Isle of Man ATC in the 1950s
 
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 ATC in the 1940s          ATC in the 1960s
 
Area Control - Start of the UK Airways System
 
After much deliberation, the UK government had decided on the future of Air Traffic Control in the UK. Corridors of controlled airspace 'Airways' would link the major airports and be defined by radio beacons at strategic locations. The first airway brought into use was 'Green One' from Strumble on the south-west Welsh coast, via Bristol to London. Intended for use by transatlantic flights it came into use on 1st August 1950. The second phase included more routes around the London area, with phase three being routes northwards to Scotland and Northern Ireland. This included airway 'Red Three' which had a segment from Wallasey on the Wirral peninsula, over the Isle of Man and onwards to Belfast. Initially the airways applied to aircraft flying under Instrument Flight Rules only, aircraft flying under Visual Flight Rules were free to fly where they wished, including across or along the airways! Subsequently, with higher performance passenger aircraft coming into use, the Airways were restricted to IFR flights only.
 
 
National Airways Plan
Phase Three
 
Showing Airway Red Three overhead the Isle of Man. M/F Range beacon at Cregneash with Markers at Portaferry, Dean Cross and Wallasey.
 
(Diagram courtesy Flight Global)
 
The initial radio beacons used were Radio Ranges and Fan Markers, a proven technology used in the USA and based on the German pre-war 'Lorenz' beam principle. The Radio Ranges operated in Medium Frequency band and so could be received on the radio sets as commonly fitted to aircraft of the day. The beacon radiated on four different legs, which were aligned with the airways. They transmitted an audible morse code 'A  - .' and 'N  . -' letters, if the aircraft was left of track the pilot would here the letter 'N'  in his headphones, if right of track the letter 'A'. When on track they would merge to a continuous tone. It must have been quite tiring!  There was a development to produce a cockpit instrument to indicate visually if the aircraft was to left or right of the track, the forerunner of today's navigation instruments. The fan markers worked on a VHF frequency of 75 Mhz and were located at a distance along the legs of the beam and transmitted a single morse letter, which also illuminated a light in the cockpit as the aircraft passed overhead, providing a position fix at that point and indicate that it was time to tune in the next beacon.
 
A Radio-Range was established in the Isle of Man at Cregneash, operating on 391 Khz with an identification of 'MYI'  This radiated four 'legs', towards Belfast, Wallasey, Dean Cross (Cumbria) and Dublin with associated Fan Markers at Wallasey, Dean Cross and Portaferry.  There was also an non directional beacon (NDB) at Cregneash 'GCF' on 312.5 KHz, which was designed more for marine use, operating as part of an Irish Sea network on the same frequency and transmitting according to a set timetable, although still usable for air navigation.
 
 
The Cregneash Radio Range
'MYI' 391 Khz
 
Showing the four 'legs' of the range, two defining 
airway Red Three. The Isle of Man Control Zone also shown. At this point the other two legs point out into uncontrolled airspace, but 'Advisory Routes' were to follow.
Link to Wikipedia Article on Radio Ranges 
 
Advisory Routes
 
By 1956 additional Advisory Routes had been added to the Airways System radiating from the Isle of Man Range. ADR 157 went from the IOM northwards to Milleur Pt and catered for the Glasgow and Prestwick flights, ADR158 went from Dublin, via the IOM to Dean Cross and Newcastle and ADR159 went from the IOM to Blackpool. An Air Traffic Control service was provided to participating traffic only. Interestingly, the map shows ADRs along airway Red Three and Green Two, was this the changeover point to banning VFR flights along airways at times?
 
Control Zone Change
Also published in 1956, this RAF planning chart shows the Isle of Man Control Zone has been changed to a rectangular shape, dimensions
22nm x 10nm

 
ATC at Ronaldsway
Whilst Ronaldsway retained the Control Zone, the rules regarding its use had changed somewhat. Instead of 'QBI' being declared by ATC, it was now up to the pilot to decide if he could fly using the Visual Flight Rules (VFR) or needed to use Instrument Flight Rules (IFR). If operating under VFR, the pilot could proceed into the zone without permission, using the Rules of the Air to keep clear of other aircraft. If operating IFR he needed to call ATC and obtain a clearance into the Control Zone and obey ATC instructions.
 
Control Tower and ATC Signals Square - 1953
BEA Dakota by the Control Tower - 1950s
 
Control was carried out from the second floor of the tower, the Navy 'Watch Office' on the roof not appearing to be used operationally, probably due to insufficient space for Controller, ATC clerks, radio operators and Direction Finder operators who required to be in close proximity due to the ATC systems in use at the start of the decade. At first Control was by either Medium Frequency or VHF radio, with ground direction finders and radio reports from aircraft being the only means of determining aircraft positions. Flight Progress strips came into use in this era showing aircraft details and having control instructions written on them, probably required with the setting up of the airways and the need to record clearances issued by Preston Centre. The M/F services including the direction finding station were withdrawn from use on March 1st 1951 as more aircraft were equipped with VHF radios. A former Royal Navy FV5 VHF Direction Finder was installed on the airfield, this gave a remote indication of aircraft bearings directly to the controller on a CRT indicator in the Control Room, although changing the radio frequency used was evidently sufficiently complicated to warrant a log book entry every time! A Pneumatic Lamson Tube system was used to connect the different sections within the tower building, ATC, the Met Office and Teleprinters.
 
ATC Control Room - 1950s
Former RN 'Watch Office' on the roof
 
 
Enlarged view of the Control Desk
Airfield Lighting 'Mimic' on the ceiling
 
 
1958 Floor Plan of Control Room Area
 
 
Radio Aids
 
Ronaldsway was equipped with Medium Frequency Non Directional Beacon (NDB)  'GJE' (the old w/t radio callsign for Ronaldsway) operating on 322 KHz and SBA 'Standard beam Approach' on runway 27, also coding 'GJE', operating on 33.3 Mhz (the chart below in fact shows 38.6 MHz, so the frequency was probably changed at some point) with an Inner Marker beacon on 38 MHz. SBA was a development of the pre-war 'Lorenz' approach aid developed in Germany and installed at Croydon Airport in the 1930s. SBA gave similar audio indications to the radio range, providing what we now know as a Localizer approach to the runway. It could also provide a rudimentary glideslope indication on a cockpit instrument, the pilot choosing which of several 
paths to follow down. 
 
The Standard Beam Approach Procedure
 
The initial approach to the airfield could be made using one of several aids, probably mainly the 'GJE' NDB or by bearings from the ATC Direction Finding unit, descending to a height not below 3,900 feet.  Quite possibly, the Radio range at Cregneash could also be used. On arriving overhead the airfield the pilot would fly a course of 091 degrees outbound letting down to a height of 1,555 feet and after three minutes perform a 'procedure turn' to the right, to establish on the inbound course of 271 degrees. He would maintain the centreline by listening to the Morse code from the main beacon. If he was too far to the right he would hear a Morse letter 'N' (dash dot) and if too far to the left a Morse letter 'A' (dot dash).  On the centreline the two letters would merge together to give a continuous tone. Once established inbound, descent would be commenced at a rate of 400 feet per minute, flying at 120 knots, down to a minimum height of 300 feet. This could be maintained until passing overhead the Main Beacon, an Inner Marker beacon just inside the airfield boundary indicated that the runway threshold was just ahead.  If the runway was not sighted a missed approach was flown, climbing ahead to a height of 2,700 feet.
 
 
SBA Approach Chart for Ronaldsway
1954 Ronaldsway Landing Chart
Ronaldsway Airport 1954
 
Non-directional Beacon and Direction Finder Approaches
 
 There would have also been approaches published based on the 'GJE' NDB for both runways 27 and 09. The FV5 VHF Direction Finder could be used to provide instrument approaches to aircraft not equipped to use radio navigation aids, either a pilot interpreted 'D/F Approach' or a controller interpreted 'QGH Approach'
 
Chart for pilot interpreted D/F Approach
Diagram of controller interpreted QGH Approach
 
From the December 1951 RAF Radio Facility Charts book,, Ronaldsway is show having H/F radio on 3255 KHz, with Approach Control on VHF 119.7 MHz and Tower on 118.7 Mhz. Also available was 121.5 MHz (Civil Emergency) and 116.1 MHz (Military Emergency). 
Approach aids available are VHF Direction finding on 119.7, 121.5 and 116.1, NDB 'GJE' and Standard Beam Approach.
 There are also two light beacons published for the airfield, an airport beacon showing alternating White and Green and an identification beacon that would flash the Morse code letters 'JE' in green (showing a civil airport)
 
The Ballahick Transmitting Station - 1958
Inside the Ballahick Transmitting Station
 
Transmitter frequencies at Ballahick in 1958 were: 
1190 Khz (Point to Point & Emergency)
126.7 MHz Approach
121.5 MHz Emergency
 
 
 Instrument Landing System Installed
 
 By 1955 an Instrument Landing System (ILS) was commissioned on runway 27. It would appear that initially only the Localizer (LLZ) was installed and operational. This was likely due to the need for an Outer Marker Beacon for a range check to safely descend on the Glidepath (G/P), which would normally be installed between 4 and 5 miles from the runway, for Ronaldsway's runway 27 but this would have put it in the sea! An Inner Marker beacon was however installed close to the threshold of the runway. In the 1960s a solution was found and an offset Outer Marker beacon was placed on Santon Head, allowing the Glideslope to be used.
 
ILS Inner Marker Aerial
 
Remains of the Inner Marker in 2009. Crossing this beacon indicated imminent arrival over the
runway threshold. This aerial was swept away with the RESA (Runway End Safety Area) project not long after the picture was taken.
 
The full ILS would give pilots an accurate indication of both lateral (Localizer) and vertical (Glidepath) position on final approach, displayed on a Course Deviation Indicator instrument in the cockpit. The Localizer aerial was at the far end of the runway with the Glidepath aerial by the side of the runway close to the touchdown point. With this precision system, landings could be accomplished in much poorer weather conditions than before. The SBA continued in operation for non ILS equipped aircraft.

 
RAF Jurby
 
Although RAF Jurby had closed in 1947, the airfield remained under care and maintenance and was re-opened in 1950 as No 1 Initial Training School, where prospective RAF pilots and navigators underwent an 18 week (later increased to 24 week) basic course covering such subjects as navigation, meteorology, aerodynamics and radio. Being a military unit, other important subject covered included drill, outdoor sports and leadership exercises! There was no flying training in the syllabus but some gliding experience was available using Sedburgh gliders. The 'Station Flight' operated an Avro Anson for communications purposes and possible also a DHC Chipmunk for air experience flights. Anson VM418 came to an unfortunate end on the 6th September 1953 when it crashed into Clach Ouyr, near Snaefell, killing all on board including the Jurby Commanding Officer, Group Captain Worthington and the incoming C.O. Wing Commander Fenton. In May 1953 the unit became No 1 Officer Cadet Training Unit.
RAF 1951 area chart centred on Jurby
 
Basic ATC services were retained at Jurby, the 1951 RAF Radio Facilities book showing that the airfield was available on Prior Permission Only Mon - Fri 0800 - 1630 and Saturday 0800 - 1200. Control was on 117.9 MHz with 104.76 MHz D/F by arrangement and Military Distress frequency 116.1 MHz available with D/F. Jurby had a light beacon available on request which would flash the letters 'JY' in red. Sodium Approach Lighting funnels were provided for all runways with electric runway lighting on 26/08 only.
Jurby entry in the Dec 1951 RAF Radio Facilities Charts Handbook
 
1951 Approach Chart for RAF Jurby
1951 Landing Chart for RAF Jurby
 
RAF Jurby was also available for diversion from Ronaldsway, in this case the NDB beacon was radiated on 358 KHz 'JY' and civil frequency 118.7 was manned for the diversions. This was the same frequency used for Ronaldsway Tower. A civil control team would be dispatched from Ronaldsway to provide the air traffic control, using the RAF control tower. Facilities were very basic, probably consisting of a radio set, flight progress strip board, clock and telephone.  In the Ronaldsway watch log of 26th July 1956 there is a note that a suggestion has been made to the ATCO i/c that radio recording facilities should be provided at Jurby as a result of the operations there on 8/7/56 as the 'written R/T log proved quite unsatisfactory'! The R/T log covering that date has also survived and backs this up, with six pages of radio messages recorded with a total of 43 aircraft movements between 0800 and 2200. It seems unlikely that the requested recorders were installed.
Enlarged section of RAF chart showing Jurby Airfield
ATC facilities in Jurby Tower
 
 
Airshows
 
At least one airshow was held at Jurby during the 1950s, possible it was an annual event for 'Battle of Britain' Day.
I am indebted to Tim Harris for the pictures below, taken 1950 - 1952 when his father, Squadron Leader Malcolm G Harris DFC, DFM was either in command or most likely 2nd in command of the training unit.
 
RAF Jurby Airshow
 
 
Air Defence Radar - The Snaefell Radar Station
 
At the end of WW2 most of the extensive radar defence network that had been established around the United Kingdom was closed down and either dismantled or put on 'care & maintenance'. This included the stations in the Isle of Man (see 1940s pages for details). Defence planners had not anticipated another conflict for at least ten years and were somewhat take by surprise by the start of the 'Cold War' towards the end of the 1940s. It was realised that the UK was vulnerable to attack by Soviet bombers and attempts were made to resuscitate elements of the WW2 radar network, often without success, as was the case with the Dalby Chain Home station in the IOM. Technicians tried to restore operations 1949 but were unable to re-activate it.
 
The 'Rotor' Radar Plan
A new radar defence network code-named 'Rotor' was devised for the UK, using some WW2 vintage radar systems but also new ones then under development. The overall plan used the same principles of the WW2 Reporting and Control network with manual reporting of hostile contacts by radar stations through a 'filter' office, plotting on an operations table and fighters controlled by separate Ground Control of Interception (GCI) radar stations. Priority was given to the east and south coast of the UK as this was where the greatest threat was perceived, but 'Rotor 3' covered the west coast of the UK and this was where the Dalby station would have been used. Instead a new location was selected at Snaefell and construction commenced with an aim to have the station completed and operational with a 'Stage One' radar (WW2 type equipment) by April 1956.
 
It was soon realised that the old Reporting and Control system was far too slow to deal with jet bombers and that the new Type 80 'Green Garlic' radar could be used for both Early Warning and Fighter Control from the same station, cutting out the time consuming 'middle man' of the filter system. This new concept made many elements of the originally planned Rotor system redundant, including the Snaefell station. The Type 80 radar installed at Killard Point in N. Ireland could cover the whole area on it's own and it is possible that the Snaefell station didn't even become operational. A large 'Type R11' Operations block was constructed adjacent to the Bungalow station on the Snaefell Mountain Railway, but siting the actual radar aerial here would have resulted in severe screening from the surrounding hills in most directions so the most likely location would been on the summit.
Snaefell Radar Station - 2005
 
 The Snaefell station was designated as a Chain Home Extra Low (CHEL) and equipment provided for these was either a Type 7 or Type 14 radar. The Type 7 operated on a frequency of around 200 Mhz and had a large square mesh aerial that probably wouldn't have survived the winds on Snaefell so most likely a Type 14 radar would have been specified, a centimetric radar operating in the 10 Cm band. 
 
Plinth mounted Type 14 radar
Type 14 radar mounted on a gantry
 
Whether the radar was actually installed remains open to question, but eventually the Operations Block was used as 'Murray's Motorcycle Museum' for a while until 2005, but is currently (2014) unoccupied. It is probably one of the best preserved above ground Cold War 'Rotor' radar stations surviving.
 
Type 14 Radar aerial
The Snaefell Radar station buildings as repainted in 2009
 
 (Thanks to Subterrania Britannica and The Radar Pages for much of the above information)

 
Area Control - Preston Air Traffic Control Centre
 
The new Airways were controlled from Preston Air Traffic Control Centre at Barton Hall, one of three civil units established in the UK, the others being Scottish at Prestwick and Uxbridge in London. Area Control within the airways was by 'procedural' means, with separation being either vertical or lateral, using time intervals between aircraft, proved by aircraft reports over defined 'reporting points'. 
 
1951 Chart of Irish Sea Airways
1951 Chart of Solway Firth Airways
 
Preston used VHF 119.3 KHz (with H/F 3270 KHz as backup) for all its airways, with VHF 118.5 KHz and H/F 5692 KHz available for Flight Information Service.  The Flight Information Service was the natural follow on from the old 'Communication Areas' and would provide weather and airfield details together with information on other aircraft know to be operating outside controlled airspace. The RAF had their own Control Centre at Preston for control of military aircraft. Weather reports and forecasts for Ronaldsway (and other northern airports) were broadcast from Preston on frequencies 404.4, 3953 & 8942 Khz, the forerunner of the present VOLMET and ATIS services. The pictures of the ATCC below are from a later period. 
Preston Centre closed in 1975.
 
Preston Air Traffic Control Centre 1
 
Controllers working on the 'D' side of the Flight Progress Boards. Each flight had multiple flight progress strips, placed under designators for reporting points along the route. Colours used for area control strips were:
 
Blue = Westbound Flights
Buff = Eastbound Flights
Red = Airways Crossing Flights
 
Preston Air Traffic Control Centre 2
 
Assistants working on the 'A' side of the Flight Progress Boards. Data Extraction Cell where strips were produced from Flight Plan information is on the left, with Flight Information Service controllers at the back of the room.
 
 
(Preston ATCC pictures via GATCO)
 
1950s Flight Plan Form
 
Pilots would file their flight plans with the ATC Flight Clearance Office at the departure airfield. They would be transmitted via teleprinter on the Aeronautical Fixed Telecommunications Network (AFTN) to the en-route Air Traffic Control Centres and the destination airport. Flight Progress Strips would be hand written by ATC Assistants and when the flight became active, displayed on the controllers Flight Progress Boards.
 
 
 
New Area Navigation Systems?
 
Towards the end of the decade there was international discussion to determine a new 'standard' navigation aid system for short ranges.
The British proposed an area navigation system 'Decca Mk 10' which was based upon the wartime 'GEE' system and could provide for
any track required anywhere within the coverage of the particular chain. Four such chains could cover the whole of the UK. It was in use with BEA and even had a 'moving map' provision within the cockpit, giving a continuous plot of the aircraft position. The USA wanted to continue
with their 'point source' system of VHF Omni Directional Ranges (VOR), which required a large number of beacons and confined navigation to radials originating from each beacon. To 'fix' an aircraft position required a 'cross cut' of radials from two beacons within range, or a newly developing 'Distance Measuring Equipment' (DME) working on UHF frequencies which when co-located with a VOR would fix the position on a particular VOR radial (bearing) and DME distance. The British system had far more potential at a much lower cost, but the USA already had an extensive network of VORs and the final decision was really a forgone conclusion. The UK would start installing VORs and DMEs in the next decade and a true area navigation system would have to wait for the satellite based GPS, many years in the future.
 
Decca Flight Plotter
Example of an early moving map display driven by the Decca Navigator System. It used paper charts which had to be loaded for each flight, the track of the aircraft was drawn by pen on the map. This picture dates from 1950 of one installed in an Airspeed Ambassador flight test aircraft.
 
 
The Winter Hill Disaster and Radio Beacon Identification
 
On the 27th February 1958, Silver City Bristol Wayfarer G-AJCS crashed into Winter Hill, Lancashire with the loss of 35 lives. The aircraft was on a flight from Ronaldsway to Manchester Ringway under the control Manchester Approach, having previously been working Preston Centre. It should have been navigating to the Wigan NDB (code 'MYK') on 316 Khz where it would have turned right to Manchester but the first officer had inadvertently tuned in the Oldham NDB (code 'MYL') on 344 Khz.  The beacon tuning error was not noticed by either pilot and the aircraft flew past Wigan until it eventually hit Winter Hill, close to the television transmission mast. Neither Preston Centre nor Manchester Approach had radar covering the initial track although the error was detected at the last minute by the Manchester Approach Radar controller who attempted to avert the disaster by giving an emergency turn 
to the aircraft, but unfortunately it was too late. 
 
 
Manchester Area Airways Chart
 
There are six different medium 
frequency radio beacons located 
around Manchester, all in the 300KHz frequency range and with their morse identifications all starting with 
the letter 'M'
 
As a result of the accident investigation it was recommended the the morse code radio identifications of navigation aids should be changed to something like the actual name of the location, all UK beacons at that time having a three letter identification starting with either 'G' or 'M'. For example the Ronaldsway NDB originally coded 'GJE' but was changed to 'RON' and then to 'RWY' The Cregneash radio beacon coded 'MYI' and was changed to 'IOM' 
 
 
Manx Airlines Bristol Wayfarer G-AIMH
 
Picture taken around 1958, not long before the new Control Room was added to the top of the tower
 
Picture by and © Rich Rimmer GD3YEO
 
 
New ATC Control Room (1959)
 
 At the end of the decade it was decided to build a new control room on top of the old RN Watch Office. This provided accommodation for the Aerodrome Controller, Approach Controller and the Air Traffic Control Assistant. For the first time all of the airfield and surrounding airspace could be seen from one location, without having to walk outside onto a balcony! 
 
 
 
CTB Front Elevation 1958
Proposed new Visual Control Room
Installation of the new Visual Control Room must have resulted in a major disruption to ATC services. Apart from the physical alterations
to the buildings with the pre-fabricated room being installed on top of the former RN Watch Office, all ATC equipment, radio aerials and the Lamson Tube system needed to be re-located. Once in operation all ATC services were provided from the new location. The former Control room on the third floor became another equipment room housing radio receivers and ancillary equipment,
 
 ATC in the 1960s
 
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