Boeing's much-delayed 787 Dreamliner has hit another production problem.
Hairline cracks have been discovered in the wings of some 787s that are being built. The Chicago-based manufacturer said none of the 122 jets already flown by airlines around the world is affected.
"We are confident that the condition does not exist in the in-service fleet," Boeing spokesman Doug Alder said.
"We understand the issue, what must be done to correct it and are completing inspections of potentially affected aeroplanes."
Boeing said that roughly 40 aeroplanes might be affected and that it will take one to two weeks to inspect each plane and fix any cracks found on shear ties on a wing rib.