Description

On 3 November 2008, a Saab 340B being operated on a domestic passenger flight by Regional Express AL was tracking in daylight to join a 7nm final for Runway 34R at destination Sydney, when a passenger sustained minor injuries as the result of a transient encounter with turbulence that had led to a momentary loss of control of the aircraft and which was suspected as being of wake vortex origin.

The Investigation

An Investigation was carried out by the Australian Transport Safety Board who found by examination of the available radar, meteorological and aircraft operational data that the momentary upset probably resulted from wake turbulence generated by an Airbus A380 that was conducting a parallel approach to Runway 34L. It was noted that there was a 35 knot crosswind from the left affecting the approaches of both aircraft.

The encounter was found to have occurred at an altitude of about 2,400 feet amsl and involved an uncommanded 52º roll to the left (which led to an uncommanded autopilot disconnect) and a simultaneous 8º nose-down pitching motion. Immediately after, the aircraft rolled through wings level to a 21° right bank angle. The encounter led to an altitude loss of 300 to 400 ft in the 9 to 15-second period during control was regained. At the time of the event it was estimated that the aircraft was about 260 metres to the right of the Runway 34R centerline.