A Sealant Gap Has 60 US Dreamliners Headed for Inspection

The Federal Aviation Administration has ordered inspections of certain Boeing 787 Dreamliners over concerns that defective sealant inside the fuel tanks could create a spark during a lightning strike. The airworthiness directive was published in the Federal Register on November 2 and takes effect on December 7. It covers specific 787-8, 787-9 and 787-10 aircraft identified by Boeing.

According to the FAA, the problem traces back to manufacturing. Sealant in the center wing fuel tanks of some jets may not have received the required visual and adhesion inspections, and Boeing could not produce records confirming the checks were done. If an ignition source developed, the agency warns, a lightning strike could in theory lead to a fuel tank explosion, although Boeing says the 787 has several other layers of lightning protection.

Sixty US-registered aircraft fall under the order. United operates 97 Dreamliners, American 70 and Alaska six, and some foreign carriers fly under US registration too, so the worldwide total could be higher if other regulators follow. Operators must check the sealant where the wings meet the fuselage on the left, right and center sections, run adhesion tests and repair anything defective.

The FAA estimates 34 work-hours and about $2,890 per aircraft, or $173,400 across the 60 jets, not counting repairs, and Boeing has indicated some costs may fall under warranty. Lightning strikes hit commercial aircraft routinely and modern designs are tested to resist them, so this is a maintenance directive rather than a grounding. It is, however, the latest in a string of 2026 FAA actions on 787 production issues.

Sources: Simple Flying