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Airbus's A400M May Face Design Overhaul To Meet Performance Targets | AVIATION WEEK
Airbus's A400M May Face Design Overhaul To Meet Performance Targets
Jan 25, 2009
By Jens Flottau and Robert Wall
Airbus is facing much more than just contractual and schedule challenges in its A400M military airlifter program - the company may need to do a great deal of re-engineering work to achieve the aircraft's performance targets.
Numerous issues threaten to make the A400M a less attractive and capable aircraft, industry officials say, on top of the well-publicized delays in the flight-test program linked to the lagging engine Fadec development.
One key area of concern is that the A400M is overweight, which would negatively affect its payload and range capabilities. According to Airbus Military data, maximum payload is 37 tons and range is 1,780 naut. mi. with a full payload. But people close to the program say the aircraft is considerably heavier in its current development status. The first six units to be used in the flight-test program are 12 tons heavier than planned, according to those executives. A weight-saving campaign has identified a reduction potential of 7 tons. Early production aircraft will only incorporate reductions of 5 tons at most, leaving payload below the 30-ton mark.
Airbus Military appears to have informed procurement agency Occar about the likely weight penalty. Some Occar members, including France, have accepted the changes, but Germany, whose air force needs the aircraft for so-called out-of-area deployments that are both payload- and range-critical, has not. If the A400M falls far short of the previous design targets, missions to places such as Afghanistan would become much more complex and costly.
Germany plans to use the A400M to transport the Puma armored fighting vehicle that weighs 31.5 tons in its basic version. If Airbus Military cannot recoup more of the payload capabilities, the aircraft would only be able to carry the Puma with a sizable range restriction.
Government officials indicate it is unlikely that Germany would reduce its A400M order in favor of other models, such as the C-130J or the C-17 that are being evaluated by the U.K., but mainly for political reasons. A proposal by EADS CEO Louis Gallois to use Airbus A330-200Fs as an interim solution is receiving a lukewarm response at best.
"If we wanted to have a commercial freighter, we could simply charter one from Cargolux or somebody else," one German military official says angrily. But Germany's current C-160 Transall transport fleet flies a lot of short-haul domestic legs in Afghanistan to places that cannot accommodate an A330F. One air force official hints that the Transalls could continue operating for several more years instead, as they are well maintained. But Germany leases some Antonov An-124s for missions beyond the C-160 capabilities.
If the A400M's biggest customer (60 of 192 units on order) insists on the previous performance guarantees, it could force a major redesign of the aircraft, such as a larger wing to allow for more fuel. But that seems highly unlikely, given the already huge financial and schedule challenges that made Airbus CEO Thomas Enders describe the terms of the current program as being a "mission impossible."
On Jan. 9, EADS and Airbus announced a delay of up to four years in the A400M project and proposed renegotiating the contract with the Occar nations. According to the original terms committed to in 2003, EADS is carrying most of the financial risk of the program and may face big penalty payments if no solution is found. In their statement early in the month, Airbus Military and EADS said they "want to discuss the program schedule along with changes to other areas of the contract, including certain technical characteristics of this first-class military aircraft." No additional details were mentioned and Airbus/EADS officials have declined to comment further.
Responsibility for the A400M was recently shifted under the Airbus umbrella to reduce management complexity and improve program oversight.
Airbus officials suggest the main performance criteria aren't at any particular risk. The executive vice president of programs, Tom Williams, says the more he has been reviewing the program, the more certain he has become that "this is still going to be a bloody good airplane." The aircraft is beating its short-field performance and load targets, he says.
However, the fact that Airbus has halted A400M prototype production until "adequate maturity is reached" is interpreted by industry insiders as an indirect admission that there are probably massive changes to the aircraft in the works, making continued production obsolete at this point.
Industry officials say the weight problem could well turn out to be the primary issue with the aircraft, and no longer engine software. One observer believes the A400M payload will end up 3-4 tons below the original target, even after the design changes, which could include the introduction of carbon fiber composites in non-critical areas. The three-year timeframe proposed by EADS between the first flight and first delivery at the end of 2012, at the earliest, suggests that modifications to some parts of the aircraft structure are also possible.
Some weight-saving initiatives are affecting aircraft operations, though. A hydraulic system to lower the main landing gear on the ground in order to ensure an even loading ramp has been scrapped. That decision means floor beams may have to be reinforced, since heavy tanks are planned to virtually drop down when their center of gravity has passed the loading edge.
Executives close to the Europrop International (EPI) engine consortium say Fadec issues with the TP400 are expected to be resolved by June. Gallois said early this month that once an acceptable standard Fadec was provided, the A400M could fly about a month later. But, in addition to software, there are also hardware problems involving the engines. Because of unexpectedly high loads, cracks were found in some of the original design engine gearbox casings. Those needed to be partially strengthened. The executives say upgraded casings have been delivered to the Seville, Spain, final assembly line and will be installed to replace the original parts.
Some special operational performance goals are also in doubt, according to people familiar with the details. For example, the A400M may not be able to fly "Sarajevo profile" steep approaches because of possible flutter issues with the propellers.
Moreover, officials familiar with the program say some systems may be rejected by the European Aviation Safety Agency (EASA). The agency appears not to agree with how oxygen bottles and fire protection systems are installed in the fuselage and main gear bay. If no agreement is reached, the A400M will not be given the EASA approval needed for planned civil certification. An EASA official says the agency does not comment on ongoing certification processes.
EADS is talking with customers about some requirements relief, but company officials claim these have to do with special needs and are not related to fundamental aircraft performance aspects. Enders says both customers and the company's own engineers contributed to some requirements being added that are "technologically hardly feasible or only feasible at a disproportionate amount of cost."
Williams says one example is an extreme tactical navigation requirement. It calls for the aircraft to fly low and remain entirely passive - not even using a terrain-following, terrain-avoidance system - to support special operations.