Aviation safety investigations & reports

Operational non-compliance - Airbus A320, VH-VNG, 17 km ENE Melbourne Airport, Vic, 7 June 2011

Investigation number:
AO-2011-070
Status: Completed
Investigation completed

Safety summary

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What happened 

At 2102 Eastern Standard Time on 7 June 2011, an Airbus A320 aircraft, registered VH-VNG and operated by Tiger Airways, was on an approach to runway 27 at Melbourne Airport, Victoria. Air traffic control (ATC) had cleared the aircraft to descend to 2,500 ft. Shortly after, ATC identified that the aircraft had descended to 2,000 ft, which was below the limiting altitude for that segment of the approach. ATC notified the flight crew of the deviation. The crew re-established the aircraft at 2,500 ft, then continued the approach and landed. 

What the ATSB found 

The ATSB found that the flight crew had based the descent profile on information displayed on the aircraft’s Multipurpose Control and Display Unit (MCDU). The MCDU drew on information stored in the aircraft’s flight management guidance system (FMGS). The FMGS information included data provided through a third party that had a missing altitude limitation; that limitation was, however, included in the paper charts also used by the crew. The data error was not identified by the crew during their preparation for the approach. 

The ATSB also found there was an increased risk of inadvertent non-compliance with published instrument approach procedures because of the inconsistent application of the operator’s safety management system to the identification and management of database anomalies. In addition, different assumptions by the data suppliers and the operator compromised the quality assurance of the navigational data. 

The action by ATC to alert the flight crew triggered their recovery from the descent below the required flight profile. 

What has been done as a result 

In response to this occurrence, the operator implemented an auditable process for identifying and managing any navigational database anomalies in its aircraft fleet. 

Safety message 

This occurrence reinforces the safety benefits of a resilient safety management system and operator procedures in the management of safety-critical database and other information. The accurate application of those procedures by all key personnel is also important as a safety defence.

Download Final Report
[Download  PDF: 1.52MB]
 
 
Alternate: [Download  DOC: 1.56MB]
 

Preliminary

Download Preliminary Report
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Preliminary report released 7 July 2011

At 2102 Eastern Standard Time on 7 June 2011, an Airbus A320 aircraft, registered VH-VNG and operated by Tiger Airways, was on an approach to runway 27 at Melbourne Airport, Victoria. Air traffic control (ATC) had cleared the flight crew of the aircraft to descend to 2,500 ft. Shortly after, the aircraft's track was seen on the ATC radar to descend to 2,000 ft. ATC notified the flight crew, who climbed the aircraft to 2,500 ft, continued the approach and landed.

Download Preliminary Report
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Alternate: [Download  DOC: 250KB]
 

Safety Issues

Go to AO-2011-070-SI-01 - Go to AO-2011-070-SI-02 -

Data integrity system

The operator’s lack of awareness of the data providers’ assumption that the operator was complying with DO-200A Standards for Processing Aeronautical Data, which was not mandated in Australia, meant that the quality of the data was not assured.
Safety issue details
Issue number: AO-2011-070-SI-01
Status: Adequately addressed

Database anomaly acquittal

The inconsistent application of the operator’s safety management system to the identification and rectification of database anomalies, and intermittent notification of these anomalies to crews increased the risk of inadvertent flight crew non compliance with published instrument approach procedures.
Safety issue details
Issue number: AO-2011-070-SI-02
Status: Adequately addressed
General details
Date: 07 June 2011   Investigation status: Completed  
Time: 21:02 EST   Investigation level: Complex - click for an explanation of investigation levels  
Location   (show map): 17 km ENE Melbourne Airport    
State: Victoria   Occurrence type: Operational non-compliance  
Release date: 19 November 2012   Occurrence class: Airspace  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Airbus Industrie  
Aircraft model A320  
Aircraft registration VH-VNG  
Serial number 3674  
Operator Tiger Airways  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Brisbane, Qld  
Destination Melbourne, Vic.  
Last update 14 November 2018