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• August 8, 2016 Create Date
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Aviation Short Investigation Bulletin - Issue 18

On 4 December 2012, at about 1618 Western Standard Time1, a Qantas Airways Boeing 737-838
aircraft, registered VH-VZL (VZL), was taking off on runway 06 at Perth Airport, Western Australia
on a flight to Canberra, Australian Capital Territory. The captain was the pilot not flying and the
first officer was the pilot flying.

During the take-off run, approaching the take-off reference speeds2 of V13 and VR4, 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 tailwind5 of about 20-25 kt. The
captain disconnected the auto-throttle and ‘fire-walled‘6 the thrust levers. During the initial climb,
the first officer performed a Windshear7 escape manoeuvre.8

While there was some cumulonimbus cloud9 activity about 20—30 NM north of the airport, there
were no indications of an impending wind change before takeoff.

After takeoff, the crew advised air traffic control (ATC) that they had experienced a significant
tailwind component of about 20 kt during the take-off run. ATC advised the next aircraft due to
depart from runway 06 that there was now a threshold wind of O60°T at 10 kt and a centre-field
wind of 280°T at 15 kt. Takeoffs were then temporarily suspended from runway 06 and aircraft
departed using runway 03.