AD 2026-13-03

This AD is effective August 6, 2026.

The Director of the Federal Register approved the incorporation by reference of a certain publications listed in this AD as of August 6, 2026.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2025-4000; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

Material Incorporated by Reference:

• For Boeing material identified in this AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110 SK57, Seal Beach, CA 90740-5600; telephone 562 797 1717; website myboeingfleet.com.

• You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. It is also available at regulations.gov under Docket No. FAA-2025-4000.

Taylor Stanley, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 407-852-7677; email: taylor.stanley@faa.gov.

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 747-8F series airplanes. The NPRM was published in the Federal Register on November 17, 2025 (90 FR 51227). The NPRM was prompted by reports of cracking in stringers and splice fittings located at stringer splices at multiple body stations. In the NPRM, the FAA proposed to require an inspection of each free flange of the stringers at the stringer splice for radius fillers at certain fastener locations, an inspection for cracking of the stringers and stringer splice fittings at certain stringer splice locations, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products.

The FAA received comments from an individual who supported the NPRM without change.

The FAA also received comments from the Citizens Rulemaking Alliance. The following presents the comments received on the NPRM and the FAA's response to each comment.

The Citizens Rulemaking Alliance requested that the FAA either provide its justification for finding good cause to bypass notice and comment procedures, or convert this action to an NPRM and bifurcate the urgent and non-urgent elements. The commenter asserted the FAA has not adequately justified use of the good cause exemption to bypass notice and comment and the 30-day delayed effective date.

The FAA notes the comment was submitted in response to an NPRM for which the FAA provided a 45-day comment period. This final rule is effective 35 days after its publication in the Federal Register. Therefore, no change to this AD is necessary.

The Citizens Rulemaking Alliance requested that the FAA make IBR material available and free to the public during the comment period and add the IBR materials to the AD docket.

In the preamble of the NPRM, the FAA notified the public that the IBR material would be available for review under Docket No. FAA-2025-4000 at regulations.gov. This material was posted to the AD docket on November 19, 2025. Therefore, no change to this AD is necessary.

The Citizens Rulemaking Alliance requested that the FAA revise the AD to comply with the PRA. If reporting is not required, the commenter requested the FAA clarify that in the AD.

The FAA notes this AD does not require reporting. If an AD were to require reporting, the preamble of the AD would include a paragraph titled “Paperwork Reduction Act” that would provide the applicable OMB control number, required PRA statements, and the estimated time to collect the required information (burden). Any costs associated with the reporting requirement would be included in the Costs of Compliance section in the preamble of the AD. Therefore, the FAA did not change this AD as a result of this comment.

The Citizens Rulemaking Alliance requested that the FAA either prepare an initial regulatory flexibility analysis, or provide the factual basis for its conclusion that the AD will not have a significant economic impact on a substantial number of small entities.

The FAA identified two carriers affected by this AD. Based on the Small Business Administration (SBA) size standard shown in the table below, both entities are classified as large businesses.

Under section 605(b) of the Regulatory Flexibility Act (RFA), if an agency determines that a rulemaking will not result in a significant economic impact on a substantial number of small entities, the head of the agency may certify. Therefore, as provided in section 605(b) and based on the foregoing, the head of FAA certifies that this AD will not result in a significant economic impact on a substantial number of small entities. The FAA did not change this AD as a result of this comment.

The Citizens Rulemaking Alliance requested that the FAA supplement the economic analysis to reflect realistic costs for parts, labor, airplane downtime, and repetitive action costs and confirm the AD is not significant under Executive Order 12866. The commenter stated that the FAA omitted indirect costs such as airplane downtime, repetitive actions, engineering development of alternative methods of compliance, supply chain constraints, and training and operational disruptions. The commenter also stated that the AD should specify whether the Unfunded Mandates Reform Act (UMRA) threshold is met.

The FAA notes that in preamble of the proposed AD, the FAA certified that this regulation is not a “significant regulatory action” under Executive Order 12866, which means, in part, that the regulation will not have an annual effect on the economy of $100 million or more. Further, in the Costs of Compliance section of the proposed AD, the FAA disclosed that the required inspections are estimated to cost U.S. operators up to $344,080, per airplane. The repetitive inspections are estimated to cost $85 per inspection area, every 48 or 96 months, depending on findings.

The FAA recognizes that, in doing the actions required by an AD, operators might incur indirect costs in addition to the direct costs. The cost analysis in an AD typically does not include indirect costs since the FAA lacks data on those costs, and they vary significantly among operators. Since the FAA has assessed and disclosed all known costs of the AD requirements in the Costs of Compliance section of the proposed AD, and the commenter did not provide additional cost data for the FAA to consider in its cost analysis, the FAA determined that the existing analysis is complete. Based upon the analysis provided throughout the proposed AD and in the previous comment response, the FAA certifies that this AD is not a “significant regulatory action” under Executive Order 12866. The FAA did not change this AD as a result of this comment.

The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

The FAA reviewed Boeing Alert Requirements Bulletin 747-53A2907 RB, Revision 1, dated March 14, 2025. This material specifies procedures for an inspection of each free flange of the stringers at the stringer splice for radius fillers at the fastener locations, a detailed inspection for cracking of the stringers and stringer splice fittings at certain stringer splice locations, and applicable on-condition actions. On-condition actions include detailed inspections for cracking or radius fillers, removal or installation of radius fillers, and contacting Boeing for repair instructions and doing the repair ( i.e., replacement of a cracked splice channel).

This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

The FAA estimates that this AD affects 11 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary on-condition actions that would be required based on the results of the inspection. The agency has no way of determining the number of aircraft that might need these actions:

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

2026-13-03—Boeing Company: Amendment 39-23385; Docket No. FAA-2025-4000; Project Identifier AD-2025-00440-T.