Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2023-23-12, Amendment 39-22614 (88 FR 85836, December 11, 2023) (AD 2023-23-12). AD 2023-23-12 applied to all CFM Model LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 engines. The NPRM was published in the Federal Register on April 15, 2025 (90 FR 15670). The NPRM was prompted by a manufacturer investigation that revealed that certain HPT rotor stage 1 disks and a certain compressor rotor stages 6-10 spool were manufactured from material suspected to have reduced material properties due to iron inclusion. Since the FAA issued AD 2023-23-12, the manufacturer has identified additional parts that were manufactured from material suspected to have reduced material properties due to iron inclusion, which prompted this AD. In the NPRM, the FAA proposed to continue to require replacement of certain HPT rotor stage 1 disks and a certain compressor rotor stages 6-10 spool. In the NPRM, the FAA also proposed to expand the applicability to include additional affected HPT rotor stage 1 disks that were manufactured from the same material suspected to have reduced material properties due to iron inclusion. The FAA is issuing this AD to address the unsafe condition on these products. Discussion of Final Airworthiness Directive Comments The FAA received comments from three commenters. Commenters included the Air Line Pilots Association, International (ALPA), ProTech Aero Services Limited (ProTech), and United Airlines. ALPA and ProTech supported the NPRM without change. United Airlines had no comments or objections to the NPRM. Conclusion The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting the 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. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed CFM Service Bulletin (SB) LEAP-1B-72-00-0402-01A-930A-D, Issue 001, dated January 23, 2024. This material specifies the part numbers and serial numbers of additional affected HPT rotor stage 1 disks and includes procedures for replacement of HPT rotor stage 1 disks. The FAA also reviewed CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002, dated September 5, 2023, which the Director of the Federal Register approved for incorporation by reference as of January 16, 2024 (88 FR 85836, December 11, 2023). 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. Costs of Compliance The FAA estimates that this AD affects 51 engines installed on airplanes of U.S. registry. These 51 engines require replacement of the HPT stage 1 disk. The FAA estimates that there are no engines installed on airplanes of U.S. registry that require replacement of the compressor rotor stages 6-10 spool. The FAA estimates the following costs to comply with this AD: Estimated Costs Action Labor cost Parts cost Cost per product Cost on U.S. operators Replace HPT rotor stage 1 disk 8 work-hours × $85 per hour = $680 $215,635 (pro-rated) $216,315 $11,032,065 Replace compressor rotor stages 6-10 spool (0 affected US engines) 8 work-hours × $85 per hour = $680 $37,660 (pro-rated) 38,340 0 The new requirements of this AD add no additional economic burden. 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: a. Removing Airworthiness Directive AD 2023-23-12, Amendment 39-22614 (88 FR 85836, December 11, 2023); and b. Adding the following new airworthiness directive: 2025-14-08 CFM International, S.A.: Amendment 39-23086; Docket No. FAA-2025-0621; Project Identifier AD-2024-00796-E. (a) Effective Date This airworthiness directive (AD) is effective August 25, 2025. (b) Affected ADs This AD replaces AD 2023-23-12, Amendment 39-22614 (88 FR 85836, December 11, 2023) (AD 2023-23-12). (c) Applicability This AD applies to CFM International, S.A. (CFM) Model LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 engines. (d) Subject Joint Aircraft System Component (JASC) Code 7230, Turbine Engine Compressor Section; 7250, Turbine Section. (e) Unsafe Condition This AD was prompted by a manufacturer investigation that revealed that certain high-pressure turbine (HPT) rotor stage 1 disks and a certain compressor rotor stages 6-10 spool were manufactured from material suspected to have reduced material properties due to iron inclusion. The FAA is issuing this AD to prevent fracture and subsequent uncontained failure of certain HPT rotor stage 1 disks and a certain compressor rotor stages 6-10 spool. The unsafe condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the aircraft. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Retained Required Actions (1) For engines with an installed HPT rotor stage 1 disk having a part number (P/N) and serial number (S/N) identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM Service Bulletin (SB) LEAP-1B-72-00-0392-01A-930A-D, Issue 002, dated September 5, 2023 (CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002): At the next piece-part exposure of the HPT rotor stage 1 disk, or before exceeding the applicable cycles since new (CSN) threshold identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002, whichever occurs first after January 16, 2024 (the effective date of AD 2023-23-12); or if the applicable CSN threshold has been exceeded as of January 16, 2024 (the effective date of AD 2023-23-12), within 50 flight cycles (FCs) from January 16, 2024 (the effective date of AD 2023-23-12); remove the HPT rotor stage 1 disk from service and replace with a part eligible for installation. (2) For engines with an installed compressor rotor stages 6-10 spool having a P/N and S/N identified in Compliance, paragraph 3.E., Table 3, of CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002: At the next piece-part exposure of the compressor rotor stages 6-10 spool, or before exceeding the applicable CSN threshold identified in Compliance, paragraph 3.E., Table 3, of CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002, whichever occurs first after January 16, 2024 (the effective date of AD 2023-23-12); or if the applicable CSN threshold has been exceeded as of January 16, 2024 (the effective date of AD 2023-23-12), within 50 FCs from January 16, 2024 (the effective date of AD 2023-23-12); remove the compressor rotor stages 6-10 spool from service and replace with a part eligible for installation. (h) New Required Actions For engines with an installed HPT rotor stage 1 disk having a P/N and S/N identified in Compliance, paragraph 3.E., Table 1, of CFM SB LEAP-1B-72-00-0402-01A-930A-D, Issue 001, dated January 23, 2024 (CFM SB LEAP-1B-72-00-0402-01A-930A-D, Issue 001): At the next piece-part exposure of the HPT rotor stage 1 disk, or before exceeding the applicable CSN threshold identified in Compliance, paragraph 3.E., Table 1, of CFM SB LEAP-1B-72-00-0402-01A-930A-D, Issue 001, whichever occurs first after the effective date of this AD; or if the applicable CSN threshold has been exceeded as of the effective date of this AD, within 50 FCs from the effective date of this AD; remove the HPT rotor stage 1 disk from service and replace with a part eligible for installation. (i) Retained Definition, With Updated Service Information Reference For the purpose of this AD, a "part eligible for installation" is an HPT rotor stage 1 disk or compressor rotor stages 6-10 spool that does not have a P/N and S/N identified in Compliance, paragraph 3.E., Tables 1 through 3, of CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002; or Compliance, paragraph 3.E., Table 1, of CFM SB LEAP-1B-72-00-0402-01A-930A-D, Issue 001. (j) Retained Installation Prohibition, With Updated Service Information Reference After the effective date of this AD, do not install an HPT rotor stage 1 disk or compressor rotor stages 6-10 spool that has a P/N and S/N identified in Compliance, paragraph 3.E., Tables 1 through 3, of CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002; or Compliance, paragraph 3.E., Table 1, of CFM SB LEAP-1B-72-00-0402-01A-930A-D, Issue 001, on any engine. (k) Retained Credit for Previous Actions This paragraph provides credit for the actions required by paragraph (g) of this AD, if those actions were performed prior to January 16, 2024 (the effective date of AD 2023-23-12) by following the Accomplishment Instructions specified in CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 001, dated March 7, 2023. (l) 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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of the AIR-520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (m)(1) of this AD and email to: AMOC@faa.gov. (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. (m) Additional Information (1) For more information about this AD, contact Mehdi Lamnyi, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7743; email: mehdi.lamnyi@faa.gov. (2) Service material identified in this AD that is not incorporated by reference is available at the addresses specified in paragraph (n)(5) of this AD. (n) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) 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. (3) The following material was approved for IBR on [DATE 35 DAYS AFTER PUBLICATION OF THE FINAL RULE]. (i) CFM International, S.A. (CFM) Service Bulletin (SB) LEAP-1B-72-00-0402-01A-930A-D, Issue 001, dated January 23, 2024. (ii) [Reserved] (4) The following material was approved for IBR on January 16, 2024 (88 FR 85836, December 11, 2023). (i) CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 002, dated September 5, 2023. (ii) [Reserved] (5) For CFM material identified in this AD, contact CFM International, S.A., GE Aviation Fleet Support, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45215; phone: (877) 432-3272; email: aviation.fleetsupport@ge.com. (6) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1200 District Avenue, Burlington, MA 01803. For information on the availability of this material at the FAA, call (817) 222-5110. (7) 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 July 9, 2025. Peter A. White, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.