Continuing “challenges” involving the assembly of the first Boeing 787 prototype have forced the company to delay first flight and certification by at least six months, Boeing said today. It now expects to fly the airplane for the first time by the end of next year’s first quarter and start deliveries in either late November or December 2008.

“While we have made some progress over the past several weeks completing work on our early production airplanes and improving parts availability across the production system, the pace of that progress has not been sufficient to support our previous plans for first delivery or first flight,” said Boeing Commercial Airplanes president and CEO Scott Carson. “We deeply regret the impact these delays will have on our customers, and we are committed to working with them to minimize any disruption to their plans.”

Today’s announcement marked the second delay of the 787’s first flight. In early September Boeing moved back first flight by some three months due to parts shortages, delays in coding flight control software and completion of so-called traveled work–tasks originally meant for partners but passed on to Boeing’s final assembly facility in Everett, Wash. At the time, however, Carson said that the revised schedules still supported plans to deliver the first production airplane to All Nippon Airways next May.

According to Boeing, the new schedule for first flight and delivery “addresses the production challenges and restores margin for the program to deal with issues that may be uncovered in final ground or flight testing.” Boeing also said today that flight control software and systems integration activities “are not pacing items” in the revised schedule.