Aviation safety investigations & reports

Loss of separation involving Bombardier DHC-8, VH-LQG, and Boeing 777, ZK-OKF, near Sydney Airport, New South Wales, on 9 December 2016

Investigation number:
Status: Completed
Investigation completed

Final Report

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On 9 December 2016, a QantasLink Bombardier DHC-8-402, registered VH-LQG (LQG) departed runway 16 left at Sydney Airport. The aircraft was operating a scheduled passenger flight from Sydney to Tamworth, New South Wales.

When LQG departed, an Air New Zealand Boeing 777-219ER, registered ZK-OKF (OKF), operating a scheduled passenger flight from Auckland, New Zealand, was on descent to Sydney.

The projected routes of the aircraft conflicted and Sydney air traffic control planned to apply vertical separation between them by assigning LQG an intermediate altitude of 5,000 ft and OKF and intermediate altitude of 6,000 ft.  LQG did not maintain 5,000 ft, reaching an altitude of 5,600 ft, and separation was not maintained between the aircraft.

The ATSB determined that the flight crew were cognisant of the requirement to maintain 5000 ft and had configured the autopilot accordingly. An unexpected autopilot mode changed occurred, before the assigned altitude was reached, and the PF decided to hand fly the aircraft until the autopilot was again correctly configured. They then attempted to reconnect the autopilot but in doing so made a mistake and the autopilot did not reconnect. The flight crew both believed the autopilot was reconnected and did not realise the mistake until after the level excursion occurred.

The incident highlights the critical nature of effective crew resource management in multi crew operations.

Aviation Short Investigations Bulletin - Issue 58

Download Final Report
[Download  PDF: 124KB]
Alternate: [Download  DOCX: 279KB]

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General details
Date: 09 December 2016   Investigation status: Completed  
  Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): near Sydney Airport    
State: New South Wales   Occurrence type: Loss of separation  
Release date: 24 March 2017   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer Bombardier Inc  
Aircraft model DHC-8-402  
Aircraft registration VH-LQG  
Serial number 4376  
Type of operation Air Transport High Capacity  
Sector Turboprop  
Damage to aircraft Nil  
Altitude 5600 ft AMSL  
Departure point Sydney NSW  
Destination Tamworth NSW  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer The Boeing Company  
Aircraft model 777-219ER  
Aircraft registration ZK-OKF  
Serial number 777-219ER  
Operator Air New Zealand  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Altitude 6000 ft AMSL  
Departure point Auckland NZ  
Destination Sydney NSW  
Last update 14 November 2018