border with Indonesia to the southeast near Sydney. There are two Air Traffic Service Centres (ATSCs), one in Brisbane and another in Melbourne each responsible for providing air traffic control services in their FIRs. The Brisbane Centre is responsible for the FIR northeast of the line, and the Melbourne Centre for the FIR southwest. With the implementation of OneSKY, the Brisbane FIR will be merged in to the Melbourne FIR and the Melbourne Centre will thus be responsible for the entirety of Australia's enroute airspace. The physical Brisbane Centre will remain, however its facilities will only be used for air traffic control in the local area around Brisbane, as is the current case with the Terminal Control Units (TCUs) located in Adelaide, Perth and Sydney which were once responsible for their own FIRs under the previous structure. The TCUs in Adelaide, Perth and Sydney are responsible for providing air traffic control services in their Terminal Areas (TMAs), which laterally cover radii of around Adelaide and Perth, and a radius of in the case of Sydney; and vertically cover from the surface to in the case of Perth, in the case of Adelaide and in the case of Sydney. The physical Brisbane and Melbourne Centres contain 42 individual workstations divided into groups responsible for different sectors within each of their FIRs. A number of safeguards have been built into the system to reduce the risk of malfunction. For example, almost all of the electronic systems have been duplicated – standby equipment is ready to switch into immediate operation if the main equipment fails. Both Brisbane and Melbourne Centres contain a simulator for training new air traffic controllers, but these simulators can be converted to operational control suites for the other control centre within 48 hours in the event of a devastating failure. TAAATS incorporates ADS-B from more than 70 stations located at various sites across the country. The system introduced new features to air traffic control in Australia including conflict alerting and conformance monitoring. Previous structure Australian airspace was previously divided into six FIRs, based roughly on State boundaries. So, for example, when an aircraft flew from Perth to Sydney, the pilots would communicate with air traffic control in the following order: The tower at Perth Airport gave instructions for runway taxiing and scheduling of take-off; A departure controller in Perth gave instructions for the climb out of Perth; An en