Airbus will have to compress the original 15-month flight-test program planned for the A350-900 into a 12-month exercise to accommodate an extension of the program's detailed design phase. The flight test program will involve five airplanes-all but one of which will fly in 2012, according to the company. Plans to deliver the first A350-900 in the middle of 2013 remain unchanged, despite the fact it now has scheduled final assembly to start several months later than last planned. 

Additional design activity associated with aircraft sizing, the wing root joint, the fuselage electric structural network and fuselage damage tolerance has depleted three months' worth of the “buffer” built into the schedule, according to the program update issued by the company on April 19. However, the timing of systems, cabin and powerplant development hasn't changed, said the company.

“There is no 'delay' overall to the A350XWB program,” insisted an Airbus spokesman. “It is true there are changes to the flight-test schedule, but the EIS target remains the same-mid-2013.”

“From the start we built in the buffers, and a 15-month flight-test program was very, very generous,” he added. “So we are still very good now with 'only' 12 months.”