The WS-61 Sea King HAS Mk. 5 Is a medium-lift transport and utility helicopter built under licence by Westland Helicopters. It first took flight in 1969. The HAS Mk.5 variant first entered service in 1981.
As with the Dragonfly and Whirlwind, the Sea King is a British-made version of an American Sikorsky helicopter. In this case the Sikorsky S-61.
Following the success of anti-submarine helicopters such as the Whirlwind HAS.7, there was quite a bit of enthusiasm for improving this method of keeping the seas safe from the enemy.
While the HAS.7, which was introduced in the mid-50s, had to work in hunter-killer groups, this new generation of ASW helicopter could hunt and kill all by itself.
It can carry four Mk. 46 torpedoes. Alternatively it can also be armed with Mk.11 depth charges. The HAS Mk.5 also has more powerful Rolls-Royce Gnome engines that produce 1 660 shaft horsepower each.
The Sea King HAS Mk.5 uses submersible hydro-acoustic buoys and long range radar, coupled with advanced acoustic processing technology.
Around 85 HAS Mk.5 units were built. Of these 30 were entirely new and 55 were converted from earlier Sea King Models. Of these some were yet again converted into the HAR.5 search and rescue variant.