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Last updated: 21 October 2021
Datum:Montag 8 Juni 1959
Flugzeugtyp:Silhouette image of generic COMT model; specific model in this crash may look slightly different
de Havilland DH-106 Comet 4
Fluggesellschaft:British Overseas Airways Corporation - BOAC
Kennzeichen: G-APDA
Werknummer: 6401
Baujahr: 1958
Triebwerk: 4 Rolls-Royce Avon 524
Besatzung:Todesopfer: 0 / Insassen: 9
Fluggäste:Todesopfer: 0 / Insassen: 44
Gesamt:Todesopfer: 0 / Insassen: 53
Sachschaden: schwer beschädigt
Konsequenzen: Repaired
Unfallort:Calcutta-Dum Dum Airport (CCU) (   Indien)
Flugphase: Annäherung (APR)
Betriebsart:Internationaler Linienflug
Flug von:Bangkok-Don Muang International Airport (BKK/VTBD), Thailand
Flug nach:Calcutta-Dum Dum Airport (CCU/VECC), Indien
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

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

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path.
Distance from Bangkok-Don Muang International Airport to Calcutta-Dum Dum Airport as the crow flies is 1600 km (1000 miles).

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.
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