Royal Navy - Naval Aviation - Sea King Helicopter - n5a3 - Armed Forces



Royal Navy Westland Sea King HC 4 prepares to land aboard the U.S. Military Sealift Command (MSC) ship USNS Pecos

The Westland Sea King is a licence-built version of the US Sikorsky S-61. The Royal Navy's HAS Mark 1 aircraft's first flight was in 1969. Since that time, the aircraft has been extensively upgraded and passed through a series of Marks.

The Sea King Mk 7 is used for airborne surveillance and control and has Search Water 2000 Radar carried in a radardome that can be swivelled down underneath the aircraft for operational air and sea searches. In addition, there is an Orange Crop Electronic Support Measures system fitted. A detachment of 3 x AEW 2 aircraft generally deploys with each assault ship. The newly upgraded Merlin Mk 2 will replace the Sea King Mark 7 and is capable of fulfilling several roles, including provision of the Airborne Surveillance and Control capability.

The Sea King HC4 (Commando) is a tactical military helicopter capable of transporting 28 fully equipped troops or 6,000 lbs (2,720 kg) as an internal load. Carrying 28 troops the aircraft has a range of about 246 miles (396 km). The first HC4 deliveries were made to the Royal Navy in 1979.

By the end of 2015, 20 x Merlin Mk 3 Medium Support Helicopters will be transferred from the RAF to the Commando Helicopter Force.

The Mk 5 aircraft in service with 771 Sqn are SAR aircraft (Search & Rescue). RN SAR aircraft are stationed at Prestwick and Culdrose.


From 2016, 10 x Sikorsky S92s and 10 x AgustaWestland AW189s operated by Bristow Helicopters will replace the Sea Kings Mk 5. Current plans suggest that the last Sea Kings will retire from service at the end of March 2016.

Sea King HC 4 Specifications


1 x pilot and 1 x aircrewman

Fuselage Length






Weight (empty)


Max Take-off weight


Rotor Diameter


Cruising Speed

208km/h (129mph) at sea level

Service Ceiling 1,220m
Engines 2 x Rolls Royce Gnome H 1400 IT turboshafts mounted side by side above the cabin