On 3 July 1968, BKS Air Transport Flight C.6845, an Airspeed Ambassador registration G-AMAD of BKS Air Transport crashed at Heathrow Airport, damaging two parked Trident airliners as it cartwheeled into the incomplete Heathrow Terminal 1, then under construction.

[1] The crash was blamed on the failure of a flap-operating rod due to metal fatigue, resulting in asymmetrical lift.

The Ambassador, construction number 5211,[2] had previously been British European Airways' Sir Francis Drake.

The Ambassador cartwheeled following the impact and slid upside down coming up against the ground floor of the terminal building where there was an explosion.

The Department of Transport report concluded that whatever the pilot's actions, it was "doubtful" whether an accident could have been avoided.