Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 787-8 airplanes. This proposed AD was prompted by reports of degraded bond-line performance of co-bonded upper wing stringer-to-skin joints. This proposed AD would require repetitive inspections of certain upper wing stringers for any disbond and corrective actions, if necessary; and a terminating preventative modification of installing disbond arrestment (DBA) fasteners. This proposed AD would also require revising the inspection or maintenance program to incorporate an airworthiness limitation. We are proposing this AD to address the unsafe condition on these products.