Westland Sea King AEW.2/AEW.5
Although studies had long existed for AEW variants of the Sea King it was not until 1982 at the height of the Falklands War that a hurried project was begun. Impressively the first two aircraft were flying within 11 weeks of the start of the project and arrived in theatre aboard HMSIllustrious just after hostilities had ceased. Nine aircraft were converted from Sea King HAS.2s before new production based on the Sea King HAS.5 began. Equipped with the same Searchwater radar, there were only minor differences between both variants, although the Mark 5 had improved avionics. Sea King AEW.2s and 5s served aboard every British aircraft carrier during the war and from land bases. They also occasionally operated from other suitable warships, RFAs and from the occasional merchant ship.
Westland Sea King AEW.7/ASaC.7
While externally very similar to the previous AEW variants of the Sea King the Mark 7 is different enough to warrant its own entry. Equipped with a much improved Searchwater 2000 radar, often now called the Cerberus (after name of the upgrade project), Link 16 and a host of other electronic systems the navy does not like to talk about, the Mark 7 is a step-change from the Mark 2 and 5. The change of designation from Airborne Early Warning (AEW) to Airborne Surveillance and Control (ASaC) reflects the greater capabilities of the aircraft. Moreover as well as airborne surveillance duties the Mark 7 demonstrated in Afghanistan that it was capable of tracking ground targets very effectively, in essence becoming a mini Sentinel R.1. It is currently planned that the Mark 7 will remain in service until around 2018, when the successor enters service.
AWI Merlin ASaC.5
That ‘something else’ will be the Merlin ASaC.5, which is being developed as part of ‘Project Crowsnest’. The RN studied a number of potential replacements for the Sea King Mark 7 (q.v), including AEW variants of the V-22 Osprey, before deciding that a Merlin based solution was the best option. Currently two different teams, one led by Lockheed Martin, the other by Thales, are offering competing radar systems. No decision has been taken as to which bidder has will be chosen has yet been taken, although Merlins have been spotted fitted with the competing systems. The first Merlin Mark 5s are due to join the fleet in late 2017, early 2018.