Power on

Airservices provides aerodrome control from 28 control tower locations plus one aerodrome flight information service facility. The flight information service at Port Hedland will change to aerodrome control in late 2014, once an airspace classification change is implemented.

The National Towers Program will ultimately replace or refurbish all 28 control towers that Airservices operates across Australia. Greg Hood, Airservices’ executive general manager ATC, explains: “In 2008 Airservices commenced a program to systematically refresh its asset base. As part of this program we identified a need to build new control towers. The first phase involved constructing four new control towers at locations that needed replacement but were also representative of all tower ‘types’ ie, Melbourne, Adelaide, Broome and Rockhampton. The project also involved equipping each location with INTAS technology. ” “Melbourne Tower cost $19m to complete, it is 75m tall and is a prototype design for our major international airports. Adelaide is the same design as Melbourne, but at 45m is slightly smaller. Rockhampton and Broome provide the design prototypes that will be used at major provincial and Class D (general aviation) tower locations. ” Hood adds: “Rockhampton enabled the INTAS technology to be embedded but is not fully integrated into the Eurocat ATM system. We cannot justify the cost of integrating INTAS at all control towers into Eurocat ahead of the new OneSKY ATM system. It is prudent that we wait to fully integrate INTAS at some locations until after OneSKY is operational. ” Stage Two will involve a ‘life extension’ program at a further four locations. “These locations have a sound structure but need their mechanical, electrical, fire and water services upgraded,” Hood says. “The upgrade project will also involve equipping the towers with INTAS technology. The program has not been finalised but is likely to include Cairns, Gold Coast, Brisbane and Perth. These locations present the big challenge of implementing INTAS into a live operational control tower without slowing down existing operations. Implementation into a new control tower is relatively straightforward compared to the difficulty in commissioning the system in a live environment. ” Hood adds: “We expect these four locations will be undertaken quite soon. The full INTAS rollout will take around three years. Implementation of INTAS at major control towers, that link into Eurocat, will take place before OneSKY is commissioned. ” A typical control tower has meteorology, communications, airfield lighting equipment, system monitoring and ATIS equipment housed in large fixed consoles situated toward the centre of the cab. Other specialist equipment such as radar displays, strip printers, display boards with paper flight progress strips, are placed on top, inside or near the console. An international control tower requires up to 30 systems to meet operational requirements. Controller positions in the old control towers can have 3-4 screens, each with a separate keyboard and mouse.

Space in control towers with centre consoles is tight. The existing tower systems are not really integrated into the Eurocat ATM system, therefore manual intervention is required to input data. Air traffic controllers still have to write flight progress strips for local operations plus record transactions on the strip. They are also required to receive and send data using various systems. The tower clutter problem has been exacerbated by the introduction of advanced surface movement guidance and control systems (A-SMGCS) at major international towers.

In contrast, INTAS involves self- contained controller workstations located around the perimeter of the control tower cab. Placement of controllers on these operational positions is flexible, depending on the traffic flow, whereby controllers can change workstations when needed, such as to gain a better view of aircraft using a crossing runway. INTAS involves having only four monitor screens in each workstation with control by touch screen or a single keyboard and mouse. Inputs from the various computer and control systems areconsolidated in an equipment room beneath the cab and directed to the cab through workstation servers. All system components supporting INTAS now fit into three racks.

Airservices control towers can be grouped into four segments based on the nature of operations and traffic levels, which are major international, capital city, regional and capital city Class D towers (formerly named GAAP). INTAS systems at all locations will include the tower data manager (TDM), operational data manager (ODM), electronic surveillance system (ESS) for air situation displays and voice switch command control system (VCCS). Major airports also have A-SMGCS incorporated into ESS for ground surveillance as part of INTAS.

Eurocat provides the information for the air situation display, as well as being the master repository of flight data information for the TDM. The ESS shows aircraft arriving, departing or operating in the vicinity of an airport. As with other radar displays, an aircraft symbol is assigned a label detailing the callsign, level and speed. Depending on the surveillance systems available at an airport, ESS will present aircraft information that is based upon radar (PSR and/or SSR), The new Melbourne tower stands 75m tall. airservicesADS-B and/or multi-lateration.

The previous manual system required tower controllers to use flight information generated by both the Eurocat system along with manually prepared information about local traffic. Flight progress strips are prepared for all aircraft for controllers to record instructions and events. These strips are generated automatically when the aircraft’s flightplan is contained in the flight data system or, for local VFR flights, strips are hand-written by the control tower staff. Therefore controllers were required to align locally generated information with that provided from Eurocat.

In contrast, INTAS requires that all aircraft are recorded electronically into the flight data system. Aircraft information is displayed electronically on the TDM in a similar format to that used on manual flight progress boards. Aircraft are recorded by strip colour depending on whether they are arriving (buff), departing (blue) or over-flights/specials (pink).

Up to three levels of information can be incorporated onto the electronic strips. Clearances issued to the aircraft are electronically recorded onto the strip using pop-up menus. Routine transactions, such as takeoff time are recorded by touching the appropriate box on the electronic strip. Airports that have regulated operations involving standardised clearances ie major international airports are most easily addressed, often requiring only two levels to input required information onto the strips. Regional and capital city Class D airports that have a high number of local VFR operations require a greater number of levels to record necessary information on the strip.

Strips are automatically generated by the tower data manager, based on predetermined time parameters, when the controller needs to become informed of the aircraft. The TDM display groups aircraft depending upon their flight phase or route. At regional/capital city Class D airports, due to the high number of VFR aircraft and random operations, a revised INTAS screen configuration is used. In the place of an A-SMGCS display is an extended TDM, spanning two screens. This enables electronic strips to be displayed in a number of bays to represent operations on and around the airport.

In the old tower environment controllers were positioned sideby side along the central console. When the responsibility for the control of an aircraft transferred from one position to another, a controller merely handed the paper strip to their colleague. In the new environment, controller workstations are not necessarily located in close proximity to each other and the transfer of responsibility occurs electronically from one TDM to another. Defining areas of responsibility for controllers around an airport in the ATM system, along with electronic transfer of responsibility, sees control tower operations becoming more similar to that undertaken by radar sectors.

Recording all aircraft information in the Eurocat flight data system also enables safety nets and alerts to be available for all aircraft. Formerly this safety functionality could only be applied to aircraft whose details were recorded in the flight data management system, not for local VFR traffic that was manually recorded.

Work flow and business rules have been incorporated into the TDM logic which, as far as possible, will be applied by all control towers but with some adaptation to suit local operations. These workflow and business rules determine the actions that can be performed by air traffic controllers for aircraft on particular routes and in specific weather conditions. As an illustration rules have been established to allow the aerodrome controller to clear an aircraft for takeoff, without prior approval of the departure radar controller, depending on the performance of the following aircraft, distance of aircraft on approach and weather conditions. This ‘auto release’ procedure reduces the coordination workload of the aerodrome and approach radar controllers.

Underlying the development of workflow and establishment of business rules is defining the various modes of operation for an airport. An operational mode is selectable via a popup menu on the TDM which then activates a range of procedures that must be followed by the controllers. These procedures are written into the operational logic of the TDM. A controller’s actions are constrained by defining the information that can be entered onto the electronic flight progress strip, which reflects in the correct instructions issued to aircraft. Selection of an operational mode also activates aerodrome systems. For example, nomination of CAT3 ILS mode automatically brings into operation different separation standards, procedures and various airfield lighting systems.

Airservices has progressively been implementing new flow management initiatives at major airports in Australia. These flow management initiatives include the ‘pre-tactical’ Metron system, which matches ATM capacity with forecast aircraft demand. Metron is initiated the day prior to operations and takes account of the forecast weather conditions and operational procedures that will influence the movement rate at an airport.

A Maestro flow management system is currently incorporated into Eurocat. This system helps manage the tactical arrival flow for a runway. Metron is integrated into Eurocat to improve the accuracy of flight planning. The Maestro interface between the Eurocat system and INTAS enables data to be sent to the TDM to update/present up-to-date information on electronic strips.

VCCS for each workstation is presented through the TDM. Two forms of display are available, either a short form window – presented on the display and activated by touch; or full functionality – accessed via the short form window. This VCCS system enables communications

The same workstation design will be used in all locations and for all operational positions.

functions to be assigned to any workstation so that operational roles to be combined when there is reduced staffing is adopted in periods of low traffic.

The ODM provides a single front end display to consolidate an extensive array of equipment provided by many different suppliers. Information accessed through the ODM includes: aerodrome data and serviceability –such as online aerodrome charts and NOTAMs; AFTN messages; weather radar and data; airfield lighting; and emergency alarm monitoring. Controllers are able to update information transmitted via digital ATIS as well as perform controls on cabin equipment eg sunblinds, task lighting, door access.

An electronic image of the aerodrome and essential equipment is displayed on the ODM. This display highlights when a runway is not available for use by aircraft. It also presents areas of unserviceability on the airport as well as the operational status of airfield lighting. Of particular importance is the presentation of the operational status of stop bars (at present only provided for at Melbourne), whose operation regulates entry onto runways, helping to prevent unauthorised incursions.

Workstations have been custom- designed by Airservices. The same workstation design will be used in all locations and for all operational positions. Seven workstations, located around the perimeter of the cab, will be installed at major towers. Other towers may have as few as three.

INTAS provides a number of operational benefits. The use of electronic data and easy access to information will allow controllers to reduce heads-down time, enabling them to concentrate more on observing aircraft, which should lead to improved situation awareness. Further, spending less time on ‘low value’ tasks such as strip writing, probably will increase their traffic handling capability. Having aircraft data recorded electronically and stored within the flight data system, means that workload issues can be managed by both the tower and radar sectors. The electronic recording aerodrome data provides greater information about airport operations, which can be used to enhance airport efficiency.

INTAS provides a step change for control tower operations. It is replacing a largely manual system with automation that, in time, will link all control towers with the main ATM processing system.