History of the Flight
On 16 June 2013, a Bombardier BD-700-1A11 (registration M-YSAI) operated by Capital Investment Worldwide Inc. was on a private flight from Delhi, India, to Seletar Airport in Singapore. The pilot-in-command, seated in the left seat, was the Pilot Flying (PF), while the co-pilot was the Pilot Monitoring (PM). Seletar Airport is a Visual Flight Rule (VFR) airfield with a single runway (Runway 3/21). The aircraft was cleared to land on Runway 21.
At 22:05:35, the aircraft was 6 NM from the runway. The crew acknowledged the runway in sight and were cleared to continue the approach. The weather radar showed clear conditions in the approach path but heavy precipitation about 5–7 NM to the right of the runway. The tower controller provided wind information: initially 260° at 4 knots, later updated to 250° at 11 knots, then 260° gusting to 15 knots, and finally 290° at 25 knots. At 22:08:16, the controller informed the crew of severe low-level windshear in the vicinity and that the runway was wet. The crew acknowledged and continued the approach, noting rain intensifying as they crossed the Singapore shoreline.
At 22:10:09, when the aircraft was at 220 ft above ground, the Enhanced Ground Proximity Warning Computer (EGPWC) generated a windshear caution. At 22:10:17, at 108 ft, a windshear warning was issued. The PF did not notice either alert; the PM momentarily heard the aural warning but did not initiate a go-around as per procedures.
Runway Excursion
At approximately 50 ft, the aircraft began to pitch up. The PM requested increased engine power, which the PF applied. The aircraft then drifted left of the runway centreline. During the flare, the aircraft touched down with the right main gear on the runway pavement near the left edge, while the left main gear and nose gear touched down on the grass patch to the left of the runway. The PF applied right aileron and full right rudder to correct the drift, but the aircraft initially continued leftward before responding after touchdown. The aircraft subsequently taxied to its parking bay after making a 180° turn on the runway in heavy rain.
Aircraft Damage
The aircraft sustained damage to its left flaps, left flap track fairings, left landing gear door, and left thrust reverser lower clamshell door. Two signboards on the left side of the runway were damaged by contact. No injuries were reported among the five persons on board.
Discussion
According to the investigation, the flight crew's delayed response to the windshear warning contributed to the loss of directional control. The PF did not recall hearing the windshear warning, and the PM, though hearing it, did not initiate a go-around. The crosswind associated with the windshear caused the aircraft to drift left, and the crew's control inputs were insufficient to maintain runway alignment.
Conclusion
The investigation concluded that the runway excursion occurred as a result of the loss of directional control after the aircraft encountered a severe crosswind associated with windshear. The loss of directional control was exacerbated by the flight crew’s delayed response to the windshear warning.