2026-21-08: Wings

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2026-21-08 The Boeing Company: Amendment 39-23497; Docket No. FAA-2026-2725; Project Identifier AD-2025-00999-T. (a) Effective Date This airworthiness directive (AD) is effective December 1, 2026. (b) Affected ADs None. (c) Applicability This AD applies to The Boeing Company Model 737-700, -700C, -800, and -900ER series airplanes, certificated in any category, as identified in Boeing Alert Requirements Bulletin 737-57A1359 RB, Revision 1, dated June 25, 2026. (d) Subject Air Transport Association (ATA) of America Code 57, Wings. (e) Unsafe Condition This AD was prompted by a leak through the form-in-place (FiP) gasket at the engine fuel shutoff valve access panel found during a leak check. An investigation found that the fairing requirements of the engine fuel shutoff valve access panel caused thin regions of the FiP gasket, which caused non-permitted sealant to be applied after the initial FiP gasket had cured, resulting in an uneven sealing surface on the engine fuel shutoff valve access panel and leak. The FAA is issuing this AD to address incorrect or missing sealant installation. The unsafe condition, if not addressed, could result in fuel leaking onto the engine exhaust nozzle and a possible fire on the ground. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions Except as specified by paragraph (h) of this AD: At the applicable times specified in the "Compliance" paragraph of Boeing Alert Requirements Bulletin 737-57A1359 RB, Revision 1, dated June 25, 2026, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 737-57A1359 RB, Revision 1, dated June 25, 2026. Note 1 to paragraph (g): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 737-57A1359, Revision 1, dated June 25, 2026, which is referred to in Boeing Alert Requirements Bulletin 737-57A1359 RB, Revision 1, dated June 25, 2026. (h) Exceptions to Requirements Bulletin Specifications Where the Compliance Time columns of the tables in the "Compliance" paragraph of Boeing Alert Requirements Bulletin 737-57A1359 RB, Revision 1, dated June 25, 2026, refer to the original issue date of Requirements Bulletin 737-57A1359 RB, this AD requires using the effective date of this AD. (i) Credit for Previous Actions This paragraph provides credit for the actions specified in paragraph (g) of this AD, if those actions were performed before the effective date of this AD using Boeing Alert Requirements Bulletin 737-57A1359 RB, dated October 3, 2025, except as specified by paragraphs (i)(1) through (3) of this AD: (1) Where Table 1 and Table 2 in the Compliance and Accomplishment Instructions paragraphs of Boeing Alert Requirements Bulletin 737-57A1359 RB, dated October 3, 2025, specifies "Do a fluid leak test of the engine fuel shutoff valve access panel for any leak. If any leak is found, do all applicable on-condition corrective action(s) and repeat the leak test until no leak is found", this AD requires replacing that text with "Do a fluid leak test of the engine fuel shutoff valve access panel for any leak. If any leak is found, replace the FiP gasket and repeat the leak test until no leak is found". (2) Where step 4.b. of Appendix A in Boeing Alert Requirements Bulletin 737-57A1359 RB, dated October 3, 2025, specifies "If any water leaks from the engine fuel shutoff valve access panel in less than two minutes, the fluid leak test has failed", this AD requires replacing that text with "If any water leaks from the engine fuel shutoff valve access panel in less than two minutes, the fluid leak test has failed. Replace the FiP gasket in accordance with Figure 3 and repeat the leak test until no leak is found". (3) Where step 4.b. of Appendix B in Boeing Alert Requirements Bulletin 737-57A1359 RB, dated October 3, 2025, specifies "If any water leaks from the engine fuel shutoff valve access panel in less than two minutes, the fluid leak test has failed", this AD requires replacing that text with "If any water leaks from the engine fuel shutoff valve access panel in less than two minutes, the fluid leak test has failed. Replace the FiP gasket in accordance with Figure 4 and repeat the leak test until no leak is found". (j) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520, Continued Operational Safety Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or responsible Flight Standards Office, as appropriate. If sending information directly to the manager of the Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k)(1) of this AD. Information may be emailed to: [email protected]. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards Office. (2) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by The Boeing Company Organization Designation Authorization (ODA) that has been authorized by the Manager, AIR-520, Continued Operational Safety Branch, FAA, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane, and the approval must specifically refer to this AD. (k) Additional Information (1) For more information about this AD, contact Erica Bayles, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 907-271-5844; email: [email protected]. (2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (l)(3) of this AD. (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise. (i) Boeing Alert Requirements Bulletin 737-57A1359 RB, Revision 1, dated June 25, 2026. (ii) [Reserved] (3) 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. (4) 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. (5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected]. Issued on October 20, 2026. Lona C. Saccomando, Acting Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2026-21862 Filed 10-26-26; 8:45 am]BILLING CODE 4910-13-P