Aviation safety investigations & reports

Stall warning device event - Bombardier Inc DHC-8-315, VH-TQL, Sydney Airport, NSW, 1 March 2011

Investigation number:
AO-2011-036
Status: Completed
Investigation completed

Summary

Download Final Report
[Download  PDF: 709KB]
Alternate: [Download  DOC: 1.24MB]
 

On 1 March 2011, a QantasLink Bombardier Inc DHC-8-315, registered VH-TQL, was conducting a regular public transport flight from Tamworth Airport to Sydney Airport, New South Wales. The crew were conducting a Sydney runway 16 left (16L) area navigation global navigation satellite system (RNAV(GNSS)) approach in Vertical Speed (VS) mode. The aircraft's stickshaker stall warning was activated at about the final approach fix (FAF). The crew continued the approach and landed on runway 16L.

The stickshaker activated at a speed 10 kts higher than was normal for the conditions. The stall warning system had computed a potential stall on the incorrect basis that the aircraft was in icing conditions. The use of VS mode, as part of a line training exercise for the first officer, meant that the crew had to make various changes to the aircraft's rate of descent to maintain a normal approach profile.

On a number of occasions during the approach the autopilot pitched the aircraft nose up to capture an assigned altitude set by the pilot flying. The last recorded altitude capture occurred at about the FAF, which coincided with the aircraft not being configured, the propeller control levers being at maximum RPM, and the power levers at a low power setting. This resulted in a continued speed reduction in the lead-up to the stickshaker activation.

Each factor that contributed to the occurrence resulted from individual actions or was specific to the occurrence. The Australian Transport Safety Bureau is satisfied that none of these safety factors indicate a need for systemic action to change existing risk controls. Nevertheless, the operator undertook a number of safety actions to minimise the risk of a recurrence.

In addition, the occurrence highlights the importance of effective crew resource management and of the option of conducting a go-around should there be any doubt as to the safety of the aircraft. Transport Canada, which regulates the aircraft manufacturer, advised that it will publish a summary of this occurrence and recommend that operators consider using it in their scenario-based crew resource management training programs.

Download Final Report
[Download  PDF: 709KB]
 
 
Alternate: [Download  DOC: 1.24MB]
 
General details
Date: 01 March 2011   Investigation status: Completed  
Time: 1810 EDT    
Location   (show map): Sydney Airport   Investigation level: Complex  
State: New South Wales   Occurrence type: Stall warning  
Release date: 28 May 2012   Occurrence class: Operational  
Report status: Final   Occurrence category: Incident  
  Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Bombardier Inc  
Aircraft model DHC-8  
Aircraft registration VH-TQL  
Serial number 603  
Operator QantasLink  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Tamworth, NSW  
Destination Sydney, NSW  
Last update 14 November 2018