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. Six of the eight people on board the Ambassador were killed, along with the eight racehorses being transported on it.[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. It had recently been converted to a "horsebox" transport and was on a flight from Deauville, France, to Heathrow Airport. Flight C.6845 was transporting eight racehorses belonging to businessman William Hill together with five grooms. As the aircraft was landing on Heathrow's runway 28R the left wing dropped, and the wing tip and left landing gear touched the grass adjacent to the runway. The crew tried to increase power to go-around and climb away, but the bank angle increased. The aircraft hit two parked empty British European AirwaysHawker Siddeley Tridents, knocking the tail fin off one (G-ARPI) and slicing off the entire tail section of the other (G-ARPT). 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.[3]
G-APKF, one of the aircraft involved in the accident
Six people on board the Ambassador died, including the flight crew and three of five grooms, along with all eight horses. The other two grooms were seriously injured as were two people on the ground. A further 29 people on the ground received slight injuries.
Of the two Trident aircraft, G-ARPT was damaged beyond economic repair and G-ARPI was subsequently repaired. G-APRI was involved in an incident in 1972 resulting in the deaths of 118 people and becoming the deadliest non-terrorist aviation incident in the UK. A Viscount (G-APKF) received slight damage.[3] The Viscount was also repaired but later too involved in a fatal hull-loss accident as XW-TDN in 1975.[4]
All other Ambassadors were grounded pending the result of an inquiry.[3] The starboard rod from the aircraft was tested and found satisfactory but rods from some other Ambassadors showed signs of cracking and when tested failed in a similar manner to G-AMAD's port rod. The rods on aircraft were strengthened and shown to be capable of 37,000 hours flight time.
Probable cause
The port (left) flap operating rod had failed due to metal fatigue. While the mechanism had failed, the compensating mechanism between the two sets of flaps remained intact. The port flaps had retracted but the compensator caused the starboard ones to extend further. The resulting asymmetry of lift resulted in the roll to port.
The pilot probably tried to overshoot and set the flaps to the correct 10 degrees, but due to the mechanism design this was not sufficient to cause the starboard flaps to retract (which would have taken 25 seconds in any event). The Department of Transport report concluded that whatever the pilot's actions, it was "doubtful" whether an accident could have been avoided.
After the accident all Ambassadors were fitted with steel reinforcements to the flap operating rods.[1]
"Report on the Accident to Ambassador AS.57 Series 2, G-AMAD, at Heathrow Airport, London, on 3 July 1968". CAP 322, HMSO
"Ambassador accident cause detailed" Flight International 1969. 12 November 2012 at the Wayback Machine
External links
Photograph of severed tail section of Trident 1 G-ARPT – taken in 1972
Another photograph showing the severed tail of Trident 1C G-ARPT
Photograph showing damage to tail of Trident 1C G-ARPI
Trident accidents and incidents
BKS Air Transport Ltd history site
Pre-crash photographs of Airspeed Ambassador G-AMAD
at the Wayback Machine (archived 12 November 2012) a 1969 Flight article
A short clip showing the accident of G-AMAD
March 11, 2023
transport, flight, 6845, july, 1968, airspeed, ambassador, registration, amad, transport, crashed, heathrow, airport, damaging, parked, trident, airliners, cartwheeled, into, incomplete, heathrow, terminal, then, under, construction, eight, people, board, amba. 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 Six of the eight people on board the Ambassador were killed along with the eight racehorses being transported on it 1 The crash was blamed on the failure of a flap operating rod due to metal fatigue resulting in asymmetrical lift BKS Air Transport Flight C 6845 1 Airspeed Ambassador G AMAD in 1966AccidentDate3 July 1968SummaryMechanical failure caused by metal fatigueSiteHeathrow Airport England 51 28 24 N 0 27 00 W 51 4734 N 0 4501 W 51 4734 0 4501 Coordinates 51 28 24 N 0 27 00 W 51 4734 N 0 4501 W 51 4734 0 4501AircraftAircraft typeAirspeed AmbassadorOperatorBKS Air TransportRegistrationG AMADOccupants8Passengers5Crew3Fatalities6 people and 8 horsesSurvivors2 Contents 1 Accident 2 Probable cause 3 See also 4 References 5 Further reading 6 External linksAccident EditThe Ambassador construction number 5211 2 had previously been British European Airways Sir Francis Drake It had recently been converted to a horsebox transport and was on a flight from Deauville France to Heathrow Airport Flight C 6845 was transporting eight racehorses belonging to businessman William Hill together with five grooms As the aircraft was landing on Heathrow s runway 28R the left wing dropped and the wing tip and left landing gear touched the grass adjacent to the runway The crew tried to increase power to go around and climb away but the bank angle increased The aircraft hit two parked empty British European Airways Hawker Siddeley Tridents knocking the tail fin off one G ARPI and slicing off the entire tail section of the other G ARPT 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 3 G APKF one of the aircraft involved in the accident Six people on board the Ambassador died including the flight crew and three of five grooms along with all eight horses The other two grooms were seriously injured as were two people on the ground A further 29 people on the ground received slight injuries Of the two Trident aircraft G ARPT was damaged beyond economic repair and G ARPI was subsequently repaired G APRI was involved in an incident in 1972 resulting in the deaths of 118 people and becoming the deadliest non terrorist aviation incident in the UK A Viscount G APKF received slight damage 3 The Viscount was also repaired but later too involved in a fatal hull loss accident as XW TDN in 1975 4 All other Ambassadors were grounded pending the result of an inquiry 3 The starboard rod from the aircraft was tested and found satisfactory but rods from some other Ambassadors showed signs of cracking and when tested failed in a similar manner to G AMAD s port rod The rods on aircraft were strengthened and shown to be capable of 37 000 hours flight time Probable cause EditThe port left flap operating rod had failed due to metal fatigue While the mechanism had failed the compensating mechanism between the two sets of flaps remained intact The port flaps had retracted but the compensator caused the starboard ones to extend further The resulting asymmetry of lift resulted in the roll to port The pilot probably tried to overshoot and set the flaps to the correct 10 degrees but due to the mechanism design this was not sufficient to cause the starboard flaps to retract which would have taken 25 seconds in any event The Department of Transport report concluded that whatever the pilot s actions it was doubtful whether an accident could have been avoided After the accident all Ambassadors were fitted with steel reinforcements to the flap operating rods 1 See also EditList of accidents and incidents involving commercial aircraft Air Vanuatu Flight 241 in which an aircraft departed the runway and collided with two parked aircraft British European Airways Flight 548 Aviation incident in which G APRI was also involvedReferences Edit a b c Accident description at the Aviation Safety Network citing Aircraft Illustrated Vol 1 nr 4 Oct 1968 p 127 Denham Terry 1996 World Directory of Airliner Crashes Sparkford Patrick Stephens Ltd pp 85 107 ISBN 1 85260 554 5 a b c BKS Crash Fatigue failure Flight International 42 Archived from the original on 7 August 2018 Viscount c N 396 operational record Further reading Edit Report on the Accident to Ambassador AS 57 Series 2 G AMAD at Heathrow Airport London on 3 July 1968 CAP 322 HMSO Ambassador accident cause detailed Flight International 1969 Archived 12 November 2012 at the Wayback MachineExternal links EditPhotograph of severed tail section of Trident 1 G ARPT taken in 1972 Another photograph showing the severed tail of Trident 1C G ARPT Photograph showing damage to tail of Trident 1C G ARPI Trident accidents and incidents BKS Air Transport Ltd history site Pre crash photographs of Airspeed Ambassador G AMAD Ambassador Accident Cause Detailed at the Wayback Machine archived 12 November 2012 a 1969 Flight article A short clip showing the accident of G AMAD Retrieved from https en wikipedia org w index php title BKS Air Transport Flight C 6845 amp oldid 1142662791, wikipedia, wiki, book, books, library,
