Westland WS-61 Sea King

The Westland WS-61 Sea King is a British licence-built version of the American Sikorsky S-61 helicopter of the same name, built by Westland Helicopters. 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 computerized 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 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 and the Afghanistan War, the Sea King is perhaps most well known in its capacity as a Royal Navy Search and Rescue (red and grey livery) and RAF Search and Rescue Force (yellow livery) helicopter. The Sea King was also adapted to meet the Royal Navy's requirement for a ship-based airborne early warning platform.
As of 2014, the WS-61 Sea King remains in operation in Britain, as well as several export customers: Germany, Norway, Egypt and India. Some operators have replaced, or are planning to replace, the Sea King with more modern helicopters, such as the NHIndustries NH90 and the AgustaWestland AW101 Merlin.
==Variants==
===Royal Navy variants===
*Sea King HAS.1: The first anti-submarine version for the Royal Navy, with Gnome H.1400 engines, a five-bladed tail rotor, a Plessey Type 195 dipping sonar and MEL ARI 5995 search radar in a dorsal radome. The Westland Sea King HAS.1 first flew on May 7th 1969. Fifty-six built, many of which were converted to HAS.2.
*Sea King HAS.2: Upgraded anti-submarine version for the Royal Navy, based on Australian Mk 50. More powerful Gnome H.1400-1 engines, six bladed tail rotor and upgraded avionics (including new Type 2069 dipping sonar), and improved navigation and communications equipment; 21 new build aircraft plus conversions from HAS.1s. Some were later converted for AEW (Airborne Early Warning) duties.
*Sea King AEW.2: Conversion of Sea King HAS.1 or HAS.2s into AEW aircraft after lack of AEW cover was revealed during the Falklands War. Fitted with Thorn EMI Searchwater radar in inflatable radome, with sonar removed. Normally flown with three person (pilot and two observers) crew compared with four-person crew for ASW Sea Kings. Nine converted.
*Sea King HAR.3: Search and rescue version for the Royal Air Force. Fitted with relocated rear cabin bulkhead giving greater cabin length, extra fuel and additional observation windows; Nineteen built.
*Sea King HAR.3A: Improved search and rescue version of the Sea King HAR.3 for the Royal Air Force. Fitted with upgraded avionics; six built.
*Sea King HC.4/Westland Commando: Commando assault and utility transport version for the Royal Navy, with simplified undercarriage, and lengthened cabin. Capable of transporting 28 fully equipped troops; 42 built.
*Sea King HC.4A: One aircraft first flown on April 10th 1989 for the Empire Test Pilots' School.
*Sea King HC.4X: Two helicopters based on the HC.4 for trials/test beds at the Royal Aircraft Establishment at Farnborough. Fitted with various nose and/or dorsal sensor installations.
*Sea King HAS.5: Upgraded anti-submarine warfare version for the Royal Navy, with longer range MEL Super Searcher radar in enlarged dorsal radome, new AQS902 acoustic processing system with provision to use sonobuoys. Entered service in June 1981. Thirty new build aircraft plus about fifty-five converted from earlier versions. Some later converted into the HAR.5 for Search and Rescue.
*Sea King HAR.5: Conversion of HAS.5 to search and rescue role for the Royal Navy, with ASW equipment removed but retaining Sea Searcher radar.
*Sea King AEW.5: Four Sea King HAS.5s were converted into AEW helicopters for the Royal Navy.
*Sea King HU.5: Surplus HAS.5 ASW helicopters converted into utility role for the Royal Navy.
*Sea King HAS.6: Upgraded anti-submarine warfare version for the Royal Navy. fitted with improved avionics, with new sonar processor, improved tactical displays and better communications equipment; five new build aircraft plus conversions.
*Sea King HAS.6(CR): Five surplus HAS.6 ASW helicopters converted into the utility role for the Royal Navy. The last of the Royal Navy's HAS.6(CR) helicopters was retired from service with 846 NAS on March 31st 2010.
*Sea King ASaC7:Upgraded AEW2/5 for the Royal Navy with Searchwater 2000AEW replacing original Searchwater radar.
===Export variants===
*Sea King Mk.41: Search and rescue version of the Sea King HAS.1 for the German Navy, with longer cabin; Twenty-three built, delivered between 1973 and 1975. A total of Twenty were upgraded from 1986 onwards with additional Ferranti Seaspray radar in nose and capability to carry four Sea Skua Anti-ship missiles.
*Sea King Mk.42: Anti-submarine warfare version of the Sea King HAS.1 for the Indian Navy; Twelve built
*Sea King Mk.42A: Anti-submarine warfare version of the Sea King HAS.2 for the Indian Navy, fitted with haul-down system for operating from small ships; three built.
*Sea King Mk.42B: Multi-purpose version for the Indian Navy, equipped for anti-submarine warfare, with dipping sonar and advanced avionics, and anti-shipping operations, with two Sea Eagle missiles; Twenty-one built (with one crashing before delivery).
*Sea King Mk.42C: Search and rescue/utility transport version for the Indian Navy with nose mounted Bendix search radar; six built.
*Sea King Mk.43: Search and rescue version of the Sea King HAS.1 for the Royal Norwegian Air Force, with lengthened cabin; 10 built.
*Sea King Mk.43A: Uprated version of the Sea King Mk.43 for the Royal Norwegian Air Force, with airframe of Mk.2 but engines of Mk.1; single example built.
*Sea King Mk.43B: Upgraded version of the Sea King Mk.43 for the Royal Norwegian Air Force. Upgraded avionics, including MEL Sea Searcher radar in large dorsal radome, weather radar in nose and FLIR turret under nose. Three new-build plus upgrade of remaining Mk.43 and Mk.43A helicopters.
*Sea King Mk.45: Anti-submarine and anti-ship warfare version of the Sea King HAS.1 for the Pakistan Navy. Provision for carrying Exocet anti-ship missile; six built.
*Sea King Mk.45A: One ex-Royal Navy Sea King HAS.5 helicopter was sold to Pakistan as an attrition replacement.
*Sea King Mk.47: Anti-submarine version of the Sea King HAS.2 for the Egyptian Navy; six built.
*Sea King Mk.48: Search and rescue version for the Belgian Air Force. Airframe similar to HAS.2 but with extended cabin; five built, delivered 1976. Retired in 2018.
*Sea King Mk.50: Multi-role version for the Royal Australian Navy, equivalent to (but preceding) HAS.2; 10 built.
*Sea King Mk.50A: Two improved Sea Kings were sold to the Royal Australian Navy as part of a follow-on order in 1981.
*Sea King Mk.50B: Upgraded multi-role version for the Royal Australian Navy.
*Commando Mk.1: Minimum change assault and utility transport version for the Egyptian Air Force, with lengthened cabin but retaining sponsons with floatation gear; five built.
*Commando Mk.2: Improved assault and utility transport version for the Egyptian Air Force, fitted with more powerful engines, non-folding rotors and omitting undercarriage sponsons and floatation gear; Seventeen built.
*Commando Mk.2A: Assault and utility transport version for the Qatar Emiri Air Force, almost identical to Egyptian Mk.2; three built.
*Commando Mk.2B: VIP transport version of Commando Mk.2 for the Egyptian Air Force; two built.
*Commando Mk.2C: VIP transport version of Commando Mk.2A for the Qatar Emiri Air Force; one built.
*Commando Mk.2E: Electronic warfare version for the Egyptian Air Force, fitted with integrated ESM and jamming system, with radomes on side of fuselage; four built.
*Commando Mk.3: Anti-ship warfare version for the Qatar Emiri Air Force, fitted with dorsal radome and capable of carrying two Exocet missiles. Eight built.
==Users==
*Australia
**Royal Australian Navy
*Belgium
**Belgian Air Component
*Egypt
**Egyptian Air Force
*Germany
**Bundesmarine
***Marineflieger
**Luftwaffe
*India
**Indian Navy
*Norway
**Royal Norwegian Air Force
*Pakistan
**Pakistan Naval Air Arm
*Portugal
**Portuguese Air Force
*Qatar
**Qatar Emiri Air Force
*Sierra Leone
**Sierra Leone Air Force
*Ukraine
**Ukrainian Navy
*United Kingdom
**Royal Air Force
**Royal Navy
***Royal Marines
==See Also==
===Related Development===
*Sikorsky S-61
*Sikorsky S-61R
*Sikorsky SH-3 Sea King
*Sikorsky CH-124 Sea King
===Comparable Aircraft===
*AgustaWestland AW101 Merlin
*NHIndustries NH90
*Sikorsky UH-60 Blackhawk
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