The de Havilland DH.110 Sea Vixen is a British twin-engine, twin boom-tailed, two-seat, carrier-based fleet air-defence fighter flown by the Royal Navy's Fleet Air Arm during the 1950s through to the early 1970s. The Sea Vixen was designed by the de Havilland Aircraft Company during the late 1940s at its Hatfield aircraft factory in Hertfordshire, developed from the company's earlier first generation jet fighters. It was later called the Hawker Siddeley Sea Vixen after de Havilland was absorbed by the Hawker Siddeley Corporation in 1960. The Sea Vixen had the distinction of being the first British two-seat combat aircraft to achieve supersonic speed, albeit not in level flight. Operating from British aircraft carriers, it was used in combat over Tanganyika and over Yemen during the Aden Emergency. In 1972, the Sea Vixen was phased out in favour of the American-made McDonnell Douglas Phantom FG.1 interceptor. There have been no flying Sea Vixens since 2017. The de Havilland Sea Vixen was a jet-powered fleet defence fighter, equipped with a modern radar and air-to-air missiles for its primary role. When it entered service, it was the first British aircraft to be solely armed with missiles, rockets and bombs; this made it the first fighter aircraft operated by the Fleet Air Arm with no gun armament. The Sea Vixen FAW.1 was armed with four de Havilland Firestreak air-to-air missiles, while the Sea Vixen FAW.2 could also carry the later, more capable Red Top missile. The original DH.110 design offered to the RAF was armed with four cannon before soon being replaced with an all-missile armament. The Red Top homing head was pointed in the direction of the target by slaving it to the AI18 radar, which was operated by the observer. In addition to its principal fleet-defence role, the Sea Vixen was also used in the ground-attack role for which it could be armed with two Microcell unguided two-inch (51 mm) rocket packs, Bullpup air-to-ground missiles, and four 500 lb (227 kg) or two 1,000 lb (454 kg) bombs. The Sea Vixen was equipped with a refuelling probe for aerial refuelling from tanker aircraft to extend its range. It could also be equipped as a tanker for refueling other aircraft. The Sea Vixen FAW.1 was cleared to carry the Red Beard free-fall nuclear bomb in the event of an "extreme operational emergency". The Sea Vixen was powered by a pair of Rolls-Royce Avon 208 turbojet engines and could reach a maximum speed of 690 mph (1,110 km/h) and a range of up to 600 mi (1,000 km). It had a twin-boom tail configuration, as used on the earlier de Havilland Sea Vampire and Sea Venom fighter aircraft. The internal volume of the tail boom was used for both fuel and avionics, and was considerably enlarged for this purpose on the improved Sea Vixen FAW.2. The twin-boom tail reduced the length and height of the aircraft, which reduced the stowage area and head-room required onboard aircraft carriers; it also minimised asymmetry during single engine flying, reduced the length of the jet pipes and improved maintenance access. The Sea Vixen had a crew of two, a pilot and a radar operator. The pilot's canopy was offset to the left-hand side of the fuselage, while the radar operator sat to the right completely within the fuselage, the latter gaining access to his position through a flush-fitting top hatch, nicknamed the "Coal Hole". For more details of the background, design and development, and operational history, click here. There is a Sea Xixen on public display at Queensland Air Museum, Caloundra. Airframe complete, but internals removed.