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On 18 May 2009, an Airbus Industrie A320-232 aircraft, registered VH-VNC was on a regular public transport flight from Mackay, Queensland (Qld) to Melbourne, Victoria when at about 1249 Eastern Standard Time, the aircraft started to vibrate. Cockpit indications showed that the left aileron was oscillating. The crew diverted the aircraft to the Gold Coast Aerodrome, Qld and landed.

The source of the aileron oscillation was an internal fault in one of the left aileron's hydraulic servos. The fault was introduced during manufacture by an incorrect adjustment of the servo, which caused internal wear in a number of the servo's hydraulic control components. The aileron servo manufacturer has incorporated a new method of adjusting the aileron servos during assembly to minimise the likelihood of a recurrence of the problem.

During the investigation, it was found that an identical fault had occurred to the same aircraft 8 months prior to this incident. The previous incident was not reported to the Australian Transport Safety Bureau by the operator as required by the Transport Safety Investigation Act 2003. The operator has improved the training of its staff and the reportable event requirements in its safety management system manual in an effort to address the non-reporting risk.

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Safety issues

AO-2009-021-SI-01 - AO-2009-021-SI-02 -  

Aileron servo valve adjustment

The servo valve within the left green aileron servo was incorrectly adjusted during manufacture.

Safety issue details
Issue number:AO-2009-021-SI-01
Who it affects:The aircraft manufacturer and aircraft type operators
Status:Adequately addressed


Reporting of incidents

The aircraft operator did not comply with the reporting requirements of the Transport Safety Investigation Act 2003.

Safety issue details
Issue number:AO-2009-021-SI-02
Who it affects:The aircraft operator
Status:Adequately addressed

General details
Date: 18 May 2009 Investigation status: Completed 
Time: 1300 EST  
Location   (show map):520km NW Gold Coast Aerodrome Investigation type: Occurrence Investigation 
State: Queensland Occurrence type: Flight control systems 
Release date: 24 August 2010 Occurrence class: Technical 
Report status: Final Occurrence category: Incident 
 Highest injury level: None 
Aircraft details
Aircraft manufacturer: Airbus Industrie 
Aircraft model: A320 
Aircraft registration: VH-VNC 
Serial number: 3275 
Type of operation: Air Transport High Capacity 
Damage to aircraft: Nil 
Departure point:Mackay, Qld
Departure time:1249 EST
Destination:Melbourne, Vic
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Last update 14 November 2018