The de Havilland Comet
The de Havilland Comet Air Disasters
On 27 July 1949 de Havilland’s chief test pilot, John Cunningham, took the Comet prototype out on its maiden flight. The aircraft took-off from Hatfield Aerodrome and flew for 31 minutes with Harold Waters as co-pilot, John Wilson and Frank Reynolds as flight engineers and Tony Fairbrother as the test observer. The success of this first flight gave the company the confidence to show the aircraft off at the Farnborough Air Show the same year, before the prototype began its flight trials. A second prototype was soon completed and was delivered to BOAC, where it went through 500 hours of route proving work and aircrew training.
It was the fifth Comet to be built that was the first to receive a Certificate of Airworthiness, gaining its wings six months earlier than expected on 22 January 1952. The aircraft entered service with BOAC four months later in May 1952 when it commenced the world’s first commercial jet-airliner service. Within a year de Havilland Comets had carried some 30,000 passengers and were operated on routes from London to Johannesburg, Singapore and Tokyo.
Despite the aircraft’s popularity and early international success, the Comet’s story began to sour shortly after it was introduced. The first crash was on 26 October 1952 at Ciampino Airport in Rome and although not fatal did mark the start of a turn of events that would see the Comet withdrawn from service and its Certificate of Airworthiness temporarily revoked.
The first fatal crash of a de Havilland Comet occurred on 3 March 1953 when a Canadian Pacific Airlines Comet 1A, Empress of Hawaii, stalled while attempting to take-off at Karachi in Pakistan. All of five crew and the six passengers on-board were killed.
On 2 May 1953, two months after the accident at Karachi another BOAC Comet 1 crashed, on this occasion near Calcutta, India. The aircraft came down in bad weather just six minutes into its flight. One eye-witness reported seeing the aircraft lose its wings and then plunge, in flames, into the Indian Ocean. All forty-three passengers and crew lost their lives. The Indian government launched an inquiry and after much of the wreckage had been recovered from the ocean it was found that a left-hand elevator spar in the stabiliser had failed. The inquiry concluded that the failure created extreme negative G-force during take-off, which combined with the weather conditions, caused down loads on the aircraft sufficient for it to lose its wings.
On 10 January 1954 BOAC Flight 781 broke apart in mid-air and crashed into the sea off the Italian coast south of Elba twenty minutes into its flight. All thirty-five passengers and crew were killed. The aircraft had taken-off from Rome’s Ciampino Airport, the scene of the first Comet accident the previous year. There were no eye-witnesses to the accident and air-traffic-controllers had only partial radio messages from which investigators could try to draw any conclusions. De Havilland immediately put forward a list of sixty modifications that it felt were necessary to prevent such an incident in the future and BOAC voluntarily chose to withdraw its fleet from passenger operations.
The Abell Committee, established by the British government to investigate the cause of the crashes, suggested that the most likely cause was fire and as a result numerous modifications were made to the engines and wings to minimise the possibility of a fire breaking out if they were to suffer any damage while in flight. In the absence of any other evidence the British government put pressure on the committee to end their investigations without exploring any further options. As a result BOAC’s Comet aircraft were allowed to resume operations on 23 March 1954.
Two weeks later two weeks later, on 8 April 1954, South African Airways Flight 201, with Comet 1 G-ALYY Yoke chartered from BOAC, came down off the Italian coast, north of Stromboli, killing all twenty-one passengers and crew.
All Comet aircraft were immediately grounded. Their Certificate of Airworthiness was revoked and production at the de Havilland factory at Hatfield in Hertfordshire was suspended. A committee, under the chairmanship of Lord Cohen was established on 19 October 1954 to investigate and report on the causes of the Comet disasters. The investigation team established by the Cohen Committee was led by Sir Arnold Hall, director of the Royal Aeronautical Establishment at Farnborough.
For the first time the investigation team considered the possibility of metal fatigue as one of the most likely causes of the two most recent accidents. Wreckage was recovered and brought to Farnborough and BOAC gave the team the Comet airframe G-ALYU. The entire fuselage was immersed into a special water tank in order to simulate pressurization. The airframe was subjected to more than 3,000 flight cycles, with repeated re-pressurization and dramatically following extensive tests the team were able to cause the fuselage to rip open at a corner of the forward, port-side escape hatch cut-out.
The de Havilland Aircraft Company undertook a major redesign of the Comet, making it significantly larger and stronger. The operational Comet 2 aircraft were refitted and modifications were made to overcome the design flaws that had been identified by the Cohen Committee. The new design work led to the introduction of the Comet 4, which received its Certificate of Airworthiness on 24 September 1958. Two days later BOAC took delivery of its first two Comet 4 aircraft and were once again able to resume jet-airline passenger services.
British television network Channels broadcasts a special one-hour documentary on the Comet air disasters and the subsequent investigations. For details of the various programmed documentaries consult Great British Air Disasters on the Internet.