The 36-seat British De Havilland Comet 1 was the world's first jet-powered commercial aircraft, and was powered by four De Havilland Ghost 50 engines mounted within its wings. It first flew on 27 July 1949 and made its first scheduled passenger-carrying flight, between London, UK, and Johannesburg, South Africa, on 2 May 1952, when BOAC (The British Overseas Airways Corporation – predecessor to British Airways) inaugurated the first commercial jet service. Flying at speeds as high as 800 km/h (500 mph) it made scheduled stops in Rome, Khartoum (Sudan), Entebbe (Kenya) and Livingstone (near the Victoria Falls in Zambia). A series of disastrous crashes in 1953 and 1954 led to the aircraft being withdrawn from service. A design flaw related to the aircraft's square windows (favoured over round windows purely for cosmetic reasons) caused metal fatigue and resulted in weaknesses in the aircraft's structure. By the time the aircraft returned to service, the Boeing 707 and Douglas DC-8 had become the market leaders and the Comet enjoyed only modest success thereafter. Only about 90 Comets ever reached commercial operators, and most were removed from service by the early 1980s. A few additional Comet aircraft (No 216 Squadron) were used by the British Royal Air Force, but only the Nimrod, a Comet derivative, remains in use in the maritime and reconnaissance roles.