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Summary

Summary

The incident occurred on the morning Class E Radar airspace was introduced. Class E Radar airspace included defined airspace within radar coverage over NSW, from south of Ballina to north of Canberra from 8,500 ft to Flight Level (FL) 125. It excluded existing Class C, Class D and military restricted airspace. To operate in Class E Radar airspace, Instrument Flight Rules (IFR) flights required an airways clearance. Air traffic control provided separation from other IFR traffic. VH-GKB, on an IFR flight, was cruising at 9,000 ft, and reported overhead Williamtown at 0731 ESSuT, estimating Taree at 0754. VH-SMH, also on an IFR flight, departed Williamtown at 0732 tracking direct to Point Lookout, and climbing to planned level FL 250. At 0733.40, the flight service officer coordinated the departure of SMH to Brisbane Control. At 0734.28, the flight service officer instructed SMH to transfer to the Sector 15C frequency, and suggested that SMH maintain 8,000 ft due to IFR traffic at 9,000 ft. Sixteen seconds later, SMH contacted Brisbane Control, advising an altitude of 8,800 ft. The controller immediately advised the pilot that clearance was not available, and instructed him to descend to 8,000 ft. At this time, the indicated altitude of the aircraft on the controller's radar display was 8,700 ft. The horizontal distance between the aircraft was 4.7 NM. The minimum separation standard required was 5 NM horizontally, or 1,000 ft vertically. The operator advised that the aircraft was operating at low weight. This resulted in a high rate of climb. The crew was aware of the lower limit of the Class E Radar airspace and expected to receive a clearance before the aircraft reached 8,500 ft. In the event, the expectation of a clearance combined with the high rate of climb of the aircraft resulted in insufficient anticipation being applied to level the aircraft at 8,500 ft. Replay of the recorded radio transmissions revealed that the transmission from the flight service officer suggesting that the aircraft maintain 8,000 ft was broken, incomplete and slightly garbled. Consequently, the crew did not hear the suggestion to maintain 8,000 ft. Prior to the occurrence, company practice when climbing into controlled airspace had been to set the lower limit of the airspace (in this case 8,500 ft) pending receipt of an airways clearance. However, this provided only 500 ft separation from traffic cruising at 9,000 ft in Class E Radar airspace and advice from ATC was that traffic information is not passed in such situations. Based on this information, and the circumstances of the incident, company procedures were amended to set 8,000 ft in the assigned altitude indicator.
 
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