was immediately acquired by Trans Australia Airlines and entered airline service in Australia as VH-TVB. In 1959 it appeared at that year's Farnborough Airshow. It was sold to Ansett-ANA in 1962 and re-registered as VH-RMQ. In September 1968 the aircraft was transferred to Western Australia and operated by MacRobertson Miller Airlines, by then a subsidiary of Ansett-ANA. In 1958 the operator, Trans Australia Airlines, replaced both inner lower booms. In 1964 the new owner, Ansett-ANA, again replaced both inner lower booms. In February 1968 the aircraft became the first Australian Viscount to reach 30,000 flying hours. It was last inspected by Ansett-ANA in May 1968 when it had made 7,169 flights since the 1964 lower boom replacement. It made another 922 flights before the accident. By 31 December 1968 the aircraft had made 25,336 flights and had flown for 31,746 hours. Since its previous complete overhaul it had made 6,429 flights and had flown for 7,188 hours. Recorders The aircraft was equipped with a flight data recorder and a cockpit voice recorder. The flight data recorder functioned throughout the flight and continuously recorded the aircraft's pressure altitude, indicated airspeed, vertical acceleration and magnetic heading until the moment of impact with the ground. The cockpit voice recorder was slightly damaged in the impact and subsequent fire but there was no damage to the record of radio transmissions from the aircraft during the final 30 minutes of the flight. The record of ambient noise in the cockpit was also preserved and revealed the precise moment at which the frequency and volume of noise increased suddenly. Safe-life design The wing of the Vickers Viscount used a single main spar made up of a centre section in the fuselage, two inner sections and two outer sections. The main spar comprised an upper boom, a shear web and a lower boom. The aircraft was designed and type-certificated to the principle of a safe-life. Before a component reaches its safe-life it must be removed from the aircraft and retired. At the time of the accident, the retirement life of the lower boom in the centre section was 20,500 flights; the inner lower boom was 11,400 flights; and the outer lower boom was 19,000 flights. The retirement life of the spars in the horizontal tailplanes and the vertical fin was 30,000 flights. The retirement life of the wing spar of a transport category aeroplane type-certificated to the