The Westland WS-61 Sea King is a British version of the American Sikorsky S-61 helicopter. Westland Helicopters had a long-standing license agreement with Sikorsky Aircraft to allow it to build the Sikorsky helicopter, and they extended the agreement soon after the Sea King's first flight in 1959.
Westland independently developed the Sea King, with the key changes including the use of a pair of Rolls-Royce Gnome turboshaft engines and the implementation of a fully computerised flight control system.
Many of the differences between the Westland-built Sea King and the original helicopter were as a result of differing operational doctrine.
While the U.S. Navy Sea Kings were intended to be under tactical control of the carrier from which they operated, the Royal Navy intended its helicopters to be much more autonomous, capable of operating alone, or co-ordinating with other aircraft or surface vessels.
The Sea King was primarily designed to perform anti-submarine warfare (ASW) missions.However this anti-submarine role was extended to include anti-ship warfare by the Pakistan Navy and Qatar Emiri Air Force by the addition of Exocet missiles.
Six were built with this modification for Pakistan and eight were built for Qatar.
The need for AEW cover was revealed during the Falklands War when the RN lost a number of ships as a result of not having this capability.
One of the most extensively modified variants was the Westland Commando, which as adapted as a troop transport.The Commando had the capacity for up to 28 fully equipped troops, and had been developed for the Egyptian Air Force for operations over land [and desert].
An assault and utility transport version built for the Qatar Emiri Air Force, was almost identical to Egyptian Mk.2; but only three were built.
The Egyptian Air Force also ordered four electronic warfare units fitted with an integrated ESM and jamming system, with radomes on side of fuselage, and they further modified two additional Commandos to serve as VIP transport aircraft.The Qatar Emiri Air Force also ordered one of these VIP transports.
In British service, the Westland Sea King provided a wide range of services in both the Royal Navy and the Royal Air Force.As well as wartime roles in the Falklands War, the Gulf War, the Balkans conflict, the Iraq War and the Afghanistan War.
As of 2014, Westland had produced a total of 330 Sea Kings; with export customers in addition to the Royal Australian Navy, including Germany, Belgium, Norway, India, Pakistan, Egypt and Qatar.
The Sea King Mk.50 was the Australian carrier-borne multi-role anti-submarine search and rescue helicopter, that was also used for delivery of people and provisions between ships and between ship and shore, detection and reporting of hostile shipping, army support when the army moves from ship to shore, disaster relief and aid to the civil community.
Australia ordered 10 Mk 50's in 1974 and then two 2 improved Mk 50A in 1981.
At a later date we ordered an unspecified number of the further upgraded Mk.50B helecopters.
The Length of the Mk50 was 22.15 metres, its height was 5.13 metres, and it weighed 6,201 kilograms.It had a wing span: 18.9 metres for its five bladed main rotor, and it had a six bladed rear rotor.Earlier British models only had four blades at the rear.
It was powered by two 1,500 shp Rolls Royce Gnome H 1400 shaft turbine engines. These allowed improved high temperature hover performance, a speed of 230 kph, and a range of 925 kilometres.Its initial rate of climb was 3,000 ft/minute, and its ceiling was 14,700 ft
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.
It could be fitted with door mounted Mag 58 machine guns, and had 4 Mk44 or Mk 45 torpedoes (external) in ASW configuration
In 1974, Australia purchased 12 Westland Sea King Mk 50's, replacing the HMAS Melbourne's complement of Westland Wessex HAS31.
For some 35 years the Sea King was the workhorse of the RAN's fleet. It was a large and very versatile helicopter with the ability to pick up loads heavier than a Land Rover.
The aircraft could operate day and night, in good weather and bad, at low level over the sea and over land.
However, early operations were troubled by a series of accidents.
Between October 1975 and May 1979, four aircraft were lost in accidents; the primary causes were the loss of oil from the main gearbox.
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.
During the 2003 Iraq War, Sea Kings were heavily used in logistical roles, such as the first delivery of humanitarian aid to the Iraqi capital, Baghdad.
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.
Prior to retirement, the last major missions were flown during the 2010–2011 Queensland floods, in which Sea Kings provided SAR coverage of the region and delivered aid relief to citizens in the flooded areas.
The replacement of the Fleet Air Arm's Sea King fleet commenced faster than initially planned following the loss of a Sea King during a humanitarian aid mission in Indonesia in April 2005, resulting in nine deaths. Investigators uncovered serious faults in the condition of the Sea King's mechanical flight control system, resulting from maintenance deficiencies.In May 2007, the six remaining Sea Kings were grounded for two months following the discovery of a number of missing parts.
On 1 September 2011, the Australian Minister for Defence Materiel, Jason Clare, announced that the Sea Kings would be withdrawn from service in December 2011; having flown in excess of 60,000 hours in operations in Australia and overseas.
The farewell flight was conducted on 15 December 2011; three Sea Kings flew over Sydney Harbour and across to Canberra, passing Lake Burley Griffin and the Australian War Memorial before landing at Nowra.
On 16 December 2011, the Chief of Navy presided over the ceremonial decommissioning of 817 Squadron RAN at NAS Nowra.Five of the withdrawn helicopters have been made available for sale.
The replacement for the Sea King is the MRH 90.