Airbus has revealed the first details of the A350 XWB's flight test programme, which will involve five aircraft flying about 3,000h. The airframer intends to begin flight-testing a cabin-equipped aircraft early in the programme to understand the interior's behaviour in the carbonfibre fuselage.

The -900 is the lead A350 variant and final assembly of the first aircraft is due to start in Toulouse by mid-2011, with first flight scheduled to follow "eight to nine months" later in the first quarter of 2012, says A350 programme chief Didier Evrard. Certification and service entry is due to follow a 15-month flight-test programme of about 3,000h, in mid-2013.

"All five aircraft will run in parallel to achieve a short flight test and certification time," says Evrard. "We are planning to put them all into the programme very quickly - within a couple of months."

A350 cabin
 © Airbus

Although 15 months have been allocated to the flight-test programme, Evrard says the exercise could take as little as 12 months.

Two aircraft, No 2 and 5, will be equipped with a cabin, and No 6 will be the first delivered to a customer, he adds.

"With the second aircraft, we want to use it to rehearse our aircraft definition freeze process."

Evrard says No 5 will be used for "early long flight" demonstrations, with simulated passenger flights operated with Airbus staff as passengers, along similar lines to the A380 test programme.

The emphasis on flying the cabin early in the test programme is due to the fact that the A350's carbonfibre fuselage will have "different behaviour" to a conventional metallic aircraft, says Evrard.

Areas to be investigated early in the flight-test programme are cabin noise levels and sound damping, and the satisfactory functioning of the "electrical structure network" developed to conduct current in the carbonfibre fuselage, which is "something you get for free in a metallic aircraft", he adds.

With the A350, Airbus is trying to achieve an unprecedented level of system maturity before first flight by using the digital mock-up and virtual and actual functionality testing.

"Maturity at first flight is one of the challenges, knowing that at this point we will already have a lot of aircraft and components in our factories," says Evrard.

"We aim to reduce the number of modifications needed during flight-testing. This will enable the flying programme to focus on the certification effort."

The rear galley layout, which was the one part of the A350 design not finalised when the detailed definition freeze (dubbed "maturity gate (MG) 5") was reached last December, has now been agreed with customers. "We had proposed a D-shaped galley, but some customers had concerns about the amount of workspace and turnaround time," he adds. "The new design is more of a V shape. It has the number of chilled trolleys they want and customers are happier with the serviceability."

The next key milestone for the A350-900's design effort will be reaching "maturity [level] B" mid-year, following maturity A achieved at MG5 last December.

Meanwhile, development of the smaller A350-800 and -1000 stretch continues in parallel, with the former due to reach MG5 at year end and the latter in April 2011. Service entry of these two variants are due to follow one and two years, respectively, after the A350-900.

Source: Flight International