(Sorry, Mods - I see this has already appeared in another thread!)
From Flight Global - link below
Boeing again faces a manufacturing quality issue, requiring inspections and repairs of its 787 fleet.
Structural stiffeners were found to be improperly joined to the composite skin in the aft sections of the aircraft, causing parts of the aircraft's carbon fibre structure to delaminate, confirms the airframer.
"Boeing has found that incorrect shimming was performed on support structure on the aft fuselage on certain airplanes in our facility in Everett, [Washington]," said the airframer.
I believe that large structural use of carbon fibre in civil aviation is new. Let's hope the Dreamliner doesn't fall to earth.