Isle of Man Aviation and ATC in the 1930s
 
Island Images
IOM ATC Index
 Manx Aviation Pre 1930s
1933 - Regular air Services to the Isle of Man
 
In March 1933 Blackpool and West Coast Air services was established with a main base at Blackpool Aerodrome and operated charter services to Ronaldsway using a DH83 Fox Moth. By August they were operating scheduled services with one daily flight from Liverpool and two from Blackpool using a twin engine de-Havilland DH84 Dragon G-ACGU. These services stopped for the winter in September but in 1934 four other companies were operating to Ronaldsway, Midland & Scottish Air Ferries, Hillman Airways, Northern Airways and Railway Air Services. Towards the end of 1934 Captain Olley of Olley Air Services acquired Blackpool & West Coast with Captain Higgins as chief pilot and secured the landing rights at Ronaldsway, a temporary aerodrome license was issued to Ronaldsway at the start of 1934 pending improvements to the airfield and facilities. 
 
A hanger capable of housing a DH Dragon was erected together with a wooden traffic office, the hanger not lasting long, being blown down in February and subsequently replaced by a larger structure in March. A holding company, Isle of Man Air Services was created to run the aerodrome and other airlines had to pay to use the facilities. Blackpool & West Coast now had four Dragons in service: G-ACGU, G-ACNA, G-ACPY and G-ADCR. In 1936 the airline introduce four engined de-Havilland DH86 'Express' airliners and with the Irish Airline, Aer Lingus Teoranta starting services from Dublin, Ronaldsway was becoming a hub for routes across the Irish Sea.
 
Isle of Man (Ronaldsway) Airport
From 1938 Newnes Aeronautics Guide
Enlargement of the aerial photo of Ronaldsway
from Newnes 1938 guide
 
 
Ronaldsway in the 1930s courtesy of the Terry Farragher Collection
Blackpool & West Coast DH84 Dragon G-ACPY 
refuelled by Shell - 1934
Railway Air Services DH89 Dragon Rapide
G-AEBX 'Star of Scotia' - 1936
 
Airport Buildings - 1936
 
DH86 Express G-ADVJ with 
DH89 Rapide G-AEAK - 1937
1938 Aerial view of Ronaldsway
 
 
 
 
Hall Caine Airport, Ramsey
 
In 1934 a rival to Ronaldsway was established at Close Lake, just to the west of Ramsey on the St Jude's road, named after the famous Manx author Sir Hall Caine. Services commenced in April 1935 operated by United Airways using three engined Spartan Cruiser monoplanes. One service per day operated Blackpool - Hall Caine - Carlisle and return and three others Liverpool - Blackpool - Hall Caine and return. From May 1935 Northern & Scottish commenced a weekly service from Glasgow building up rapidly until it became twice daily by July. A series of airline amalgamations took place by the end of the year resulting in a new company, British Airways Ltd being formed. In the summer of 1936, Northern & Scottish (operating on behalf of British Airways) were operating Glasgow services twice a day, Liverpool and Blackpool twice or three times a day and once a day to Belfast and Carlisle. Aircraft used were Spartan Cruisers, Dragons and Dragon Rapides, with occasional visits by an Armstrong Whitworth Argosy which could carry up to 28 passengers. Both passengers and mail were handled and there is a mention in 'Manx Aviation in War & Peace' that on the 12th September 1936, 28 flights were handled, carrying 69 passengers, 612 lb of Mail and 1,375 lb of baggage. Despite such a busy season in 1936, airline operation had ceased by the following year, the last scheduled flight leaving on the 2nd August 1937, the aerodrome remaining open for private flying until the outbreak of war in September 1939. Although M/F W/T radio was installed at Hall Caine for airline message handling, there was never any ATC service offered.
 
Aerial view of Hall Caine Airport in the 1930s
 
Hall Caine Aerodrome Diagram
Hall Caine Airport with Spartan Cruisers and a DH Dragon
 
 
Google Earth image of the area occupied
by Hall Caine Airport
Oblique Google Earth view of the site occupied by Hall Caine
Airport, with Ramsey behind
 
Spartan Cruiser
Armstrong Whitworth Argosy
 
Hall Cain Airfield diagram from the 1939 Air Pilot
 
Hall Caine in 2014
 
Some other airfields with services to the Isle of Man
 
Diagrams from the 1938 Newnes Aeronautics Guide.  Click for larger and use your browser 'Back' button to return here.
Liverpool (Speke)
Manchester (Barton)
Blackpool (Stanley Park)
London (Croydon)
Glasgow (Renfrew)
Leeds/Bradford (Yeadon)
 

Air Traffic Control in the UK
 
Further south, in the London area, commercial air traffic was becoming much busier and it was decided by the UK Government that something had to be done to improve safety when aircraft were operating in conditions of poor visibility - Air Traffic Control was about to start in Great Britain.
 
 
November 19th 1933 - First UK Air Traffic Control Service established at London Croydon
 
Due to the ever increasing danger of aerial collisions in bad weather, the first UK Air Traffic Control service was introduced at Croydon Airport, London. An irregularly shaped 'Controlled Zone' based on geographical features came into operation when visibility dropped to below 1000 yards or cloud was below 1000 ft - in the 'Q' code used for the W/T (morse) communications of the day this was 'QBI'. 
 
Standard routes were also defined over south east England, mainly following railway lines and using the 'right hand traffic' rules , i.e. every aircraft flew to the right hand side of a line feature which would hopefully allow opposite direction aircraft to pass well clear.
 
Click for map of Croydon Controlled Zone and air routes
 
If 'QBI' was in force, pilots had to obtain permission by wireless before entering the zone or land clear at another airfield and wait for the weather to improve. Departing aircraft captains would report in person to control for any departure restrictions before taxiing to the departure point on the airfield and awaiting a light signal from the 'lookout man' when cleared for take off by the controller. 
 
Croydon ATC 1935
Croydon ATC 1937
 
'Lookout Man' Croydon Airport 1937
 
After becoming airborne the pilot or wireless operator would pay out the long trailing aerial required for the Medium Frequency radios used and make contact with control, reporting when level at his assigned altitude and when he estimated clear of the controlled zone. Direction finding (D/F) bearings would be available to assist navigation of both inbound and departing aircraft and control would plot positions of aircraft based on D/F bearings from Croydon, Lympne and Pulham. Each station would report a 'bearing line' on a transmission and by plotting these on a map a position could be obtained for the aircraft. The controller would mark aircraft positions on his map using coloured flags and information on conflicting flights together with suggestions on altitudes or routes to be flown would be transmitted to pilots.  'Communications Areas' were established over southern England within which pilots could contact a control agency by radio and obtain information on other aircraft together with advice on avoiding aerial collisions, e.g. a change in altitude.
 
Plotting D/F Bearings - Croydon 1937
Radio Operator - Croydon 1937
 
  
 
Air Traffic Control in the USA
 
Across the Atlantic it was also realised that some sort of control was needed to prevent collisions between aircraft at airfields, so in the late 1920s a system of 'Flag men' was established at a few airports, the first being at St Louis, Missouri in 1929.  By the early 1930s, airports were starting to be provided with control towers equipped with radio, these early ATC units were operated by the airlines and only controlled traffic within visual range of the controller.  Routes between cities, later know as 'Airways' were defined by light beacons at night, but in the early 1930s 'Radio Range' stations became established enabling pilots to safely navigate along the route in cloud, creating the possibility of mid air collisions between aircraft 'following the beam'.  In 1935 the US Government published a set of rules governing flights using instruments along the airways and by the end of the year the first 'Airway Traffic Control Station' was established at Newark, New Jersey, with further stations opening in 1936 at Chicago and Cleveland.  Initially operated by the airlines, the US Government took over operations in July 1936 and hired 15 'Airways Controllers', mainly the airline staff who had been doing the job already.  Control of traffic was based on Flight Plans received from the airlines and radio reports filed to airline dispatchers which were then telephoned to the controllers. These messages were recorded onto a blackboard and then used to plot aircraft positions on a chart using 'Shrimp Boats' - small wooden markers holding a piece of paper with the aircraft details.  Positions were updated every fifteen minutes and control instructions relayed to the aircraft via the airline dispatch offices.  Control only applied to aircraft flying under the 'Instrument Flight Rules', aircraft flying visually could proceed as they wished although airliners were encouraged to report their positions to control.
 
Newark Airway Traffic Control Station, 1930s
Plotting Aircraft Positions
 
The number of Airway Traffic Control Stations was rapidly expanded once under government control and by the end of 1939 there were twelve in operation.  Also established during the 1930s and 1940s were 'Approach Control' units at airports, controlling aircraft beyond the visual range of the tower controllers.  In this regard the USA seemed to lag behind the UK, as Croydon Airport was effectively operating Approach Control from 1933.
 
Washington Centre 1943
Chicago Tower, 1943. Note use of Flight Progress Strips
 
Whilst in Europe the outbreak of World War Two halted the expansion of civil aviation, it continued apace in the USA and by the end of the war there were twenty eight centres, serving air routes defined by the medium frequency Radio Ranges and Non Directional Beacons (NDBs).  The developments in the USA were to have a profound influence on development of ATC procedures in the UK and Europe in the 1950s, with Radio Ranges being established to define new airways and Air Traffic Control Centres set up to control aircraft.  This is covered in more detail in the 1950s section.

 
 
8th July 1937, Air Traffic Control Service Established at Ronaldsway - 'GJE' on 363Khz
 
Only three and a half years after ATC started at Croydon Airport, Air Traffic Control was established at Ronaldsway Airport. This was due to the large number of commercial flights operating acros the northern Irish Sea, many of them stopping at the Isle of Man. Whereas in the UK, the preferred mode of long distance travel for most was by the extensive railway network, travel to the island involved a lengthy and often rough boat journey across the Irish Sea. Air travel for those who could afford it was much faster and more comfortable.
 
Map of Internal Air Routes 1936
'Flight' article - 'Radio for Ronaldsway' 1937
 
 
Ronaldsway first 'Control Tower'
 
The first ATC Watch Office at Ronaldsway. Located next to the airport terminal at Derbyhaven with the direction finding station close by. The radio receiving aerials were adjacent, but the 70' high transmitter aerials were further to the west. Signals to aircraft and other ground stations would be passed on colour coded message slips to the W/T operators in the room behind the control office for transmitting by Morse Code. Replies would be similarly passed on message slips. 
 
The 1937 Ronaldsway Watch Office
Mobile Marconi D/F Station
Ronaldsway Radio Room 1937
 
From the Newnes 1938 Ronaldsway page and the 1939 Air Pilot, it would appear that signals giving permission to land and take off were probably not used at Ronaldsway.  In accordance with the Air Navigation Order, it was up to pilots to ensure that they formed a proper traffic circuit and landed or departed in turn, making a left turn after landing as subsequent aircraft might be landing to their right.  If required, supplementary instructions could be given from the ground by Aldis signalling lamp or a coloured very pistol signal. Initially the colours used varied from location to location, but a standard set of signals was agreed and can still be used today, although from personal experience very few pilots seem to look at the tower for such signals even if they have a known radio failure!
 
Aldis Signalling Lamp - 2012
Demonstrating that some things never change in ATC!
 
 
The Controlled Zone
 
A 'Controlled Zone' was established on the 8th July 1937 comprising a circle 10 miles around Ronaldsway to a height of 3000 ft. Control only came into action in 'QBI' - i.e. poor weather conditions.  The principle was one aircraft inside the zone at a time, arriving and departing aircraft could be assigned levels to fly and expected times to enter the zone. If QBI was not in force, aircraft could arrive overhead the airfield to observe the ground signals square, which would give them the information needed as to landing and circuit direction. As the airfield was grass, with no delineated runways, the 'Landing Tee' was pivoted to rotate with the wind and pilots would always land into wind. In light winds the Tee would be fixed in one direction to avoid confusion if it drifted around.. Pilots would join the visual circuit keeping a good lookout for other aircraft and touch down once the landing area was clear of other aircraft. Unless otherwise instructed all turns were to be made to the left.
 
Signals Square at Manchester Barton
Signals Square at Ronaldsway - 1950s
 
Landing Tee
Although the zone was 'Controlled' in QBI conditions, this really only extended to regulating aircraft entering and leaving the zone. Once cleared inside, it was up to the pilot how he conducted his flight. D/F bearings would be passed as requested and it was up the him to decide what headings to fly and what was a safe height to descend to. In low cloud at Ronaldsway it would be likely that a pilot would obtain bearings until he was indicated overhead the D/F station and then set a course to let down over the sea until he was visual with the surface, obtaining regular bearings and using time to estimate his position. The controller or his assistant would stand outside the watch office and listen for the aircraft engines and a message would be passed to the pilot, e.g. 'engines east'. Once visual with the surface further D/F bearings could be passed to 'home' the aircraft back towards the airfield.
 
 
The Isle of Man and Manchester Communications Area
 
A new 'Communications Area' was established over the northern Irish Sea, jointly administered by Ronaldsway and Manchester Barton. A purpose designed brick control tower had been built at Barton in 1933 and is still in use today. Positions of aircraft would be plotted on a map based on position reports and estimates from the pilots. A frequency of 363 KHz was used (by both Ronaldsway and Barton), using W/T - wireless telegraphy by means of Morse Code. (Speech Radio Telephony had been used by aircraft previously, but was largely abandoned by this time due to congestion on the very limited frequencies available). Radio equipped passenger aircraft would carry a wireless operator as it would not have been practical for the pilot to both fly the aeroplane and operate the radio. Direction finding bearings were available to assist pilots in navigation, but this would be a time consuming process as bearings were manually obtained at the ground stations before being re-transmitted to the aircraft. To keep messages short, the 'Q' code was used, most regular phrases needed being covered by a three letter code starting with the letter Q. More information on the 'Q' code below.
 
Communications Areas & Controlled Zones 
January 1938
The Isle of Man & Manchester
Communications Area 1938
 
Manchester Barton 1930s Control Tower in 2013
Liverpool Speke Airport 1930s Control Tower in 2009
 
As the controllers had no authority to issue compulsory instructions within the area, information on conflicting known flights would be passed together with 'suggestions' as to how the conflict could be resolved. Most pilots, if flying 'blind' in cloud would have been only too pleased to accept the suggestions!
 
The controllers didn't communicate directly with aircraft, messages from pilots were received by radio operators and transcribed onto paper message slips, colour coded according to the message type, before being passed to the controller. After considering his actions, the controller would write his reply onto another message slip and pass it to the radio operator for transmission to the aircraft.
 
 
Ballahick and Red Gap Radio Stations
 
In 1936 two new radio stations had been constructed to serve Ronaldsway.  A transmitting station at Ballahick, just outside Ballasalla and a recieving and Direction Finding station at Red Gap, just west of Castletown.  The Red Gap d/f station used  the 'Adcock' system which gave more accurate bearings during the hours of darkness. This needed to be located away from the airfield due to the four 100 ft high radio masts needed. These were arranged in a square with a quite large building in the centre, housing the wireless equipment and plotting table. Both buildings still exist in 2020, Ballahick has been converted into a private residence and Red Gap is a ruin.
 
Aerial view of Ballahick in 1944
The Ballahick Transmitting Station in 1958
 
Aerial view of the Red Gap Radio Station site in 2020
Red Gap Receiving and Direction Finding Station - 2009
 
Adcock Direction Finding station at Pulham
Marconi-Adcock Direction Finding Receiver
 
 'Flight' Diagram of working a Controlled Zone in QBI
(Click either image below for full diagram)
Controlled Zone around aerodrome 'XEP'
'Q' codes used and instructions issued
 
A typical flight to Ronaldsway in QBI conditions
 
Some sets of message slips have survived from the 1930s and we can follow the flight of Dragon Rapide G-AFFF from 
Glasgow Renfrew to Ronaldsway on the 14th June 1939.
 
 
 ATC Watch Log entry for 14 June 1939
showing 'QBI' in force
 
The weather was poor at Ronaldsway so the Controlled Zone was in operation (QBI). Each slip represents a message sent using Morse Code between the aircraft and a ground station. Extensive use was made of the 'Q Code' to shorten transmissions.  There were 33 messages in total to get one aircraft into land! The 'ATC Diary' entry for the day indicates that QBI had been in force from 07:55. If I've worked this out correctly. pink slips are for arrival and departure messages, white slips for 'general' messages from and to the W/T station and green slips are for Air Traffic Control messages.
 
Follow the Flight
 
ATC & M/F D/F message slips for just one aircraft to enter the Controlled Zone and be 'homed' into Ronaldsway
 

ATC Developments 
Even in this period ATC was becoming overloaded with traffic and it was suggested that medium frequency radio 'beacons' were set up to allow suitably equipped aircraft to obtain their own bearings to stations using on board direction finding equipment. The equipment was bulky which meant that it was only really practical in the airliners of the day. At Croydon Airport a 'Lorenz' radio beam system was installed in 1936 to enable aircraft to approach the airport in poor visibility and descend on a safe path until the airfield appeared ahead (hopefully!) The 'beam' could be followed either aurally (through the pilots headphones or by using a special instrument. This was the for-runner of today's Instrument landing Systems. (ILS)
 
'Flight' diagram from 1935 showing the principle of the Lorenz system
 
 
 
Advert for a Lorenz receiver and indicator, made by Smith's
 
Codes and SIgnals
 
Before the widespread introduction of Radio Telephony (R/T) i.e. speech transmissions, which started for RAF fighter aircraft in the 1940s and only became prevalent for civil aircraft with the introduction of VHF radios in the 1950s, methods were devised for signalling between aircraft, ships and ground stations. Many used ground markings, flags, light and pyrotechnic signals and an international 'Code of Signals' was devised and published under the Air Convention of 1919.  The book illustrated on the left was issued by the UK Air Ministry in 1940 and consists of 156 pages illustrating these various codes and signals.  In addition, a system of three letter codes that could easily be transmitted using Morse Code on Wireless Telegraphy (W/T) was introduced from 1913 onwards, initially for ships but expanded for aviation use in the years following WW1 when radio equipment became more commonly fitted to aircraft.  The second volume illustrated is a much more modern version issued by the International Civil Aviation Organisation (ICAO), this one being the fourth edition published in 1989.
Air Ministry 1940 Signal Book
ICAO Abbreviations & Codes 1989
 
 
Light and Ground Signals
 
Some of the light signals and ground information signals persist in use today, the two illustrations below from
a 2010 'AFE Flight Guide' illustrate some of them.
Light Signals
Ground Signals
 
Sample 'Q' Codes
 
The Same 'Q' Code could be used as either a question or an answer and a selection of codes are shown below.  I have paraphrased some for the sake of brevity, many 'Q' codes contain multiple options.
 
QAB
May I have clearance for....
You are cleared.....
QAH
What is your height above...
I am at altitude...
QAL
Are you going to land at...
I am going to land at...
QAM
What is the latest meteorological observation for...
Meteorological observation is...
QBF
Are you flying in Cloud?
I am flying in cloud at altitude...
QBI
Is flight under IFR (Instrument Flight Rules) compulsory?
Flight under IFR is compulsory
QDM
What is the magnetic heading to steer to you?
The magnetic heading to steer to me is...
QFE
What (pressure) should I set on my altimeter to read height?
Set.... on your altimeter to read height.
QFU
What is the runway in use?
The runway in use is...
QNH
What should I set on my altimeter to read altitude?
Set.... on your altimeter to read altitude.
QRM
Are you being interfered with?
I am being interfered with.
QRZ
Who is calling me?
... is calling you.
QSY
Shall I change to another frequency?
Change to another frequency (can be specified)
QTH
What is your position?
My position is...
QTO
Are you airborne?
I am airborne.
 
There are a total of 248 'Q' codes in the 1989 publication and any good pilot, radio operator or Controller would be expected to know all of the relevant ones used in everyday operations.  The message slips shown above show that they were used on the written messages between controller and radio operator just as much as actually on the radio.  Some of the codes are still in daily use today as telephony abbreviations, such as QNH, QFE, QDM, QSY.

 
A 1939 ATC System Roundup
 
By then end of the decade, the ATC system had expanded to include several 'Controlled Zones' around busy airports, including Ronaldsway, plus three 'Civil Aviation Areas' where a control service was provided from the ground to aircraft operating in 'Cloud or Reduced Visibility' (1939 Air Pilot).  This was defined as when the base of a continuous cloud level was less than 1,000 feet above sea level, which was known as 'Visibility 3 Minus' from the equivalent height in metres.  In flight it was defined as when horizontal visibility was less than 1,000 metres.
 
 
If flying in clear weather pilots could choose courses and level as they wished but in what we now call Instrument Meteorological Conditions a separate set of rules applied.  If flying below 1,500 feet or above 18.600 feet, flights were unrestricted, but otherwise pilots had to obey certain rules designed to prevent them coming into close proximity.  Within the zones and areas, pilots request and be allocated altitudes to fly at that would prevent them coming into conflict with other aircraft, but such controlled areas only covered a small proportion of UK airspace and so a system know as the 'Directional System' was mandated.  The diagram below illustrates how it applied do different areas and levels.
 
1939 Airspace Regulations Diagram (from 1939 'Air Pilot')
 
Civil Aviation Area III, which covered the Manchester and Liverpool areas, north over Cumbria and up to just north of Glasgow, then west to include Belfast and south to the North Wales coast was controlled from Manchester Barton.  There were separate W/T radio frequencies for the Main Area and West Areas.  For the West Area, Ronaldsway was listed as a 'collaborating station', but there seems to have been no third direction finding station available to enable the exact position of an aircraft to be fixed by wireless.  Other aeronautical wireless stations around the north west area were located at Manchester Ringway, Glasgow Renfrew and Newtownards in Northern Ireland. There is an entry in a Ronaldway log book about them 'taking over' from Manchester when the latter were having radio problems.
 
 
The Directional System
If pilots were flying in Reduced Visibility Conditions (including in cloud) outside the zones and areas, they had two options available to them, either fly below 1,500 feet or in compliance with Directional System.  If the latter they were required by regulations to carry a 'Course Height Indicator' to calculate the appropriate altitude to fly at. Flight between 1,500 feet and 3,300 feet was discouraged unless under ATC Control or for climbing and descending as quickly as possible.
 
Further south, in Civil Aviation Area I, a much more comprehensive control system was operating, although still only in conditions of reduced visibility.  In addition to the air traffic control services offered, two 'Air Routes' were defined for traffic operating from the coast of SE England routing towards the airports in the London Area.  Controlled from Croydon, aircraft postiions could be determined by wireless direction finding using the stations at Croydon, Lympne and Pulham.  At night the routes were defined by light beacons where required, the forerunner of later airways defined by radio beacons.
 
The London - Continent Airway Area in 1939
 
 
All of these civil air traffic control developments were to be suspended later on in the year after the momentous events of September that year with the outbreak of war and it was not until the late 1940s that most would be re-introduced, although a service was provided from Ronaldsway and Liverpool throughout the wartime years.

Wartime
 
On the 1st September 1939 as Nazi Germany invaded Poland, an Air Ministry air traffic controller arrived at Ronaldsway to assist in training the local staff in requirements for wartime operation. Signals now needed to be encoded before sending via radio and pilots needed to be issued with the 'colours of the day',  recognition Very lights to be fired if challenged by a fighter aircraft or a ship. With war declared on 3rd September, civil air services were cancelled and all aircraft ordered to the UK for possible impressment into military service. However, the importance of the Isle of Man air route was recognized and a limited service was re-instated from November 1939, using Dragon Rapides. All flights had to be authorized in advance, but there were often occasions when they were challenged by ships. Special routes had to be  followed into the Liverpool area to avoid the protecting barrage balloons and anti-aircraft defences. The Rapides still had civil registrations but were now painted in camouflage and had the passenger windows blacked out. Photography was forbidden.
 
Preserved DH89 Dragon Rapide G-AGJG
in wartime camouflage
 
 
Some ATC Log Book entries from September to December 1939 (click for larger)
2nd September 1939
20th November 1939
22 December 1939
 
 
RAF Jurby
 
RAF Jurby was conceived under the 1930 expansion plan to provide training facilities to allow the RAF to counteract the rapidly expanding Luftwaffe.  It was designed as an Armament Training Station to train gunners and bomb aimers, with handy local bombing ranges being established just off Jurby Head and The Ayres and also in Ramsey Bay.  Construction started in late 1938 and the grass airfield was ready for use by September 1939.  More information on RAF Jurby will be found in the 'ATC 1940s' section of this website.
 
1940 'War Edition' map of the Jurby area.
1942 Aeronautical Map of the Isle of Man
 
 
ATC in the 1940s
 
An Island Images webpage © Jon Wornham