Boeing has begun modifying two 787 Dreamliners as it pushes toward meeting its goal of flying the aircraft by the end of 2009.

The company's first 787 to fly, ZA001, along with the static test airframe, ZY997, are currently undergoing modification to return full static strength to the upper stringers of the structure that joins the wing to the side of body of the aircraft.

Boeing says the entire process of preparation, installation and restoration will take about three months, with programme sources indicating that the installation itself will take roughly 30 days to complete.

After the installation is complete, Boeing will have to restore ZA001 to flying condition which includes a thorough aqueous wash to remove any debris accumulated during the work inside the fuel tanks.

Boeing says that to gain access to the area being modified, some systems and access doors were removed and will have to be reinstalled.

Following the completion of the installation, Boeing will first analyse the fix on ZY997 through a series of static tests that will validate the design, ultimately clearing ZA001 for flight.

After being in the shop for three months, ZA001 will go through a "warm up" process by repeating some gauntlet testing and taxi testing to prepare the 787 for it's maiden flight, says Boeing.

The company announced 23 June that it had discovered that the upper stringers of the wing to body join were not strong enough to meet FAA certification requirements for static strength, curtailing plans to achieve first flight by the close of the second quarter.

Source: Air Transport Intelligence news