Study Sets New Following Distance Limits

Following three years of exhaustive studies, the Airbus A380 Wake Vortex Steering Group has rendered its conclusions. The Steering Group comprised representatives from the Joint Aviation Authorities (JAA), Eurocontrol, US Federal Aviation Administration (FAA), and Airbus.

The study demonstrated that en route the A380 is similar to the Boeing 747. In cruise and when flying in a "holding pattern", the A380 is considered to be identical to any other aircraft, both for vertical and horizontal spacing between it and any following aircraft.

The study has also established that there are no wake constraints for the A380 following any other aircraft, including another A380.

On approach, the study recommends increasing the spacing compared with the existing rules. For a "heavy" aircraft following the A380 spacing would increase to six miles and to 8 miles for "medium" and "small" aircraft. Current guidance requires all aircraft to remain 10 miles behind the A380.

The good news is since A380 is unaffected by wake turbulence from ANY aircraft currently flying -- not even another A380 -- it can land as close as practicable to a preceding aircraft. In a perfect ATC world, that would help compensate for the additional spacing required by aircraft following the A380.

On departures, a "heavy" aircraft following the A380 will have to wait two minutes, and the "medium" sized and "small" aircraft will have to wait three minutes. But here again, the A380 can take-off as close as possible to any preceding airliner.

Though not specifically addressed, flight tests provided no indication of impact on parallel runway operations for runways separated by more than 760 m (2500 ft). This should be monitored in operational service for verification.

Of course, all recommendations from the study are subject to review and possible change based on any further studies. A interesting by product of this study is a consensus among participants of the need for a future review of the existing aircraft categories taking into account operational experience.

The detailed scientific work for this study was conducted by leading international experts in the field. Airbus's flight test program totalled 180 hours. They did back-to-back comparisons of different aircraft, cruise wake encounter tests, and took ground and airborne measurements of wake vortexes using a laser-based radar, or LIDAR.

FMI: www.airbus.com