Hawker Siddeley HS 748

Powered by the popular Rolls-Royce Dart turboprop engine, it was specifically designed as a modern feederliner to act as a replacement for the aging Douglas DC-3s then in widespread service.As a means to differentiate the new airliner from competitors, it was designed to possess a high level of performance, including its short takeoff and landing (STOL) capabilities and overall ruggedness.Several different models would be developed of the regional airliner, typical improvements being the adoption of increasingly powerful Dart engines and a higher gross weight.Ten years prior, it had launched a civilian airliner, the Avro Tudor series, but this had encountered few sales; thus, during 1958, it was decided to commence work upon a clean-sheet design, which would eventually become the HS 748.[1] By this point, the four-engined Vickers Viscount had already secured the larger end of the short-haul market, therefore Avro decided that it would design a smaller regional airliner, powered by a pair of Rolls-Royce Dart turboprop engines.To differentiate itself from the competition, Avro decided to focus its efforts upon achieving a more rugged design that offered superior short takeoff and landing (STOL) performance, which enabled the prospective airliner to be operated from smaller and more austere airports, including those without modern runways.[citation needed] During the early 1960s, Avro's individual identity within the Hawker Siddeley Group was expunged, after which the airliner was marketed by the parent company as the HS 748.The series 2 was largely similar to its predecessor, principally benefiting from the adoption of more powerful Dart RDa 7 Mk 531 engines and an increased gross weight.[2] Other changes would likely have been incorporated, including the addition of lift dumpers and adaptive brakes for better landing performance, while electrical, hydraulic and air conditioning systems would be redesigned; externally, a dihedral would have to be introduced to keep the tailplane clear of the jet exhaust.According to BAE Systems, a successor company to Hawker Siddeley, during the type's production life, a total of 381 aircraft had been produced, which included both the Andover and HAL-built examples.[4] Another key market for the HS 748 was the executive role; the type was repeatedly procured to serve as the designated aircraft for various heads of state, including those of Argentina, Brazil, Chile, India, Venezuela, Zambia, Thailand and the United Kingdom.During 1972, Hughes performed several flights of the type, each time accompanied by Hawker Siddeley test pilot Tony Blackman, flying from the company's airport in Hatfield, Hertfordshire.