Aviation safety investigations & reports

Breakdown of separation - VH-­NXK and Dingo 42, 22 km NW of Perth aerodrome WA, 4 March 2010

Investigation number:
Status: Completed
Investigation completed


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On 4 March 2010, a Boeing Company 717-200 (717) departed Perth, Western Australia (WA) on a scheduled passenger service to Port Hedland, WA.
The aircraft was tracking on a GURAK 3 standard instrument departure, which involved transiting through Pearce military controlled airspace. While maintaining flight level (FL) 1201 and turning left onto a heading of 330 degrees under the control of Pearce air traffic control (ATC), the crew
received a traffic advisory (TA) warning from the traffic alert and collision avoidance system (TCAS). The crew advised ATC and were instructed to continue the turn onto a heading of 360 degrees. During the turn, the crew received a resolution advisory (RA). The crew responded and climbed the aircraft to FL125.

The crew were advised by ATC that the conflicting aircraft, a military-operated Raytheon Aircraft Company 350 (King Air) descending through FL120 on a reciprocal track, had the 717 in sight and was maintaining separation. By this time, the radar separation standard had reduced below the required distance of 3 NM (5.6 km).

This occurrence reinforces the importance of effective coordination between ATC positions, and highlights the challenges faced by air traffic controllers when managing aircraft operating within the same airspace, but under the control of different ATC positions.

Download Final Report
[Download  PDF: 2.47MB]
General details
Date: 04 March 2010   Investigation status: Completed  
Time: 1039 WST   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): 22 km NW of Perth aerodrome    
State: Western Australia   Occurrence type: Loss of separation  
Release date: 14 October 2010   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer The Boeing Company  
Aircraft model 717  
Aircraft registration VH-NXK  
Serial number 55092  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Perth, WA  
Destination Port Hedland, WA  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Raytheon Aircraft Company  
Aircraft model 350  
Aircraft registration Unknown  
Type of operation Military  
Damage to aircraft Nil  
Departure point Pearce, WA  
Destination Pearce, WA  
Last update 14 November 2018