NDT.net May 2005, Vol. 10 No.05

Concerns about NDT of new Airbus A380

The aviation press has reported that the FAA is going to require Airbus to conduct additional strength analysis and testing of new materials used in the A380.

First Officer Dave Hayes of ALPA's A380 Project Team says: "We asked Airbus for more information about non-destructive testing of these new materials, mostly out of concern about the ability of airlines to maintain the material in service. Regarding American Airlines Flight 587 -- the A300 that crashed in Belle Harbor, N.Y., in November 2001 -- some aviation safety experts think that the airplane might have been weakened by a previous, documented encounter with severe turbulence.

"We're concerned about the capability of operators to conduct NDT of these materials. If you hit them with a catering truck, which happens all the time in the real world, what have you damaged?" he asks. "So we're interested in what NDT methods are going to be assigned to the operator, and what are relegated to the manufacturer, and under what rules. These are questions we're going to be asking other manufacturers who intend to use composite materials in their airplanes. Some of these materials are fairly exotic and require using sophisticated imaging techniques for NDT."

The full-Story:
ALPA Weighs In on the A380

Air Line Pilot, March 2005, p.24-28
News from ALPA's Committees
Jan W. Steenblik, Technical Editor
Source: Air Line Pilots Association, Washington, DC www.alpa.org

The numbers are staggering: Wingspan, 261 feet 8 inches. Length, 239 feet 3 inches. Height, 79 feet 7 inches. Maximum gross takeoff weight, as much as 1.3 million pounds. Passenger capacity, 550 growing to as many as 853. Range, with all seats filled, about 8,100 nm. Price, about $290 million.

ALPA Engineering & Air Safety Airbus SAS rolled out--actually, the new parlance is "revealed"--the A380 with theatrical ceremony on January 18. ALPA's first vice-president, Capt. Dennis Dolan, who is also president of the International Federation of Air Line Pilots Associations, attended the ceremony.

Ten days later, the European consortium announced a Chinese order for the A380, swelling their order book for the airplane to 154 orders and commitments from 15 customers. FedEx will be the launch customer for the freighter version, the A380F, expected to enter service in 2008.

The A380 is the first of a new generation of airliners, new large aircraft, or NLAs. At least a dozen U.S. airports, and more around the world, are bracing for the arrival of this latest "aluminum overcast." Some airports are spending tens of millions of dollars to modify runways, taxiways, bridges, and gates to accommodate the A380.

ALPA has been participating in ongoing meetings of a government/industry group, the New Large Aircraft Facilitation Group, whose purpose is to ease the introduction of the A380 into service at U.S. airports. A number of issues remain unresolved.

ALPA also has used every venue at its disposal to communicate with Airbus, plus the FAA and the European Aviation Safety Agency (EASA), line pilots' concerns about several aspects of development and introduction of the A380.

In April 2004, ALPA safety representatives met with senior Airbus officials at the Association's Herndon, Va., offices to discuss progress of the A380 design and development. At that meeting, ALPA asked for more information regarding several issues of concern, including

  • discussions of various Airbus customer focus groups;
  • the proposed auto-recovery enhanced GPWS system, which would automatically make the airplane climb and/or maneuver to avoid terrain or other obstacles if the EGPWS determined that the airplane was in danger of flying into them;
  • nondestructive testing of GLARE, a composite material used extensively in the upper half of the A380 fuselage;
  • the proposed onboard oxygen-generating system and its intended use;
  • inflight fire detection and suppression;
  • required runway width in relation to Vmcg;
  • operating limitations and performance;
  • wake turbulence;
  • requirements for alternate airports;
  • plans for cabin and cockpit evacuation; and
  • possible plans to harden the airplane against internal and external attacks by terrorists.

Capt. John Cox, then ALPA's Executive Air Safety Chairman, wrote to the head of the Airbus delegation that met with the ALPA pilot safety representatives and staff engineers, stating, "Of course, at this stage in our discussions and in the development of the aircraft, we still have many questions, and several issues continue to be a concern to us. They include: How an aircraft that is nominally ICAO Code F will operate into Code E airports [which Airbus has proposed], the prospects for full-scale evacuation testing, ARFF [aircraft rescue and firefighting] requirements at alternate airports, airport requirements in general, wake vortex strength determination, and auto-recovery EGPWS operation."

Since then, ALPA's A380 Project Team, led by First Officer Dave Hayes (Northwest), the ALPA Wake Vortex Separation Project Team, led by Capt. Dave Smith (Alaska), and the ALPA Airport and Ground Environment (AGE) Group, chaired by Capt. Mitchell Serber (Comair), have continued to carry the ball for ALPA.

F/O Hayes gave Air Line Pilot this progress report not long after the A380 "reveal":

"Two things have changed since our June 2004 letter," he notes.

"First, the senior Airbus official with whom we met has moved to a different position within the company. We haven't had the opportunity to meet with his successor yet. We look forward to meeting him and discussing how pilots might best interface with Airbus.

"Second, some issues have resolved themselves through the normal processes in place between the regulators and manufacturers and through some discussions with ALPA. For example, we understand that Airbus does not now intend to install the auto-recovery EGPWS on the A380. We'd expressed our concerns on how it would work operationally--the pilots would be non-voting members of the flight crew in the original Airbus proposal. They wouldn't have any way to override the system. Anytime anyone proposes to build an automatic system that pilots can't override, it gets our attention," he cautions.

Another system originally proposed for the new airplane was the onboard oxygen-generating system. F/O Hayes reports, "We've heard that won't be installed after all."

Moreover, he explains, "Fuel tank inerting technology separates nitrogen and oxygen from engine bleed-air and uses the nitrogen to inert the tank, or make it less flammable. The technology to use the separated oxygen for additional cabin air has apparently become too cumbersome; therefore, the oxygen by-product will be dumped overboard. The initial passenger versions of the A380 will not have a center fuel tank; therefore, inerting will not be necessary."

ALPA senior staff engineer Joe Bracken adds, "The FAA is looking at a novel aspect of the design of the A380--the air cycle machines are located in the leading edge of the wing. Because this may result in higher wing tank temperatures, the FAA is evaluating the need to reduce the flammability of the fuel in those tanks. This situation may be resolved simply by adding extra insulation in the area of the air cycle machines."

Airbus originally proposed using existing A330 and A300 evacuation data to prove that the A380 met evacuation requirements. "They wanted to use A330 certification data for the upper deck and A300 data for the lower deck," explains F/O Hayes." We don't want the first time the aircraft needs to be evacuated to be the first time the aircraft is evacuated."

Another ALPA concern regarding evacuation is that the height of the airplane--especially the upper deck--might lead to more balking by passengers reluctant to jump from so high. Also, the Association is concerned that some passengers may decide to walk or run down the wide stairs, like those of a cruise ship, from the upper deck to the lower deck.

Yet another concern: Because the A380 has so many exit slides, and some of them necessarily converge where they meet the ground, passengers using them will likely run out of room at the bottom of the slides. A passenger pileup next to the airplane would not be conducive to minimizing injuries, or to permitting ARFF personnel to approach the airplane.

Regarding wake vortex testing, another certification requirement that Airbus proposed to resolve by computer modeling alone, the FAA has advised ALPA that Airbus has agreed to conduct flight tests in which the A380 wake vortices will be measured by lidar on the ground. Members of ALPA's A380 and Wake Vortex Separation Project Teams will likely witness these tests, alongside representatives from the FAA and EASA.

The aviation press has reported that the FAA is going to require Airbus to conduct additional strength analysis and testing of new materials used in the A380.

F/O Hayes continues, "We asked Airbus for more information about non-destructive testing of these new materials, mostly out of concern about the ability of airlines to maintain the material in service. Regarding American Airlines Flight 587--the A300 that crashed in Belle Harbor, N.Y., in November 2001--some aviation safety experts think that the airplane might have been weakened by a previous, documented encounter with severe turbulence.

"We're concerned about the capability of operators to conduct NDT of these materials. If you hit them with a catering truck, which happens all the time in the real world, what have you damaged?" he asks. "So we're interested in what NDT methods are going to be assigned to the operator, and what are relegated to the manufacturer, and under what rules. These are questions we're going to be asking other manufacturers who intend to use composite materials in their airplanes. Some of these materials are fairly exotic and require using sophisticated imaging techniques for NDT."

On a different subject, F/O Hayes reports, "From the briefings we've had on the airplane, A380 cockpit design and operability appear to be very much like those of other members of the Airbus fly-by-wire family. Handling qualities and characteristics will be addressed in certification flight testing. But we haven't had the opportunity to discuss with Airbus the interoperability of pilots with some of the aircraft systems."

One interesting twist to the design philosophy of cockpit commonality, which has market appeal by reducing training costs, is that commonality can lead to stagnant design. "We [ALPA] see cockpit technology as evolutionary, not stationary," says F/O Hayes. "You must make sure that your processes allow you to keep pace with evolving technologies."

ALPA has not historically developed the degree of rapport with Airbus that it has with Boeing and other aircraft manufacturers, exemplified by Boeing sharing the prestigious Collier Trophy, awarded for development of the B-777, in 1996 with ALPA and other stakeholders with whom Boeing worked closely.

However, as Capt. Cox wrote to the leader of the Airbus delegation that met with ALPA pilot safety representatives in April 2004, "Our experience with dialogue with manufacturers has demonstrated that through continuing such productive discussions, ALPA can become a valuable ally in the introduction of new models into service when we are able to help explain processes, products, features, and philosophies to our members."

And, as F/O Hayes points out, "We have the expertise to help make an optimized design."


© NDT.net