Aviation safety investigations & reports

Powerplant/propulsion event - Launceston Aerodrome, 20 August 2009

Investigation number:
AO-2009-053
Status: Completed
Investigation completed

Summary

Download Final Report
[Download  PDF: 881KB]
 

At approximately 1137 EST on 20 August 2009, a Boeing 737-8BK aircraft, registered VH-VOC, departed Launceston, Tasmania on a scheduled passenger service to Sydney, New South Wales. Following takeoff, several loud bangs were heard from the left engine, consistent with a compressor surge. The left engine was reduced to flight idle and the aircraft returned to land at Launceston.

The compressor surge and damage to the left engine was the result of advanced variable stator vane bushing/shroud wear, which caused a seal retainer to dislodge from the inner shroud segment and move into the compressor gas path. The liberated seal segments then progressed downstream, causing significant impact damage to the remaining stages, resulting in a loss of compressor efficiency.

The manufacturer was aware of the propensity for inner bushing wear, and had previously released a number of service bulletins aimed at eliminating the issue.

The operator had incorporated the relevant service bulletins into their inspection and maintenance program as required; however the event occurred prior to the engine reaching the earliest threshold for inspection.

Download Final Report
[Download  PDF: 881KB]
 
 
 

Safety Issues

Go to AO-2009-053-SI-01 - Go to AO-2009-053-SI-02 -

Inadequate maintenance intervals

The CFM56-7B engine had sustained bushing and shroud wear sufficient to cause rotor-to-stator contact, after a time in service that was less than the minimum threshold period specified by the manufacturer, for an initial inspection targeted at identifying this problem

Safety issue details
Issue number: AO-2009-053-SI-01
Who it affects: The engine manufacturer, operators and maintainers of CFM56-7 and CFM56-5 engines
Status: Partially addressed

Engine failure susceptibility

The CFM56-7B engine design was susceptible to VSV bushing and shroud wear that can lead to internal mechanical damage and potential in-flight performance difficulties.

Safety issue details
Issue number: AO-2009-053-SI-02
Who it affects: The engine manufacturer, operators and maintainers of CFM56-7 and CFM56-5 engines
Status: Adequately addressed
General details
Date: 20 August 2009   Investigation status: Completed  
Time: 1137 EST   Investigation level: Complex - click for an explanation of investigation levels  
Location   (show map): Launceston Aerodrome    
State: Tasmania   Occurrence type: Powerplant/propulsion - Other  
Release date: 27 July 2010   Occurrence class: Technical  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer The Boeing Company  
Aircraft model 737  
Aircraft registration VH-VOC  
Serial number 30623  
Type of operation Air Transport High Capacity  
Damage to aircraft Minor  
Departure point Launceston, Tas.  
Departure time 1137 EST  
Destination Sydney, NSW  
Last update 14 November 2018