Boeing announced today that it has postponed first flight of the 787 Dreamliner once again, this time due to a need to reinforce areas within the side-of-body sections of the aircraft. Last due to fly by the end of this month, the 787 remains grounded nearly two years after its July 8, 2007, rollout ceremony.
Boeing said it identified the need to delay the first flight following detailed analysis of regularly scheduled tests on the full-scale static test airplane. However, Boeing Commercial Airplanes vice president of airplane programs Pat Shanahan conceded that the problem, involving several small areas of unexpected stress along the upper part of the wing-to-body joints, became apparent late last month, during a series of wing-bending tests.
“During one test the team identified stress in an area of the side-of-body structure that was in excess of expectations,” said Shanahan. “Our preliminary analysis of these results indicated that we could proceed with first flight. After further testing and analysis, which we finished late last week, our team concluded that a productive flight test program could not take place without structural reinforcement in limited areas within the side-of-body joint.”
Asked why it took until today to finally reveal a problem that Boeing discovered as early as a month ago, Boeing Commercial Airplanes CEO Scott Carson said the company hoped that it could fly the airplane while it worked on a solution, but that it didn’t reach the conclusion that it couldn’t perform productive flight tests until late last week.
“When we were at Paris last week we had been through the preliminary analysis of the data and were of a mind that the airplane could enter flight test with a credible flight test envelope,” said Carson. “The work done by the team through last week narrowed the envelope to the point where on Friday we determined that to fly would be such a small envelope for us that it would be an interesting exercise in having the airplane in the air but not particularly useful in terms of preparing the airplane for certification.”
Shanahan specifically stressed that the likely solution will involve a structural reinforcement, and that materials or workmanship played no part in the problem. “Composites are the right choice for airplane structure,” insisted Shanahan, who added that wing component maker Mitsubishi, side-structure supplier Fuji and Boeing will all participate in the design of the reinforcements.
BCA’s vice president and general manager of the 787 program, Scott Fancher, explained that the areas in question involve 18 one- to two-square-inch stress points on each side of the airplane, where multiple materials, including titanium, composites and aluminum, reside.
“The exact number may change a little bit as we analyze it, but that’s approximately the number,” Fancher said. “And I really want to emphasize…this is not a problem that extends out the wings or down the aircraft. It is a very limited area that needs structural reinforcement. We’re talking about a handful of parts in each location and each one of those parts you can literally hold in your hand. So it’s not complicated by any means.” Fancher also said the modification would result in a “negligible” increase in the weight of the airplane.
Nevertheless, Boeing said it could take several weeks before it publicizes a new schedule for first flight and delivery, because it hasn’t yet determined the exact fix. Meanwhile, it said, the 787 team will continue ground testing on Z001, including final “gauntlet” testing and low-speed taxi runs. It will also continue to work on the other five flight test aircraft and the subsequent airframes in the production system.
“We understand the nature of the fix–and I would say the nature–not the specifics of the fix yet, because we have to complete the models, run those models and then test the solution,” Carson said. He added that he had begun the process of talking to customers late last night about the potential effects to the delivery schedules.
“We’ve talked to a substantial number,” said Carson. “I think all of them respected the process with which we are working and respected our judgment that we should fix this and make it right as we worked through the flight test program. Obviously, they will be monitoring our progress, but most importantly they’re interested in the final delivered product and the integrity of the product and we’re going to keep them well informed as we walk through this.”