BA149 departed from London Heathrow International Airport on August 1, 1990, destined for its final destination in Kuala Lumpur, with stopovers planned in Kuwait City and Madras. At the same time, the flight had been delayed initially by several hours due to an issue with the aircraft auxiliary power unit. The flight officially departed the British Capital at 18:05 that evening local time, with 367 passengers onboard.