Westland Sea King ASaC.7, ZA126, operated by 849 Naval Air Squadron based at RNAS Culdrose, is seen here displaying at RNAS Yeovilton Air Day 2018, probably for the last time as these helicopters, the last of the UK's Sea King fleet still operational, are due to be retired during the second half of 2018.
The Sea King ASaC.7 Airborne Surveillance and Control – known throughout the Navy as Baggers – are the ‘eyes in the sky’ of the Navy, searching for aerial threats to the Fleet – or suspicious movements on the ground in support of land forces.
The nickname results from the distinctive inflatable black sack or bag, which covers the radar on the side of each helicopter.
It may look a rather cumbersome piece of kit from the outside, but inside that sack is the cutting-edge Searchwater 2000 radar capable of remarkably-accurate detection of surface and air targets.
Once enemy units are detected, the helicopter’s observers can direct friendly air, sea or ground forces to intercept – as they did with devastating effect during the fighting in southern Iraq in 2003.The Royal Navy's airborne early warning (AEW) capability had been lost when the Fairey Gannet aeroplane was withdrawn after the last of the RN's fleet carriers was decommissioned in 1978. During the Falklands War, a number of warships were lost and casualties suffered due to the lack of an AEW platform. The proposed fleet cover by the RAF Shackleton AEW.2 was too unresponsive and at too great a distance to be practical. Consequently, two Sea King HAS2s were modified in 1982 with the addition of the Thorn-EMI ARI 5980/3 Searchwater LAST radar attached to the fuselage on a swivel arm and protected by an inflatable dome. This allowed the radar to be lowered below the fuselage during flight and for it to be raised for landing. These prototypes, designated HAS2(AEW), were both flying within 11 weeks and deployed with 824 "D" Flight on HMS Illustrious, serving in the Falklands after the cessation of hostilities. A further eight HAS2s were modified to a production standard, known as the AEW2. Two remained "fitted for but not with". These entered operational service in 1985, being deployed by 849 Naval Air Squadron. Three Sea King HAS5/6s were later converted as part of the ASaC Mk7 programme, bringing the Mk7 fleet to 13; still 3 below the requirement.
The upgrade programme resulted in the Sea King AEW fleet being upgraded with a new mission system, Comms, NavAids, JTIDS, Active Noise Reduction and Videographic recording. The Mission System Upgrade (MSU) component (Radar and partial JTIDS integration) was based around the improved Searchwater 2000AEW radar, with an all-new man Machine Interface. This MSU component was later termed "Project Cerberus" by Thales, after successful integration was conducted by Westland and GEC-Marconi. This variant was initially referred to as the Sea King AEW7, but renamed ASaC7 just before In Service Date. (Airborne Surveillance and Control Mk.7). The main role of the Sea King ASaC7 is detection of low-flying attack aircraft; it also provides interception/attack control and over-the-horizon targeting for surface-launched weapon systems. In comparison to older versions, the new radar enables the ASaC7 to simultaneously track up to 400 targets, instead of an earlier limit of 250 targets. The effectiveness of the AEW7 was greatly increased via the addition of a Link 16 data link, allowing gathered radar information to be analysed and rapidly put to use by multiple allied platforms in range.
The ASaC7s will remain in service until they are replaced under the "Crowsnest" programme; intended as a podded capability onboard Merlins. Previous proposed replacement programmes, Future Organic Airborne Early Warning (FOAEW) and MASC (Maritime Airborne Surveillance and Control) were initiated and then cancelled, due largely to the erroneous assumption that the entire ASaC Mk7 system could simply be lifted and plugged into another aircraft type. However, as a result of the time gap between the planned out of service date of the Sea King in 2016, and the introduction of "Crowsnest" seven Sea King ASaC.7 helicopters will remain in service with the RN through to the second half of 2018.
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