Aviation safety investigations & reports

In-flight engine failure, VH-OAA, Cessna 'Conquest II' 441, 23 km N of Ardrossan, SA, 25 July 2007

Investigation number:
AO-2007-030
Status: Completed
Investigation completed

Summary

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On 25 July 2007, a twin engine Cessna 441 (Conquest II) aircraft carrying three passengers was being operated on a scheduled passenger flight from Port Augusta to Adelaide, SA. At 1035 Central Standard Time, while cruising at flight level 210, the aircraft's right engine failed suddenly approximately 23 km north of Ardrossan, SA.

When the failed right Garrett TPE331-8 turboprop engine was removed from the aircraft and subsequently disassembled, it was revealed that the compressor bearing at the front end of the engine had catastrophically failed. That bearing provided both axial and lateral support for the turbine section. Once that support was lost, the engine's rotating turbine section shifted forward under the influence of thrust loads, resulting in rotor-to-case contact and rapid engine failure.

The aircraft had been inspected two months prior to the engine failure for a suspected lightning strike, however the inspection did not reveal any obvious electrical damage at that time. Considerable levels of residual magnetism were found within the compressor bearing and other engine components during the ATSB examination. Such levels indicated that direct electrical current (DC) from an aircraft lightning strike had passed through the engine during service. The passage of such currents resulted in undetected electrical damage and led to the eventual failure of the compressor bearing.

Download Final Report
[Download  PDF: 971KB]
 
 
 
General details
Date: 25 July 2007   Investigation status: Completed  
Time: 1035 CST   Investigation level: Complex - click for an explanation of investigation levels  
Location   (show map): 23 km NNE Ardrossan    
State: South Australia   Occurrence type: Engine failure or malfunction  
Release date: 01 April 2009   Occurrence class: Technical  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 441  
Aircraft registration VH-OAA  
Serial number 4410102  
Type of operation Air Transport Low Capacity  
Damage to aircraft Nil  
Departure point Port Augusta, SA  
Destination Adelaide, SA  
Last update 14 November 2018