A380 Makes Big Waves... In Its Wake
If "conservative" computer models generated by the International
Civil Aviation Organization prove accurate, airplanes following the
A380 will have to fly up to three times the normal distance behind
the massive airliner in order to avoid its wake turbulence. Such
requirements could put some airports' plans to handle the
superjumbo in a tailspin.
According to the London Sunday Times, the ICAO models show the
double-decker aircraft will produce "significantly stronger" wake
vortices off its wingtips than either the Boeing 747 -- the largest
commercial airliner flying at the moment -- and even the Boeing
757, a notorious wake generator.
"To date, we've come up with some preliminary guidelines for the
aircraft... in normal air traffic control operations," said ICAO
spokesman Denis Chagnon to Aero-News. "The models reveal the
horizontal vortex may have been larger than anticipated, than even
the vertical one."
The required safety guidelines, issued earlier this month,
recommend aircraft flying directly behind an A380 at cruising
altitude should keep minimum spacing of 15 nautical miles, compared
to the industry standard of five n.m. On final approach, a minimum
10 n.m. separation would be required -- far above the standard of
3-8 nautical miles currently in force, depending on the comparative
sizes of the aircraft.
Combined with an additional minute added to departure
regulations for aircraft taking off behind an A380, and the wake
turbulence guidelines become a real issue -- and puts to question
just how much the A380's added passenger capacity offsets such
issues.
"If the wake vortex requires separation larger than the 747...
it would require adjustments in air traffic control operations,"
said Chagnon.
(Editor's Note: You may listen to our
entire conversation with Chagnon in today's Aero-News
Aero-Briefing, available here.)
Wake vortices are essentially "mini-tornados" formed by air
rolling off the plane's wingtips (and, to a far lesser extent, the
horizontal stabilizer) anytime those surfaces are generating lift.
Aircraft encountering these vortices can be displaced, much like
when they encounter regular turbulence.
In extreme cases, an
aircraft that encounters a strong wake vortex can lose control
completely.
Many in the industry believe the ICAO guidelines, which were
based off flight tests of the A380 prototypes, are conservative...
which is something Airbus is counting on.
"We don’t want to jump to any conclusions," said an Airbus
spokesman. "We are still expecting the (wake of the) aircraft to be
similar to the 747."
The guidelines will not be finalized until summer of 2006.