Aviation safety investigations & reports

Significant wind change during takeoff involving Boeing VH-VZL, Perth Airport, WA, 4 December 2012

Investigation number:
AO-2012-168
Status: Completed
Investigation completed

Summary

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On 4 December 2012, at about 1618 Western Standard Time, a Qantas Airways Boeing 737‑838 aircraft, registered VH‑VZL, was taking off on runway 06 at Perth Airport, Western Australia on a flight to Canberra, Australian Capital Territory.

During the take-off run, approaching the take-off reference speeds, the airspeed stopped increasing and did not start increasing again for several seconds. The captain noticed that the wind vector on the navigation display was showing a tailwind of about 20-25 kt. The captain disconnected the auto-throttle and ‘fire-walled’ the thrust levers. During the initial climb, the first officer performed a windshear escape manoeuvre.

While there was some cumulonimbus cloud activity about 20–30 NM north of the airport, there were no indications of an impending wind change before takeoff.

Before takeoff, both pilots checked the windsocks, which showed that headwind conditions existed. Late in the take-off run, a significant wind change occurred and the aircraft began to experience tailwind conditions of about 20 kt. As the performance calculations had assumed nil wind for takeoff, the aircraft failed to achieve the predicted take-off performance.

This incident serves as a reminder to pilots that significant wind changes can occur during takeoff, can be difficult to predict, and can occur in the absence of thunderstorm activity. The wind conditions at each end of a runway may differ significantly so that headwind conditions can exist at one end and tailwind conditions at the other end.

Although it did not assist in this case, it is important to monitor the available windsocks before takeoff as it is the final opportunity to detect wind changes before the take-off roll begins.

Aviation Short Investigation Bulletin - Issue 18

Download Final Report
[Download  PDF: 383KB]
 
 
Alternate: [Download  DOC: 1.24MB]
 
General details
Date: 04 December 2012   Investigation status: Completed  
Time: 1618 WST    
Location   (show map): Perth Airport   Investigation type: Occurrence Investigation  
State: Western Australia   Occurrence type: Weather - Other  
Release date: 17 May 2013   Occurrence class: Environment  
Report status: Final   Occurrence category: Serious Incident  
  Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer The Boeing Company  
Aircraft model 737  
Aircraft registration VH-VZL  
Serial number 34194  
Operator QANTAS  
Type of operation Air Transport High Capacity  
Damage to aircraft Nil  
Departure point Perth, WA  
Destination Canberra, ACT  
Last update 14 November 2018