Airbus evaluates heavier A380

MAX KINGSLEY-JONES / TOULOUSE

Manufacturer to decide within three months if it will offer increased take-off weight on 550-seater from service entry

Airbus has come closer than ever to conceding that it has failed to achieve its weight-saving targets for the A380, with the revelation that it is studying a higher gross weight for the aircraft from entry into service.

Airbus says it will decide "within three months" whether it will offer customers a new maximum take-off weight (MTOW) A380 variant from entry into service in March 2006, which will feature a 9t increase over the current specification aircraft, to 569t.

Although Airbus declines to be specific about the reasons for the increase, A380 customer sources say it is as a result of the aircraft being heavier than the target "manufacturer's weight empty" specification.

Airbus's official line is that the higher weight option is to "satisfy customer payload/range requirements… the additional 9t can be used either to enrich the aircraft's definition as per the customer's requirement, or to increase the payload or the range". It adds that it decided to offer the proposal because it wants to have all aircraft built to the same production standard from the start.

Robert Lafontan, who is senior vice-president engineering for the A380 programme, says the higher weight will require "local structural reinforcing". He adds that a decision on the variant, and the refining of its specification, will be made within three months.

Airbus indirectly concedes that initial A380s will be overweight, by saying that aircraft built to the first production standard will incorporate weight savings. "Airframe weight estimates are now progressing for the first production standard incorporating weight savings and the current standard of loads," says Lafontan.

The first aircraft built to this standard will be the fourth and fifth A380s to fly - manufacturer's serial number (MSN) 007 and 003 respectively - which will be the first to go to customers. Lafontan says primary structural weight estimates have been completed for the first airframe, MSN001 (due to fly in early 2005), but declines to specify what these are as it "is not designed with the same objectives" as customer aircraft. The first drawings for MSN003 and 007 have been released.

"Individual component weighing [of the first airframe] is progressing with production," says Lafontan. "The first major wing section weighing took place at Airbus France's Nantes plant on 22 August. The results were within 0.4% of that estimated and fell within the acceptable margins for both weight and centre of gravity established by A380 programme management," he says.

In terms of performance, Lafontan says the higher MTOW is likely to result in a 1% increase in operating costs, depending on mission and configuration. But the aircraft will meet all other performance goals set for the standard A380, including the ability to reach FL350 (35,000ft) within 370km (200nm) and 30min of brake release.

The aircraft will still comply with the QC2 departure noise limits at London Heathrow. Lafontan says while the standard 70,000lb-thrust (310kN) engines do not need to have an increased rating for performance reasons (the higher weight adds around 120m [390ft] to the take-off run), a 72,000lb-thrust rating gives better climb performance than the baseline aircraft, and reduces the noise footprint.

Source: Flight International