Design work began in 1946 under Ronald Bishop and the intention was to have a commercial aircraft by 1952. The DH 106 Comet first flew on July 27, 1949. The design was similar to other airliners except that four of the new, albeit underpowered, de Havilland Ghost 50 turbojets were mounted within the wings, in pairs close to the fuselage. The airliner underwent almost three years of tests and fixes and the first commercial flights did not begin until January 22, 1952 with BOAC. The first passenger flight was in May to Johannesburg. The airliner proved to be around twice as fast as contemporary craft and with almost 30,000 passengers carried in the first year over fifty Comets were ordered.
The first sign of a flaw in the Comet came on May 2, 1953 when a Comet crashed soon after take-off from Calcutta; further crashes (January 1954 and April 1954) with no clear cause led to the entire fleet being grounded for investigation. It was found in February 1955 that, as suspected, metal fatigue was the problem; after thousands of pressurized climbs and descents the thin fuselage metal around the Comet's distintictive right-angled large windows would begin to crack eventually causing sudden depressurization.
All the extant Comets were either scrapped or modified but they did not fly again until 1958, when the much improved 110-passenger Comet 4 was also manufactured. However, the interruption of commercial service and the damage to the aircraft's reputation meant that the jetliner market was dominated by Boeing (the 707 first flew in 1954) and Douglas. Only fifteen airlines ever used the Comet, the proposed Comet 5 was never built, and all the remaining craft were slowly withdrawn from service. The last variant was the 4C which first flew in October 1959, production ending in 1962.
Perhaps as a mark of respect, a preserved Comet 4 in BOAC livery is on display at the Museum of Flight, next to Boeing's Seattle factory.
The Nimrod, a military maritime patrol aircraft, is a larger and heavily modified variation on the Comet design. It is the only large aircraft still in service that has engines built into its wings rather than slung beneath them or mounted either side of the rear fuselage.