Airbourne Early Warning

The Shackleton Years 1972-1991

The Importance of Airborne Early Warning

With the planned scrapping of HMS Ark Royal, the Royal Navy’s last conventional aircraft carrier, the RN was worried that their task groups would loose their airborne early warning capability.  This had been achieved by using the Fairey Gannet, fitted with the AN/APS 20 radar.

The solution to this problem was to fit the Gannet’s radar to a long-range land based aircraft until a more modern system could be designed.  The Nimrod MR1 had recently entered service with the RAF and this had released Shackleton airframes to be fitted with the Gannet radar.

Still Displaying Fighter Flashes! (8 Sqn)

As a result, 8 Squadron reformed at RAF Kinloss on 1 Jan 1972 and were equipped with the “new” Shackleton AEW Mk 2.  Navy Gannets continued to operate from Lossiemouth, which was 15 miles from Kinloss.  No 8 Squadron moved to join them once the runways and taxiways at Lossiemouth had been strengthened.

Increasing the radar horizon was also the aim of the United Kingdom’s ground based radar air defence sites and it was found that the Shackleton could help to cover the areas of sea to the North and East of the British Isles.  Therefore the MOD decided to procure a modern AEW aircraft to carry out both Naval and UK air defence roles.

The aircraft chosen for these tasks was the Nimrod AEW Mk3.  The old Shackletons with their even older radar sets would have to provide radar cover until the new aircraft was delivered – this was planned to happen in the early 1980s.

Originally equipped with eleven Shackleton aircraft and eleven crews, No 8 Squadron was halved in size in the John Nott defence cuts of 1981.  (The Squadron found out by watching the BBC evening news).  Squadron strength was reduced to six crews with six aircraft.  These aircraft served until July 1991 when they were replaced by the E-3D Sentry aircraft which had been bought following the Nimrod AEW Mk3 debacle.

What is Airborne Early Warning?

Radar waves, like light, travel in straight lines.  Therefore, a radar set at ground level can only detect low level targets out to the horizon.  To increase the range of the radar horizon, radar antennae were fitted to the top of ships masts using the same principle as the lookout in the crow’s nest:

The radar horizon from the top of a ship’s mast is about 25 miles.  However, if you build a mast up to 30,000 feet high then the radar horizon is pushed out to 220 miles.  Building a mast this high is not practical but you can put the radar into an aircraft to achieve the height!

The other advantage of fitting the radar to an aircraft is that you gain mobility and can quickly position your radar up threat for even more early warning.

The first AEW was carried out by the US Navy in the Pacific at the end of WWII.  It was used by the Americans to give early warning of kamikaze attacks against their aircraft carriers.

The AN/APS 20 radar was developed during this period and first flew in a Grumman Avenger in 1946.  This is the same radar set that was used in the Shackleton AEW until 1991!

The Aircraft and the Mission

The Shackleton AEW Mk2

The Shackleton Mk2 was originally designed for maritime patrol and anti-submarine operations.  Powered by four Rolls Royce Griffon engines, the Shackleton was the last in the line of AVRO heavy bombers, started by the Lancaster, and carried on by the Lincoln.  The Mk2 Shackleton had been replaced by the Mk3 in the maritime role because it was considered too noisy and uncomfortable – the Mk3 had a tri-cycle undercarriage and 2 additional viper jet engines fitted to its wing tips.  Unfortunately, the Mk3 suffered from high fatigue and so the older Mk2 was chosen to carry the AN/APS 20(F) AEW radar.

The Shackleton could stay airborne for about 12 hours with its fuel load of 3,284 gallons of 120 octane petrol.  It would operate at an altitude between 2,000 and 7,000 feet – any higher would put too much noise from sea returns into the radar.  The aircraft would normally fly at 160 kts, although “Friday night cruise” could give a speed up to 180 kts!  The AEW Shackleton carried a crew of 9 – originally 2 Pilots, Air Engineer, 2 Navigators (one running the radios) and 4 mission crew.  After 1981, the radio navigator was replaced by an additional mission crew member.

The mission crew comprising of Tactical Coordinator (TACO), Controller, and 2 Operators would man the 3 x 7” radar scopes.  The “off duty” operator would provide frequent hot drinks and food from the small galley in the rear of the aircraft.  The 5th mission crew manned the radios when extra mission crew personnel replaced the second navigator in 1981.

Shackleton AEW Tasks

Shackleton AEW Mk2, WL741 “PC Knapweed” Most of 8 Sqn’s Shackletons were named after characters from the TV programme “The Magic Roundabout”. The remainder, as with this aircraft, came from “The Herbs”. (Sqn Archive) Click Image to Enlarge

The task of an AEW aircraft is to Detect, Direct and Report.  The Shackleton crew operator would detect and report the position of radar contacts by voice radio to ground radar sites and ships.  This procedure is called “Voice Tell”.

Once a “hostile” aircraft was detected, the Controller would direct friendly fighter aircraft onto the target. Fighter control was practised with F4 and Lightning fighters over the North Sea, working with the Sector Operations Centres (SOC) at Buchan, Boulmer and Neatishead.  Student controllers could call on the services of 100 Sqn flying Canberras who would act as both fighters and targets for training.  (These practise intercepts are still used to train controllers and fighter aircrew today although the aircraft types have changed.

As well as having the ability to detect aircraft, the Shackleton radar could also detect ships.  Therefore the crews had the capability of carrying out raids on hostile shipping by controlling attacking aircraft.  Many an hour was spent, acting as “orange forces” directing attacks by 12 and 208 Sqn Buccaneers (also based at Lossiemouth), against NATO Navies being exercised around the British coast.

Secondary tasks also helped to give variety to flying.  The Shackleton carried search and rescue equipment in its bomb bay, and Lindholm dinghy drop procedures were regularly practised.  The Shackleton was also extensively used to simulate a defecting “hostile” aeroplane for Taceval and other station exercises in both the UK and abroad.

In a similar vein, 8 Squadron was regularly invited to participate in exercises with the USAF Forces in Keflavic, Iceland, where we would act as a target for F-4Es (Exercise Fan Angel).  Spoofing, and communications jamming was employed by the mission crew, and on one memorable occasion, the Shackleton TACO convinced two F4s that he was the real controller.  On pulling them on to one of our discrete frequencies he split the aircraft into cloud, moved them around on fictitious contacts for ten minutes, and finally talked the wingman into shooting down his leader.

Operating the Shackleton

“The Business End” Radar Consoles in the AEW Mk2 (Sqn Archive) Click Image to Enlarge

The radar screens of the AN/APS 20 radar were small 7” cathode ray tubes and needed total darkness to see the small radar echoes of aircraft.  The radar screen had no “afterglow” and so all contacts on the scope were marked with a white china-graph pencil.  If, on the next radar scan, the contact moved from under the china-graph mark, then it was redrawn.  After a minute or so, moving contacts would have a small data trail of china-graph dots – static contacts would not.  Unfortunately, breaking waves also gave returns and these obscured the picture close to the Shackleton.

The Shackleton radar had a theoretical max range of up to 200 miles, although detection ranges for smaller aircraft were much less.  If you could detect an F4 at 80 miles on 2 scans out of 6 then you were doing well!  Often contacts had to be plotted using dead reckoning for several scans until they were regained.

The Shackleton radar operators would spend hours peering into the small set, armed with their china-graph pencils and report the moving contacts to ground sites.  The addition of an IFF interrogator to the radar set gave the operator assistance because it gave a small “eyebrow” behind the radar response.  However, the method of decoding these responses was slow and made identification difficult.

The Shackleton also carried the “Orange Harvest” radar warning receiver (RWR).  This could give the bearing of any radars which illuminated the Shackleton; the display was a 3” cathode ray tube above the “C” operator’s position.  The receiver for “Orange Harvest” looked like a giant spark plug and sat on top of the fuselage.

Life in the Shackleton

Although the Shackleton is often remembered with affection, life in the aircraft could be down right uncomfortable.  The aircraft was noisy – very noisy – and after a long sortie a crew- member’s ears would ring for many hours after the engines had been switched off.  The majority of those who flew the Shackleton are permanently high tone deaf as a result.

The aircraft was un-pressurised and flew over the hostile waters of the North Sea.  Therefore, it was COLD.  The crew wore a fleece “bunny suit” underneath a heavy waterproof immersion suit, which was sealed at the neck and wrists by rubber.  Fitted rubber socks were worn inside flying boots.

The Shackleton was “heated” by petrol heaters, using aircraft fuel to warm air inside the cabin.  Unfortunately they were not very efficient and so the engineer ran them on full.  One of the heater outlets was by the feet of the radar operator in the “A” seat.  He would suffer the indignity of having very warm legs, which caused him to sweat into his waterproof suit, while the rest of his body was cold.  It was not a comfortable existence.

Another indignity was suffered by the TACO who sat at the middle console (“B” position).  His seat was not placed directly behind his radar tube because of the position of the port emergency escape hatch and the proximity of the aircraft’s wing spar.  The result was that the poor TACO had to lean to one side – this was uncomfortable, especially when wearing a heavy life jacket and even more so when a flying helmet was worn.  To cure this problem, the TACO would sit on the right hand edge of his seat, which consisted of a metal rim holding the usually comfortable leather seat.  The result was a pressure line giving “TACO’s bum” which was also uncomfortable.

Long sorties meant that the crew had to be fed and watered.  The off duty operator would provide a continuous supply of tea and coffee, and a good operator could cook decent food for the crew in the small galley.  Breakfast, (cooked from scratch in the small oven) consisting of bacon, sausage, egg, mushrooms, tomatoes and beans, could be served to the whole crew only 30 minutes after takeoff by a well-organised chef.  One of the Shackleton specialities was “Honkers’ Stew”.  There is no recipe for this dish – it consists of everything that is left (including Mars Bars) thrown into a pan and warmed through.

Quick Reaction Alert (QRA)

For the greater part of its operation life, the Shackleton AEW operated through the cold war era.  The aim of UK Air Defence during that time was to maintain the integrity of the UK air defence area, which surrounded the UK and extended north towards Iceland beyond the Faroe islands and towards Norway.  Any Soviet aircraft entering this area had to be intercepted by UK fighters, and fighter squadrons took turns to hold Northern and Southern QRA.  Tanker forces also held alert to support the fighters, and if needed, a Shackleton was also on call.

The 12 crews of 8 Sqn held a 2 hour alert, 24 hours a day, seven days a week.  Once Soviet aircraft had been detected heading into the North Atlantic by Norwegian air defence sites, it was usual for the Duty Controller at RAF Strike Command to scramble the Shackleton to cover the Iceland-Faroe’s gap.

It could take up to 3 hours for the Shackleton to reach its barrier position and wait for the fighter scramble to take place.  Often, the intruders would turn back before reaching UK airspace, but occasionally they would enter our airspace.

The Shackleton operator would report the intruders via HF radio to one of the air defence stations – Saxa Vord, Polestar (on the Faroe Islands) Benbecula or Buchan.  The controller would take control of the fighters and tanker and vector them towards the intruders.  There was nothing more satisfying than to successfully prosecute a gaggle of Soviet Bear aircraft with a pair of Lightning fighters!

Following the reduction of crews in the “John Nott” defence cuts of 1981, QRA became a Monday to Friday task with no replacement crew for the rest of the day once launch had taken place.  QRA ceased at 1700 on the Friday and at 1701 it was common for a Shackleton crew to hit the Squadron beer call.  One Duty Controller at Strike Command tried to scramble a Shackleton crew at 1710 on Friday.  He was nine minutes and fifty seconds too late.

TACEVAL

Being The Enemy A Shackleton being escorted while acting as an intruder during a Taceval.  Note the day-glow star next to the rear door! (Sqn Archive) Click Image to Enlarge

Throughout the Cold War Era, NATO needed to be always ready to counter any attack by the Soviet Union.  NATO commanders tested units’ readiness to repel the Soviet Hordes by means of the Tactical Evaluation or “Taceval”.

As well as having to be ready for Lossiemouth’s own taceval, 8 Sqn used to help the evaluators by simulating a defecting Soviet aircraft.  The Sqn was lucky enough to posses a couple of fluent Russian speakers, and they would be on board when the Shackleton would turn up unannounced at an airfield and request permission to land.  Once landed, the crew would negotiate their defection and treatment in return for information about the aircraft.

One of the crew members would be “injured” and his treatment was often a bargaining tool.  The make up of these injuries added to our entertainment – a string of sausages once used to protrude from a gaping stomach wound.  At one period in its history the Sqn was fortunate enough to have as one of its members an AEO who had an artificial leg.  He would loosen this leg and be the casualty.  During one exercise at an USAF base in Europe, he was dumped at the Shackleton door and the Americans were told that we would surrender once our injured colleague had received medical treatment.  A US guard picked the AEO up to put him on a stretcher and his leg came off in his hands.  He did not see the funny side….  It was not unusual for some of the crew who did not wish to surrender to try and escape the cordon and cause havoc around the airfield.  One Navigator once used a bicycle!  All in all, it was a fun task – especially because it was often the only means of escaping Lossiemouth for a couple of days.  Exercises in Germany were very popular and often gave rise to an extended stay.  One crew spent three days in the Holiday Inn at Baden Baden courtesy of a double brake sack leak after an exercise at the Canadian base at Sollingen in West Germany.