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Factual Information

Summary

Sequence of events

On 13 October 2005 at 0618 Eastern Standard Time, a Saab Aircraft AB 340B (Saab), registered VH-UYA, departing Townsville Airport, Qld, came within the minimum separation standard of 1,000 ft vertically and of 3 NM horizontally of an inbound Cessna Aircraft Company 310R (Cessna), registered VH-TFP. There was an infringement of air traffic control separation standards.

The crew of the Saab was operating a scheduled passenger flight to Trepell, in central Queensland, in accordance with the instrument flight rules. Air traffic control issued a clearance to the crew to track via waypoint CATEY, a track of 243 degrees magnetic from Townsville. At 0611, the crew taxied for runway 01 1. After the crew reported ready for departure, the aerodrome controller issued the crew with a departure clearance, including an instruction to turn left, heading 350 degrees, visual. The pilot in command confirmed the instruction with the copilot. The copilot, who was the pilot flying, then read back the clearance to the aerodrome controller. Both pilots reported that the departure clearance was written on the Takeoff and Landing Data Card before completing the pre take-off checks and commencing the take-off roll.

Recorded information showed that as the Saab was rolling, the Cessna was 9 NM from Townsville, inbound from Cairns, Queensland on the 329 radial, and was on descent to 1,800 ft.

When the Saab had reached an altitude of between 600 and 700 ft the copilot commenced a left turn, engaged the autopilot, and selected a heading of about 210 degrees to intercept the planned outbound track of 243 degrees. At about 1,000 ft the pilot in command, as the pilot not flying, set the power levers to climb power. During the turn, at a heading of about 290 degrees, the pilot in command realised that they had flown through the assigned heading and alerted the copilot. The copilot reported that at about the same time he also realised they had flown through the assigned heading. He disengaged the autopilot and quickly turned the aircraft to the right onto the assigned heading of 350 degrees. During the turn, the Saab's Traffic Alert and Collision Avoidance System (TCAS) produced a traffic advisory (TA) consisting of an aural alert of 'traffic traffic' and the crew observed an amber symbol on the TCAS display that was indicating traffic below them. The crew attempted to sight the traffic, but were unsuccessful. The pilot in command advised the approach controller that they were turning onto 350 degrees.

Both the approach controller and the aerodrome controller noticed that the Saab appeared to be turning as if to intercept the flight planned 243 radial. The aerodrome controller attempted to contact the Saab crew however, at that time the crew were in the process of transferring to the approach frequency and had not yet established contact. The approach controller provided traffic information to the pilot of the Cessna and when the pilot reported that he had not sighted the Saab, the approach controller instructed him to make a left orbit. The Saab crew subsequently contacted the approach controller and advised that they were turning onto a heading of 350 degrees visual, passing 2,200 ft. The approach controller passed updated traffic information to the Cessna pilot who then sighted the Saab about 500 ft above him and 0.5 NM ahead.

Recorded radar information indicated that when the horizontal distance reduced to approximately 3 NM between the closing aircraft, there was 400 ft vertical separation and the Saab subsequently flew about 500 ft directly over the Cessna.

Operational aspects

Prior to engine start, the Saab crew set the Electronic Horizontal Situation Indicator (EHSI) heading selectors to the runway heading and the course deviation indicators to the outbound track of 243 degrees.

The operator did not require any change to the EHSI heading selectors or course deviation indicators in response to heading assignments in departure clearances. The operator required pilots to set the EHSI heading selector to runway heading in readiness for a one engine inoperative situation. It was common practice for the operator's crews to confirm a departure clearance with each other before it was written down and read back to the controller.

The pilot in command indicated that, as the pilot not flying, he monitored the conduct of the flight. However, there was no specific operator requirement for the pilot not flying to monitor the turn and ensure that the pilot flying captured assigned headings.

The Saab crew reported that they were observing the 'sterile cockpit' policy specified in the operator's aircraft operating manual. That policy prohibited discussion about anything except the immediate operation of the aircraft while an aircraft was climbing or descending below 10,000 ft. They indicated that their workload was normal and that they were not rushing. The copilot considered that he was not tired and there was no apparent reason for him forgetting about the assigned heading. He also said that most of the Saab operations from Townsville involved visual departures to the west and the assignment of radar headings with departure clearances was unusual.

The TCAS fitted to the Saab provided aural and visual traffic advisories when an aircraft equipped with a functioning transponder was within about 45 seconds of the projected closest point of approach. When an aircraft was within approximately 30 seconds of the closest point of approach, the TCAS issued aural and visual resolution advisories. The operator's requirements for crew response to a TCAS traffic advisory was: 'Conduct a visual search for the intruder. If successful, maintain visual acquisition to ensure safe separation.'

The weather conditions were reported to be a light wind with greater than 10 km visibility and 1 to 2 eighths cloud coverage at 2,000 ft.


  1. Runway 01 heading is 016 degrees M.
 
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