The Avro Type 748 is a twin turboprop airliner, powered by two Rolls-Royce Dart engines, that was sold successfully world-wide for both airline and military transport service. The first prototype (G-APZV) first flew on 24th June 1960.
Designed by AV Roe & Co Ltd, the type was later built by Hawker Siddeley Aviation Ltd, British Aerospace and Hindustan Aeronautics Ltd (HAL) and is most widely known as the HS748, the majority having been built under the aegis of Hawker Siddeley Aviation. The aircraft continued in production until 1988, and is still in limited service today, more than fifty years after its first flight. With the rationalisation of the aircraft industry in 1960, A.V. Roe Ltd were absorbed into Hawker Siddeley Aviation and with it the designation changed to the HS748. The HS748 was a remarkably successful aircraft and was an effective Douglas DC-3 replacement in many parts of the world. A total of 381 aircraft were built including 89 aircraft manufactured by HAL, with the first Indian-built aircraft flying on 1st November 1961.
The type was designed from the outset for operation from short, unimproved airstrips and was aided by the fitment of large Fowler flaps and reverse thrust propellers and an effective braking system. The use of the Rolls-Royce Dart engine also ensured excellent reliability. In 1983, and following the privatisation under the heading of British Aerospace, advertising for the type highlighted that the aircraft was “in-service with seventy-nine operators in fifty countries around the world”, with more than 300 aircraft having been exported by that time.
Significant users included Indian Airlines (Hindustan Aeronautics-built); Aerolineas Argentinas; VARIG; Phillipine Airlines; Thai Airways; LAN-Chile; Bouraq Airlines; the Indian Air Force (Hindustan Aeronautics-built); Brazilian Air Force; and the Royal Australian Air Force. Two aircraft were used by the Civil Aviation Authority (CAA) in the UK, mainly for radio navigation and landing aid calibration, with a further six being used for the same duties in West Germany.
24 HS748 Srs 1 were built before production switched to the 52-seat HS748 Srs 2 with its more powerful Rolls-Royce Dart RDa7 Mk.531 engines. This was then followed by the HS748 Srs 2A and HS748 Srs 2B, with further increases in power and maximum weight. The prototype HS.748 Srs 2 (G-ARAY) flew at Woodford on 6th November 1961. In India, two of the locally-built HS 748 Srs 2M aircraft were modified with a large, circular, pylon-mounted surveillance antenna carried above the fuselage as the HAL 748 ASP (Airborne Surveillance Platform).
One HS748 Srs 2A (G-BCDZ) was modified to carry a maritime search radar mounted under the forward fuselage. This aircraft was marketed as the 'Coastguarder' and was designed around a crew of five (two pilots, a navigator and two observers). A flight endurance of up to 11 hours was available, taking advantage of an increased fuel capacity. However, no sales were achieved and the aircraft subsequently reverted to a standard configuration.
The military freighter derivative, the HS748MF flew on 21st December 1963. The type could be distinguished by larger propeller blades. The HS748MF take-off weight was increased to 50,000 lb with the power being provided by two 2,970 hp Dart R.Da.12 engines.
The original Avro 748 prototype (G-APZV) was modified to become the aerodynamic prototype for the HS748 Andover (re-registered as G-ARRV). Thirty-one HS748 Andover C. 1 were built, the first production aircraft (XS594) flying on 9th July 1965. This type is also referred to as the HS780. The HS748 Andover C.1 could typically carry 48 troops or 40 paratroops whilst for casualty evacuation it carried 15 sitting and 18 stretcher cases. After the HS748 Andover C.1 was withdrawn from RAF service from 1975 (whilst being operated in the tactical transport role), ten were sold to the Royal New Zealand Air Force and others were disposed of to civil operators, mainly in Africa. One HS748 Andover C.1 PR (XS596) remained in use with the RAF at least until 2008, being used as the nominated UK aircraft under the international Open Skies treaty. This treaty allowed the mutual inspection of sites in NATO and ex-Warsaw Pact nations as a confidence building measure. A small number of aircraft were also converted for electronic calibration duties, these being designated as HS748 Andover E.3 or HS748 Andover E.3A. There were also six HS748 Andover CC.2's built - these were versions of HS748 Srs 2 which were specially modified for VIP transport roles. Three served in the Queens Flight, the aircraft unit entrusted with the transport of the British royal family, entering service in 1964, with the last retiring in 1991.
The last British HS748 to be built made its maiden flight at Woodford on 1st December 1988.