A400M Problems Range Far Beyond Engines

PARIS – Airbus is facing much more than just contractual and schedule challenges in its A400M military airlifter program, as the aircraft may need massive re-engineering work to achieve its performance targets.

In turn, numerous issues threaten to make the A400M a less attractive and capable aircraft for its customers, industry sources tell Aviation Week. They come in addition to the well-publicized delays in the flight-test program that are linked to the lagging engine full authority digital engine control (FADEC) development (Aerospace DAILY, Nov. 25, 2008).

One key area of concern appears to be the A400M being overweight, which would negatively affect the aircraft’s payload and range capabilities. Sources close to the program say the aircraft is significantly heavy in its current development status. The first six units to be used in the flight-test program are 12 tons heavier than planned, those sources say. A weight savings campaign has identified a reduction potential of 7 tons. Early production aircraft will only incorporate reductions of 5 tons at the most, leaving payload below the 30-ton mark.

Airbus officials suggest the main performance criteria aren’t at any particular risk. Executive Vice President for Programs Tom Williams says the more he has reviewed the program, the more certain he has become “this is still going to be a bloody good airplane.” The aircraft is beating its short field performance and load targets, he says.

Yet, industry sources say the weight problem could well turn out to be the primary issue with the aircraft, rather than engine software. One observer believes the A400M payload will end up 3-4 tons below the original target even after all possible design changes, which could include the introduction of carbon fiber in noncritical areas. The three-year time frame proposed by EADS between the first flight and first delivery at the end of 2012 at the earliest would suggest that modifications to some parts of the aircraft structure also are possible.

Sources close to the Europrop International engine consortium say that FADEC issues with the TP400 are expected to be resolved by June. The EADS chief executive said earlier this month that once an acceptable standard FADEC was provided, the A400M could fly around one month later. But in addition to software, there are also hardware issues surrounding 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 sources say that upgraded casings already have been delivered to the Sevilla, Spain, final-assembly line and will be installed to replace the original parts.

Some special operational performance goals also are in doubt, according to people familiar with the details. The A400M may not be able to fly “Sarajevo profile” steep approaches because of possible flutter issues with the propellers.

Finally, some systems may be rejected by the European Aviation Safety Agency (EASA), people familiar with the program say. 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 EASA approval needed for the planned civil certification.

An EASA official says the agency does not comment on ongoing certification processes.

Photo: Airbus Military

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