AD 2023-25-10

This AD is effective February 7, 2024.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of February 7, 2024.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2023-1648; 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 service information identified in this final rule, 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 service information 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-2023-1648.

Tony Koung, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3985; email: Tony.Koung@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 787-8, 787-9, and 787-10 airplanes. The NPRM published in the Federal Register on August 22, 2023 (88 FR 57012). The NPRM was prompted by a reported quality escapement where the seat track fitting nuts were under-torqued on some flight attendant seats in production. In the NPRM, the FAA proposed to require re-torquing each free-standing attendant seat track fitting nut. The FAA is issuing this AD to address under-torqued seat track fitting nuts. The unsafe condition, if not addressed, could result in the forward-facing flight attendant seats breaking free in a high load event, causing injury to flight attendants and blocking the exits during emergency egress.

The FAA received comments from Boeing and United Airlines who supported the NPRM without change.

The FAA received additional comments from American Airlines (AAL). The following presents the comments received on the NPRM and the FAA's response to each comment.

AAL requested that the FAA increases the work-hour estimate provided in the Costs of Compliance section of the proposed AD to 3 hours.

The FAA agrees with the commenter's request. The FAA has revised the Costs of Compliance section of this AD accordingly.

AAL requested the compliance time for the actions (re-torquing each free-standing attendant seat track fitting nut) be revised to one year after the effective date of this AD. AAL noted that a one-year compliance time would provide flexibility and allow the task to be accomplished during the A-checks within the AAL maintenance program. AAL also noted it has accomplished maintenance review board (MRB) task 25-146-00 on 85% of its affected airplanes with zero reports of findings. AAL stated the MRB task specifies to verify the seat track fittings are fully installed and cannot be moved manually and to correctly torque the seat track fitting if it is not tight. However, AAL acknowledged that MRB task 25-146-00 does not require a torque check. AAL stated that a one-year compliance window is a reasonable compliance time and will maintain the desired level of safety.

The FAA does not agree with the commenter's request to revise the compliance time from six months to one year. The FAA does not base compliance intervals on nonspecific intervals such as an A-check as those intervals are operator specific. Further, MRB task 25-146-00 does not check any torques of any of the fitting nuts that are identified in Boeing Service Letter 787-SL-25-025, dated September 6, 2022, which is the appropriate source of service information for accomplishing the re-torquing of each free-standing attendant seat track fitting nut required by this AD. The MRB task only checks for looseness of the fitting, which means the seat jumped the tracks. For the MRB task, if the seat did not move and the fitting was in the track, no actual checking of the nut torque was accomplished; therefore, the seat track fitting nut still needs to be re-torqued. The FAA has determined that accomplishing the re-torquing of each free-standing attendant seat track fitting nut within 6 months after the effective date of this AD is necessary to address the identified unsafe condition. Therefore, the FAA has not changed this AD in this regard.

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, and any other changes described previously, 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 Service Letter 787-SL-25-025, dated September 6, 2022. This service information specifies procedures for re-torquing each free-standing attendant seat track fitting nut to 140-150 in-lbs. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in ADDRESSES.

The FAA estimates that this AD affects 134 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some or all 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: