Aviation safety investigations & reports

Unsafe proximity and radar vector below minimum vector altitude involving a Boeing 777-31HER, A6-EBU, and two 737-838s, VH-VXS and VH-VYE, Melbourne Airport, Victoria, on 5 July 2015

Investigation number:
AO-2015-084
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final Report

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What happened

On the evening of 5 July 2015, land and hold short operations (LAHSO) were in effect at Melbourne Airport, Victoria. This allowed for simultaneous landings on crossing runways, with the requirement that one aircraft stops well before the intersection of the runways. On this evening, an Emirates Boeing 777 was cleared for an immediate take-off from runway 34 while two Qantas Boeing 737s were on approach to runways 34 and 27. This resulted in the crew of the Boeing 737 on approach to runway 27 initiating a missed approach, followed by the crew of the Boeing 737 on approach to runway 34 being instructed by air traffic control (ATC) to go-around. The Boeing 737 on approach to runway 34 was then radar vectored by ATC below the minimum vector altitude.

What the ATSB found

The ATSB found that, since 2011, Airservices Australia had been aware of the hazard associated with the inability to separate aircraft that were below the appropriate lowest safe altitude at night but had not adequately mitigated it. This resulted in a situation where, in the event of a simultaneous go-around at night during LAHSO at Melbourne Airport, there was no safe option available for air traffic controllers to establish a separation standard and to ensure a mid-air collision did not occur when aircraft were below minimum vector altitude. Though Airservices Australia had implemented a number of preventative controls prior to this occurrence in response to concerns expressed by the Civil Aviation Safety Authority (CASA), a recovery control was not implemented until 2016.

Additionally, the compromised separation recovery training provided to the air traffic controllers employed in the Melbourne ATC Tower did not include a night scenario for missed approaches during LAHSO.

What's been done as a result

Airservices Australia has received an exemption from CASA to radar vector aircraft below the minimum vector altitude at night at Melbourne Airport under certain conditions. Airservices Australia has also instigated a stagger procedure for land and hold short arrival pairs such that aircraft will not come into unsafe proximity in the event of a missed approach. Training in compromised separation recovery at night during LAHSO has also been introduced for Melbourne ATC Tower controllers.

Safety message

Though air traffic controllers have a duty of care to intervene in a situation where they believe that the safety of an aircraft may be in doubt, such interventions can have unintended consequences. When assessing possible actions to address a hazard, the air traffic service provider should consider both preventative and recovery controls. Additionally, simulator training is useful for developing emergency response skills and, as such, should address all credible compromised separation recovery scenarios.

Download final report
[Download  PDF: 2.29MB]
 
 
 

The occurrence

Context

Safety analysis

Findings

Safety issue and actions

Sources and submissions

Additional details

Safety Issue

Go to AO-2015-084-SI-01 -

Hazard associated with the inability to separate aircraft below the appropriate lowest safe altitude at night

The hazard associated with the inability to separate aircraft that are below the appropriate lowest safe altitude at night was identified but not adequately mitigated. This resulted in a situation where, in the event of a simultaneous go-around at night during land and hold short operations at Melbourne Airport, there was no safe option available to air traffic controllers to establish a separation standard when aircraft were below minimum vector altitude.

Safety issue details
Issue number: AO-2015-084-SI-01
Who it affects: Air traffic controllers employed in the Melbourne Tower
Status: Adequately addressed
General details
Date: 05 July 2015   Investigation status: Completed  
Time: 1811 EST   Investigation level: Complex - click for an explanation of investigation levels  
Location   (show map): Melbourne Airport   Investigation phase: Final report: Dissemination  
State: Victoria   Occurrence type: Flight below minimum altitude  
Release date: 06 August 2018   Occurrence class: Operational  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft 1 details

Aircraft 1 details
Aircraft manufacturer The Boeing Company  
Aircraft model 737-838  
Aircraft registration VH-VYE  
Serial number 33993  
Operator Qantas Airways Ltd.  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Canberra, ACT  
Destination Melbourne, Vic.  

Aircraft 2 details

Aircraft 2 details
Aircraft manufacturer The Boeing Company  
Aircraft model 737-838  
Aircraft registration VH-VXS  
Serial number 33725  
Operator Qantas Airways Ltd.  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Sydney, NSW  
Destination Melbourne, Vic.  

Aircraft 3 details

Aircraft 3 details
Aircraft manufacturer The Boeing Company  
Aircraft model 777-31HER  
Aircraft registration A6-EBU  
Serial number 34484  
Operator Emirates  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Nil  
Departure point Melbourne, Vic.  
Destination Changi, Singapore  
Last update 14 November 2018