Westland Sea King
in
Fleet Air Arm

When an initial order for 60 Sea King HAS.1s was placed with Westland Aircraft Ltd by the UK Ministry of Aviation on behalf of the RN for £24 million in late 1966, it was the largest order for helicopters ever placed with a British company.

Approx 112 HAS type were in service by Oct 2003. First Westland built airframe was c/n WA630 (XV642) which flew on 7 May 1969 from Yeovil. At least 8 marks for the Royal Navy since that date, either as new build or rework on existing airframes.

The Sea King HAS.1 retained the Sikorsky H-3 watertight hull, 5 bladed all metal main rotor and fixed tail wheel. Wessex HAS.3 radar/sonar and UK Gnome H.1400 engines. Initial production was of the HAS.1, 56 of which were delivered to the Royal Navy, (remaining 4 were the development machines).

By 1974, the HAS.2 was designed. New build HAS.2 with improved Gnome H.1400-1 engines, increased fuel capacity, a 6 bladed tail rotor and air intake deflectors/filters. Order for 13 in Nov 1974 and 8 more in 1976. Internal improvements include a Marconi Acoustic Processing & Display suite. XZ570 ff 18 Jun 1976, all delivered by Oct 1979. The remaining 48 HAS.1s were upgraded at RNAY Fleetlands, and NASU Culdrose and known as HAS.2A; All front line Sea Kings were at HAS.2/2A standard by Jul 1978.

The Sea King HAS.5 was developed from the HAS.2, beginning in Jan 1979 with major avionics update and introduced a Magnetic Anomaly Detector (MAD) housed in the starboard undercarriage sponson and winched away from the airframe for operations. f/f 14 Aug 1980, first 2 handed to RN on 2 Oct 1980. From 1980, 30 (new) Sea King HAS.5 were built with a Thorn-EMI (MEL) Sea Searcher radar, Plessey dipping sonar, Racal Orange Crop ESM, Jezebel passive sonobuoys and composite rotors to replace original all-metal ones. 35 HAS.2A conversions were rebuilt as HAS.5 in early 1980s.

Following the critical lack of an airborne radar picket during the Falklands campaign of 1982, the folly of relying on RAF Shackleton AEW.2s for out-of-theatre operations, after the 1978 retirement of the carrier-based Gannet AEW.3 by HM Treasury-led cuts was evident.  Westland rushed two HAS.2A development airframes through an intensive programme between May and Aug 1982 to fit the Thorn-EMI Searchwater radar (as in the Nimrod) into an air-pressured, external, swivelled Kevlar housing (known as a dustbin) on the starboard side of the airframe, Cossor Jubilee Guardsman electonic warfare system was fitted and the internal observer stations were updated. The first airframe was available at the end of 1982. 10 Sea King HAS.2s were converted into AEW.2As.

The Sea King HAS.6 (six new and 69 conversions from 1990, with Westland kits) operated from 1989 and feature improved airframe and tranmission, GEC-Marconi 2069 dipping sonar, further improved signal processing, internal-mount MAD, revised Racal Orange Reaper ESM and Gnome H1400-2 engines. Includes the GEC-Marconi AD3400 VHF/UHF secure speech radio.  The HAS.6 was also the last version of Sea King to be used in the anti-submarine role, following its withdrawal from the front line in 2004.  By Aug 2004, the Royal Navy had no effective, primary role anti-submarine helicopter, while the Merlin remained non-operational and is still grounded.

9 Sea King AEW.2As have been converted to AEW.7 standard with Gnome H1400-2 engines, renamed Sea King ASaC.7 and introduced in 2001.

Some low flying hours Sea King HAS.6s are having their anti-submarine sensors and signal processing stations removed to function in the main role of Commando assault with a secondary Carrier Onboard Delivery (COD). The Sea King HAS.6C was converted at DARA Fleetlands during 2004 and retains its main wheel sponsons but the undercarriage is fixed in the lowered position and an improved defensive package fitted. The first of type were issued in mid 2004.