Air Traffic Control over Australia

1. Air Traffic in WA

2. Air Traffic Control over Australia

3. Geography and Weather in WA

4. Airspace Management over WA

5. The Perth Traffic Management Plan

6. Flow Control and Sequencing

7. Military Operations

8. Working at West Radar

9. ATC Training

10. The Controller/Pilot Relationship

Airservices Australia, a government business enterprise, is the national ATC provider, providing all ATC, flight information, briefing, firefighting and navaid services over 16% of the Earth's surface. It operates about 405 Very High Frequencies (VHF) from over 200 sites around Australia.  Outside of VHF coverage, 8 High Frequency (HF) radio sites service 17 HF frequencies.  Increasingly, Controller to Pilot Data Link Communications (CPDLC) are being utilised for communication with domestic and international flights outside of VHF coverage.

Additionally, Airservices Australia is responsible for 280 Non Directional Beacons (NDB), 102 VHF Omni-Directional Ranges (VOR) and 74 Distance Measuring Equipment (DME) facilities.  There are 29 Instrument Landing Systems (ILS), mainly at capital city airports.  Satellite navigation systems are increasingly providing an alternative to ground based radio navigational aids, both for approach and landing guidance, as well as for enroute tracking.

The main surveillance tool for air traffic control purposes is Secondary Surveillance Radar (SSR), which requires a transponder in each aircraft.  The transponder sends aircraft identification and altitude information to the ground station.  Airservices Australia operates 20 SSR sites providing radar surveillance along the east coast from Cairns to Adelaide - the "J Curve". Separate coverage is provided around Perth.  The RAAF provides the radar at Darwin.  Primary radar redundancy is provided at the capital city airports.

Automatic Dependent Surveillance-Broadcast (ADS-B) ground station equipment is being introduced at 28 sites throughout Australia.  This will provide radar-like surveillance across most of Australia for high-level traffic. 

Enroute air traffic is controlled from two centres.  Melbourne Centre, in Victoria, controls the larger south-western Flight Information Region (FIR) while Brisbane Centre, in Queensland, controls the north-eastern FIR.  A redundancy feature is the capacity of either Centre to take over the other Centre's airspace in the event of catastrophic failure.  The diagram below indicates the high-level sectors over the continent.

The sectors (blue-grey) over the Indian Ocean, around Perth and over Western Australia are controlled by West Group.  This group is subdivided into West-Radar, with three sectors around Perth, and West-Procedural, the sectors covering outback WA and the Indian Ocean.

As well as the two centres, Terminal Control Units are located at Sydney, Adelaide, Perth and Cairns, and there are 25 control towers providing aerodrome control services. Flight information services are provided from the Australian Flight Information Centre (AusFIC) located in Brisbane.  The RAAF provides ATC services at Darwin and Townsville (and at its own bases).

In 1999 ATC moved into the digital age with The Australian Advanced Air Traffic System (TAAATS), developed by Airservices Australia and the French company Thompson (now Thales).  Remote radar, VHF and HF signals are beamed to Melbourne and Brisbane centres by satellite and land-links making use of the public telecommunication network provided by carriers such as Telstra and Cable and Wireless Optus. Airservices Australia operates more than 100 satellite ground stations using the Australian satellite system. In addition, microwave radio bearer links and copper or fibre-optic control cable systems link facilities at the capital city and larger regional airports.  

The controller's radar display (or more correctly, the Human Machine Interface - HMI) permits interaction with the aircraft's flight plan via windows which are displayed on the screen, or the interactive label attached to the radar position indicator (RPI - the radar return from an aircraft).  The main screen displays the controller's sector.  The smaller screen on the right displays  adjacent sectors.  The scale on both of these screens is adjustable and the controller can "zoom" in to monitor aircraft in close proximity.  The screen on the lower left displays the voice switching network - intercoms, frequencies, etc.  The screen on the top left displays meteorological radar, timer alarms, memory aids, etc.

The controller can interact with the flight plan so that any changes automatically carry through to all relevant sectors.  Inter-sector coordination is greatly reduced and much quicker.  Requests for track changes, level changes, and other flight plan amendments are dealt with far more expeditiously because the next sector can see what is being requested at the adjacent sector and respond almost immediately.  

Aircraft are displayed on the HMI with several different symbols.  The air traffic controller must constantly be aware of the symbols; as aircraft leave and enter radar or ADS-B coverage, update with ADS (satellite), and so on, different separation standards must be applied depending upon the symbol displayed.  A controller must be able to move seamlessly between standards as the situation changes.