Approach and Weather Conditions
The copilot was completing the approach to Bangkok-Don Mueang Airport in poor weather conditions, with low visibility and heavy rainfall resulting from a tropical storm. During the approach, the ILS equipment failed, but the crew decided to continue.
Descent and Flight Path
At an altitude of 700 feet, the pilot-in-command was able to locate the runway lights. At that point, the aircraft was slightly too high on the glide slope and too far to the left of the intended path. Continuing the descent, at 300 feet altitude, the indicated airspeed (IAS) was 127 knots, approximately five knots above the planned speed. The copilot then decided to reduce the speed to 122 knots.
Loss of Height and Hard Landing
Shortly after the speed reduction, the airplane suddenly lost height. The captain elected to regain control, but it was too late. With a relatively high sink rate, the airplane landed very hard. The impact caused both main landing gear to puncture the wings. The aircraft then came to rest after traveling several hundred yards along the runway.
Occupants and Damage
All 75 occupants escaped uninjured. However, the aircraft sustained damage beyond repair.
Probable Cause
Official findings indicate that windshear is suspected as a contributing factor, as stated by the investigation.