Aviation safety investigations & reports

Airspace related event involving a Boeing 737, VH-VOM, near Darwin, NT on 27 February 2014

Investigation number:
Status: Completed
Investigation completed

Final Report

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What happened

At 1253 Central Standard Time on 27 February 2014, a Boeing Company 737-8FE, registered VH-VOM (VOM), was radar vectored when outside controlled airspace, near Darwin, Northern Territory. Radar vectoring outside controlled airspace was not permitted, and may have brought VOM into conflict with aircraft that were unknown to air traffic control.

What the ATSB found

The ATSB found that weather in the Darwin area resulted in the majority of inbound aircraft diverting around storm cells. These diversions increased workload for the Approach East controller. The increased workload resulted in the controller using non-standard phraseology and not cancelling radar vectors prior to VOM leaving controlled airspace. Additionally, the flight crew of VOM had not reported ‘clear of weather’ as expected by the controller. This resulted in a lack of shared understanding between the flight crew and the controller.

What's been done as a result

Following this occurrence the Department of Defence introduced theoretical and simulator-based training to assist air traffic controllers to resolve unusual situations using clear communication and direction. The training reinforces positive and assertive control measures, skills that are especially necessary in high workload situations.

Safety message

This occurrence highlights that effective communication is essential for a shared understanding between flight crew and air traffic controllers. On this occasion, the use of non-standard phraseology by both parties resulted in different expectations and delay. Additionally, coordination between controllers is an essential component of their duties; however, this is not transmitted via radio. As a result, silence on an air traffic control frequency should not be interpreted by flight crew as an indicator of low workload for the controller.

Download Final Report
[Download  PDF: 988KB]

The occurrence


Safety analysis


Sources and submissions

General details
Date: 27 February 2014   Investigation status: Completed  
Time: 12:50 CST   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): near Darwin Airport    
State: Northern Territory   Occurrence type: ANSP operational error  
Release date: 15 April 2016   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer The Boeing Company  
Aircraft model 737  
Aircraft registration VH-VOM  
Serial number 33794  
Operator Virgin Australia  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Sydney, NSW  
Destination Darwin, NT  
Last update 14 November 2018