Aviation safety investigations & reports

Loss of separation involving a Airbus A320-211, VH-HYB and Mcdonnell Douglas Corp. DC-10, UNKNOWN, 64km W Griffith, NSW on 16 December 1992

Investigation number:
Status: Completed
Investigation completed


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VH-HYB, on track between Mildura and Griffith, en route to Sydney, was maintaining non-standard Flight Level 380. The non-standard level was approved by air traffic control to help the aircraft avoid turbulence. UTA 147, flying on the same track in the opposite direction was maintaining Flight Level 350 but requested a climb to Flight Level 370. This request was immediately approved by air traffic control Sector 4. An adjacent controller noticed the altitude readout on UTA 147 as Flight Level 363 when both aircraft were about 10 nautical miles apart nose to nose. He immediately called out to the Sector 4 controller who was engaged in coordination. Before the UTA 147's altitude clearance could be amended to Flight Level 360, to achieve the required 2000 feet vertical separation, the pilot of UTA 147 read back "maintaining Flight Level 370". The controller immediately attempted to pass traffic information to UTA 147 but because of language difficulties, the information was not understood before both aircraft had passed with the reduced separation of 1000 feet.
Download Final Report
[Download  PDF: 11KB]
General details
Date: 16 December 1992   Investigation status: Completed  
Time: 17:50 ESuT    
State: New South Wales   Occurrence type: Loss of separation  
Release date: 26 April 1993   Occurrence category: Incident  
Report status: Final    

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Airbus  
Aircraft model A320-211  
Aircraft registration VH-HYB  
Sector Jet  
Damage to aircraft Nil  
Departure point Perth WA  
Destination Sydney NSW  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer McDonnell Douglas Corp.  
Aircraft model DC-10  
Aircraft registration UNKNOWN  
Sector Other  
Damage to aircraft Nil  
Departure point Sydney NSW