Late last year, Airbus shifted its A350 schedule by six months. But increasingly, suppliers are expressing concerns that a more serious delay could be just around the corner.

Airbus will be forced to postpone its entry-into-service date by at least another year, due to the complex trickle-down effect of late design changes that is affecting various parts of the aircraft, but which is likely felt most painfully in the area of cabin installation, according to various industry sources. Costs are going up and supplier relations are being strained exponentially.

“The systems side is a nightmare,” says one CEO of a major Airbus supplier. “The interiors will be late by at least one year,” he believes. That does not mean that first flight is necessarily affected that much, because the initial flight tests will not need a functional cabin anyway. The full effect would not be felt until later in the flight-test campaign, when cabin testing is included.

The massive amount of redesign and the resulting delays are also understood to have led to significantly higher development costs. There is no clear picture about the precise amount, and Airbus will not address the issue. But one executive believes the total overruns might by now have reached €3.5 billion ($4.6 billion). According to Airbus's standard supplier contracts, additional costs up through the critical design review stage, which was reached for many individual parts last year, are to be covered by suppliers. But at least one Airbus partner—Diehl Aerosystems—now wants the manufacturer to participate in the cost overruns.

Diehl says it is in talks with Airbus regarding technical and commercial issues. A Diehl representative points out that the A350 is its single biggest development program and is its scale is challenging.

Several Diehl units are involved with the A350, including Diehl Aircabin, a joint venture with Thales and the former Airbus cabin plant in Laupheim, Germany. The apparent problems could also be linked to the transition from a former Airbus unit to an independent supplier, says an industry source. Cabin development engineers have historically been based in Hamburg, while the Laupheim factory was mostly dedicated to implementing pre-developed designs.

At the time of the sale, Airbus was believed to have pushed through significant cost-improvement targets that resulted in lower prices. Neither side is willing to comment.

There have been changes to aircraft geometry and component location, concedes a senior Airbus official. But, he adds, the changes are typical for a development program. Sometimes those changes fall to the supplier who can most easily implement them, given planning maturity, he argues. He declined to specify whether Diehl was in that category. Engineering work based on a joint digital mockup (DMU) should also help keep all participants on the same level, particularly when it comes to design changes, Airbus argues. But one industry source claims that the DMU itself is “in a big mess.”

Airbus also refutes claims that the A350 schedule is already behind. The official says that, so far, the manufacturer is on track to meet all the program milestones after the latest schedule revision.

But EADS CEO Louis Gallois is more cautious. In his view, “A lot of difficult challenges are ahead of us, but efforts in risk management are paying off.” He admits that “the schedule is tightening as Airbus approaches the next milestones, particularly final assembly.” The first static-test aircraft is now planned to enter final assembly in April, slightly later than anticipated. It was originally slated to enter that phase in late 2011. From a group perspective, Gallois considers the A350 to be “our single biggest risk.” He lists three categories of buffers for the program: the design process; flight tests and certification; and “the difference between our industrial time schedule and the commercial time schedule.”

“We are progressively eating those buffers,” Gallois concedes. He says that when it is noted this is happening too quickly, “we launch mitigation actions and try to preserve buffers in other processes that are not yet impacted. For the time being, clearly we are [adhering] to the time schedule we announced in November.” It calls for first flight in early 2013 and entry into service a year or so later.

But GKN, another significant A350 supplier, says the A350 is “challenging,” both technically and in terms of schedule. CEO Nigel Stein recently told reporters that the company was working “incredibly hard,” but he would not predict a service-entry date. That's a matter for Airbus to sort out, he stated.

Aer Lingus CEO Christoph Mueller also joined the ranks of those who are concerned that the schedule might shift again. He says he will soon begin talks with Airbus about an updated delivery plan, but would not comment further.

One Airbus observer believes that the A350 program is headed for a management reshuffle, but probably not until after the leadership transition from Thomas Enders to Fabrice Bregier in June.

Airbus has often noted that although it has learned a lot from mistakes made in the Boeing 787 program, the A350 remains challenging. When flaws are detected, they are to be resolved immediately without work traveling to the next development phase or location. That is how Airbus explained the delay of up to six months that was announced late last year, when it concluded that composite fuselage panels made by Spirit AeroSystems could not be completed on target.

One source indicates that small, but numerous changes to the detailed fuselage layout, which involve the exact location of stringers and other components, forced changes further down the line in the design process. Some replanning was needed related to quality issues with the composite panels, and some others due to material limits, one executive explains. Excessive weight remains an issue, although the situation is allegedly much less dramatic than in the case of the 787. However, the weight situation seems to be well on the way to being resolved, the executive notes.

Additional lessons for the A350 program could still emerge from the A380, particularly as Airbus examines how its design system failed to recognize a design flaw that led to cracks in wing rib feet across the entire fleet. The cost of repairing the existing fleet is estimated at €105 million. Repairs on the first 17 aircraft have confirmed that estimate. The figure does not include additional expenses for the redesign efforts.

“We are looking at a manufacturing solution, but we don't know if that will trigger an increase in costs,” Gallois says. He points out that the target to breakeven in the program in 2014 or 2015 depends on the euro/dollar exchange rate. That guidance only includes the recurring costs of production versus revenues, not development costs.

The Type 2 cracks in wing rib feet have the potential to grow in both directions. Tom Williams, Airbus's executive vice president of programs, says “more airworthiness directives (AD) are on the horizon between now and the summer.”

Williams says Airbus is considering switching aluminum alloys (from Al 7449 to Al 7210). A change in materials could lead to “a change in thickness of some sections,” mainly on the inboard side of the pylon of the outboard engines. That in turn could lead to an increase in aircraft weight of 90 kg (198 lb.).

It is too early to tell when the redesign exercise will be finished, but Williams does not believe it will affect this year's A380 production rate.

The damaged rib feet have been found on Ribs 24-26. Williams says approximately 20 pieces have been affected per aircraft, but there are about 2,000 such parts per wing. The damage was caused during manufacturing, when two pieces of wing skin were joined. In some cases, the gap between the pieces has been greater than anticipated. Thus more force than planned was induced upon the parts when the bolts were tightened.

Williams says that in spite of the recent spate of ADs for the A380, the total number is actually in line or below industry average. Since first flight, there have been 43 ADs for the A380, around 14 per year. When only the time of airline operations is taken into account, that number drops to nine per year. That compares with 18 per year for the Boeing 777 and 21 for the 747, an industry source says.