The US Federal Aviation Administration has issued a final airworthiness directive requiring inspections of sealant installations in the fuel-tank areas of certain Boeing 787-8, 787-9 and 787-10 aircraft. It estimates that 60 US-registered aircraft are affected. The directive takes effect on 7 December 2026; the aircraft covered and compliance deadlines are specified in a Boeing requirements bulletin, so the action does not apply to the entire 787 fleet.
Some sealant installations in the centre wing fuel-tank area did not receive required visual and adhesion inspections during production. The FAA identifies a potential safety risk: defective sealant could provide an ignition source inside a tank and lead to an explosion in the event of a lightning strike.
Operators must conduct detailed inspections of specified sealant installations in the left, right and centre wing side-of-body areas, test adhesion and complete any required corrective actions. Some repairs may need an FAA-approved method. The directive’s inspection intervals are set out in the referenced Boeing bulletin.
The FAA estimates 34 work-hours and $2,890 per aircraft for inspection and adhesion testing, or $173,400 across the affected US-registered fleet. It has not provided a definitive estimate for repair costs.