Isle of Man ATC in the 1970s
 
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Controlled Airspace around the Isle of Man 1970
 
Airway Red 3 routed overhead the 'IOM'  VOR/DME from Wallesey to Belfast, both also defined with VORs although Belfast at this stage hasn't been equipped with DME. The VORs are backed up by medium frequency NDBs, the 'IOM' beacon radiating on 391 Khz. Although the old Radio Ranges have been replaced by the VORs, the associated 75 Mhz marker beacons are still there, with the Portaferry and Point Lynas markers shown. Airway Red 3 has a surprisingly low base level of  Flight Level 40. Also shown are Advisory Routes 'Delta Whiskey 2', from the Pole Hill VOR to Carnane NDB ('CAR' on 366.5 KHz) and 'Delta Green 27' from Blackpool to Carnane. To the south west, another advisory route 'Delta Whiskey 11' has two options, both start at the 'IOM', one routes to the Dublin VOR and one to the Rush NDB. Controlling authority for the airways and advisory routes is Preston Centre using 125.1 MHz with Radar available. Flight Information Service also available outside controlled airspace with Preston on 126.85 MHz.
 
1970s Airway Chart
 
Controlled airspace to the south and east of the Isle of Man,
 
The Isle of Man Control Zone has been expanded from the original circle to an oval shape, no doubt to accommodate the instrument approaches to runway 27/09, the zone goes from surface to Flight Level 55. Ronaldsway has an NDB 'RON' on 322 KHz and 'Homer' (VHF D/F) on 120.85 MHz. There is another NDB on the airfield at Jurby 'JY' on 358 Khz
 
1970s Airway Chart
 
Controlled airspace to the north
of the Isle of Man
To the north, advisory route 'Delta Green 27'  has made a kink from Carnane to the 'IOM' and then continues to the Killantringan reporting point on the Mull of Galloway before continuing to the Prestwick VOR. Similarly 'Delta Whisky 11' has kinked from the 'IOM' to Carnane before heading north east to the Dean Cross NDB in Cumbria and onwards to Newcastle.
 
Preston Air Traffic Control Centre
 
Procedural Airways Control - Flight Progress Strips, clocks, radio & telephones!  By this time Preston did have radar, but the controllers were at the Preston Air Traffic Control Radar Unit (PATCRU) which was in fact at Manchester Airport. Procedural and Radar controllers worked on the same frequency with an intercom available between the positions.
 
(Picture via GATCO)
 
Preston Air Traffic Control Radar Unit
(PATCRU)
 
A radar control console at PATCRU located at
Manchester Airport
 
(Picture via GATCO)
 
 
When using procedural control, i.e. without radar, the two radio beacons and the kink in the advisory routes made operating easier as the 'IOM' and 'CAR' beacons were 'deemed separated' e.g. an inbound aircraft from Blackpool could be cleared to the 'CAR' at 3000 ft at the same time as one from Dublin was cleared to the 'IOM' also at 3000 ft. For Ronaldsway, if the radar was out of service, the holds at 'IOM' and 'CAR' would be very useful for climbing or descending an aircraft though the level occupied by another, knowing that while in the hold they were separated from each other. Right up until the 1990s the usual mode of operations for Ronaldsway was that the procedural 'Approach' would solve as many separation problems as possible before handing control to Radar. All aircraft had to be cleared to a beacon procedurally separated from all others until the radar controller had identified the relevant 'blips' on his screen and could then use radar separation between aircraft at the same level.
 
 
Concorde Flight Testing
There are regular notes in the Ronaldsway watch log from about August 1970 regarding supersonic test flights by the Concorde prototype 002, G-BSST,  based at Fairford in Oxfordshire. A test route had been established from Fairford, eastwards to The Wash, then accelerating to supersonic speed along the east coast of England, up around the north of Scotland and back along the west of Scotland and Wales, which must have been close to the Isle of Man. A monitoring station was installed at Ronaldsway in the D/F hut and presumably the equipment needed to be turned on when a run was about to happen. After a run had been recorded, a Devon aircraft from the Royal Aeronautical Establishment would fly into Ronaldsway to collect the data recorded.
(Thanks to Chris Cook for the information on this) On the 12th November 1970 captained by Brian Trubshaw Concorde 002 achieved Mach 2.0 for the first time. Unfortunately, apart from notification of the flight taking place, there is no other comment in the log.
 
Concorde Flight Plan
As received on the teleprinter at West Drayton. This was by one of the later flight test aircraft, G-AXDN No 01,  for a supersonic flight out over the Atlantic Ocean and back to Fairford. This aircraft is preserved at Duxford.
 
Concorde 002 G-BSST
Preserved at the Fleet Air Arm
Museum, Yeovilton Somerset
 
 
 
Changes on the Airfield
 
At Ronaldsway, the aircraft parking aprons had continued to expand to cope with the larger aircraft now coming into service. From the 1960s Vickers Viscount turboprops were common, first with BEA and then Cambrian Airways when they took over the Isle of Man routes in 1963. Viscount G-ALWF pictured below was operated by Cambrian from 1966 to 1971 and would have often been operating on Isle of Man routes. It is now preserved at Duxford.
 
Preserved BEA Viscount 700 G-ALWF
 
Initially the control tower remained in splendid isolation on the airfield and aircraft could taxi and park between the tower and the terminal building, but it was decided to build a pier connecting the two together and so in 1971 they were linked by a 'temporary' wooden pier, used for the new phenomena of security screening departing passengers who then waited in a holding lounge (Gate 8) until boarding their aircraft. If it was parked on the west apron, progress to or from the control tower was hindered as the corridor would be closed off to allow the departing passengers to cross over. 
 
Constructing the pier in 1971
Aerial view of the completed pier in 1975
 
The control tower accommodation was also improved in the 1970s with an extension built onto the west side of the radar room to provide an office for the Senior Controller (SATCO) and a combined rest and locker room for the staff.
 
The Control Tower
(Late 1970s?)
 
With the first of two annexes
built onto the side of the 
radar room
 
 
The Visual Control Room in 1971
 
Associated with Ronaldsway since the 1930s, controller and former pilot Jimmy Hesketh is pictured with ATC Assistant John Chadwick at the desk behind,
 
 
 
Area Control Changes
 
Secondary Surveillance Radar
 
During the 1970s Secondary Radar (SSR) came into widespread use in area control. Initially only having 64 discrete codes it was expanded to today's limit of 4096 codes. Modern radar displays were able to show the allocated code next to the primary radar 'blip' and aircraft could be identified using the allocated 'squawk' code as set on the aircraft transponder. This was 'Mode A' and a further development, 'Mode C'  linked an altimeter in the aircraft to the transponder and the controller was able to see the actual level of the aircraft on his display. Using early computer technology it was possible to produce a 'Code/Callsign Pair' and associate a squawk code with the aircraft callsign, e.g. transponder code 3011 might be allocated to flight BE4902. In the early systems the controller would observe the code on his display, 3011 and ask the aircraft to 'squawk ident'. The pilot pushed the 'ident' button on the transponder which activated the 'SPI' function, causing the aircraft position symbol on the radar display to flash for several seconds. It also triggered the Code/Callsign function in the radar processor and code 3011 would be replaced with the aircraft callsign 'BE4902'.
 
St Anne's Radar with SSR
A processed Radar picture from the St Annes
S264A and SSR
 
1975 - Preston Centre Closes - Manchester Sub-Centre Opens
 
Preston Centre closed in 1975 with most of its functions transferred to the London Air Traffic Control Centre at West Drayton. However a sub-centre was established in the control tower at Manchester Airport, which remained responsible for the airways around the Isle of Man at lower levels. Co-ordination would have remained much the same with clearances being requested by Ronaldsway for outbound airways aircraft and releases passed by Manchester on inbound flights. Every departure clearance and inbound 'release' was individually negotiated and levels agreed based on traffic to keep procedural separation. The 'release' on inbound aircraft was a Position, Time or Level at which the Centre handed control to Approach, for instance 'Released passing flight level 90'. Communications might be transferred to Approach earlier, but until the aircraft had passed FL90 in the descent, Ronaldsway Approach or Radar could not issue any control instructions, for example radar turning the aircraft for identification.
 
Manchester Sub-Centre
A map from November 1974 showing the new
area of responsibility to be assumed by the sub-centre
 
The sectors at Manchester were West Drayton type 'Mediator' consoles, which combined the procedural and radar functions. The controller sat in front of a horizontal radar display, with the Flight Progress Strip board above and sometimes another vertical radar display behind to show the picture from an alternative radar source. In general there were two (expandable to four) controller positions on a 'suite' with a 'Senior Sector Controller' known as the 'Crew Chief' central and Assistant's positions outboard on 'the wings'. The Crew Chief's function was to oversee the operation of the sector and carry out co-ordinations with other sectors and airfield, e.g. Releases to Approach. Information written on the strips was 'colour coded' so that it was immediately apparent as to who had written what. Assistants wrote in black pen, Controllers in red and Crew Chiefs in green.
 
Area Control 'Mediator' Sector
This is actually the Pole Hill sector at
West Dayton, one of the former Preston sectors transferred in 1975. The Manchester sub-centre was similarly equipped.
If a confliction at the point of release from Centre to Approach could not be resolved procedurally it was possible to use a 'Radar Release'. This involved the radar controllers co-ordinating directly, the Manchester Centre controller would ring Ronaldsway and ask to speak to the radar controller. Starting with the words 'Radar Release' he would identify the conflicting aircraft to Ronaldsway using points marked on both displays, e.g. 'Cambrian 602 is bearing 130 degrees from the IOM at 33 miles'. Once both aircraft were identified to Ronaldsway and the terms of the release agreed the aircraft would be transferred.
 
ATC in the 1980s
 
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