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Monday, 26 May 2003
Page: 14988


Mr Martin Ferguson asked the Minister for Transport and Regional Services, upon notice, on 5 March 2003:

(1) Can he guarantee that if the Adelaide, Sydney and Perth Terminal Control Units (TCUs) are consolidated to Melbourne, the reliability of communications equipment link systems and back-up systems will be at least equal to the present systems and that future long distance third-party provided communication links will provide the same reliability as present Airservices Australia owned and maintained systems.

(2) What analysis has been conducted to assess the reliability of future systems compared to present ones and, if no analysis has been conducted, is Airservices Australia intending to conduct this analysis; if so, when and if not, why not.

(3) Is it the case that the Sydney, Adelaide and Perth TCUs currently have a back-up radio system known as the Hard Wired Air Ground Bypass that is an extremely simple, robust system that connects Air Traffic Controllers directly to their radio equipment without the need for third-party provided satellite and terrestrial links, and will the consolidation proposal for back-up radio links be as reliable as this.

(4) What technical analysis has been conducted to assess the relative reliability of proposed future back up links as compared to present ones and, if no analysis has been conducted, is Airservices Australia intending to conduct this analysis; if so, when and by whom and if not, why not.

(5) Is it the case that Airservices Australia currently transfers radio data, radar data and voice coordination information between facilities via duplicated satellite links and a back-up terrestrial link; if so, does Airservices Australia plan to use this same system to transfer data between Sydney-based equipment and Melbourne-based Sydney terminal controllers after TCU consolidation, and are these facilities adequate.

(6) Is it the case that both satellite intercommunication links and the back-up terrestrial link between the Sydney TCU and the Melbourne centre failed on 7 October 2002; if so, how will Airservices Australia ensure future links will not fail if the Sydney TCU is moved to the Melbourne centre.

(7) What analysis has been conducted to assess the reliability of proposed intercommunication links and how much will it cost to install additional redundant capability; if no analysis has been conducted, why not.

(8) Is it the case that Airservices Australia Service Failure Notification 1278 dated 31 August 2002 described a failure which caused “Total loss of air ground communications throughout MCO”; if so, do such failures reduce the ability of Air Traffic Controllers, including future terminal controllers if they are located in Melbourne, to provide a safe separation service.

(9) What steps will Airservices Australia take to ensure that this situation cannot arise if the Sydney, Adelaide and Perth TCUs are relocated to the Melbourne centre, what analysis has been undertaken to ensure that future systems cannot suffer the same failure and how much will it cost to implement any required system modifications; if no analysis has been undertaken, is Airservices Australia intending to conduct this analysis; if so, when and by whom.

(10) Does Airservices Australia Service Failure Notification 984 dated 17 July 2001 describe a failure in the primary and back-up radio links between Canberra terminal controllers located in Melbourne and their radio equipment located in Canberra; if so, did this failure cause the Canberra terminal controllers to lose contact with aircraft under their control.

(11) Is it the case that this failure reduced the ability of Canberra terminal controllers to provide a safe separation service and does Airservices Australia consider that such failures would reduce the ability of future terminal controllers, if they are located in Melbourne, to provide a safe separation service; if not, why not.

(12) What analysis has been undertaken to ensure that future systems cannot suffer the same failure and how much will it cost to implement any required system modifications; if no analysis has been undertaken, is Airservices Australia intending to conduct this analysis; if so, when and by whom.

(13) What steps will Airservices Australia take to ensure that Sydney, Adelaide and Perth terminal controllers will not lose contact with aircraft under their control if they are relocated to the Melbourne centre.


Mr Anderson (Minister for Transport and Regional Services) —The answer to the honourable member's question is as follows:

(1) Airservices Australia are conducting full design and implementation safety cases (which are subject to CASA review) to establish either -

(i) that there are no operational implications of consolidating TCUs;

(ii) identify appropriate mitigators to satisfactorily address operational issues;

(iii) indicate that consolidation issues cannot be mitigated in which case consolidation would not proceed.

Integral to the preparation of the design safety case and any integration and implementation plans is the development and review of Business Continuity and disaster recovery plans for each of the affected Terminal Control Units. The hazard identification of this process will be undertaken by an expert safety panel comprising technical experts, staff and unions.

(2) See answer to part 1.

(3) The Air Ground Bypass system provides an independent communications path in the event of a voice switch failure. As most radio equipment for terminal control is located off airport, rather than providing a direct connection between the air traffic controller and their radio equipment, the bypass system provides a direct connection from the controller to the communications bearer. The bypass system on its own provides no protection against bearer failure. This is catered for by building redundancy in the communication network. There will be no loss of bypass functionality with the consolidation proposal.

(4) See answer to part 1.

(5) Yes. Whether or not the same system will be used if integration of the Sydney TCU to Melbourne were to go ahead, will be addressed as part of the review of Business Resumption and contingency plans being undertaken as part of the TCU integration proposal (see answer to question 1). The facilities used will be to an appropriate standard and the level of redundancy within the system will not be less than that which currently exists.

(6) Yes. In this particular instance, had the Sydney TCU been co-located with the Melbourne facilities the consequences of the 7 October 2002 failure would have been significantly less.

(7) See answer to part 1.

(8) The air ground communication services using only satellite circuits failed on 31 August 2002. Terrestrially connected circuits were still available providing full communications for air traffic controllers. The primary air ground communications facility for a Sydney TCU located in Melbourne would be via this terrestrial link.

(9) See answer to part 8. In the case of failure of satellite communications, a terrestrial link will still be available as was the case in Melbourne for the failure on 31 August 2002.

(10) Yes

(11) No. Contingency procedures were put into place to ensure that at no time was there a compromise in safety of operations. The failure in Canberra was not a result of a design deficiency in the communication links between Canberra and Melbourne, rather it was caused by a site specific incident.

(12) A full investigation was conducted into the cause of the incident and recommendations implemented locally to mitigate against such an incident occurring again. No changes were required to the design of communication links between Canberra and Melbourne.

(13) See answer to part 1.