Synopsis
At approximately 13:23 hours on 6 February 2018, a T-50 Golden Eagle aircraft of the Republic of Korea Air Force (ROKAF) flying display team, participating in the Singapore Airshow, veered right of Runway 20R at Changi Airport during take-off. The aircraft zigzagged for about 750 metres, skidded off the left runway edge, flipped over, and came to rest on the grass. The tail section caught fire, which was extinguished by the airport rescue and firefighting service. The pilot, the sole occupant, extricated himself and was not injured.
History of the Flight
The flying display team of eight ROKAF T-50 aircraft was scheduled to perform an aerial display in the afternoon. At 13:18 hours, the team received clearance to line up on Runway 20R. The team planned a formation take-off in three groups: first group of three, second group of three, and third group of two. The event aircraft was part of the second group. At about 13:21 hours, take-off clearance was issued. Thirty seconds later, the first group commenced take-off roll, followed by the second group eight seconds later.
Runway Excursion Event
The three aircraft in the second group maintained formation during initial take-off roll. After rolling approximately 350 metres, the pilot of the right-hand aircraft disengaged the nose wheel steering (NWS) system to switch to rudder control. The aircraft then started to veer towards the right runway edge. The pilot reduced engine thrust to idle, deployed speed brakes, and applied full left rudder input to steer back. As the aircraft approached the right edge, the pilot re-engaged NWS and stowed speed brakes. When the aircraft moved leftward, full engine thrust was applied. Subsequently, the aircraft skidded in a zigzag manner for about 750 metres, eventually skidding off the left edge, flipping over, and resting on the grass turf. The tail section caught fire shortly after.
Aftermath
The first foam tender from the airport rescue and firefighting service arrived within 90 seconds and extinguished the fire. The pilot extricated himself without injury. The remaining two aircraft of the second group continued take-off, while the third group aborted. A runway edge light was damaged. The aircraft was destroyed. Examination found no defects in the aircraft prior to the accident; tyre pressures were within limits, and no foreign object debris was detected on the runway.
Investigation Findings
The Transport Safety Investigation Bureau (TSIB) conducted the investigation with support from ROKAF Safety Investigation Board. Cockpit examination revealed no anomalies. The aircraft's tyres showed wear marks consistent with skidding; no burst tyres. The right brake piston had mud contamination likely from the crash sequence. The ROKAF SIB found no aircraft defects after further examination in Korea.
Probable Cause
The probable cause of the accident was the pilot's disengagement of the NWS at a speed that was too low for the rudder to be effective, resulting in the aircraft veering to the right. The pilot's subsequent actions, including the reduction of thrust and deployment of speed brakes, and later re-engagement of NWS and application of full thrust, led to the aircraft zigzagging and eventually departing the runway.