2026-09-12: Fuselage

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: 2026-09-12 The Boeing Company: Amendment 39-23334; Docket No. FAA-2026-1324; Project Identifier AD-2025-00986-T. (a) Effective Date This airworthiness directive (AD) is effective June 17, 2026. (b) Affected ADs None. (c) Applicability This AD applies to The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023. (d) Subject Air Transport Association (ATA) of America Code 53, Fuselage. (e) Unsafe Condition This AD was prompted by a report of cracks found in the fuselage skin underneath the aft drain mast. The FAA is issuing this AD to address cracking or corrosion in the fuselage skin and structure common to the aft drain mast. The unsafe condition, if not addressed, could result in the inability of the principal structural element (PSE) to sustain limit loads, which may result in rapid decompression of the fuselage and loss of structural integrity of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions for Group 1 Airplanes For airplanes identified as Group 1 in Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023: Within 120 days after the effective date of this AD, inspect the fuselage skin and structure common to the aft drain mast for any crack or corrosion and applicable on-condition actions, using a method approved in accordance with the procedures specified in paragraph (k) of this AD. (h) Required Actions for Group 2 Airplanes For airplanes identified as Group 2 in Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023: Except as specified in paragraph (i) of this AD, at the applicable times specified in paragraph 1.E., "Compliance," of Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023, do all applicable actions identified in, and in accordance with, paragraphs 3.B.2., "Action 1: Do Part 2," and 3.B.3., "Action 2: Do Part 3," of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023. (i) Exceptions to Service Bulletin Specifications (1) Where the Compliance Time columns of the tables in the "Compliance" paragraph of Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023, refer to the original issue date of Service Bulletin 737-53A1409, this AD requires using the effective date of this AD. (2) Where Boeing Alert Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023, specifies contacting Boeing for repair instructions: This AD requires doing the repair using a method approved in accordance with the procedures specified in paragraph (k) of this AD. (j) Credit for Previous Actions This paragraph provides credit for the actions specified in paragraphs (g) and (h) of this AD, as applicable, if those actions were performed before the effective date of this AD using Boeing Alert Service Bulletin 737-53A1409, dated May 4, 2023. (k) 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 (l) of this AD. Information may be emailed to: AMOC@faa.gov. 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. (l) Additional Information (1) For more information about this AD, contact Wayne Ha, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 562-627-5238; email: wayne.ha@faa.gov . (2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (m)(3) of this AD. (m) 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 Service Bulletin 737-53A1409, Revision 1, dated October 27, 2023. (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 fr.inspection@nara.gov . Issued on April 28, 2026. Brian Knaup, Acting Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service. [FR Doc. 2026-09535 Filed 5-12-26; 8:45 am]BILLING CODE 4910-13-P