What happened
On 28 March 2014, an ATR 72-212A, registration PK-WFR, operated by PT. Wings Abadi Air, was performing a scheduled passenger flight from Pomala to Makassar. The flight, carrying 73 passengers and four crew members, encountered significant weather challenges during its approach to Sultan Hasanuddin Airport.
As the aircraft approached runway 03, the pilot in command took control of the aircraft due to the reported crosswind conditions. Upon touchdown in the touchdown zone, the pilot initiated braking and reverse thrust. However, as the aircraft decelerated to approximately 70 knots, it suddenly veered to the right. The pilot attempted to correct the deviation using differential rudder and nose wheel steering, but the aircraft eventually exited the runway pavement, coming to a stop 15 meters into the grass. There were no injuries reported, though the aircraft sustained minor damage to the landing gear doors.
The investigation
The KNKT investigation focused on the flight data and cockpit communications to determine why the aircraft failed to maintain the centerline. Investigators examined the flight data recorder (FDR) and cockpit voice recorder (CVR), noting that after touchdown, the pilot initially applied left rudder, which caused the heading to shift. This was followed by a significant application of right rudder, which ultimately caused the aircraft to deviate from the runway.
Analysis of the meteorological data and cockpit actions revealed that the crew was dealing with a crosswind of up to 23 knots. The investigation also looked into the crew's decision-making processes and their awareness of the weather conditions, including the presence of nearby cumulonimbus clouds.
Findings
- The primary cause of the runway excursion was the full upwind rudder pedal application at a relatively high speed under crosswind conditions.
- The pilot's attempt to recover the aircraft resulted in incorrect rudder inputs that exacerbated the deviation.
- A lack of crew discussion regarding the specific weather threats during the approach may have impacted situational awareness.
- Inadequate training regarding the aerodynamic effects of crosswinds and the correct recovery techniques contributed to the incident.