Aviation safety investigations & reports

Breakdown of separation - Cessna 172, VH-WYG and Boeing 747, N171UA, 19km north-west Sydney Airport NSW, 7 August 2011

Investigation number:
Status: Completed
Investigation completed


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On 7 August 2011, a Cessna Aircraft 172, registered VH-WYG (WYG), departed Bankstown, New South Wales, for a student solo-navigation exercise. WYG entered Sydney controlled airspace without a clearance, which subsequently resulted in a breakdown of separation with a departing Boeing 747 aircraft, registered N171UA. Air Traffic Services (ATS) alerted the crew of N171UA to the traffic, and issued instructions for N171UA to conduct an avoidance turn away from WYG.

When the pilot of WYG contacted ATS for an airways clearance to conduct the Sydney Harbour scenic route, he was informed that he had been radar-identified as having entered controlled airspace without a clearance. The pilot then remained outside controlled airspace and subsequently elected to terminate the navigation exercise and return to Bankstown via the Lane of Entry.

The pilot reported that inclement weather had influenced his en-route track decision making during the flight.

This incident highlights the importance of both weather avoidance, and awareness of proximity to controlled airspace.

Download Final Report - Bulletin
[Download  PDF: 5.43MB]
General details
Date: 07 August 2011   Investigation status: Completed  
Time: 1347 EST   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): 19km north-west Sydney Airport    
State: New South Wales   Occurrence type: Loss of separation  
Release date: 12 December 2011   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 172  
Aircraft registration VH-WYG  
Serial number 17266365  
Type of operation Flying Training  
Damage to aircraft Nil  
Departure point Bankstown, NSW  
Destination Bankstown, NSW  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer The Boeing Company  
Aircraft model 747  
Aircraft registration N171UA  
Serial number 24322/733  
Operator United Airlines  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Sydney, NSW  
Destination Los Angeles, USA  
Last update 14 November 2018