Recollections of Air Traffic Control

Thought I would start this very interesting topic off. This very nostalgic story by Brian Martin has been lifted from my Control Tower Book.

My work used to take me down to the A361 road and as I drove between Burford and Lechlade in Oxfordshire, I used to look over to my left to catch a glimpse of Broadwell tower. Sometimes, when I had time to spare, I turned off down a side road which had been built across the airfield and stopped where this road passes close to the tower. Looking at the rendered brick shell, I remembered how different it was in 1946.

On completing an R/T Operator's course at No. 1 Electrical and Wireless School, Cranwell, in July 1946, I was posted to Broadwell, where I was sent to work in Flying Control. I found that although the tower was of the standard wartime type, it was operated by a group of men who gave it a special personality of its own. In charge was the Senior Flying Control Officer (SFCO) who had a small office at the top of the stairs behind the watch office. Each watch was run by one of the Flying Control Officers, who were all commissioned pilots. To assist the Duty Flying Control Officer (DFCO), there was an ex-aircrew NCO in the tower and another in the caravan at the end of the runway in use. The third member of the watch office team was the R/T Operator who logged all the R/T messages and made most of the routine transmissions himself. The VHF receivers were located in the W/T office, which was behind the watch office and was manned by the W/T Operator. Downstairs, there was a crew room, kitchen, toilet and storerooms. These facilities were used by the duty crew who provided the men to man the crash tender, marshal visiting aircraft, change the runway boards on the side of the tower, alter the signals square, and let off pyrotechnics as required by the DFCO. But above all, they brewed char at frequent intervals and cooked supper when night flying was over.

The Controller's desk was in the centre of the watch office and was fitted with panels displaying routine navigational and operational information. I still have a penknife with both blades broken by a clumsy DFCO who borrowed it to remove a stubborn drawing pin from one of the charts. The desk was fitted with R/T handset, GPO telephones and a telephone connected to the caravan by landlines. The latter were always being cut by the grass-cutting machines out on the airfield and we were forced to communicate with the Airfield Controller by R/T. The rear wall of the watch office, to the left of the door was covered by a large map of the British Isles showing all the airfields in use. The R/T Operator's desk was to the right of the door and, further to the right, there was a hatch through the wall into the W/T office. On the left-hand wall, as you looked out over the airfield, there was a large blackboard on which the details of all aircraft flying from or to Broadwell were chalked up. In the opposite corner, between the front and side windows, there was a console which controlled the runway lighting with an illuminated diagram above it which showed the lights in use on a plan of the airfield.

The first thing I was taught was always salute when entering the watch office to take over a duty shift, although no one ever paid any attention to you. I suppose that it may have been inherited from the naval tradition of saluting the quarter deck on boarding a ship. The R/T Operator's next duty was to go into the W/T office and check the tuning of the VHF receivers (R1132). He then sat down at his desk and signed on duty in the R/T logbook. As he sat at the desk he had two candle-stick type microphones in front of him with their corresponding loudspeakers in cabinets behind them; these were for the Transport Command Approach VHF Channel A (120.96 Mc/s) and the RAF Universal Airfield Control VHF Channel B (117.9 Mc/s). To his right, on the wall, there was another loudspeaker with the corresponding microphone on a shelf below; this was for Local Airfield Control HF Channel (5063 kc/s). He also had a pair of earphones round his neck with the corresponding microphone on the shelf; this was for the Darky Emergency HF Channel (6440 kc/s). No one ever used the HF channels while I was on duty, except a Polish pilot who always used the Local Airfield Control HF Channel for all his R/T messages. This made communication with him rather difficult as there was always static on the HF channels and his English was atrocious.

When an R/T Operator came on in the morning, he spent the first hour or so answering calls from the aircraft as the wireless mechanics went round doing their DIs (daily inspections). Later, the aircraft called up for taxi clearance and then took off for operational or training flights. All the routine messages were handled by the R/T Operator, the DFCO dealt with any which required his special attention, and all messages in and out were logged by the R/T Operator. During the evening, the operational aircraft returned from their scheduled services and afterwards night flying training kept the tower busy until about midnight. When all the aircraft landed, the W/T Operator would tune in to AFN (American Forces Network) and at 2345 hours we liked to listen to the smooth strains of 'The Vocal Touch', followed at 2400 hours by the more strident tunes of the famous 'Midnight in Munich'. By this time, we would be tucking into a plateful of bacon, eggs, beans and chips, with sometimes a sausage as a special treat. Afterwards, camp beds were put up in the appropriate rooms; the DFCO in the SFCO's office, the W/T Operator in the W/T office, the R/T Operator in the watch office, and the rest of the crew downstairs in the crewroom. I always tried to get my bed as near to the centre of the room as possible as earwigs climbed the walls during the night and fell off the ceiling before they reached the middle. I can still hear the soft hiss of the VHF loudspeakers and the plop as another earwig hit the lino.

Broadwell, at that time, was in No. 46 Group, Transport Command, and was the base for No. 271 Squadron flying Dakotas (coded YS/–, call sign OFB/–) on various transport duties in Europe. Broadwell was the squadron's base for servicing and training, but all scheduled services were flown from Croydon or Blackbushe. No. 271 Squadron had an excellent war record flying from Doncaster initially and then from Down Ampney. Flt. Lt. Jimmy Edwards won his DFC and Flt. Lt. Lord, a posthumous VC with the squadron. Earlier, Broadwell had opened in No. 70 Group, but transferred to No. 46 Group in January 1944. Nos. 512 and 575 Squadrons arrived in February with Dakotas and remained until August 1945. Nos. 10 and 76 Squadrons were at Broadwell during August 1945 but were replaced by No. 77 Squadron at the end of the month, and then No. 271 Squadron replaced No. 77 in September 1945.

In October 1946, rumours began to circulate that the station was to close and everyone was going to Bicester. A scouting party actually flew across there in a Dakota and returned with gloomy tales of a grass airfield, old barrack blocks and bags of bull. However, at the end of the month, I was posted to Watton and did not see the final days of Broadwell. No. 271 Squadron was renumbered as No. 77 Squadron in December 1946, and moved to Manston at the end of the month. Broadwell finally closed down completely in March 1947.

Now, as I stand looking at the blank windows of the tower, sometimes filled with hay, I hear the crackle of the R/T 'Oboe Fox Baker Tare – This is Broadwell Tower – You are clear to join circuit – QFE 29.45 – Over'. As night falls, I hear the old tunes from AFN and smell the bacon frying. After that there is only the plop of an earwig, and then – 'Broadwell Tower Out'.

Brian Martin 1992.

This article originally appeared in an ARG Newsletter in 1978.

Here is another....

When I entered the world of ATC in the 1950s, the same as they had been during the latter half of the war years and I think that the best way to start this article is to describe the layout of a typical control tower and what took place therein.

Ground Floor

Across the width, at the front of the building, was the Meteorological. Office with a total staff of around eight civilians, divided into shifts. Their job was to provide hourly weather reports to ATC and to brief the aircrews. They also fed the local weather statistics into the National Network.

To the left, and to the rear of the Meteorological Office was the radio equipment room within which were the line amplifiers, relay racks, standby radio emergency sets and the accumulators for same. The VHF transmitters and receivers were located at remote sites that could be anywhere up to three miles from the airfield and the line amplifiers mentioned acted as an interface. Not a single tape recorder in sight! There were usually two signals technicians in attendance.

Behind the radio room was the airfield lighting relay room with its racks of heavy-duty relays and stepping motors. Two civilian AMWD electricians operated from here.

To the right, and behind the Meteorological Office was the GPO equipment room where all the telephone lines terminated, together with relay racks for the ATC telephone switch boards.

To the rear of the above was the airmen's and officers' toilets, plus a store cupboard.

First Floor

Across the full width at the front was the main control room with a large control desk in the centre. This desk was occupied by two ATC Controllers, usually of commissioned rank. One was known as the Approach Controller, the other as the Local Controller.

Two loudspeakers were mounted in this desk for the monitoring of the VHF radio channels but no headphones were then in use and the microphones were of the 'candlestick' variety as used in the old 1930s telephones. Also on the face of the desk were the Wind Direction and Speed Indicators. Each Controller had in front of him an aide-memoire board which he stuck magnets to or mapping pins into, each representing an aircraft in its relative position. Incidentally the squadrons used silly names as callsigns, such as 'Plantout', 'Sunray' or 'Wells'.

There was a centre console that carried the FGRI 5417 R/T control panel that provided only four VHF radio channels. Also on this console was the Hadley Intercom, with extensions to such places as the runway caravan, fire section, Wing Co Flying, station CO, ops room, Met. office etc. There was also the station tannoy microphone and the emergency radio selectors. There were two discrete intercom boxes to the GCA truck and the manual D/F, plus telephones to Watnall (Nottingham) Control Centre, the SSQ and the ATC switchboard. It was at this console that the supervisor sat, (usually a Flt. Lt.) known as the DATCO.

In the rear corner of the room was the rather antiquated airfield lighting panel and on the rear wall was a blackboard for displaying the details of aircraft that were due to arrive or depart that day. Next to this was a huge map of the UK with its compass rose and a distance measuring tape. All military airfields were marked on this map and it was constantly being referred to.

Near the door leading to the veranda were the green and red Aldis signalling lamps and the Verey pistol with a selection of coloured cartridges.

To the rear, and to the left of the control room, was the monitor and movements room where there were two consoles. The one facing the control room (above which was a window and a sliding panel) had two loudspeakers for the monitoring of the 'RAF Common' frequency of 117.9 Mhz and the 'Command Common' of 107.28 Mhz. An airman or airwoman operated these channels and passed elementary information to the aircraft. The other console faced the door and here were two clerks who worked the ATC telephone switchboard and dealt with visiting pilots, but most important of all, they made the tea!

To the right, and to the rear of the main control room, was the Squadron Leader SATCO's office (usually an ex-pilot) who dealt mainly with policy and officers' rostering.

To the rear of the SATCO's office was an Admin. Office with a sergeant in attendance who dealt with all admin. matters and the rostering of NCO and other ranks. This was a full time job as there were around 40 on the staff as shift work was involved.

Up on the Roof

At the rear was a small room with double doors that was used by the weather people for the filling their balloons from the hydrogen cylinders. Also on the roof was the scaffolding frame for holding the runway-in-use boards. These were large yellow boards with black figures which had to be changed when a different runway was brought into use, no mean feat on a windy day. The standby aerials were mounted up here also.

Outside the front of the tower was the signals square and the weather measuring instrument enclosure, whilst to the left was a small pyrotechnic store.

Out in the centre of the airfield was the VHF manual D/F homer mounted on a vehicle chassis known as RVT105. This was operated by signals personnel who rotated its aerial to obtain an aircraft's bearing relative to the airfield. This information was then passed to the Approach Controller via land lines. One can imagine how slow such a procedure was and it was painfully inadequate for jet aircraft working. Part way down each runway, and slightly to the left, was a hardstanding where the GCA trailers were accurately placed. This was American equipment known as MPN 11 and on loan to the RAF at a limited number of airfields. It contained three radar systems, one that surveyed 360 degrees out to a distance of twenty miles, one that scanned a narrow horizontal arc along the line of the runway, and one that scanned a narrow vertical arc along the line of the runway. This system enabled an aircraft to be talked down onto the runway, but the three Controllers had to work in very hot and cramped conditions inside the trailer.

On the perimeter of the airfield was the DME (distance measuring equipment) which was a modernised high powered version of the wartime Eureka beacon. This enabled an aircraft to obtain its range from the airfield up to 150 miles distance. It was also possible to “home” onto this beacon, all without any assistance from ground personnel.

To help in the recovery of fighters a device known as the voice rotating beacon was in use and this was housed in trailers parked on an old dispersal point. This too was a pilot interpreted system which used a VHF radio channel to radiate a steady tone signal for 350 degrees of its aerial rotation. In the gap of the other 10 degrees was a lady's voice, taken off a disc, that spoke the compass bearing of the direction that the aerial was pointing at that time. Unfortunately the rotation speed was only one revolution per minute which could be an awful long time for a pilot to wait to know his relative bearing to the station when travelling at 500 miles per hour in a Meteor. Needless to say this system only lasted a few years.

At some airfields, especially within Transport Command, a low power H/F short wave transmitter radiated a coded signal which enabled aircraft crews to use their radio compass to obtain a bearing from it. Sabre jets incidentally were also fitted with a radio compass.

Better Facilities


The first improvement in navigation aids at RAF airfields was the introduction of the CRDF. This automatic D/F system enabled the Approach Controller in the control tower to see the bearings of an aircraft displayed on a cathode ray tube in front of him, even though the processing equipment was housed in a brick building in the centre of the airfield.

It may be relevant, at this point, to explain the duties of the Approach Controller. He was responsible for aircraft flying outside the three mile radius of the airfield and his main task was informing pilots which way to steer their aircraft to reach the overhead by passing to them over the R/T the bearings presented to him on the CRDF indicator. Once overhead the pilot was given a predetermined course to steer. This heading was known as the 'safety lane' and was in a direction free from hills and other airfield lanes. Once established on this heading a pilot was told to commence descent to around half his starting height. When he reached this low level, he was instructed to turn onto a reciprocal heading and then descend to 2,000ft. This procedure brought the aircraft safely down through cloud and in visual contact with the airfield.

All this time the controller would be checking the bearings of each radio transmission made by the pilot, offering him corrections as necessary. This could really be a hot seat if the weather began to deteriorate when every aircraft was shouting for recovery and a Controller could soon become saturated if more than four aircraft requested this QGH service at the same time.

If the pilot requested a 'talk down' then the GCA Director in the trailer would 'pick off' the aircraft from the safety lane when he identified it on his radar display. Once he had aligned the aircraft up at six miles from touch-down he would hand it over to the Talk-Down Controller who would then use his radio to give guidance to the pilot right down to the end of the runway.

The duties of the Local Controller, who also operated in the main control room, were dealing with the aircraft within three miles radius of the airfield. His main task was giving aircraft permission to take off or land and passing such details as the barometric pressure, runway in use and conditions. He was also responsible for knowing what was taking place on the landing ground, including vehicle movements and contractors at work.

The fire section in the 1950s was still part of the guard room and this is where the fire crew and fire engines remained until being called forward to the control tower via the use of intercom or tannoy. During high intensity flying periods the foam producing vehicle and the rescue jeep would stand alongside the runway caravan at the end of the runway.
At airfields that did not possess the luxury of a GCA, the wartime BABS system was still in use but help was on the way. The British had developed the wartime SBA by increasing its radio frequency into the VHF band. This enabled a vertical beam as well as a horizontal beam to be employed. This system was known as ILS (Instrument Landing System) and the pilot could be guided by instruments in his cockpit down to within half a mile of the runway end. The large semi-circular aerial system which generated the horizontal beam was located at the downwind end of the runway, whereas the single pole aerial for the vertical beam was located at the upwind end of the runway. Unfortunately this system could only be used on one runway in one direction.

The Parting of the Ways

Cossor Radar Ltd. had developed a precision approach radar plus a 360 degrees surveillance radar as two separate systems. This act brought about a complete rethink to the way Air Traffic Control operated, as these new radars of the 1960s now brought the radar screens into the control tower for the first time. This meant that the main control room had to be blacked out and a separate visual control room (VCR) provided for the Local Controller. As an interim measure a crude greenhouse structure was erected on the control tower roof. Much later on, a new air conditioned room with sloping glass windows took its place, if the engineers thought that the existing building would carry the weight. At Linton-on-Ouse a steel support frame had to be provided alongside the original building, on top of which was bolted the new VCR.

Another major change to take place around 1960 was when NATO decided that all military aircraft radios would move up to the UHF frequency band, but as no British equipment was yet available American gear had to be borrowed. A new direction finder working on this band was eventually produced, known as CADF (commutated aerial D/F). A brick building with a 20ft diameter metal mesh disc on its roof appeared on all airfields.

At fighter stations large concrete hardstandings were provided at each end of the runway. This enabled fighter aircraft to scramble much more quickly when they were parked here and connected via umbilical cable to the ops centre, enabling pilots to be briefed while sitting in the cockpits. The ATC also monitored what was going on as he had the final word on giving permission to take off, on yet another intercom box.

The poor relation in receiving navigational aids was always Flying Training Command and they had to make do with only a low powered surveillance radar known as ACR7. There were two versions of this equipment; one was transportable and therefore had its display inside the trailer where the Controller had to operate under very cramped conditions. The other version had its radar head equipment out on the airfield in a small cabinet but its display was back in the control tower approach room.

Moving into Top Gear

By the late 1960s most airfields had been provided with a high powered surveillance radar known as AR1. It was located in a brick building with the revolving aerial on top of its 40ft lattice tower, which was a common sight at most airfields. This radar had a range of 70 miles and could have as many display units as one liked to install in the approach room. Because of its excellent range and 'off set' facility, this radar would often be shared by more than one station. The Approach Controller was provided with a display and was now able to see his aircraft in their controlled descents and this almost rendered the radio D/F obsolete.

The precision radar 'talk down' aspect was being provided by the Cossor 3B or 3C as the American MPN 11 had long since been returned to the States. These Cossor radars had their relevant vertical and horizontal displays in the comfortable approach room but the main equipment was mounted on a turntable close to the intersection of the runways. One version could be rotated remotely but the older model had to be turned by hand, not an enviable task on a frosty morning.

Things had also been improving for the Local Controller as he now had an assistant for the control of aircraft movements on the ground and a separate radio channel was utilised for this. A new purpose built fire section building had been erected adjacent to the control tower or in some cases, like Leeming, at the far side of the airfield. The rescue service vehicles now had mobile radio telephones fitted and a special bird scaring team was formed with a vehicle fitted with a loudspeaker, over which was played tape recordings of birds in distress. The runway caravan was now purpose designed and fitted on a Commer vehicle chassis and not the hotch potch lashup that had been used previously.

On airfields that had poor visual contact with certain runway approaches a closed circuit TV and camera was fitted and at others, such as Dishforth and Finningley, complete new visual control towers were built at the other side of the airfield.

The old Eureka/DME was replaced by TACAN, which enabled a pilot to find both his bearing and range from the beacon. At some major stations, secondary radar was fitted which triggered a transponder in the aircraft. This, in turn, sent back a digitally coded signal which, when decoded, applied the details of the aircraft and its height onto the radar tube alongside its blip. Even the basic Jet Provost was fitted with this equipment so almost all military aircraft could now be identified instantaneously.

The remote radio and transmitting sites had been moved back within the airfield boundary and aircraft now carried a radio that could be used on 1,700 channels. Multi channel tape recorders now record every word that is spoken within Air Traffic Control either on telephone, intercom or radio. Aircraft movements and timings are stored in computers and more and more VDUs are appearing in control rooms.

Final Thoughts

Air Traffic Control is a far cry from how it had been in the late 1940s, when it had taken many minutes to identify an aircraft's position and there was no chance of a landing back at base if the visibility had fallen below half a mile or so.

Gone were the days when the 'Met Man' had to launch a balloon to find the cloud base; all he has to do now is look at his cloud base recorder which uses infra red light to constantly measure both the base and thickness of cloud. He does not need to trudge outside to read his thermometers as these are now displayed electronically. Instead of having to draw weather maps from figures received by a teleprinter, the maps now come to him ready made via a Fax machine.

The airfield lighting is no longer a matter of turning big wheels, throwing heavy switches and kicking the cabinet. Now it is all done by remote control with the touch of a button, where high intensity lighting can be turned up or down as easy as winking.

Gone too are the old wartime ex-aircrew lags who used to form the backbone of the control staff. Now they have bright new Controllers who entered the ATC trade from the outset and a high percentage are females. Even the Squadron Leader SATCOs are bare chested with no war medals or aircrew wings and, to me, they are looking younger every year, or is it that I am growing old?

Guy Jefferson BEM

Guy was a civilian radio/radar engineer at Linton-on- Ouse for 35 years.