(…) However, Boeing confirmed that none of the 123 Dreamliners delivered to date are affected by the wing crack, the report said. The defect was attributed to the fasteners used to connect aluminum shear ties on the wing ribs to the carbon fiber composite wing panel, which were over-tightened without the use of manufacturing fillers, compressing a gap in the structure and in some cases causing hairline cracks of less than an inch. (…)
via WSJ: Boeing To Inspect Wings Of 43 Undelivered 787 Dreamliners For Cracks.