March marks the anniversary of the final flight of the de Havilland DH106 Comet – the world’s first jet airliner. WHT's Dan Mountney looks at the history and tragic legacy of the revolutionary Hatfield-designed and built aircraft.
When the Comet rolled out of the hanger at Hatfield Aerodrome on July 27, 1949, the airline industry changed forever. The jet age had truly arrived.
De Havilland were renowned for their ingenuity in the years leading up to the Comet’s development, with the ‘Wooden Wonder’ Mosquito and the Vampire jet-powered military fighter among their finest designs.
The company took everything they had learned from those aircraft and more when developing the Comet, and that knowledge and expertise resulted in a design like no other.
With a mirrored aluminium fuselage, swept back wings, four concealed jet engines, large rectangular windows for unrivalled views and a cruising altitude of 40,000ft, it set the standard for air travel.
After almost two years of extensive testing by de Havilland, the Comet entered service with the British Overseas Airways Corporation in 1952, making its first scheduled flight in May from London to Johannesburg – via the likes of Rome and Beirut.
The DH106 became the pride of the BOAC fleet, with the airline adding more services while de Havilland continued to take new orders for their revolutionary machine from Air France and Canadian Pacific.
Then the accidents started.
On March 3, 1953, 11 people were killed when a Comet crashed on take-off in Karachi, Pakistan. On, May 2, 1953, all 43 people on board BOAC Flight 783 died when it crashed just six minutes after taking off from Delhi, India.
Pilot error and the weather were blamed, but questions were now being asked about the Comet’s design.
Then, on January 10, 1954, BOAC Flight 781 broke up in mid-air just 20 minutes after taking off from Rome’s Ciampino airport, killing all 35 people on board. With no clear cause of the accident, all Comets were grounded.
But, with revenues falling, pressure mounted to get the aircraft back in the sky. Just 10 weeks after the Flight 781 disaster, the DH106 fleet resumed service. But then, on April 8, 1954, South African Airways Flight 201 crashed near Naples at the loss of all 21 lives.
A Royal Aircraft Establishment investigation, led by director Sir Arnold Hall, was immediately launched and the Comet was grounded again.
With concerns over the aircraft’s structure, Hall and the RAE devised a test in which a stripped-out DH106 fuselage would be placed inside the tank. Water would then be pumped in and out of the fuselage every five minutes to simulate cabin pressurisation, while hydraulic rams moved the wings up and down to recreate flight.
Hall planned to test the airframe to destruction. Less than a month into the experiment – which was predicted to take five – the fuselage ruptured.
A two-metre-long tear running along the windows and doors had opened up the Comet’s skin. The RAE team found the revolutionary square windows had been riveted rather than glued as stated in de Havilland’s original design. The punched in rivets caused minute manufacturing defects which turned into fatigue cracks after the repeated stresses of flight.
Hall found these fatigue cracks on the wreckage of Flight 781, next to a rivet for a radio signal window on the top of the fuselage. When his team put together all the recovered pieces, they found every crack led back to this rivet.
The investigation found not only the Comet’s fatal flaw, but helped save hundreds more lives by helping to further the understanding of metal fatigue and aircraft design.
As for the Comet, de Havilland made major modifications to the aircraft, which returned to service in 1958. The Hatfield-based company received orders from airlines across the globe, but with the reputation of DH106 tarnished and Boeing taking over the industry in the four years since, it was no longer the world-leader it once was.
The Comet did continue passenger flights until 1981, while the Ministry of Technology used the aircraft for radio, radar and avionics trials. It was in this role that the once-revolutionary jet would make its final-ever flight. On March 14, 1997, Comet XS235 – named Canopus – landed at Bruntingthorpe, Leicestershire, where it has remained on display ever since.
Designed and built in Hatfield, the de Havilland Comet changed the airline industry forever. The aircraft was the first of its kind and revolutionary for the time, and while it has been tarnished by its fatal reputation, it will forever hold an important role in aviation history.
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