wing roots. During the aircraft's development, Hawker had worked closely with Rolls-Royce to reduce the engine's fuel consumption and to ensure a high level of reliability. Even within the development stages, a Hawk variant was intended to also serve as a single-seat ground-attack fighter; both the trainer and fighter models were developed with the export market in mind. On single seat models, the forward cockpit area which normally houses a pilot is replaced by an electronics bay for avionics and onboard systems, including a fire control computer, multi-mode radar, laser rangefinder and forward-looking infrared (FLIR). Some export customers, such as Malaysia, have extensive modifications to their aircraft, including the addition of wingtip hardpoint stations and a fittable inflight refuelling probe. The Hawk was designed to be manoeuvrable and can reach Mach 0.88 in level flight and Mach 1.15 in a dive, thus allowing trainees to experience transonic flight before advancing to a supersonic trainer. The airframe is very durable and strong, stressed for +9 g; the normal limit in RAF service is +7.5/-4 g. A dual hydraulic system supplies power to operate systems such as the aircraft's flaps, airbrakes and landing gear, together with the flight controls. A ram air turbine is fitted in front of the single tail fin to provide backup hydraulic power for the flight controls in the event of an engine failure; additionally, a gas turbine auxiliary power unit is housed directly above the engine. The Hawk is designed to carry a centreline gun pod, such as the 30 mm ADEN cannon, two under-wing pylons, and up to four hardpoints for fitting armaments and equipment. In RAF service, Hawks have been equipped to operate the Sidewinder air-to-air missiles. In the early 1990s, British Aerospace investigated the possibility of arming the Hawk with the Sea Eagle anti-ship missile for export customers. In 2016, BAE Systems was developing the so-called 'Advanced Hawk' with a new wing using leading-edge slats, and potentially additional sensors and weapons, a head-mounted display, and a single large-screen display in the forward cockpit. Operational history United Kingdom The Hawk entered RAF service in April 1976, replacing the Folland Gnat and Hawker Hunter for advanced training and weapons training. The Hawk T1 was the original version used by the RAF, deliveries commencing in November 1976. The most famous users of the Hawk are the Red Arrows aerobatic team, who adopted the plane in 1979. From