minimal communication between the pilots regarding the approach profile and the disregard of EGPWS aural warnings.
Safety action
Following the investigation, the KNKT issued safety recommendations to the operator, PT. Deraya, to ensure pilots are proficient in the implementation of stabilized approach procedures. The recommendations also emphasized the need to review crew coordination procedures regarding EGPWS warnings and to enhance CRM training to improve situational awareness during critical phases of flight.