Turbulence/windshear/microburst involving a Boeing 737-476, VH-TJH, Melbourne, Victoria, on 19 January 1996

Runway 34 was in use and the wind was from 340 degrees T, at 15-25 knots. VH-HYJ, an A320 aircraft, commenced the take-off roll from the Juliet taxiway intersection. The aircraft was climbed on a track of 340 degrees M until about three miles from the airport, then was turned left onto a track of 230 degrees M.

VH-TJH was also cleared for take-off from the Juliet taxiway intersection. At the time of this clearance VH-HYJ had passed the threshold at the departure end of the runway. VH-TJH was also flown on a track of 340 degrees M on climb. At a height of about 1800 feet the aircraft encountered severe wake turbulence from VH-HYJ. To maintain control and prevent the aircraft from rolling excessively the captain was forced to apply and hold almost full left aileron followed by a significant amount of right aileron over a period of approximately 20 seconds.

At the time of the incident VH-TJH was about five kilometres behind the other aircraft. The longitudinal separation between the two aircraft, at the time the take off in VH-TJH was commenced, met the minimum standard specified in the Manual of Air Traffic Services.

Significant Factors

The following factors were considered relevant to the development of the incident:

1 Encounter with wake turbulence.