Aviation safety investigations & reports

Operational event involving Boeing 737, VH-YIR, Sydney Airport, NSW on 4 June 2013

Investigation number:
Status: Completed
Investigation completed

Final Report

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What happened

On 4 June 2013, a Boeing 737-800 (737) aircraft, registered VH-YIR and operated by Virgin Australia (Virgin), was on a scheduled passenger service from Melbourne, Victoria to Sydney, New South Wales. During descent into Sydney, the crew was advised by air traffic control (ATC) to expect an independent visual approach (IVA) to runway 16 Right (16R).

As the aircraft approached the extended centre-line of runway 16R, the aircraft’s traffic collision avoidance system (TCAS) provided a traffic alert followed by a resolution advisory (RA) in relation to an Airbus A320 aircraft on approach to parallel runway 16 Left (16L). As the crew commenced descent in response to the RA, the aircraft continued through the extended centreline of runway 16R by about 300 m. When the TCAS alert ceased, the pilot flying captured the extended runway centre-line from the other side. The flight crew continued the approach and landed, whilst the A320 executed a go-around procedure.

As both aircraft were cleared and utilising IVA procedures, the occurrence did not constitute an ATC loss of separation assurance.

What the ATSB found

The ATSB found that the 737 passed through the centreline as a result of the aircraft’s automatic flight control system not being set to the correct flight mode for an intercept and turn onto the runway 16R localiser. This most likely occurred due to insufficient force being applied to the approach mode push-button and, as the flight crew did not perform an effective check of either the mode control panel or the flight mode annunciator to verify a mode change, they were unaware that the aircraft’s flight mode was not set as intended.

The ATSB also found that the risk of an undetected mode selection error was increased as the Virgin procedures did not mandate that flight crew announce flight mode changes.

There were no technical failures of the aircraft, aircraft tracking systems or ground equipment in relation to this occurrence.

What's been done as a result

In response to this occurrence, Virgin introduced a flight policy requiring crews to verbally announce flight mode changes when operating above 500 ft.

Safety message

During an IVA, accurate interception and tracking of the runway centreline is essential to maintain separation with aircraft using the parallel runway. This occurrence highlights the importance of pilots remaining vigilant during this type of approach, including to the consideration of and response to all RAs. The importance of crews conducting comprehensive checks of the mode control panel and flight mode annunciator to ensure that the flight mode selected is consistent with the crew’s intention is also reinforced.


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[Download  PDF: 1.85MB]

The occurrence


Safety analysis


Safety issues and actions

Sources and submissions


Safety Issues

Go to AO-2013-095-SI-01 - Go to AO-2013-095-SI-02 -

Annunciation of mode changes

The Virgin Australia procedures did not require its flight crews to, whenever practicable, announce flight mode changes.

Safety issue details
Issue number: AO-2013-095-SI-01
Who it affects: Virgin Australia flight crews
Status: Adequately addressed

Provision of traffic information

Air traffic control did not, and was not required to provide traffic information to aircraft using adjacent runways and abeam each other during independent visual approach procedures at Sydney.

Safety issue details
Issue number: AO-2013-095-SI-02
Who it affects: All Sydney Terminal Control Unit Director controllers
Status: Adequately addressed
General details
Date: 04 June 2013   Investigation status: Completed  
Time: 1858 EST   Investigation level: Systemic - click for an explanation of investigation levels  
Location   (show map): Sydney Airport    
State: New South Wales   Occurrence type: ACAS warning  
Release date: 07 August 2015   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer The Boeing Company  
Aircraft model 737  
Aircraft registration VH-YIR  
Serial number 39925  
Operator Virgin Australia  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Melbourne, Vic.  
Destination Sydney, NSW  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer Airbus  
Aircraft model A320  
Aircraft registration VH-VFL  
Serial number 5489  
Operator Jetstar Airways  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Gold Coast, Qld  
Destination Sydney, NSW  
Last update 03 April 2020