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At 1305 Eastern Daylight-saving Time on 1 February 2011, a breakdown of separation occurred 22 km south of Williamtown (Newcastle Airport), New South Wales between a Boeing B737-7Q8 (737), registered VH-VBK, and an Israel Aircraft Industries Ltd Westwind 1124 (WW24) aircraft, registered VH-AJG. Both aircraft were in communication with and under the jurisdiction of Department of Defence (DoD) air traffic controllers based at Williamtown.

Separation between the aircraft reduced to 0.7 NM (1.3 km) on radar and 400 ft vertically when the required separation standard was 3 NM (5.6 km) or 1,000 ft. The vertical separation achieved was as a result of the 737 flight crew responding in accordance with a resolution advisory provided by their aircraft's traffic alert and collision avoidance system.

The investigation identified a series of errors by the Williamtown Approach controllers involving separation assurance, coordination and communication, and compromised separation recovery.

The investigation also identified three safety issues. The DoD advised that they reviewed and amended Williamtown procedures, introduced compromised separation recovery techniques training and trialled use of the conflict alerting function in the Australian Defence Air Traffic System at Williamtown.

Download Final report
[ Download PDF: 635KB]
 
 
 
 

Safety issues

AO-2011-011-SI-01 - AO-2011-011-SI-02 - AO-2011-011-SI-03 -  

Compromised separation recovery training

The Department of Defence’s air traffic controllers had not received training in compromised separation recovery techniques.

Safety issue details
Issue number:AO-2011-011-SI-01
Who it affects:All Department of Defence air traffic controllers
Status:Adequately addressed


 

Disabling of Australian Defence Air Traffic System conflict alerts

An important alerting function within the Australian Defence Air Traffic System had been disabled at Williamtown to prevent nuisance alerts.

Safety issue details
Issue number:AO-2011-011-SI-02
Who it affects:All RAAF Base Williamtown based Department of Defence air traffic controllers
Status:Adequately addressed


 

Air traffic control procedures at Williamtown

The Williamtown air traffic control procedures did not clearly define the separation responsibilities and coordination requirements between the Approach sectors for departing aircraft.

Safety issue details
Issue number:AO-2011-011-SI-03
Who it affects:All RAAF Base Williamtown based Department of Defence air traffic controllers
Status:Adequately addressed

 
General details
Date: 01 February 2011 Investigation status: Completed 
Time: 1305 ESuT Investigation type: Occurrence Investigation 
Location   (show map):Williamtown Airport, South 22 km Occurrence type:Loss of separation 
State: New South Wales Occurrence class: Airspace 
Release date: 07 March 2012 Occurrence category: Serious Incident 
Report status: Final Highest injury level: None 
 
Aircraft 1 details
Aircraft manufacturer: The Boeing Company 
Aircraft model: 737 
Aircraft registration: VH-VBK 
Serial number: 30648 
Type of operation: Air Transport High Capacity 
Damage to aircraft: Nil 
Departure point:Williamtown, NSW
Destination:Melbourne, Vic
Aircraft 2 details
Aircraft manufacturer: Israel Aircraft Industries Ltd 
Aircraft model: 1124 
Aircraft registration: VH-AJG 
Serial number: 281 
Type of operation: Charter 
Damage to aircraft: Nil 
Departure point:Nowra, NSW
Destination:Williamtown, NSW
 
 
 
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Last update 01 March 2016