Air Traffic Control at Ronaldsway, Isle of Man
2014 Onwards
 
Island Images Homepage
IOM ATC History Index
 
ATC Operations at Ronaldsway  since my retirement in September 2014
 
An attempt to record some of the changes to ATC operations from then up to the present day. ATC is a constantly evolving operation with new equipment and procedures being introduced on a regualr basis.  As I am no longer working there, I am using various sources to keep up with the changes.
 
For a detailed explanation of day to day ATC at Ronaldsway see ATC 2014

 
Airspace Revision - November 2014
 
With effect from the 13th November 2014 all class 'F' Advisory Routes within UK airspace were abolished, either completely or replaced with another category of Controlled Airspace.  Around the Isle of Man route W2D to Pole Hill (for Blackpool & Leeds), W911D to Dean Cross (for Newcastle) and W928D to BLACA (for Prestwick & Glasgow) were abolished and becambe Class G airspace.  Aircraft formerly using these routes now leave the air route structure as soon as they cross the Isle of Man Control Zone boundary, unless they choose a longer less direct route.  Ronaldsway Radar can provide a service until around 40 miles away and then hopefully hand the aircraft off to another agency.  In many cases Scottish Control are happy to provide a service to these aircraft, depending on controller workload.
 
Route W911D from IOM to BOYNE (for Dublin) changed to a class 'E' airway and was renamed Y911 with a base level of Flight Level 75, the airspace is also a Transponder Mandatory Zone (TMZ) for VFR aircraft wishing to operate within its confines.  Aircraft operating under the Visual Flight Rules can cross the airspace without a clearance so long as they have an operational Mode-S radar transponder, making them visible to ATC.
 
The base level of FL75 can cause some additional workload to Ronaldsway controllers, particularly when runway 08 is in use as the Manual of Air Traffic Services states that controllers should keep aircraft with Controlled Airspace if at all possible, but with a short distance to touchdown from the Control Zone boundary it is almost inevitable that pilots will request to descend below the airway to avoid additional routing and wasting fuel, the ATC service being provided to them might then change three times within around 20 miles.
Revised airspace around the Isle of Man from 13th November 2014
 

 
Changes to Ronaldsway's ATC Radio Frequencies and remote Approach Radar Radio Station
 
A project that dates back to the 1990s to improve Ronaldsway's VHF radio coverage at lower levels over the north of the island became operational towards the end of 2014. Originally planned and tested with an additional transmitter/receiver station on 120.850 at Jurby, revised plans have re-located the main Approach/Radar radio station to Snaefell summit from the airfield at Ronaldsway. Due to the new location and mountain top elevation, this required alterations to the main operating frequencies for Ronaldsway to prevent interference to other aeronautical radio stations. On the 22nd September 2014 'Radar 2' frequency 118.2 MHz was permanently withdrawn from service to allow engineering work to commence for the main frequency changes. With effect from the 11th December 2014 the new operating frequencies will be:
 
Ronaldsway Approach/Radar - 135.9 MHz
Main transmitter/receiver on Snaefell Summit, with standby at Ronaldsway
 
Ronaldsway Tower - 119.0 MHz
Transmitters & receivers remaining at Ronaldsway
 
Other (when instructed by ATC) frequencies will be 120.850 and 125.3 and can be used for a second radar position and Ground Movement Control when traffic requires. The old Tower frequency of 118.9 was replaced by 119.0 and is no longer available at Ronaldsway. This change to the primary Approach and Tower frequencies was the first since they were introduced into service on the 16th January 1964!
 

 
Replacement of ATC Surveillance systems at Ronaldsway
 
A requirment that was identified around 2010 was to replace the 15 year old Watchman PSR & Cossor SSR radar systems.  The Watchman would have required extensive refurbishment to continue in operation and the Cossor Mode A/C SSR needed to be replaced by the start of 2012 to comply with requirements to operate only Mode-S systems.  The replacement systems chosen were a Selex ATCR-33S Primary Surveillance Radar to be installed at Ronaldsway with a Wide Area Multilateration Mode-S SSR system operating from multiple sites around the island.  Part of the project included a ground surveillance system showing aircraft and vehicle positions on the airfield.
 
The equipment was installed in 2011 but due to various unforeseen technical issues,  the project had an extended development period to try and bring it up to an acceptable performance level before it could be used by ATC.  As a result of this the Watchman radar had to be modified (in common with all existing ATC 10 Cm radar systems) to prevent interference from 4G mobile phone transmissions that were planned to operate at frequencies adjacent to those of ATC radars. The Cossor Secondary Radar System suffered a major fault and was temporarily withdrawn until a new aerial could be installed and the system returned to service.  Temporary permissions had to be obtained from the UK CAA to continue operating the Mode A/C SSR system.
 
The new system went 'live' on the 3rd September 2017, operating in a combined Primary Surveillance & Multilateration Secondary radar only mode.
 
Selex ATCR-33S Radar at Ronaldsway
Selex Wide Area Multilateration Aerial
 
The new radar system is completely processed with no primary radar 'blips' displayed on the screen as with the older system.  Instead, different symbols are used to show the source and type of information displayed. The primary and secondary radar is combined electronically and aircraft tracks are then displayed to the controller.
 
A primary radar only contact is show as a vertical cross 
 
An MLAT only contact is shown as a diagonal cross  x
 
A combined contact (PSR & MLAT) is shown as a star *
 
Additional information is provided to the controller based on information being downlinked from the aircraft Mode-S transponder, depending on the type of transponder fitted into the aircraft.  The most basic information displayed shows the aircraft radio callsign, either as a Flight Number for airline flights, Aircraft Registration, or Military Callsign.  This information can be stored in the transponder in the case of aircraft registration, or has to be entered by the crew before each flight in other cases.  The aircraft vertical level (Flight Level) is also transmitted and displayed either as a flight level or an altitude if the aircraft is operating at or below the Transition Altitude, 3000 ft in the case of Ronaldsway at present, although this is due to change to 18,000 ft in the future.
 
More advanced transponders also downlink 'Enhanced Parameters'.  This can include, selected level on the autopilot, aircraft indicated airspeed, actual aircraft heading and the barometric pressure set on the altimeter. These can be displayed on the controllers display as required. From the Selex Primary Radar, digitized weather returns can be overlaid on the display to plan for weather avoiding requirements by pilots.
 
Selex data on the Situation Display
Mode-S two line Data Block
Mode-S three line Data Block
 
Primary radar returns from rain showers around the Isle of Man
 
 
Radar Interference from Wind Farms
 
It is an unfortunate fact that the growing number of both onshore and offshore wind farms are causing problems to ATC radar surveillance capabilities.  Most ATC radars cancel out unwanted 'static' returns by using filters that detect the difference between stationary and moving targets.  Wind turbines, by their very nature are presented to the radar processor as moving targets and it is therefore are difficult to remove them as clutter on the display.  The older Watchman radar at Ronaldsway suffered from this from time to time, even though the nearest wind farms at the time were technically over the 'radar horizon'. 
 
'Anaprop' Clutter on the Watchman Radar Display
 
 
Walney Transponder Mandatory Zone (TMZ)
 
The problem with newer fully processed radar systems is that when sufficient levels of data processing are introduced to remove the unwanted clutter from windfarms on the display, the actual aircraft returns can also be removed.  Secondary Surveillance Radar returns should be unaffected by the wind turbines and a Transponder Mandatory Zone (TMZ) has been established over the wind farm for the benefit of Warton airfield, located near to Blackpool and operated by BAe for the production and flight testing of Typhoon and Hawk aircraft.  The TMZ only operates during Warton's notified hours of opening from Monday to Friday and any aircraft that wishes to transit through the airspace must either be fitted with a serviceable Mode-S transponder or contact Warton for a clearance to transit.  At present, Ronaldsway is having to restrict radar services offered outside controlled airspace.
 
Restricted Airspace in the northern Irish Sea around the Isle of Man
including the Walney Transponder Mandatory Zone (TMZ)
 

 
Rationalization of the UK Ground Navigation Aid Infrastructure
 
With a major change under way to 'Performance Based Navigation' (PBN) using GPS (backed up and checked by other systems, e.g. DME beacons) as the main navigation source for aircraft there is a program by NATS En-Route Limited to reduce the number of ground based radio aids. Around the northern Irish Sea area the VOR at Dean Cross (DCS) was withdrawn from service in December 2014, leaving the DME in operation and plans indicated that the VOR beacons at Glasgow (GOW) and Turnberry (TRN) would be removed in 2016 and Manchester (MCT) in 2017. In fact, all of these beacons remain in service as of November 2017.  The New Galloway Non Directional Beacon 'NGY' was scheduled to be withdrawn in 2016 but remains in service as of November 2017.  The VOR/DME beacons at Isle of Man (IOM), Belfast (BEL) and Wallesey (WAL) are scheduled to be replaced with new equipment.  The Isle of Man beacon was re-furbished during the summer and autumn of 2017 and was due back in service on the 15th December.  Where the VOR beacons have been removed, the Distance Measuring Equipment (DME) element remains, as this is an important component for area navigation sytems in aircraft.  They can be used to determine an aircraft's exact position automatically by using the DME ranges from two or more beacons and this can be used to check the integrity of other naviagtion systems.
 
The 'IOM' VOR/DME beacon undergoing work in July 2017
 

 
Changes to agreed levels for Ronaldsway traffic on Airway L10 to the south east.
 
'Agreed Levels' are long term arrangements between different air traffic control agencies to reduce coordination requirements, every flight being climbed or descended to the agreed level, usually by a certain geographical location.  The agreed levels with Scottish Control for traffic operating on airway L10 to the south east of the Isle of Man had fo a long time been set too low for many modern high performance aircraft.
 
The revised 'Agreed Levels' with Scottish Control on Airway L10
 
The previous agreed outbound level for traffic heading south east towards Liverpool was Flight Level 70 (7,000 ft) which often caused a problem with higher performance aircraft such as the FlyBe Dash8s and EasyJet Airbus's reaching it rapidly after departure from Ronaldsway, resulting in a lot of extra telephone co-ordination between Ronaldsway and Scottish Isle of Man Sector.  Also inbound aircraft were being forced to descend earlier than they would like to achieve the agreed inbound level of FL80 (8,000 ft) abeam point KELLY, 15 miles to the south east of the airport and about 20 miles from touchdown if runway 26 was in use but 40 miles from touchdown if runway 08 was in use.  Raising the inbound agreed level to FL100 (10,000 ft) allowed outbound aircraft to be climbed up to FL90 (9,000 ft) without any co-ordination between Ronaldsway and Scottish Isle of Man Sector.
 
Another change still 'in the pipeline' is to raise the top level of the Isle of Man Control Zone from FL65, which would enable radar controllers at Ronaldsway to vector inbound aircraft for runway 26 away from the confines of airway L10 (now part of the Holyhead Control Area) while they are at a higher level, reducing the number of track miles needed to be flown and hence conserving fuel.
 
 
 
Airspace changes  to the south east of the Isle of Man
Introduction of RNAV-1 routes  -  9th November 2017
 
 In 2016, NATS notified that there was going to be a big change in the way airspace below FL245 (24,500 ft) was to be designated.  The existing 'Airways' structure dated from the early 1950s (see ATC 1950s for more information) and in recent years the designations had been in contravention of international agreements.  With the move to more Area Navigation (RNAV) systems and the removal of many of the old radio beacons, multiple routes were being designated within the same volume of airspace.  To correct the anomalies, a rolling program of re-designation of the old Airways to Control Areas was started and the airspace to the south and east of the Isle of Man was changed in early November.  Airways L10 and L70 (amongst others not affecting Ronaldsway) have had their airspace status changed from Class A to Class C and been re-designated as the 'Holyhead Control Area'.  The rather strange and short Class E Airway 'Y911' to the southwest of the Isle of Man also becomes part of the Holyhead Control Area, but retains its Class E status.
 
Within this airspace there are various routes designated, including one called L10 which in fact just follows the old airway centreline.  There are also new routes to the north and south of L10, M146 which is for northwest bound traffic and Q39 for southeast bound traffic. There are yet more, but these three are the only ones affecting Ronaldsway traffic.   The reason for such a plethora of routes is that the newer ones require aircraft navigation performance to RNAV-1 (with a higher accuracy required) whereas there are still many aircraft around that can only manage RNAV-5, which has a lower accuracy requirement, ATC radar being used to ensure separation between the two classes.  Eventually it will be a requirement for all aircraft using the Controlled Airspace System to carry RNAV-1 when, presumably, the structure can be simplified.
 
Northern Irish Sea Airspace classes from 9/11/17
Lower Airspace ATS Routes from 9/11/17
 Normal practice is to link these routes to an airport via Standard Terminal Arrival Routes (STARs) and Standard Instrument Departures (SIDs) which are pre-programmed into most modern aircraft Flight Management Systems (FMS).   The pilot then just has to select the appropriate SID from his departure airfield, then the relevant routes until connecting with the STAR at his destination which in turn connects to the Instrument Approach Procedure for the runway in use.  At present Ronaldsway does not have STARs and SIDs, which can cause some confusion to visiting aircrew as to how they connect with the en-route structure.
 

Manual of Air Traffic Services Part 1
 
7th Edition published - Effective date 28th December 2017
 
The MATS Part 1 is effectivley the 'bible' of Air Traffic Control in the UK (and Isle of Man) and the First Edition was published in 1974, not long after I had started my career in ATC the previous year.  Before then the publication had been known as the Manual of Air Traffic Control.  To quote from sections of the forword of the latest version:
'The Manual of Air Traffic Services contains procedures, instructions and information, which are intended to form the basis of ATS within the UK'.
 
Part 1 of the Manual contains instructions that apply to all UK ATSUs and is published by the UK CAA.  Part 2 contains instructions that apply to a particular ATSU and is produced locally but are approved by the CAA.  A copy of the latest edition of Part 1 can be downloaded here.
 
New editions are published when there are major changes to ATC procedures and Edition 7 is mainly concerned with changes associated with the move to a Standardised European Rules of The Air (SERA).
 
 
 All pictures on this website unless otherwise credited are  © Jon Wornham