This is the third time the hot-selling airplane has been delayed, an embarrassment that has cast a shadow on the company's credibility.
"I know our credibility is ... being tested on this program, and it is up to us to deliver on what we say we will do," Scott Carson, chief executive of Boeing's Seattle-based commercial airplane division, said in a conference call with analysts.
After a six-month delay announced last October, Boeing had been aiming to start test-flying the new midsize, long-haul plane by the end of March and deliver the first one to Japan's All Nippon Airways Co. by the end of the year.
The new schedule calls for test flights to begin by late June. The company did not say how soon in 2009 it believes it can start delivering the plane, which has won more than 800 orders so far.
One of the first key milestones for the first plane - turning on its power - has been delayed until early in the second quarter, said Pat Shanahan, general manager of the 787 program. After that, it will take two to three months to run all the ground tests needed before the plane can fly.
Carson said the delay will prevent the company from meeting its ambitious goal of delivering 109 planes by the end of next year. He said the company will spend the next few months analyzing the status of the program before specifying how much it is lowering that target.
Boeing has outsourced an unprecedented amount of the 787's design and production to manufacturers scattered across the globe. Workers in the company's widebody assembly plant north of Seattle have had to do a lot of so-called "traveled work" that suppliers were supposed to handle themselves. That problem has become more challenging than others the company has faced, including a shortage of small parts and the tiny fasteners that hold pieces of the plane together.
"We underestimated how long it would take to complete someone else's work," Shanahan said. "We designed our factory to be a lean operation. And the tools and the processes, the flow of material, the skill of the personnel are all tailored to perform last-stage high-level integration, check-out and test.
"We thought we could modify that production system and accommodate the traveled work from our suppliers, and we were wrong."
Boeing has beefed up staffing and dispatched workers to factories throughout its supply chain to get the production problems under control.
Despite the problems, Carson said he remains confident the 787 program is fundamentally sound. "When we have tested the technology and its application to this new family of airplanes, our confidence has only increased," he said.
Analysts have their doubts.
"Boeing is not going to be able to prove they have a handle on this thing until they get the plane into the air and are able to actually begin producing the airplane without any glitches," a point the company won't reach until the end of this year, said Scott Hamilton, managing director of the Seattle-area aerospace consulting group Leeham Companies LLC.
Boeing shares rose $2.14, or nearly 3 percent, to close at $80.00 Wednesday, after slipping about 5 percent the day before following news reports that another delay was imminent. The company's stock has fallen about 20 percent since last July, before the first delay was announced.
It was not immediately clear how many of 787 customers will be affected by the latest delay. Last fall, the company said it was working on revised delivery schedules with about 15 customers. To date, Boeing said 55 have place 817 orders for plane.
Some analysts estimate Boeing faces as much as a few million dollars in penalty payments for every plane that's delivered late.
"This further delay in the delivery of the 787 is extremely regrettable," All Nippon Airways said in a statement e-mailed by company spokesman Damion Martin. "We will work with Boeing on the revised schedule and decide how to proceed from there."
Boeing said the delay's impact on its 2008 earnings guidance is not expected be significant. The company said it would update guidance for the current fiscal year when it reports fourth-quarter 2007 earnings on Jan. 30, and guidance for 2009, the first year it's likely to be hit with substantial penalties, in late April.
Hamilton surmised that because Boeing has won so many orders for the 787, it could take a bigger financial hit than rival Airbus SAS did with its A380 superjumbo, which was delivered to its first customer last fall after nearly two years of delays.
The 787 is Boeing's first newly designed jet since airlines started flying the 777 in 1995. It will be the world's first large commercial airplane made mostly of carbon-fiber composites, which are lighter and more durable than more aluminum and don't corrode like metals.
Boeing has promised it will be more fuel-efficient and cheaper to maintain and offer passenger comforts than comparable planes flying today.