Bangkok Airways Flight 125
Bangkok Airways Flight 125 was a scheduled domestic flight from Don Mueang International Airport to Koh Samui Airport. On 21 November 1990 the Dash 8-103 operating the flight crashed on approach to Koh Samui Airport during bad weather, southwest of the airport, killing all 33 passengers and 5 crew. Bangkok Airways Flight 125 was the first fatal accident of Bangkok Airways.
The subsequent investigation determined that the cause of the accident was the pilots suffering spatial disorientation that led to a loss of control.