Aviation safety investigations & reports

Engine surge and high vibration involving Airbus A330, VH-EBR, 44 km north east of Gold Coast Airport, Queensland, on 15 April 2018

Investigation number:
AO-2018-033
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final Report

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What happened

On 15 April 2018, a Qantas Airways Airbus A330, registered VH-EBR, departed Brisbane Airport, Queensland, for a regular public transport flight to Auckland, New Zealand. Shortly after departure, the crew received an advisory notification indicating excessive vibration from the left engine.

The crew reduced thrust on the left engine to idle, and the noise and vibrations ceased. The crew elected to return to Brisbane, and landed uneventfully. The thrust on the left engine remained at idle during the air turn back.

What the ATSB found

The General Electric CF6‑80E1 engine utilises rows of variable stator vanes (VSV) between each of its high-pressure compressor (HPC) stages for optimal airflow. Worn bushings led to fretting damage on a lever arm in the fourth-stage VSV system. The lever arm fractured, allowing the VSV to become off‑schedule (misaligned), affecting the airflow entering the stage four HPC.

The airflow disturbance resulted in abnormal aerodynamic loading and ultimately, fatigue failure of a fourth stage compressor blade. The downstream turbomachinery was then damaged due to the progression of blade debris through the engine.

Three non-mandatory VSV lever arm inspections were carried out prior to the occurrence but were not effective in detecting the bushing wear.

General Electric intended that replacement of the complete set of bushings was required when more than half of the accessible bushings were worn. However, the operator had proactively replaced worn bushings individually when found during maintenance. As a result, the threshold to replace the complete set would not be reached and inaccessible bushings would not be replaced.

What's been done as a result

As a result of this occurrence, Qantas inspected all CF6‑80E1 engines in the A330 fleet for similar defects. No defects were identified. Additionally, Qantas issued a maintenance memo to service personnel, highlighting the maintenance actions for the VSV system and precautions to be aware of when carrying out work in this area.

Safety message

When maintenance organisations carry out additional activities to what is required, they should consider checking with the manufacturer to confirm that no unintended consequences could be introduced.

Download final report
[Download  PDF: 799KB]
 
 
 

The occurrence

Context

Safety analysis

Findings

Safety actions

Sources and submissions

General details
Date: 14 April 2018   Investigation status: Completed  
Time: 0905 EST   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): 44 km north-east of Gold Coast Airport   Investigation phase: Final report: Dissemination  
State: Queensland   Occurrence type: Engine failure or malfunction  
Release date: 19 August 2020   Occurrence category: Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Airbus  
Aircraft model A330-202  
Aircraft registration VH-EBR  
Serial number 1251  
Operator Qantas Airways  
Type of operation Air Transport High Capacity  
Sector Jet  
Damage to aircraft Minor  
Departure point Brisbane, Queensland  
Destination Auckland, New Zealand  
Last update 19 August 2020