Accepts Some Airbus Recommendations, But Not All

Following certification of the A380 with European and US regulatory agencies, the International Civil Aviation Organization (ICAO) has released it's final rules regarding safe separation times and distances to account for the superjumbo's wake vortex.

Airbus A380 product marketing manager Corrin Higgs told Engineering News, "We have been doing a lot of testing ourselves – unprecedented testing with other makes of aircraft, including the Boeing 747 and 777, as well as other Airbus types, including the A318 – to check the wake effects of the A380; we couldn't detect any such effect."

Higgs says Airbus worked with several agencies and independent experts in developing recommendations for the ICAO to work from.

"The ICAO accepted some of these recommendations, but not all," he said.

ANN reported in September the result of Airbus testing and recommendations to the ICAO. A steering group made up of Airbus engineers, ICAO officials and other experts concluded the A380 is not much different than a 747 in cruise. For aircraft behind the A380 while on approach, the group recommended six miles for aircraft designated as "heavy," and eight miles for aircraft designated as "medium" or "light." Airbus expressed hope that operational experience and further testing might allow even closer distances

According to Engineering News, the ICAO accepted the steering group's recommendation for flight during cruise abolishing all vertical and horizontal distance restrictions other than standard radar separation; the A380 is to be treated as a 747 for that phase. It also accepted the group's recommendations for mimimum following distances during approach, which has some Airbus officials scratching their heads.

Higgs says, "...a medium A320 has to follow an A380 at a greater difference than a light Cessna 172 has to follow a 747 – this is hardly logical; it shows the conservatism of the ICAO’s approach."

Also of concern for Airbus is the decision to keep the A380's following distance behind a heavy at four miles. The manufacturer had hoped the ICAO would follow the steering group's recommendation and reduce that number to 2.5 miles based on its exhaustive testing.

This decision dashed Airbus hopes to quell concerns the A380 would foul up traffic flows at high-density airports. Any increase in following distances or times has a domino effect on all following traffic. Airbus had hoped a decrease in following distances for the A380 would mitigate the longer distances other aircraft must use to follow it.

FMI: www.airbus.com, www.icao.org