The aircraft differs considerably from the American version, with Rolls-Royce Gnome engines (derived from the US General Electric T58), British-made anti-submarine warfare systems and a fully computerised flight control system. The Sea King was primarily designed for performing anti-submarine warfare (ASW) missions. A Sea King variant was adapted by Westland as troop transport known as the Commando. In 1974, Australia purchased 12 Westland Sea King Mk 50s as the Royal Australian Navy's new ASW helicopter; the Sea Kings replaced the aircraft carrier HMAS Melbourne's complement of Westland Wessex HAS31 in the following year. Early operations were troubled by a series of accidents. Between October 1975 to May 1979, four aircraft were lost in accidents, the primary causes were the loss of oil from the main gearbox. The Australian Sea Kings had similar avionics to that of the Sea King HAS.1, with the same ARI 5995 search radar in a dorsal radome, but had American Bendix AN/ASQ-13A dipping sonar instead of the Plessey sonar of the Royal Navy Sea Kings. They also had more powerful engines giving improved high temperature hover performance. Australia's Sea Kings were flown by 817 Squadron RAN from HMAS Melbourne until the carrier was retired from service, without replacement. As the Sea King was too large to operate from the Adelaide-class frigates, 817 Squadron was then forced to operate from land bases, in both ASW and utility roles, with the Sea King relinquishing the anti-submarine mission in 1990. In the aftermath of the 2004 Indian Ocean earthquake and tsunami, Australian Sea Kings played a major role in disaster relief efforts in Indonesia's Aceh province, delivering medical teams and supplies from Royal Australian Navy ships. Prior to retirement, the last major missions were flown during the 2010–11 Queensland floods, in which Sea Kings provided SAR coverage of the region and delivered aid relief to citizens in the flooded areas. Formore information, click here.
