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Analysis

Summary

Had the pilot of the Strikemaster confirmed what fare paying passenger operations were expected for the period of the joy flight before leaving the terminal the occurrence possibly would have been prevented.

There were a number of following events that probably prevented the pilot of the Strikemaster either hearing or appreciating what was being broadcast on the common traffic advisory frequency (CTAF) by the pilot of the taxiing 717. It is possible that the pilot of the Strikemaster missed some broadcasts because of intermittent radio operation or reception anomalies. The investigation was unable to determine whether the initial missed calls were due to a technical problem or as a result of shielding of some of the other pilots' radio broadcasts. However, the coincident radio transmission from the pilot of the 737 to the pilot of the Strikemaster, as the pilot of the 717 reported that he was taxiing for runway 30, probably over rode the latter's radio transmission. Consequently, the pilot of the Strikemaster remained unalerted about the fact that after departure the 717 would track to the south. Had the pilot of the Strikemaster become aware at that stage that the 717 was going to track to the south he most likely would have amended his area of operation to avoid the 717's departure track.

The pilot of the Strikemaster had another opportunity to understand that the 717 may possibly conflict with his operations when the pilot of that aircraft broadcast intentions, when lining up and after departing. On lining up, the pilot reported his intention to turn left and following departure he reported that the aircraft was turning left to intercept the one six one non-directional beacon navigation aid track. At that time the pilot of the Strikemaster had commenced his manœuvres at an altitude that prior to 24 November 2006  would have been outside the CTAF. It is possible that because he thought he was outside the CTAF area, the pilot was less attentive to radio transmissions on the CTAF. This aspect combined with distraction due to passenger commentary and workload requirements may have prevented the pilot from appreciating the developing situation.

The pilot of the Strikemaster could have clarified the intention of the pilot of 717 when he saw the aircraft turning left instead of right, as he expected. Again however, his high workload in the conduct of the flight probably caused him to dismiss the issue as a low priority at that time, and the situation remained unresolved. Overall, the pilot's situational awareness of the 717's departure track was diminished.

The pilot of the 717 also had an opportunity to query the pilot of the Strikemaster regarding his operation. However, that lack of any query by the pilot of the Strikemaster, with respect to the 717 CTAF broadcasts, indicated that there was no apparent problem with the 717's intended track. Compliance with the radio broadcast procedures by all pilots did not prevent the occurrence.

The limited radar coverage was not a factor in the occurrence. The Brisbane Centre controller had sufficient information from the Strikemaster radar returns to provide traffic information about the Strikemaster to the pilot of the 717. That traffic information, in conjunction with information from the Traffic Alert and Collision Avoidance System (TCAS) fitted to the 717, assisted the pilot to prepare to avoid the Strikemaster when alerted by the TCAS. Similarly, had the pilot of the Strikemaster requested a radar information service (RIS) it is likely that the controller would have provided traffic information on the departing 717 to the pilot in time to avoid that aircraft's track. A request by the pilot of theStrikemaster for a RIS was a preventative risk control that was available subject to controller workload. While provision of a RIS might possibly increase the pilot's workload, it should, when used in conjunction with monitoring of the CTAF frequency, improve situational awareness.

The Strikemaster pilot's original intention to avoid routes likely to be used by other aircraft during a local flight was the preferred risk mitigator for the operation. However, on the day the pilot's lapse in not checking the expected operations of fare paying passenger flights to/from Newcastle Airport, his misperception about the 717's destination and the radio problems negated that mitigator. A near collision was prevented by the combined use of radar based traffic information and TCAS.

 
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