HS 748

The Hawker Siddeley HS 748 is a twin-engined turboprop airliner designed by Avro in the United Kingdom and later marketed by Hawker Siddeley. Conceived as a 40-seat feederliner to replace the Douglas DC-3, it first flew on 24 June 1960 and entered revenue service in 1961. It is known for its short takeoff and landing performance and rough-field capability, and served widely in both civil and military transport roles.

Development

Following the 1957 Defence White Paper and the cancellation of most crewed military aircraft programmes, Avro shifted toward the civil market and began a clean-sheet design in 1958. The project was announced publicly as the Avro 748 on 9 January 1959. Initially planned as a 20–30 seat aircraft, it was enlarged to a 40-seat low-wing configuration after consultation with prospective customers. The first aircraft flew from Woodford, Cheshire, on 24 June 1960; 18 Series 1 aircraft were built, with deliveries to launch customer Skyways Coach-Air beginning in April 1962 and most going to Aerolíneas Argentinas. The Series 2 followed with Dart RDa 7 Mk 531 engines and higher gross weight, the Series 2A with Mk 532 engines in 1967, and the Series 2B in 1979 with a 4 ft wingspan increase and Mk 536-2 engines. Hindustan Aeronautics licence-built the type in India, the first HAL-748 flying on 1 November 1961; 89 were completed, 72 for the Indian Air Force and 17 for Indian Airlines. Production ended in 1988 with 381 aircraft built including Andovers and HAL examples, the last British-assembled aircraft flying on 1 December 1988.

Design

The 748 used a long high-lift wing mounted low on the fuselage with dihedral from the root, fitted with a single slotted flap with a hinged flap tab at the trailing edge and three selectable takeoff flap settings. It was among the first medium-sized aircraft designed to fail-safe rather than safe-life structural principles, and the airframe was water-tank tested to the equivalent of 100,000 flight hours. Systems were kept simple and used proven components, with internal engine ignition and structures designed for inspection and repair at unprepared strips. The Super 748 is powered by two Rolls-Royce Dart RDa.7 Mk 536-2 turboprops of 2,280 shp driving four-bladed Dowty Rotol propellers, with a maximum takeoff weight of 46,500 lb and a payload of 11,323 lb.

Operational History

By 1976, 312 aircraft had been sold, 259 of them for export. Indian Airlines was the largest operator with 26 aircraft; other customers included Aerolíneas Argentinas, Varig, Thai Airways, LAN-Chile, Bouraq and Philippine Airlines, which replaced its Fokker F27 fleet with the type. Military operators included the RAF, RAAF, Royal Australian Navy, Brazilian Air Force (as the C-91), Belgian Air Force, Sri Lanka Air Force and Indian Air Force. Two Sri Lanka Air Force aircraft were shot down by LTTE SA-7 missiles on 28 and 29 April 1995, killing all aboard. The last Western Hemisphere example, Air Creebec C-FLIY, flew to the Canadian Aviation Museum on 30 May 2025; the UK CAA withdrew the type certificate on 1 July 2025, though HAL-built aircraft continue with the Indian Air Force pending replacement by the Airbus C295.

Variants

• 748 Series 1: Original production model with Dart RDa 7 Mk 514 engines, 24 built.
• 748 Series 2: Higher takeoff weight and Mk 531 engines, entering production in 1961, 111 built.
• 748 Series 2A: Introduced in 1967 with further weight increase and Mk 532 or 534 engines, 157 built.
• 748 Series 2B: British Aerospace-era model with 4 ft greater wingspan, Mk 536 engines and modernised cabin, 28 built.
• HS 780 Andover: RAF military transport with kneeling undercarriage, raised tail and rear loading ramp.