Jump to Content
Download final report
[ Download PDF: 1.85MB]

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.


Download final report
[ Download PDF: 1.85MB]

The occurrence


Safety analysis


Safety issues and actions

Sources and submissions


Safety issues

AO-2013-095-SI-01 - 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  
Location   (show map):Sydney Airport Investigation type: Occurrence Investigation 
State: New South Wales Occurrence type: ACAS warning 
Release date: 07 August 2015 Occurrence class: Airspace 
Report status: Final Occurrence category: Incident 
 Highest injury level: None 
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 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
Share this page Provide feedback on this investigation
Last update 07 August 2015