Anti-submarine warfare (ASW), medium-lift transport and utility helicopter
British licence-built version of the American Sikorsky S-61 helicopter (SH-3 Seaking)
Sea King AEW.2 - Conversion of Sea King HAS.1 or HAS.2s into AEW (Airborne Early Warning) 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; 19 built.
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; 30 new build aircraft plus about 55 converted from earlier versions. Some later converted into the HAR.5 for Search and Rescue.