Comet 4B: Originally developed for Capital Airlines as the 4A, the 4B featured greater capacity through a 2m longer fuselage, and a shorter wingspan; 18 were produced. Comet 4C : This variant featured the Comet 4's wings and the 4B's longer fuselage; 28 were produced.

The aircraft that duly emerged was the DH106 Comet 4B, which was specifically for BEA operations. This variant can readily distinguished by its longer fuselage section (118 ft compared with 111 ft 6 in) and the lack of the wing pinion fuel tanks. 18 were built: 14 for BEA and 4 for Olympic Airways.

On 21 December 1961, a serious aviation accident occurred on this flight when the pilots lost control of the de Havilland DH-106 Comet 4B aircraft shortly after take-off from Ankara Esenboğa Airport. In the accident, 27 occupants were killed and there were 7 survivors. [1]: 1

de Havilland DH106 Comet 4 Aircraft overview: First flown in 1958 at Hatfield, the Comet 4 was a ‘stretched’ version of the Comet airliner, having higher all-up weight, with higher thrust engines and extra fuel to meet British Oversees Airways Corporation (BOAC) requirements for operating on the North Atlantic route.

The 4B was the fastest Comet capable of up to 532 m.p.h. but optimum cruising speed was 520 m.p.h. at 23,500ft and 135,000lb giving a rate of fuel consumption of 11,500lb/hr.

The Comet 4 (including 4B/4C) was the most successful. 77 were built, twice as many as all the other series put together, and they flew a total of 1.7 million hours. It was in commercial service from October 1958 to November 1980, and XS-235 continued to fly for the MoD until 1997.

Known as the D.H.106 Comet, the ailiner used four of the new de Havilland Ghost 50 turbojet engines mounted in the wing root leading edge of an otherwise fairly typical commercial airliner of the day.

BEA De Havilland DH-106 Comet 4B. credit: credits... Want More of This? We'll send you our latest and best content straight to your inbox.

It featured an aerodynamically clean design with four de Havilland Ghost turbojet engines buried in the wings, a pressurized fuselage, and large square windows. For the era, it offered a relatively quiet, comfortable passenger cabin and showed signs of …

SX-DAK de Havilland D.H.106 Comet 4B (c/n 6437) To compete with British Airways on the lucrative Athens - London route, Olympic ordered a fleet of four Comets in 1960.