Isle of Man ATC in the 1940s
 Air Traffic Control during wartime and after
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 ATC in the 1930s         ATC in the 1950s
1940 - 1945  under Wartime Regulations
 
Ronaldsway
A limited civil air service was continued during WW2 using Dragon Rapides initially to Liverpool and subsequently to Belfast. In July 1940 the services were transferred to Manchester Barton but by November were back at Liverpool, which acted as the control and authorization centre for civil Irish Sea area flights, including those between Dublin and Liverpool operated by the Irish Airline, Aer Lingus Teoranta. Although control of Ronaldsway Airport had been taken over from the civil commercial operators by the UK Air Ministry, no permanent military units were based initially and civil ATC carried on as before, although with only two Rapides flying the Liverpool and Belfast route it must have been rather quiet, on some days in June 1940 there are no flights logged for days on end.
 
Logbook Entries, March 1940 - click for larger
6th March 1940
7th March 1940
 
 
 
Development of RAF Air Traffic Control in World War Two
 
During the inter-war years there had been little need in the RAF for ATC as we understand it. Most flying took place in daylight hours in good weather conditions and aircraft recovering to land at an airfield would join overhead to observe the signals square and then integrate themselves into other circuit traffic. Control functions mostly concerned booking aircraft out and back in and alerting the Crash Crew in event of an accident and would have been performed by the 'Duty Pilot'.  In the run up to World War Two, most of the development revolved around detecting enemy aircraft and then vectoring fighters to intercept them. After the start of WW2 when much more flying was taking place at night and in poor weather it became apparent that a system of control was needed to help aircraft find their way back to airfields over a blacked out country and then not collide with other aircraft also returning to the same airfields. The military ATC system was developed through the war years with many specialist Air Traffic Control Officers trained to carry out procedures as specified in document AP3024 'Flying Control in the Royal Air Force'. Proper Control Towers were built to standard designs, but the actual control of aircraft landing and taking off was still carried out using light signals by the 'Airfield Controller'. He was situated in a moveable van to the left of the downwind end of the runway in use (where there were hard runways) but operated under the supervision of the Flying Control Officer in the airfield Control Tower.
 
Air Publication 3024 - click for larger 
Mainly under the auspices of F.T.K. Bullmore, a safety organisation was set up at the Air Defence Sector Operations Rooms to guide lost bombers back to an appropriate airfield - amazingly, initially at least, against the wishes of the air defence organisation who were only interested in fighters and saw the air traffic control officers in 'their' control room as a waste of space! Known as 'Flying Control Liaison Sections' they were the forerunner of today's 'Distress & Diversion' cells and kept weather and serviceability information on all airfields within their area and using the air defence radar plots could often identify lost bombers and using the 'Darky' system or searchlight direction could assist the aircraft to a suitable diversion airfield.
 
The 'Darky' Procedure
This was an ingenious procedure that allowed a pilot of an aircraft in distress, whose radio operator may have been killed or injured, to talk directly to Flying Control at the nearest airfield. It operated by H/F R/T on a fixed frequency of 6440 Khz and transmitter powers were deliberately low to reduce range to around ten miles. For example, a pilot requiring assistance would transmit 'Hello Darky, Hello Darky, Hello Darky, this is Koska Freddy, Koska Freddy, over'. If Jurby Flying Control heard the call they would reply 'Hello Koska Freddy, this is Jurby, this is Jurby, over' Once two way communications were established assistance could be offered to home the aircraft to the visual circuit for landing.
 
 
RAF Jurby
Under the 1930s RAF Expansion Program, a military airfield was planned for the north of the Isle of Man at Jurby, to be used for armament training. Construction started in 1938 and initially provided a grass airfield. Paul Francis' excellent study for Manx National Heritage records that between the 10th October 1939 and 16th January 1940 a total of 65 aircraft arrived for No 5 Air Observers School - 21 Blenheim's, 16 Henleys, 15 Battles and 1 Magister. 
On the 1st December the unit was re-named as 5 Bombing and Gunnery School, using the same aircraft for armament training, although reverting back to 5 AOS in July 1941. In February 1943 the unit had 60 Avro Ansons, 21 Bristol Blenheims and 10 Westland Lysander target tugs, although the Blenheims were in process of being retired from service. On the 1st February 1944 5 AOS was re-designated as the Air Navigation and Bombing School and in November started to receive a new aircraft type, the Vickers Wellington X. The unit designation was changed again on 31st May 1945 to 5 Air Navigation School before they departed for the UK in September 1945. After almost a year without a resident unit, 11 Air Gunners School arrived from nearby Andreas with Wellingtons, Martinets and Spitfires in September 1946. 
 
Although designed as a training airfield, from November 1940 fighter units were also based, initially 307 (Polish) Sqn with Defiant night fighters and then from January 1941, 258 Sqn with Hurricanes, being replaced in April by 312 (Czech) Sqn, also with Hurricanes. Another squadron rotation happened in May 1941 when 312 Sqn were replaced by 302 (Polish) Sqn, again with the Hurricane, staying until August when 457 (Australian) Sqn arrived, this time with Spitfires. The Spitfires stayed until Andreas airfield was available and they moved across to the in October. For a while there was a temporary Sector Operations Room operated at Jurby as part of 9 Group, whose headquarters were at Barton Hall, Preston, until a new operations room was opened at Ramsey, using the gymnasium of Ramsey Grammar School.
 
Jurby Airfield in 2001
Jurby Control Tower as preserved in 2001
 
Jurby Radio Room
 
Initial ATC facilities probably comprised the ubiquitous 'Runway Caravan', using light signals and Very cartridges to warn aircraft of dangers on final approach, but in the early 1940s a brick built Control Tower was added, probably at the same time as tarmac runways were laid and electric airfield lighting installed. Control instructions would be relayed by either telephony (R/T) or telegraphy (W/T) using High Frequency (H/F) radio with a range of 5 to 20 miles for R/T and 300 to 800 miles for W/T, depending on atmospheric conditions. An H/F direction finding station would have been established close to the airfield for providing bearings on aircraft transmissions and to enable Controllers to provide 'QGH' let downs, homing the aircraft initially to overhead the D/F station then on an outbound course before turning back towards the D/F station  letting down via a 'safety lane' until they were clear of cloud and could join the visual circuit and land. As the D/F station was remote from Flying Control, bearings obtained by the operator had to be passed back by land line to Control before the control officer could decide what instructions to issue. At longer ranges, communications would have to be by H/F W/T (Morse code) via a radio operator in the tower but at closer ranges the Flying Control Officer could use direct H/F R/T speech although in larger aircraft the messages would be received by the radio operator and relayed to the pilot on the aircraft intercom.  Actual control of aircraft using the runway remained with the Airfield Controller in a caravan that was moved according to the runway in use.  Light signals using an Aldis Lamp were the preferred method of control with Very pistol signals as a backup, the use of radio for local control was discouraged except in emergencies.
 
RAF 1944 QGH Approach Procedure
 
 The main runway was lengthened in late 1944 after a a series of accidents with aircraft running off the end of the runway. The Control Tower, along with aircraft and hangers, was badly damaged on the 20th May 1945 when a Short Sunderland flying boat crash landed at Jurby. Although a successful landing was carried out, after the crew had escaped depth charges on board exploded causing extensive damage around the airfield.
 
On the 15th October 1947 11 Air Gunners School was disbanded and the airfield was placed under care and maintenance for the rest of the decade until re-opened in 1950 as an officer cadet training establishment.
 
Preserved WW2 Control Tower at Elvington Airfield
At the Yorkshire Air Museum, located on Elvington Airfield to the east of York, the World War Two Control Tower has been restored to show the typical Flying Control provided at a bomber airfield. The facilities at Jurby Control Tower would have been very similar.
 
 
Elvington Flying Control
Approach Control
Approach Control Pinboard
Local Control Pinboard
Operations Board
Radio Operators Room
 
RAF Hall Caine
Although closed as a civil aerodrome on the outbreak of war in September 1939, Hall Caine was taken over as a satellite airfield for RAF Jurby in the same month. It was used as a Relief Landing Ground and to support air to air gunnery target towing operations. The target towing aircraft would overfly Hall Caine at 2000 ft heading out to the ranges over Ramsey Bay. After the trainee air gunners had done their best, the target towing aircraft would fly back to Hall Caine and drop the drogue overhead the airfield at not below 500 ft. A Control Officer was deployed from Jurby to oversee operations and report the 'scores' back to Jurby by telephone. Aircraft used for target towing included the Fairey Battle, Hawker Henley and Westland Wallace. When RAF Andreas opened in 1941 the use of Hall Caine as a Relief Landing Ground ceased but it continued to support the target towing operations for a while. After the RAF vacated the airfield it was obstructed to prevent possible use by enemy aircraft. After the war the airfield was returned to its original owners and continued to be registered as an airport (albeit with no actual flying) until 1971, although being used for a short time in the 1990s for glider flying.
 
RAF Andreas
Andreas airfield was constructed on farmland to the north east of the village and from the start was designed as a fighter airfield to offer protection from air raids on the cities of Manchester, Liverpool, Glasgow and Belfast. Convoy protection work in the Irish Sea was also an important task. Construction started towards the end of 1940 and the airfield became operational with the arrival of 457 (Australian) Sqn from Jurby, their Spitfires arriving in October 1941. A purpose built brick control tower was provided for Air Traffic Control to a standard RAF wartime design, but supplemented by an extra visual Control Room on the roof, which was more usual on night fighter stations. 
 
Andreas Airfield in 2001
Andreas Control Tower in 2003
 
In November 1941 another unit arrived, a detachment of 275 Sqn which was a specialized Search and Rescue unit based at Valley on Anglesey with another detachment at Eglinton in Northern Ireland. The squadron was responsible for SAR operations over the whole of the Irish Sea and was mainly equipped with Westland Lysanders and Supermarine Walrus Amphibians, but also operated Defiants, Ansons and Spitfires. 275 Sqn (det) remained at Andreas until departing back to the UK in April 1944.
 
In March 1942, 457 Sqn were replaced by another Australian unit, 452 Sqn again equipped with Spitfires, who departed at the end of May, being replaced by 93 Sqn, many of whose Spitfires had seen previous service with 157 and 452 Sqn. 93 Sqn remained at Andreas until September when they departed back to the UK leaving the island without an active fighter squadron.
 
An event noted in several publications was the introduction in August 1942 of  new equipment which radically improved air to ground communications. This was probably the replacement of the former High Frequency (H/F) radio system with the new Very High Frequency (VHF) radios. This brought an major improvement in both quality and range (up to 150 miles) of signals and enabled controllers and pilots to communicate clearly and reliably for the first time. The equipment fitted to aircraft provided four (sometimes eight)  crystal controlled frequencies, usually arranged as: 
 
1) World Guard - a frequency for common use by aircraft in need of assistance unable to make use of any other frequency 
2) Group Guard - A frequency for common use by aircraft of the same Group when operating together or diverted within the group 
3) Sector Operational Control - A frequency for common use by aircraft in Squadrons of the same sector 
4) Flying Control - A frequency for Local Flying Control at the aircraft's base
 
On a typical fighter mission, an aircraft would depart using Channel 4 for communications with Andreas Flying Control, changing to Channel 3 for direction by the Sector Operations room at Ramsey. After the mission they would change back to Channel 4 for recovery to Andreas. If a diversion was required and they could make it to another 9 Group airfield, Channel 2 would be used. If they needed to divert to a 'non Group' airfield (Ronaldsway or Jurby maybe) they would use Channel 1. Normally, recovery into Andreas would be by visual means but if required a 'QGH' approach could be given using Direction Finding equipment on or adjacent to the airfield to home the aircraft through cloud on a 'safety lane' until visual with the runways. 
 
An additional type of approach available to VHF equipped aircraft was the 'ZZ' procedure. This entailed homing the aircraft to the airfield overhead and then instructing an 'outbound' course to fly, descending to a safe level until about eight mile away, using D/F bearings obtained every half minute to keep the aircraft on track and timings for the range. The pilot would then be instructed to make a 'Rate One' turn onto the correct course for landing. Again using regular D/F bearings the pilot could be kept on the correct approach path and instructed to descend until the controller estimates that he is approaching the runway. A last D/F check is made and 'if the aircraft can be heard approaching' the pilot is told 'OK to land ahead' otherwise told 'open the throttles and climb away'. If the pilot becomes visual at any point he may request to continue the approach visually. As in the 'QGH' procedure, the D/F station operator was remote from the control tower and all bearings had to relayed by land line, although in this case a 'direct loudspeaker telephone' was mandated  (From AP3024 'Flying Control in the Royal Air Force)
 
RAF 1944 'ZZ' Approach Procedure
 
In May 1943 another unit was formed at Andreas, No 11 Air Gunners School, using Miles Martinets as target tugs and Avro Ansons equipped with turrets for training the gunners. From September 1944 the Ansons were gradually replaced by Vickers Wellingtons and by early 1945 the unit had also acquired twelve Spitfire VIIs for staging fighter style attacks on the Wellingtons to train the gunners. In September 1946 11 AGS moved to Jurby and the airfield was placed on care and maintenance, being officially closed in February 1947.
 
 
Jurby/Andreas Sector Operations Room
 
As previously mentioned, a sector operations room was established using the gymnasium at Ramsey Grammar School and was operational towards the end of 1940. Originally known as the Jurby Sector, the name was changed when Andreas airfield opened in 1941 and the fighters moved over from Jurby. This formed part of 9 Group whose headquarters were at Barton Hall near Preston, later to become the home of the Preston Air Traffic Control Centre in the 1950s. The Sector Operations room directed operations for all fighter aircraft within the sector and was fed with information from the filter room at Barton Hall but also direct from the radar stations on the Isle of Man. 'Chain Home' radar stations had been established at Scarlett, Bride and Dalby and a 'Chain Home Low' station at Cregneash.  Information on aircraft tracked by the radars was supplied to the Group filter room at Preston and directly to Ramsey, where it would be displayed in a graphical format on the Plotting Table.  The Fighter Controller sat on a raised dais overlooking the table and direct the defending aircraft using 'Vectors' towards hostile or unknown aircraft. Alongside the controller were assistants manning telephones in contact with Anti Aircraft Command, Royal Navy Douglas HQ and Air Sea Rescue. Everything that was said on the radio was recorded by clerks sitting in four radio cabins behind the controller. Also on the site was a large communications section with teleprinters, a cypher office and radio transmitters and receivers. The operations room was duplicated at a remote site at Regaby, as a backup in case the main building was bombed or otherwise put out of service. When the interception was completed the fighters would be given a 'Steer' back to base for recovery and instructed to contact Andreas.
 
Restored Sector Operations Room
at RAF Digby
 
Training Flying Control Centre
 
By 1943 the need for the air defence Sector Operations room at Ramsey had all but disappeared and it was converted into the Training Flying Control Centre under the supervision of F.T.K Bullmore, who had earlier fought to establish the Flying Control Liaison Sections. There was a huge amount of flying training taking place around the Irish Sea and the purpose of the centre was to keep an overall picture of the location of aircraft and offer assistance as required. A main plotting table, originally at St Angelo in Northern Ireland was set up together with ten subsidiary tables, each keeping track of the aircraft from one airfield. The airfields controlled were: West Freugh, Wigtown, Dumfries, Jurby, Millom, Cark, Cranage, Bobbington, Llanwrog and Bishopscourt. A homing searchlight was set up on the island to direct lost aircraft to Jurby or Andreas and radio aerials erected in the school grounds, presumably replacing the VHF installations provided for the fighters with H/F equipment used by the training aircraft.. The unit had considerable staff numbers, in 1944 consisting of 46 RAF and 163 WAAFs 
 
 
Air Defence Radar Stations
(I am indebted to the work of Paul Francis and particularly the late Alan Cleary for much of the information below)
Radar Sites on the IOM in WW2
 
There were four main Air Defence Radar sites located on the Isle of Man. At Scarlett, Dalby and Bride, AMES Type 1 'Chain Home' (CH) radars were built, aircraft plotted being reported to the Fighter Command Filter Room at Bentley Priory, London and also directly to the Jurby/Andreas Sector Operations room at Ramsey. The first station to be constructed was Scarlett, with work commencing in July 1940, becoming initially operational in September.
The Chain Home radar used large fixed transmitting and receiving towers and operated on a frequency of 22.7 to 29.7 MHz or alternately 42.5 to 50.5 Mhz. Aircraft returns were displayed to the operator on a Cathode Ray Tube showing range from the station. Using Goniometers to vary input from the different receiving masts, bearing and height could be estimated. Plotting was most accurate in range, with bearing and height less so.
 
Type A display used in CH stations
CH Operator
 
Aircraft Position Reporting

Aircraft positions observed were reported back by telephone using a decimal square grid system covering the UK and surrounding waters based on an origin line at the Isle of Wight.

 
The radar station at Cregneash was quite different. Whilst the Chain Home stations were good at detecting high flying aircraft, anything below 3000 ft would not be plotted reliably so 'lower looking' radars were developed and these were deployed at this site. There were a total of five radar systems installed at Cregneash, two AMES Type 2 Chain Home Low (CHL), an AMES Type 52 Chain Home Extra Low (CHEL), Identification Friend or Foe (IFF) and a Royal Navy AMES Type 31 Coastal Defence Radar.
Aerial view of the Cregneash Site taken in 2015
 
The AMES Type 2 CHL radars worked on a frequency of 200 Mhz using a rotating five bay four stack mesh type aerial and could detect an aircraft flying at 500 ft at a range of 110 miles. The rotation speed could be varied between 1 to 2.3 RPM or could be stopped or reversed. Aircraft detected were displayed on a 'Plan Position Indicator' (PPI) type display. There was no height information available.
AMES Type 2 CHL Radar
Plan Position Indicator Display
The AMES Type 52 CHEL was a centimetric radar operating on a frequency of around 1000 MHz (3 cm or 'S' Band) with a rotating dish type aerial mounted above a nissan hut, based on the Royal Navy 277 radar. The aim was to detect aircraft flying below 500 ft. Returns were shown on a PPI display.
AMES Type 52 CHEL Radar
 
Identification Friend or Foe (IFF) was the forerunner of today's Secondary Surveillance Radar (SSR) and followed on from the RAF 'Pip-Squeak' H/F D/F based system used during the Battle of Britain to keep track of friendly fighters. IFF interrogated a transponder fitted to friendly aircraft which produced an enhanced return on the ground operators display to distinguish it from enemy or unknown aircraft. The first IFF sets operated on the same frequencies as the air defence radars, but due to the proliferation of frequencies used, a separate band was set up just for IFF (IFF Mk III) with frequencies used in the 157 - 187 MHz band. This was the type of equipment installed at Cregneash. The aircraft transponder receiver swept across the frequency range with ground station allocated a spot frequency to prevent mutual interference between stations. Aircraft transponders were only interrogated as required to prevent the enemy using the radiated signals to home onto aircraft.
 
As with the Chain Home stations, any aircraft returns observed at Cregneash were reported back to the Filter and Sector Operation Rooms, with no actual control of aircraft carried out from the site.
 
The final type of radar at Cregneash was an AMES Type 31 Coastal Defence No1 Mk V operated by the Royal Navy for observing ships in the Irish Sea. This was a 10 cm set very similar to CHEL and used a parabolic dish aerial.
Royal Navy AMES Type 31 Radar
 
 
RAF Ronaldsway
Ronaldsway was requisitioned by the RAF in May 1940 and some  additional hangers constructed to house the aircraft of the No1 Ground Defence Gunner's School which commenced training courses in July. Aircraft used were Westland Wallaces, Hawker Harts and Gloucester Gauntlets used for banner towing for ground to air gunnery, with the Westland Lysander arriving later. The RAF established a Flying Control in the airport booking office while the civil ATC continuing to operate independently. There may also have been a 'runway van' for the Duty Pilot, whose main duties were to fire red warning pyrotechnics or use a signalling lamp to warn of dangers to aircraft landing, e.g. other aircraft close by but maybe not visible to the pilot, or a machine with retractable undercarriage approaching with the wheels still up.
 
Aerial view of RAF Ronaldsway - 31 July 1942
 
 
 
 
Gloster Gauntlet
 
Westland Wallace
Westland Lysander
 
Hawker Hart K3045 at Ronaldsway
Picture via the Ronaldsway Aviation & Military Museum
 
An RAF Direction Finding station was built to the north east of the airfield, being able to 'home' aircraft flying in or above cloud until they had sight of the surface and could proceed visually to the airfield. As the station was built on a hill some way away from the airfield it would be presumed that aircraft would be homed to the D/F station overhead and then out to sea to let down to circuit height. (See 'QGH' procedure under Jurby)
RAF octagonal D/F Tower
 
Site of the RAF D/F station
Ronaldsway is in the distance
Remains of octagonal D/F station base
at Ballafurt
 
 
 
 
1943 - Ronaldsway Rebuilt
 
The RAF unit remained at Ronaldsway under various guises until the end of March 1943 when, control of the airfield was handed to the Admiralty and a huge reconstruction started place to transform the relatively small grass airfield of the 1930s into a large and very modern Fleet Air Arm airfield with hard runways suitable to be a main training unit for the Fairey Barracuda torpedo and dive bomber aircraft. Unlike most airfields constructed during WW2 (including Andreas) to the standard RAF three runway pattern, Ronaldsway had four runways to comply with admiralty requirements - crosswinds were not a problem on aircraft carriers and so there were more choices of 'into wind' runway. The runways were also narrower than the standard 50 yards, to simulate aircraft carrier deck landings they were only 30 yards wide. Post war this would involve considerable work to widen two of them to civil standards. A log book entry from 6th September 1943 mentions that Rapide G-AEAL with captain Harrison operated off 'the runway' with full load, 'very satisfactory', however on the 18th the same captain ran off the side of the runway  in G-AFEZ and damaged the aircraft! 
 
Drawings for the re-building of Ronaldsway, dated 1944
 
Work continued at a rapid rate until completed in Spring 1944. During all this time the civil air link continued operation. Construction of the runway 13/31 necessitated demolition of the original airport buildings and on the 1st April 1944 civil ATC moved to a new location at the 'Barn Site', part of the original Ronaldsway Farm. The original pitched roof of the barn was flattened at one end to enable the radio receiving aerials to be located above the control room. This may have also been the time at which the transmitters, located to the west of the field in the 1930s, were moved to the Ballahick site just east of Ballasalla. A logbook entry of 27th June states '6 hours overtime re window extension', presumably a reference to the new window fitted to the control room to improve visibility. 
 
Aerial shot of Ronaldsway October 1944
 
Aerial view of the 'Barn Site', home of Civil ATC in 1944
The 1944 Civil ATC control office showing the flattened roof
 
1944 Civil ATC Control Room
at the Barn Site
Southwest elevation of the
Control Room
The ATC Window
 
 
 
RNAS HMS Urley - The Royal Navy take over at Ronaldsway
 
Ronaldsway Naval Air Station was officially commissioned on 21st June 1944 under commanding officer Captain W. P. Shirley-Rollinson.
The Royal Navy were very firmly in control of the airfield and operated from a new four storey brick control tower on the north side of the airfield. Civil ATC operated from the 'Barn Site' on the southern edge of the airfield. Royal Navy aircraft would be communicating with their control tower using VHF speech radio whilst the civil Dragon Rapides would communicate with civil ATC using morse code on Medium Frequencies.  So how did they manage to operate safely using the same runways?
 
The Royal Navy would decide on the Runway in Use and (usually!) communicate this to Civil ATC so the the civil pilots would know what runway to expect.  Aircraft wishing to depart would taxy using the perimeter taxiway as far as the holding position for the runway in use and then await a light signal from the 'Control Van' which was parked on a purpose built concrete loop road adjacent to the landing threshold.  Arriving aircraft would join the visual circuit, integrating themselves visually with other traffic and observe the control van for light signals.  On turning final for the runway they would either receive a green 'cleared to land' or a red 'overshoot' signal.  After landing they would vacate the runway and taxy to their parking locations.  By this means civil and military aircraft, totally unable to talk to each other's control towers could be safely integrated.
 
There are occasional complaints by RN ATC noted in the surviving logbooks about civil aircraft not completing proper circuits, operating off other than the 'Runway in Use' and blocking taxiways. Very little of the airfield could in fact be seen from the barn site window so there was probably not a lot civil ATC could do about this. It would seem that they was more concerned with the en-route operation of the air link, express permissions having to be obtained from Liverpool Speke for each individual flight. This possibly explains the orientation of the extended window, as although most of the airfield was out of view, the civil parking apron behind Derbyhaven Crescent was directly ahead and the important signals requesting departure clearance and indicating arrival of inbound flights could be sent by observing the Dragon Rapides movements.
 
Ground view of the RN Control Tower
Aerial view of the RN Control tower
 
A logbook entry of 13th July states that the RN Flying Control Orders were submitted to the civil operators and is followed on subsequent days by several comments of aircraft not following instructions! On the 31st there is a comment in the log 'Please warn Sumner and any LV (Liverpool) pilot to wait for flashing green light for taxiing and continuous green light for take-off given by airport van' - it would seem that the civil pilots were having a little difficulty in getting used to operating to RN regulations and having to get permission to take off and land!
 
The Runway Control Van
(and is that the NAAFI van visiting?)
 
The new Ronaldsway had four asphalt runways giving a possibility of eight landing directions, from time to time there seemed to be a lack of co-ordination between military and civil resulting in each believing that a different runways was in use. Civil control was still by 'procedural' means with the help of D/F using Medium Frequency (M/F), but the Navy had VHF R/T (speech telephony) giving controllers instant communication to pilots.
 
The first Fleet Air Arm squadron, 747 NAS arrived on the 14th July 1944, equipped with Fairy Barracuda II aircraft, followed by 713 NAS on the 12th August, also with Barracuda IIs. The final Barracuda squadron, 710 NAS reformed at Ronaldsway on 7th October, equipped with Barracuda II & III, also operating the Fairy Swordfish biplane. The three permanently based squadrons had a total of 92 Barraucudas between them out of a total of 120 naval aircraft based at Ronaldsway.  There were also several temporary detachments of squadrons to HMS Urley, including four Miles Martinets from 725 NAS based between August and November to provide Air to Air firing facilities. During 1945 there were two detachments from 772 NAS, normally based at Ayr, Scotland. This squadron flew several different aircraft types including the Hawker Sea Hurricane, Vought Corsair, Fairy Swordfish, Miles Martinet, Douglas Boston and Fairy Firefly. Avro Ansons were also used at Ronaldsway for initial training of Observers in the use of the Air to Surface Vessel radar (ASV) before progressing to the faster and more advanced Barracuda.
 
Airfield looking south along runway 13
Airfield looking SE past the RN Control Tower
 
 
Practice Aircraft Carrier Landings
 
Royal Navy aircraft practising aircraft carrier landings would be 'batted down' by the Landing Signals Officer 
standing on the side of the runway, dummy arrester wires were painted on the runways.
 
 
 
Fairey Barracuda, Mk II nearest with Mk III behind
 
The Barracuda Mk II was fitted with a metric wavelength Air Surface Vessel Radar (ASV) with Yagi type aerials on the wings, the Mk III had a centimetric ASV with the scanner housed in a blister under the rear fuselage. The Mk III radar was optimized for anti submarine work.
 
WRENs loading torpedoes
Barracudas taxy out
 
Waiting at the holding point
 
 
Royal Navy Navigation & Approach Aids
 
Apart from the usual radio direction finding facilities, it seem likely that the Royal Navy installed an early Surveillance and Precision Approach radar at Ronaldsway that could 'talk down' aircraft until almost over the runway. Certainly the ground infrastructure was built, including concrete loops at the far end of the runways for the mobile radar installations to park on.  Some of these are still observable today.  The loops were offset slightly from the runways (presumably for the safety of the equipment and operators) so the final approach path would have been at a slight angle to the runways.  Many present day military ILS installations (and Ronaldsway's runway 08) are the same.
 
According to some contemporary reports there was a surveillance radar installed that was used to monitor aircraft using the Port Soderick and Perwick Bay bombing ranges. The likely site was on the small hill to the north east of the airfield, on plans labelled as 'Ground Control of Interception Site'. As there would be no requirement for a GCI service for the Barracuda's this would most likely refer to the type of radar installed here, probably a Royal Navy Type 277 as installed on ships. The buildings are still in existence in 2015.
 
1944 RN Surveillance Radar Site
Surveillance Radar site buildings
 
YG Radio Beacon
A radio beacon system widely used by the Fleet Air Arm both on ships and land bases was 'YG'. The ground beacon could be in a fixed position or mounted on a vehicle. The beacon worked in the 234 - 258 MHz range and had a rotating aerial that transmitted a two letter identification code and then single morse code letters for every 30 degrees of rotation. There were six radio channels available, Ronaldsway was on Channel Two. 
The only other station likely to be received on that channel in the IOM area would be Ayr, so if to the north of the island at altitude correct identification of the beacon was important!
Table of YG Beacons
YG Sector Decode Chart
 
To use the beacon the pilot would turn on the aircraft ZBX receiver and select the appropriate channel for the beacon required. Initially many of the sector codes would be heard and he would turn down the sensitivity control on the set until he could hear just three which would place him in the centre sector of the three. For example, homing to Ronaldsway from somewhere to the south; select Channel Two and identify the beacon. Turn down the sensitivity until only three sector codes can be heard, e.g. M N & R. Using the chart this places the aircraft to the south west of Ronaldsway in the 'N' sector and the pilot has to steer a course between 028 and 058 degrees to home to base. As the aircraft flew closer to the beacon the sectors narrowed and course corrections were applied to keep in the required sector, the receiver sensitivity being progressively reduced until only one letter could be heard. The aircraft could be descended in accordance with terrain safe levels until the airfield was sighted or reception of all the letters with sensitivity to minimum indicated arrival in the overhead. Presumably if homing to Ronaldsway from the north (over the hills), once having passed though the overhead at terrain safe level a course could be selected to let down further over the sea.
 
The advantage of YG over other homing methods was that it was independent of the other aircraft radios so could be used in a radio failure situation and compared to medium frequency non-directional beacons gave a course indication for safe descent. In many respects it could be considered a forunner of today's VOR beacons.
 
(I am indebted to Lieut. Richard Collins RNVR via the Airfield Information Exchange for the operating description of YG)
 
 
Air Traffic Control - Aircraft Carrier Style 
 
So far, I've been able to find nothing about Royal Navy style Air Traffic Control at land bases such as Ronaldsway in the 1940s, but thanks to documents available online at the Royal Navy Museum of Radar and Communications, I have found out a little about ATC on aircraft carriers and wonder if something similar was used at Ronaldsway. They were, after all, training crews to operate from aircraft carriers so it would seem logical to use similar control techniques on the shore base, so here is some information, I would appreciate if anyone could correct this or provide further information.
 
The core of air operations was the Action Information Centre where information and intelligence was received and filtered and operational directions issued, this consisted of several rooms. The Operations Room was the headquarters of the Action Information Control Officer and contained a filtered Air Plot of the current situation together with relevant maps and charts to enable the AIC Officer to direct air operations. Logically, at Ronaldsway this would be located in the control tower building. The Air Direction Room maintained the main situation plot and actively directed aircraft using radar. This could have been located in the control tower, but I think a more likely location would have been on the remote Surveillance site located on the hill just outside the north east corner of the airfield (see pictures above). The logic for this reasoning is that the 'raw' radar data was available here and would have been more easily transferred locally than to the control tower some distance away. The third room found on ships, the Target Indication Room was mainly concerned with the defence of the ship and so was probably not required at Ronaldsway.
 
Diagram of the Action Information Organisation
 
When aircraft were recovering to land on aircraft carriers after a mission, they would first be directed to navigate to a 'Picket Marshalling Position', usually a radar beacon located on a destroyer or cruiser (or an airfield located Eureka beacon could have been used to fly to a position away from the airfield awaiting radar pickup). Aircraft would then be identified and directed using Type 293 or 277 surveillance radar to a 'Carrier Marshalling Point' about 10 to 15 miles away from the ship before individual flights were brought onwards to the 'Approach Waiting Position' about 6 to 8 miles astern before individual aircraft were directed along the final approach lane using the Type 962X Ground Controlled Approach Radar until final carrier landing instructions would be given by bat signals. At a land airfield either bat signals for a practice carrier landing or light signals from the runway van would be used for landing clearance. Three VHF frequencies were required:  'Button A' for homing to the Picket Marshalling Position, 'Button B' (with two controllers using this frequency) using surveillance radar to the CMP and then the AWP and 'Button C' for the Ground Controlled Approach 'talkdown'. On an airfield the GCA radar caravan would require moving according to the runway in use (see 'Ground Controlled Approach' section below), but the direction information could possibly have been remoted to the Air Direction Room.
 
Diagram showing Carrier Recovery Technique
GCA recovery using Type 962X Radar
 
 
Ground Controlled Approach (GCA)
 
Developed during the 1940s by the Massachusetts Institute of Technology, GCA allowed a ground controller to offer a 'talkdown' service using Precision Approach radar to aircraft in poor weather conditions. No specialist equipment was required on the aircraft, just a two way radio for communications. The radar consisted of two elements, a 'search' or surveillance radar that scanned through 360 degrees (much the current radar at Ronaldsway)  and the talkdown element which scanned the final approach track with separate horizontal and vertical radar beams. The 'search' controller would radar identify inbound aircraft and marshall them onto a closing heading for the final approach track until they came within the beam of the 'Precision Approach Radar' (PAR) and the aircraft would be transferred to a separate frequency for the talkdown. The controller would give the pilot heading corrections to remain on the final approach track and at a predetermined point instruct the pilot to commence descent. The controller would monitor the descent profile and instruct the pilot to alter descent rate if the aircraft started to drift either high or low and continue giving heading corrections to keep the aircraft on the centreline. The talkdown would commence at about 5 miles from touchdown and be continued to 1/2 a mile from the touchdown point although the equipment was capable of displaying the aircraft right down to the touchdown point. Early PAR systems used 'trackers' manning the radar tubes who keep electronic markers centred on the aircraft return which would drive two meters in front of the controller showing lateral and vertical displacement. In later systems the trackers were dispensed with and the controller sat in front of a cathode ray tube displaying both the lateral and vertical radar traces.
 
GCA Caravan
'Flight' diagram showing the search and talkdown radars
Inside the GCA caravan
 
The whole set-up was mobile, consisting of a caravan for the operators, another housing the actual radar and radio transmiters/receivers/aerials  and a truck to tow them around, often housing a generator to power the installation. It would be towed to the appropriate hard standing for the runway in use, powered up and then aligned using radar reflectors. Changing runways would obviously take a little time. There are still traces on the airfield today of where the PAR and runway vans were located.
 
Tarmac loops still exist at Ronaldsway for the Royal Navy
GCA and runway control caravans
 
PAR radar is no longer used in civil air traffic control, but still extensively at military airfields, RAF Valley on Anglesey being the nearest 
to the Isle of Man. The radar information is now also remoted into the Approach room, so no more draughty caravans out on the airfield!
 
1940s PAR
USAF PAR Display
Computer simulated PAR display
 
 
Eureka, Rebecca & Babs
 
Also installed at Ronaldsway was Eureka, a ground radar beacon that could be interrogated by airborne radar. the aircraft navigator could provide a 'talk down' service to his pilot by interpreting the returns on the aircraft radar set.
 
There were three elements of this radar homing and approach aid operating on frequencies around 200 MHz. Eureka was the ground based radar responder beacon. Rebecca was the aircraft fitted element of the system and would interrogate the Eureka beacon to obtain a range and bearing from the airfield to enable the aircraft to home in. Babs was the approach element and when interrogated by Rebecca would provide an indication of final approach track and distance from the airfield. This was presented to the aircraft navigator on the airborne radar CRT screens and the navigator would talk the pilot down until he became visual with the runway. The Ronaldsway based RN Barracuda aircraft would most likely have been fitted with Rebecca Mk11B.
Link to external page with details of Eureka/Rebecca/Babs
 
 
The Royal Navy Depart
 
At the end of WW2 on 15th August 1945, the need for intensive training of crews vanished overnight and the establishment started to be run down. 747 NAS left on the 15th November although their 'B' flight remained with Avro Ansons. All training finished on 20th December when 710 and 713 squadrons were disbanded together with 747 NAS 'B' flight. HMS Urley was officially decommissioned on the 14th January 1946 and the airfield was handed over to the UK Ministry of Civil Aviation. All of the Royal Navy radar aids would also have been removed at this time.  At some point in 1946 the civil control moved from the barn site to the the navy control tower on the north side - and could at last see what was happening on the runways and taxiways!
 
Post War Civil Operations
 
After initially being operated by the UK Ministry of Civil Aviation, Ronaldsway was bought by the Isle of Man Government who took possession on the 1st March 1948. A new 'North West Flight Safety Region' was established to replace the old pre war Communications Area. This was administered from Liverpool Speke airport using M/F frequencies 339-341 KHz. Meanwhile the UK governments of the day tried to decide on how to organize air traffic control in the future. With a flood of cheap ex service transport aircraft such as the Douglas Dakota, becoming available plus crews to fly them it looked like the skies could become much busier.
 
At Ronaldsway In the late 1940s Air Traffic Control was being carried out much as in the pre war days with the Control Zone re-instated to 10 miles around the airport but only active in low visibility or low cloud 'QBI'. Communications were still mainly by W/T on Medium (M/F) and High (H/F) frequencies, but with more aircraft being equipped with VHF Speech telephony which enabled the controllers to talk to pilots directly, the days of the specialized radio operators were numbered. 
 
 M/F Direction Finding stations at Speke, Ronaldsway, Carlisle and Manchester Ringway could provide bearings to plot aircraft positions. Presumably 'traffic information' would be provided on other aircraft, but it was up to pilots to arrange their own separation, either visually or by flying at different heights. Ronaldsway ATC would provide control services within its 10nm Controlled Zone in 'QBI'.
 
BEA Dakota G-AHCW with Dragon Rapides behind.
Picture taken between 1946 and 1949
 
Ronaldsway Control Room 1948
Ronaldsway M/F Radio Direction Finder
 
 
Standard Approaches Mandated
 
Towards the end of the 1940s a major change was introduced in the UK regarding how pilots were to fly instrument approaches. Before, it had been entirely up to the pilot as to where he let down through cloud and to what altitude. During WW2 the RAF had instigated a rudimentary system of instrument letdowns know as QGH approaches, based on the controller interpreting Direction Finder bearings and instructing pilots to fly certain headings and levels. This was mainly to de-conflict military aircraft returning to bases often only a few miles apart and prevent aerial collisions. This principle was extended to civil aviation and defined instrument approaches published to airfields  showing courses to be flown, together with set altitudes for each 'leg' of the procedure. This also enabled traffic levels to be increased, as controllers could now hold aircraft inside the Controlled Zone, spaced at 500 ft vertical intervals, each aircraft taking its turn to fly the instrument approach. As a level was reported vacated, each aircraft above could be stepped down awaiting its turn for the approach. Minimum safe levels for descent were published for each approach taking into account the accuracy of the approach facility and terrain surrounding the airport.
 
RAF 'Safety Let Down Lanes'
 
Map at the Yorkshire Air Museum
showing the 'Safety Let Down Lanes' to 
QGH or SBA approaches at WW2 military airfields in South Yorkshire
 
ATC in the 1950s
 
An Island Images webpage © Jon Wornham