Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Airbus SAS Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes. The NPRM published in the Federal Register on September 6, 2023 (88 FR 60908). The NPRM was prompted by AD 2023-0074, dated April 5, 2023, issued by EASA, which is the Technical Agent for the Member States of the European Union (EASA AD 2023-0074) (also referred to as the MCAI). The MCAI states that stress analysis results from A321 XLR certification and fatigue and damage tolerance harmonization have revealed that cracks may appear in the center wing box at frame 42 and slanted junction areas of the affected airplanes. Cracks may appear due to the high fatigue stress in affected areas. In the NPRM, the FAA proposed to require a one-time inspection of the center wing box at frame 42 and slanted junction areas, and applicable corrective actions, if necessary, as specified in EASA AD 2023-0074. The FAA is issuing this AD to detect potential cracks in the center wing box at frame 42 and slanted junction areas. The unsafe condition, if not addressed, could affect the structural integrity of the fuselage. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2023-1815. Discussion of Final Airworthiness Directive Comments The FAA received no comments on the NPRM or on the determination of the cost to the public. Conclusion This product has been approved by the aviation authority of another country and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on this product. 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. Related Service Information Under 1 CFR Part 51 EASA AD 2023-0074 specifies procedures for one-time rototest and high frequency eddy current inspections for cracks of the center wing box rear lower spar junction area at frame 42; a rototest inspection for cracks of the frame 42 slanted beam connection; a detailed visual inspection of certain fasteners for damage; and applicable corrective actions. Corrective actions include obtaining and following instructions for crack repair and replacing damaged fasteners. 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. Interim Action The FAA considers that this AD is an interim action. If final action is later identified, the FAA might consider further rulemaking then. Costs of Compliance The FAA estimates that this AD affects 657 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Costs for Required Actions Labor cost Parts cost Cost per product Cost on U.S. operators Up to 25 work-hours × $85 per hour = Up to $2,125 * $0 Up to $2,125 Up to $1,396,125. * Additional work will be required if repairs are needed. Inspection results will determine extent (time and materials) of repair costs. The FAA has received no definitive data on which to base the cost estimates for the on-condition actions specified in this AD. Paperwork Reduction Act A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a currently valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to take approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524. Authority for This Rulemaking 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. Regulatory Findings 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. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: PART 39-AIRWORTHINESS DIRECTIVES 1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2023-23-04 Airbus SAS: Amendment 39-22606; Docket No. FAA-2023-1815; Project Identifier CAI-2023-00581-T. (a) Effective Date This airworthiness directive (AD) is effective January 16, 2024. (b) Affected ADs None. (c) Applicability This AD applies to all Airbus SAS Model A321-111, -112, -131, -211, -212, -213, -231, and -232 airplanes, certificated in any category. (d) Subject Air Transport Association (ATA) of America Code 57, Wings. (e) Unsafe Condition This AD was prompted by stress analysis results indicating that cracks may appear in the center wing box at frame 42 and slanted junction areas. The FAA is issuing this AD to detect potential cracks in the center wing box at frame 42 and slanted junction areas. The unsafe condition, if not addressed, could affect the structural integrity of the fuselage. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Requirements Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency (EASA) AD 2023-0074, dated April 5, 2023 (EASA AD 2023-0074). (h) Exceptions to EASA AD 2023-0074 (1) Where EASA AD 2023-0074 refers to its effective date, this AD requires using the effective date of this AD. (2) Where EASA AD 2023-0074 specifies to comply with "the instructions of the AOT," this AD requires compliance with the procedures marked as required for compliance (RC) in the Alert Operators Transmission (AOT). (3) This AD does not adopt the "Remarks" section of EASA AD 2023-0074. (4) Where paragraph (3) of EASA AD 2023-0074 specifies to "contact Airbus for approved repair instructions and, within the compliance time specified therein, accomplish those instructions accordingly," for this AD, if any cracking is detected, the cracking must be repaired before further flight using a method approved by the Manager, International Validation Branch, FAA; or EASA; or Airbus SAS's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. (5) Paragraph (4) of EASA AD 2023-0074 specifies to report inspection results to Airbus within a certain compliance time. For this AD, report inspection results at the applicable time specified in paragraph (h)(5)(i) or (ii) of this AD. (i) If the inspection was done on or after the effective date of this AD: Submit the report within 90 days after the inspection. (ii) If the inspection was done before the effective date of this AD: Submit the report within 90 days after the effective date of this AD. (6) Where paragraph (2) of EASA AD 2023-0074 refers to a ferry flight, a special flight permit may be issued in accordance with 14 CFR 21.197 and 21.199 provided the operators comply with the provisions specified in paragraph (2) of EASA AD 2023-0074. (i) Additional AD Provisions The following provisions also apply to this AD: (1) Alternative Methods of Compliance (AMOCs): The Manager, International Validation 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 International Validation Branch, send it to the attention of the person identified in paragraph (j) of this AD. Information may be emailed to: 9-AVS-AIR-730-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) Contacting the Manufacturer: For any requirement in this AD to obtain instructions from a manufacturer, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or EASA; or Airbus SAS's EASA DOA. If approved by the DOA, the approval must include the DOA-authorized signature. (3) Required for Compliance (RC): Except as required by paragraphs (h)(2) and (i)(2) of this AD, if any service information referenced in EASA AD 2023-0074 contains paragraphs that are labeled as RC, the instructions in RC paragraphs, including subparagraphs under an RC paragraph, must be done to comply with this AD; any paragraphs, including subparagraphs under those paragraphs, that are not identified as RC are recommended. The instructions in paragraphs, including subparagraphs under those paragraphs, not identified as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the instructions identified as RC can be done and the airplane can be put back in an airworthy condition. Any substitutions or changes to instructions identified as RC require approval of an AMOC. (j) Additional Information For more information about this AD, contact Tim Dowling, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone 206-231-3667; email: timothy.p.dowling@faa.gov. (k) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this service information as applicable to do the actions required by this AD, unless this AD specifies otherwise. (i) European Union Aviation Safety Agency (EASA) AD 2023-0074, dated April 5, 2023. (ii) [Reserved] (3) For EASA AD 2023-0074, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999 000; email ADs@easa.europa.eu; website easa.europa.eu. You may find this EASA AD on the EASA website at ad.easa.europa.eu. (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 November 9, 2023. Ross Landes, Deputy Director for Regulatory Operations, Compliance & Airworthiness Division, Aircraft Certification Service.