http://www.post-gazette.com/pg/06164/697876-28.stm
New Airbus has worrisome wake at higher altitudes
Tuesday, June 13, 2006
By Andy Pasztor and Daniel Michaels, The Wall Street Journal
The Airbus A380 airliner, already buffeted by years of production and development headaches, is likely to face a daunting challenge once it enters service next year: unprecedented operating restrictions intended to protect nearby aircraft from flying into the air turbulence churned up by the superjumbo jet.
Rules that include special flight restrictions and extra spacing could pose an immediate marketing problem for Airbus because other planes in the A380's vicinity will likely have to either slow down or wait longer to take off to allow for the additional distance. Airbus designed and marketed the $300 million plane amid promises that it would fit seamlessly into existing global air-traffic patterns.
International aviation regulators and aerodynamic experts failed again last week to reach a consensus about the extent of the safety hazards created by the A380's unusually powerful wake, according to people involved in the deliberations. Meeting behind closed doors in Montreal, a study group including U.S. and European government officials continued to disagree about permanent safeguards to ensure that turbulence created by the A380 won't affect airplanes during takeoff, cruising and landing. In extreme cases, such turbulence is capable of wrenching even a large jetliner out of control.
Without a set of permanent standards, some version of the strict interim guidelines now in effect -- requiring at least twice the normal in-flight separation when trailing the twin-deck Airbus model -- likely will stay in place until well into 2007. Barring a last-minute breakthrough, these people said, this means that the world's largest passenger aircraft is poised to begin service with significantly more-stringent separation rules than any other jet.
Airbus has touted the 555-seat A380 as "the economical solution for heavily traveled routes." But the interim guidance from the International Civil Aviation Organization calls for minimum separations of 10 nautical miles for all aircraft following a landing A380, compared with the typical five miles required when following today's largest aircraft. For aircraft flying the same route directly behind an A380 at cruising altitude, the recommended minimum spacing is tripled to 15 nautical miles. A further complication is that controller organizations previously warned they may need as long as nine months preparation time to phase in new standards.
Airbus, which is 80 percent-owned by European Aeronautic Defence & Space Co. and 20 percent-owned by Britain's BAE Systems PLC, declined to comment on the turbulence issue. Some Airbus officials recently have expressed a willingness to accept a modified version of the present standards as a first step -- with the understanding that permanent rules would follow relatively quickly. The scientific work initially was supposed to be finished around the start of this year, but verifying certain computer-modeling techniques has been especially tough.
The strength of a wake depends partly on the weight of the aircraft that produced it. Wind and weather conditions can make turbulence hard to measure accurately around airports. Turbulence levels are also particularly tough to evaluate while a jet is climbing or cruising at high altitudes.
Since the controversy erupted last year, Airbus has invested millions of dollars and months of extensive flight tests to try to demonstrate that the wake of the 500-ton A380 poses no greater potential safety threat than turbulence generated by Boeing's largest model, the 747, which weighs about 100 tons less. There haven't been any recent crashes of jetliners attributed primarily to wake encounters, though over the years some business and private planes have experienced serious incidents and even crashed after following a larger aircraft too closely near an airport.
Industry and government officials on both sides of the Atlantic increasingly predict that Airbus will be forced to accept different rules than it anticipated. Andre Auer, head of the Joint Aviation Authorities, a European umbrella group with some regulatory responsibilities, said in an interview days before last week's Montreal sessions that the interim guidelines for the A380 "are likely to stay in place until commercial service starts."
The ICAO, which issued the preliminary safety standards in November, confirmed that no final agreement has been reached. The study group is interested in "harmonizing the new specifications, whatever they may be," so they apply equally all over the world, said spokesman Denis Chagnon. He added that the study group "is working well together" and hopes to issue a report in mid-November that ICAO officials could then review.
Privately, even some Airbus officials predict the A380 temporarily may have to be put into a new air-traffic-control category, until its safety is proved in actual conditions.
The A380 has faced other head winds, including a six-month production delay. Separately, engineers were recently forced to reinforce some structural elements inside the wings after they fell short on a stress test in February.
So the real question is.... should the following aircraft be penalised an extra 5 miles (2 - 2.5 minutes each) to facilitate the Super-Heavy or whatever they will call the cateogry? Personally, I can't see why not as we accomodate Heavies already - but I am sure commericial pressures will be brought to bear by those being delayed and penalised.
Apparently, a rumour is going around that after landing in SY on RWY16R, further operations are restricted on that RWY until the A380 has exited, taxiied back, and turned clear in to the Apron, due to wingspan issues - this must be another 5 minutes minimum.