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Last updated: 25 September 2021
Date:lundi 8 juin 1959
Type/Sous-type:Silhouette image of generic COMT model; specific model in this crash may look slightly different
de Havilland DH-106 Comet 4
Compagnie:British Overseas Airways Corporation - BOAC
Immatriculation: G-APDA
Numéro de série: 6401
Année de Fabrication: 1958
Moteurs: 4 Rolls-Royce Avon 524
Equipage:victimes: 0 / à bord: 9
Passagers:victimes: 0 / à bord: 44
Total:victimes: 0 / à bord: 53
Dégats de l'appareil: Substantiels
Conséquences: Repaired
Lieu de l'accident:Calcutta-Dum Dum Airport (CCU) (   Inde)
Phase de vol: En approche (APR)
Nature:Transport de Passagers Intern.
Aéroport de départ:Bangkok-Don Muang International Airport (BKK/VTBD), Thaïlande
Aéroport de destination:Calcutta-Dum Dum Airport (CCU/VECC), Inde
Numéro de vol:931
The aircraft, which was operating the Tokyo-London passenger service Speedbird 931 of BOAC, was attempting to land at Calcutta Airport with the aid of the Instrument Landing System. The earlier stages of the approach to Runway 19L proceeded without incident. Turbulence was encountered necessitating increased power to stabilize the fluctuating air speed at the recommended figure. The increased power was applied too late with the result that sudden sinking of the aircraft and an impact with trees could not be avoided.
Thereafter, partial loss of lateral control was experienced as considerable damage had been caused to the flaps. The missed approach procedure was then successfully carried out. The next approach was made on to runway 01R. The aircraft was then being flown by visual reference. During this approach the aircraft again impacted the trees as due allowance was not made for the higher stalling speed of the damaged aircraft. Missed approach procedure was again initiated and the aircraft responded well. However, further damage had been sustained. A circuit was executed and the landing during the third attempt was successful, but the damaged aircraft failed to pull up within the available length of the wet runway because of the higher speed at which the approach had to be justifiably made.
No injury was sustained by the 44 passengers and nine members of the crew on board. The aircraft was substantially damaged.

Probable Cause:

Accident causes:
The accident is attributed to an error of judgement on the part of flying crew in not applying power when approaching to land under turbulent conditions. The subsequent power increase was applied too late to prevent the aircraft, which was being flown at a speed below the speed recommended for turbulent conditions, from sinking and striking trees.

» Flight, 8 June 1961
» Flight, 3 June 1960
» Flight, 3 Feb. 1961

Opérations de secours
Remedial action: Comet 4 flight manual approach speed was increased by 5kt after the incident


photo of de-Havilland-DH-106-Comet-4-G-APDA
accident date: 08-06-1959
type: de Havilland DH-106 Comet 4
registration: G-APDA

Ce plan montre l'aéroport de départ ainsi que la supposée destination du vol. La ligne fixe reliant les deux aéroports n'est pas le plan de vol exact.
La distance entre Bangkok-Don Muang International Airport et Calcutta-Dum Dum Airport est de 1600 km (1000 miles).

Les informations ci-dessus ne représentent pas l'opinion de la 'Flight Safety Foundation' ou de 'Aviation Safety Network' sur les causes de l'accident. Ces informations prélimimaires sont basées sur les faits tel qu'ils sont connus à ce jour.
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