The Sea Vixen originated with de Havilland’s DH 110 design of 1947, developed to meet RAF and Fleet Air Arm requirements for a jet-powered all-weather and night fighter. The RAF eventually adopted the simpler Gloster Javelin, but the DH 110 formed the basis for the development of the Sea Vixen, which finally entered service in 1959.
The type retained the twin-boom tail layout of de Havilland’s earlier Vampire and Venom fighters but was a far more powerful aircraft, with a top speed of 690mph (1,110kph; Mach 0.91). In keeping with the accepted wisdom of the period, a two-man crew was regarded as essential for the carrier-borne all-weather/night-fighter role, but the Vixen’s prolonged development meant that much of its layout was obsolescent by the time that it reached front-line squadrons.
The aircraft’s Air Intercept 18 (AI 18) radar had a reasonable performance by the standards of the time, but the displays on its primitive screens could only be read easily in darkness. This requirement was met by offsetting the cockpit to the left, allowing the observer’s (radar operator/navigator’s) seat to be buried within the forward fuselage, a position which soon became known as ‘the coal hole’. The only access was through a flush-fitting top hatch – on the first Sea Vixens, designated FAW 1 (Fighter All-Weather 1), it had only a tiny Perspex panel, and even this was fitted with a blackout blind.
