To address wake turbulence, Australian airport changes parallel runway procedures

 - January 27, 2010, 5:04 AM

Australia’s Sydney International Airport has modified its parallel runway operating procedures as a result of a November 2008 incident in which the crew of a Saab 340B lost control on approach while it was trailing an Airbus A380 landing on a parallel runway.

Controllers are now required to provide wake turbulence separation when a “super-wake-turbulence- category aircraft” and an aircraft with an mtow of less than 55,000 pounds are approaching parallel runways.

In the November 2008 incident, a Rex Airlines Saab was tracking to join a seven-nautical-mile final for Runway 34R, descending through about 2,400 feet, when the aircraft experienced an uncommanded 52-degree roll to the left with an eight-degree nose-down pitching motion. It then rolled through wings level to a 21-degree right bank and experienced an altitude loss of 300 to 400 feet in the nine- to 15-second period during which the crew fought to regain control.

The Australian Transport Safety Bureau (ATSB) believes wake turbulence from the A380 conducting a parallel approach to Runway 34L caused the loss of control for the Saab, resulting in minor injuries to one passenger. The A380 was on a four-nautical-mile final approach to Runway 34L, 72 seconds ahead of and to the left of the Saab.

The ATSB attributed the wake turbulence to a 35-knot left crosswind that affected the approaches of both aircraft, with the A380 drifting across the final approach path for 34R. At the time of the incident, which the safety bureau called “serious,” there was no requirement for wake turbulence separation to be provided by ATC with aircraft operations on the adjacent parallel runway.