Aviation safety investigations & reports

Depressurisation - De Havilland Canada, VH-XFU, 296 km NE of Perth Airport WA, 15 December 2009

Investigation number:
Status: Completed
Investigation completed


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On 15 December 2009, a De Havilland Canada DHC-8-102 aircraft, registered VH-XFU, departed Perth, Western Australia (WA) on a charter passenger service to Darlot, WA. While cruising at flight level (FL) 230, the aircraft sustained multiple system failures, followed by a depressurisation. The crew actioned the aircraft depressurisation checklist and commenced an emergency descent. During the descent, a number of system cautions and warnings illuminated. The crew elected to return to Perth and a descent to 8,000 ft was made. Shortly after, the majority of the aircraft's systems returned to normal.

A subsequent engineering investigation was unable to replicate the system faults. However, it appeared that the number-1 direct current (DC) generator output was spiking, causing power to the left DC buses to be repeatedly switched between the number-1 transformer rectifier unit and the left DC generator. This repeated power switching resulted in some of the aircraft's systems behaving erratically.

As a precaution, the number-1 generator control unit, number-1 DC generator and left bus tie relay were replaced.

Download Final Report
[Download  PDF: 1.5MB]
General details
Date: 15 December 2009   Investigation status: Completed  
Time: 1457 WST   Investigation level: Short - click for an explanation of investigation levels  
Location   (show map): 296 km NE of Perth Airport    
State: Western Australia   Occurrence type: Diversion/return  
Release date: 20 April 2010   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer de Havilland Canada  
Aircraft model DHC-8  
Aircraft registration VH-XFU  
Serial number 151  
Type of operation Charter  
Damage to aircraft Nil  
Last update 14 November 2018