Past Talks : February 2023

From the Falklands to the Middle East” (A brief history of Sea King AEW 1982-2018), by Lt Cdr Richard Lewis (Rtd) and Mike Yates ex- EMI Group Ltd


Are you sitting comfortably? Then we’ll begin. Once upon a time, Britain, through hard-won experience in WW2, became a leader in shipborne AEW (Airborne Early Warning) capable of detecting and resisting low-level threats on its fleets. In the late 1970s, the clever men with big titles and big offices decided that Britain no longer needed shipborne AEW, so the Fairey Gannets and shortly afterwards the remaining aircraft carriers were ‘retired’. It was decreed that the perceived threat was only in the northern hemisphere and would be easily handled by RAF Shackletons and Nimrods.

No one thought to broadcast this policy and to inform Argentina. In 1982 Argentina invaded the Falkland Islands, a British Overseas Territory. In a remarkably short time, a British task force was assembled and despatched to the Falklands to eject the Argentinian invaders.

Although the traditional Royal Navy aircraft carriers had been scrapped, three light ASW (Anti-Submarine Warfare) aircraft carriers had been built during the 1970s to replace them. These were HMSs Invincible, Illustrious and Ark Royal, each equipped with Sea King ASW helicopters and with Harrier VTOL strike aircraft.

To protect the British fleet against Argentine attack, missile-armed destroyers were deployed in the distance as picket ships. In response, in very short time, Argentine strike aircraft flew in at very low level and sank a number of our ships including HMS Sheffield, HMS Coventry and the Atlantic Conveyor, in part because the Sea Dart missiles could not react quickly enough.

Where was the AEW? In the scrapyard of course. The shock of these events was a mighty wake-up call. Something had to be done, immediately.

Enter our speakers for this evening – Mike Yates from radar manufacturer EMI and Richard Lewis, RN, Sea King Observer.

The manufacturers viewpoint

Mike set the scene. He had been in the RAF for 19 years and was a Chief Technician at RAF Binbrook working on the development of the Searchwater maritime surveillance radar fitted to the Hawker Siddeley Nimrod MR2 which was considered to be one of the most advanced of its kind in the world. It was an extremely capable piece of kit and exactly what was required in the Falklands – but how? In 1978 Mike joined EMI as an engineer and soon found himself at the Westland factory in Yeovil with an EMI colleague, tasked with installing Searchwater on a Sea King.  The date was 21st May 1982 and the the project had to be completed by around the 2nd August 1982, the sailing date for HMS Illustrious to the Falklands (around 10 weeks).

The Nimrod is a large aircraft, based on the DH Comet airliner and could accommodate all the Searchwater equipment, plus upwards of 11 crew with ease. The Sea King was an ASW or a Search and Rescue helicopter with far greater limitations in terms of space and lifting capability. That was not the only problem. Searchwater was designed as an ASV (Air to Surface Vessel) radar to search for slow moving targets. The Falklands required it to find fast moving low level targets, i.e. Argentine strike aircraft. Searchwater LAST (Low Altitude Surveillance Task) is what emerged.

One other factor to take into account was that computers, as we now take them for granted, did not exist. Engineers made all calculations on hand-held slide rules.

Two ASW Sea King Mk2 helicopters were made available to Westland (XV650 and XV704). I could fill the whole issue of Jabberwock with a technical description of the problems and solutions arrived at in making it happen. However, the first problem was the scanner and how to accommodate it? The dish was roughly 1 metre dia. by ½ metre deep, capable of rotating between 6¼ to 120rpm. This necessitated a large swept volume of space, far too big to fit within or under the fuselage. The solution was to create a hinged elbow joint on the side of the Sea King, to which the 5ft dia. scanner head assembly was mounted. The Radome itself was made from an inflatable Kevlar bag, very strong and very light.

Inside the Sea King the dunking sonar equipment was removed, to be replaced by purpose designed and fabricated pallets and plinths to contain the console and endless ancillary equipment. To complicate matters the system also had to be able to withstand the considerable inherent vibration of helicopters. Most fixtures and fittings were unique – and had to made in duplicate, because there were two helicopters. The working days were long and so were the nights.

Finally, when everything was in place, the real testing and proof of concept was undertaken. These included such items as validation of the C of G, precise alignment of kit to datums, pressure tests, cooling efficiency, system operations, EMC (electromagnetic compatibility), etc.. For secrecy, the latter was done at night by hanging the Sea King from a 20 ton crane to simulate being airborne while running the engines and radar to confirm no interference with the helicopter systems. There was a lot to do. Test flight results were good and search ranges up to 100 miles were achieved.

The deadline was met and 12 weeks after the start date the two Searchwater LAST Sea Kings departed aboard HMS Illustrious, along with Mike and his EMI colleague to keep an eye on them when in action during the Falklands war.

The FAA Observer’s viewpoint

At this juncture, Richard Lewis took over as speaker to describe operations from his perspective as an Observer aboard the Sea Kings, or ‘Bagger’ as they were fondly called, after the inflatable Kevlar radome bags. Richard spent 40 years in the FAA (Fleet Air Arm) principally in helicopters and in that time he accumulated considerable experience and pragmatism.

The two Sea Kings joined 849 NAS (Naval Air Squadron) which had been reformed for the AEW role, having previously operated Skyraiders and Fairey Gannets in the same role before being disbanded in 1978.

Searchwater as fitted to the Nimrod AEW aircraft had a long and successful record for carrier defence and fighter control. However, communications in the early days were by voice, but an upgrade in 2000 provided new radar and avionics. A quantum leap in changes, referred to as SKASaC (Sea King Airborne Surveillance and Control). Mixed in with this update was the Cerberus Mission System which enabled detection of targets over land, sea and air.

In the Falklands the two Sea Kings provided 24 hour cover over a 100 mile range, up to 10,000ft. They also now had integrated, secure interfaces, that enabled the Harrier support strike cover to be linked directly to the two Sea King operators, without the necessity for voice communication.

As a point of interest, the addition of Searchwater to the Sea King added considerable weight. Richard quoted a Sea King ‘Junglie’ as weighing around 16,000lb, whereas a Searchwater Sea King tipped the scales at around 21,000lb, which in hot and high areas of the Middle East had a noticeable effect on performance.

Richard laid great stress on the fact that due to the urgency of the Sea King conversions to AEW, very close co-operation developed between the FAA Sea King team and industry. What the radar operators expected to see and be able to do was quickly translated into how the EMI radar manufacturers could make it happen.

From Richard’s point of view everything must happen within three button presses, and EMI achieved it. It was the first time that the MoD Procurement process allowed aircrew (the end-users, after all) direct access and involvement with manufacturers. It was a great success, sadly not repeated. No lessons learned there.

Prior to this, and subsequently for the Merlin (Sea King replacement), an outline specification was given by the MoD to manufacturers who then told MoD how it could be done. – with no involvement of the end-user operators, who had to make the best of what they were then given.

As an example, Richard quoted an operational sequence that took 17 seconds using the two-man Sea King console. A Boeing E3 Sentry aircraft with a crew of up to 19 trained specialists, took 45minutes to achieve the same result.

A Pulse Doppler cleared all the ground clutter to reveal anything that moved. This was a massive step forward and combined with the the Cerberus Mission System and JTIDS (Joint Tactical Information Distribution System) enabled the Sea King to identify targets and relay the data instantly to the support strike aircraft to follow-up. Via the two Sea King Searchwater screens, the two Observers could control 250 tracks; 400 received tracks; 100 non-real world entities, etc., etc.. Bewildering stuff which went over my head.

Much of this new capability bore its real fruit later in the Middle East and at Camp Bastion in Afghanistan, in conjunction with US forces.

For the Observers, every operation was a hive of activity and potentially satisfying. For the pilots it could be yet another boring drudge for hours on end, just flying to and fro on a steady course.

The success of the Sea King systems led Richard to declare frequently, with a big grin, that “Baggers are the master-race”.

It was not all one-way however. Enemy fighters would quickly identify the Sea Kings as the ‘eyes’ directing strike aircraft against them, so they were a constant target. However, if the ‘eyes’ were doing their job properly they would see the threat and eliminate it through control of their own support aircraft before it caused any damage. Other Sea King threats and limitations included a duration of only 4 hours; Icing; ESM (Electronic Support Measures) and self-defence capabilities; etc..

In due course, 849 squadron operated nine Sea King Mk7 ASaC helicopters (Airborne Surveillance and Control) which were divided into three elements (A Flight, B Flight, etc.), and later still into 854 Sqn and 857 Sqn, before being re-absorbed into 849 Sqn. The last Sea King Mk7 AEW flight was made on the 26th September 2018 after which 849 Sqn briefly operated the new Merlin HM Mk2, before being decommissioned itself on 21st April 2020.

Thank you Richard Lewis and Mike Yates for an engrossing and detailed account of how the RN belatedly won back its Airborne Early Warning capability. A justifiably well attended talk both in the auditorium and via Zoom. Do join us next time.