Reported wing flaw in Boeing Dreamliner is more serious
The wing damage that grounded Boeing’s new composite 787 Dreamliner occurred under less stress than previously reported — and is more extensive.
An engineer familiar with the details said the damage happened when the stress on the wings was well below the load the wings must bear to be federally certified to carry passengers.
In addition, information obtained independently and confirmed by a second engineer familiar with the problem shows the damage occurred on both sides of the wing-body join — that is, on the outer wing as well as inside the fuselage.
The structural flaw in the Boeing design was found in May during a ground test that bent the wings upward. Stresses at the ends of the long rods that stiffen the upper wing skin panels caused the fibrous layers of the composite plastic material to delaminate.
The damage at the end of each of the 17 long stiffening rods, called stringers, on each wing’s upper skin happened just beyond the aircraft’s “limit load,” which is the maximum load the wing is expected to bear in service…
Because the wing test fell short of the ultimate load target, the plane could have flown only under restrictions that would have severely limited the usefulness of a test flight.
It also helps explain why Boeing canceled the first flight planned for the end of June.
The fact that there is corresponding damage on the fuselage side of the wing join adds to the complexity of any fix and the time and cost involved in implementing it…
The way the stringers terminate and mate at the join, the focus of the problem, is Boeing’s responsibility and not that of its Japanese partners. Boeing will have to pay for the cost overruns.
The Dreamliner is two years late. Now.
Boeing officials say they will have a new schedule for first flight and delivery in another couple of months. On paper.