Amberley airspace was de-activated during the previous night and was to become active for military operations at 0800 local time. At 0747 a controller at Amberley co-ordinated the activation with the Brisbane Approach Planner. The planner informed the radar operators and set the planner console to show pending status. The co-ordination was conducted by Amberley with the Sector 4 controller shortly afterwards. Between 0755 and 0815 the person filling the planner position changed on two occasions. The Brisbane Terminal Airspace Co-ordinator (TAC) had been expecting the Amberley airspace activation but had been in a conference during this time. At 0815, the current planner received co-ordination on the departure of VH-NJW. The planner conducted the appropriate co-ordination with the Sector 4 controller. None of the radar maps were showing the Amberley airspace as active at this time. NJW subsequently departed and was transferred to the Sector 4 frequency. The Sector 4 controller had not queried the transfer as Amberley radar had been unserviceable and the controller assumed that the alternative had been to direct the aircraft to Sector 4. Amberley Approach later enquired as to whether the Sector 4 controller had a radar return in the area about 50 NM west of Brisbane. The approach controller was informed that the aircraft was VH-NJW. There was no breakdown in aircraft separation. An investigation by Airservices Australia found that the TAC position was not occupied at the time of the airspace activation. In addition, the quick changes of staff in the planner position resulted in the loss of the information to the later staff. The activation times were routinely co-ordinated between Amberley Approach and the Brisbane planner position. This was considered the most appropriate method. The investigation found that the planner had not ensured that the radar maps were set correctly at 0800. Procedures were changed to log the Amberley airspace activation and de-activation times in the Airways Operations Journal. Annotations confirming that the radar consoles had been set correctly were also to be entered.