Summary
We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 787-8 and 787-9 airplanes. This proposed AD was prompted by a report indicating that a portion of the sealant above the engine pylon between the wing skin and the vapor barrier may have been omitted. This proposed AD would require an inspection for missing sealant in the seam on the outside and inside of the engine struts, and corrective actions if necessary. We are proposing this AD to detect and correct missing sealant above the engine pylon between the wing skin and the vapor barrier, which can create an unintended leak path for fuel, potentially draining onto the aft fairing heat shield above the engine and onto hot engine parts or brakes, which could lead to a major ground fire.