Any weight savings found as Airbus evolves the A350's structural design could be incorporated when the -800 variant arrives, around a year after the service debut of the baseline -900 version in 2013.

Two areas of the A350's design that have held up production of the first aircraft - the carbonfibre fuselage's electrical structural network, which provides a return path for electrical current, and the fuselage's damage tolerance - have been completed to enable construction to begin of A350-900 MSN001.

However, A350 programme chief Didier Evrard says Airbus is validating the electrical structural network and structural design to see if further improvements can be introduced on later aircraft to generate weight savings.

"We have to be conservative in the first place, then [can improve] through validation," he says.

While there is no specific airframe number in the XWB production plan at which a block change could be introduced, Evrard says that there are several "natural points", adding: "We have the first four -900 development aircraft, then we have the last development aircraft and the first deliveries, and then we have the introduction of the A350-800 one year later.

"So if we have opportunities, we would take the -800 introduction as the natural point of embodiment."

Evrard estimates that the first A350-800 would be around "aircraft 20".

Source: Air Transport Intelligence news