A final FAA airworthiness directive, AD 2026-22-05, requires operators of certain Boeing 787-8/-9/-10 airplanes to inspect and adhesion-test production sealant installations in the center wing fuel tank that never received their required checks. About 60 U.S.-registered 787s are in scope. FLEX AI™ does not inspect sealant, and it does not replace this AD or any check in it.
Sixty U.S.-registered Boeing 787s need a second look at fuel tank sealant that has no record of its required checks. The sealant may be fine. The record cannot show it. And that gap now costs hangar time the same way a confirmed defect would.
On November 2, 2026, the Federal Register published a final Federal Aviation Administration airworthiness directive, AD 2026-22-05, for certain The Boeing Company Model 787-8, 787-9 and 787-10 airplanes. The rule takes effect December 7, 2026.
According to the FAA, the directive was prompted by a report that, during production, certain sealant installations within the center wing fuel tank did not receive the required visual and adhesion inspections. Nobody can show those installations were checked the way the manufacturing process required, so the fleet now has to check them in service.
The unsafe condition is not a crack finding or a leak report. It is the potential for sealant defects. If not addressed, the FAA says, that condition could result in development of an ignition source within the fuel tank volume and a risk of a fuel tank explosion during a lightning strike.
The sealant may be good. The record cannot show it. A gap in the record costs hangar time just like a defect does.
The final rule (Federal Register Doc. 2026-22318; Docket No. FAA-2026-1322; Project Identifier AD-2025-01665-T; Amendment 39-23507; RIN 2120-AA64) follows a notice of proposed rulemaking published on February 24, 2026. It applies to airplanes identified in Boeing Alert Requirements Bulletin B787-81205-SB570053-00 RB, Issue 001, dated November 5, 2025, which the rule incorporates by reference.
In plain terms, operators must:
The work is structural access work inside a fuel tank. It is not a paperwork exercise you can finish from a desk, even though the reason for the rule began with a production inspection record that was never completed.
The FAA estimates that the AD affects 60 airplanes of U.S. registry. The detailed inspection and adhesion test are estimated at 34 work-hours at $85 per hour, or $2,890 per airplane and $173,400 across U.S. operators. Parts for the inspection itself are estimated at $0. The FAA has no definitive data on which to base the cost of on-condition repairs. According to the manufacturer, some or all of the costs of the AD may be covered under warranty.
By commercial widebody standards, $2,890 per airplane for the check itself is modest. The larger cost is the one operators already know how to count: tank access, scheduled downtime, and the cascade that starts when an on-condition repair turns a planned visit into a longer one.
ALPA, United Airlines and an individual supported the NPRM without change. American Airlines, Boeing and the Foundation for Aviation Safety added comments on repairs, exceptions and the clarity of the inspection area in the service information. The FAA revised the final rule in places, including how sealant installation repairs are handled relative to applicable airworthiness limitations, and left other requests where they stood.
None of that changes the core of the rule. The production step was missed or not recorded. The in-service fleet now has to prove the installations are acceptable. Support without change from operators and ALPA is a useful signal that the industry saw the same gap the FAA did.
Here is the part that stays with me. This directive is not about a part that failed in service. It is about work that was supposed to leave a record and did not. The airplane may be carrying good sealant. The manufacturer and the operator still have to spend hangar time recovering confidence that should have been banked on the production line.
Aviation is very good at acting on findings. It is also very good at acting on the absence of proof. When the record cannot show that a required check was done, the safe answer is to do the check again. That is not bureaucracy. That is how a system that cannot afford ignition sources inside a fuel tank behaves when the evidence is incomplete.
The cost of missing evidence looks a lot like the cost of a defect: access, labor, schedule disruption and, if anything is found, repair. The difference is that a defect starts with something wrong on the airplane. Missing evidence starts with something missing in the history.
Production and maintenance records are one kind of history. They tell you what was installed, what was inspected, and what was signed off. Directives like this one exist because that history has to be conclusive. When it is not, the airplane goes back into the hangar.
What the structure lives through between visits is another kind of history, and far less of it gets written down. Loads, temperatures, routes, how hard one airframe is working compared with its sister ships. Between two required checks, all of that is still happening. Most of it never becomes a record anyone can hand to engineering the next time a question arrives.
This AD is about the first kind of history. The broader lesson for operators is that incomplete history is expensive whether the gap is a missed production inspection or a blank stretch between scheduled visits.
787 operators are used to tank work, AD planning and the discipline of proving configuration and inspection status from records before anyone opens a panel. Many will line this directive up against existing heavy visits so the side-of-body access is not a one-off. Warranty conversations with the manufacturer will matter for both the inspection labor and any on-condition repair. That kind of planning is what keeps a fleet safe and a schedule intact, and no sensor replaces it.
FLEX AI™, from Platinum Eagle Aerospace, is built to give structures a measured history between checks, so the people responsible for an airframe have more context when the next question arrives. FLEX AI™ measures strain and temperature today.
To be clear about scope: FLEX AI™ does not inspect sealant. It does not perform adhesion tests. It does not replace AD 2026-22-05 or any check in it, and it does not replace any airworthiness directive. It complements required inspections. It does not replace them.
We are pursuing an FAA STC for FLEX AI™. Platinum Eagle Aerospace is ISO 9001 certified and is working toward AS9100.
How much of your inspection workload is about proving something was done, rather than finding something wrong? I would like to hear how other operators draw that line.
Source: Federal Register, "Airworthiness Directives; The Boeing Company Airplanes," Doc. 2026-22318, published November 2, 2026, effective December 7, 2026 (AD 2026-22-05). This article summarizes a public regulatory document for general information and is not maintenance or compliance guidance. Always follow the AD and the approved manufacturer material.
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