 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 . 
