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 Department of Transportation Federal Aviation Administration 14 CFR Part 39
[Docket No. FAA-2024-2668; Project Identifier AD-2024-00561-E]
RIN 2120-AA64
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD) 2023-09-06, which applies to all CFM International, S.A. Model (CFM) LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP-1A26, LEAP-1A26CJ, LEAP-1A26E1, LEAP-1A29, LEAP-1A29CJ, LEAP-1A30, LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A (LEAP-1A) engines. AD 2023-09-06 requires replacement of certain high-pressure turbine (HPT) rotor stage 1 disks (HPT stage 1 disks), forward outer seals, and compressor rotor stages 6-10 spools. AD 2023-09-06 also prohibits installation of an HPT stage 1 disk, forward outer seal, or compressor rotor stages 6-10 spool that has a part number and serial number identified in the service information onto any engine. Since the FAA issued AD 2023-09-06, the manufacturer identified additional affected parts that were manufactured from material suspected to have reduced material properties due to iron inclusion, which prompted this AD. This proposed AD would retain the requirements to replace certain HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools and expand the applicability to include additional affected parts manufactured from the same material suspected to have reduced material properties due to iron inclusion. The FAA is proposing this AD to address the unsafe condition on these products.
 DATES: The FAA must receive comments on this proposed AD by February 6, 2025.
 ADDRESSES: You may send comments, using the procedures found in 14 CFR 
                        ( print page 104463)
                        11.43 and 11.45, by any of the following methods: *Federal eRulemaking Portal:*
                         Go to 
                        *regulations.gov.*
                         Follow the instructions for submitting comments.
                    *Fax:*
                         (202) 493-2251.
                    *Mail:*
                         U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
                    *Hand Delivery:*
                         Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. *AD Docket:*
                         You may examine the AD docket at 
                        *regulations.gov*
                         under Docket No. FAA-2024-2668; 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 NPRM, any comments received, and other information. The street address for Docket Operations is listed above. *Material Incorporated by Reference:* For CFM material identified in this proposed AD, contact CFM, GE Aviation Fleet Support, 1 Neumann Way, M/D Room 285, Cincinnati, OH 45215; phone: (877) 432-3272; email:*aviation.fleetsupport@ge.com.*
                    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.
 FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7743; email: 
                        *mehdi.lamnyi@faa.gov.*


SUPPLEMENTARY INFORMATION: Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the 
                    **ADDRESSES**
                     section. Include “Docket No. FAA-2024-2668; Project Identifier AD-2024-00561-E” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may revise this proposal because of those comments. Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to 
                    *regulations.gov*, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. Confidential Business Information CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Mehdi Lamnyi, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking. Background The FAA issued AD 2023-09-06, Amendment 39-22429 (88 FR 32092, May 19, 2023) (AD 2023-09-06), for all CFM Model LEAP-1A engines. AD 2023-09-06 was prompted by a manufacturer investigation that revealed that certain HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools were manufactured from material suspected to have reduced material properties due to iron inclusion. AD 2023-09-06 requires replacement of certain HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools. The agency issued AD 2023-09-06 to prevent fracture and consequent uncontained failure of certain HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools. Actions Since AD 2023-09-06 Was Issued Since the FAA issued AD 2023-09-06, further analysis by the manufacturer identified additional affected parts that were manufactured from material suspected to have reduced material properties due to iron inclusion. This condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the airplane. FAA's Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed CFM Service Bulletin LEAP-1A-72-00-0507-01A-930A-D, Issue 001, dated January 24, 2024, which identifies the part numbers and serial numbers of HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools with potentially reduced material properties and specifies procedures for replacement of these parts. This proposed AD would also require the following material, which the Director of the Federal Register approved for incorporation by reference as of June 23, 2023 (88 FR 32092, May 19, 2023): CFM Service Bulletin LEAP-1A-72-00-0470-01A-930A-D, Issue 003, dated March 3, 2023.
                CFM Service Bulletin LEAP-1A-72-00-0493-01A-930A-D, Issue 002, dated November 17, 2022.
                CFM Service Bulletin LEAP-1A-72-00-0496-01A-930A-D, Issue 001, dated March 7, 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. Proposed AD Requirements in This NPRM This proposed AD would retain all of the requirements of AD 2023-09-06. This proposed AD would require replacement of certain HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools. This proposed AD would also prohibit installation of an HPT stage 1 disk, forward outer seal, or compressor rotor stages 6-10 spool that has a part number and serial number identified in the material incorporated by reference onto any engine. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 42 engines installed on airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:
                    ( print page 104464) Estimated Costs
Action
Labor cost
Parts cost
Cost per 
                             product
Cost on U.S. operatorsReplace HPT stage 1 disk (42 affected parts)
8 work-hours × $85 per hour = $680
$215,635 (pro-rated)
$216,315
$9,085,230Replace forward outer seal (24 affected parts)
8 work-hours × $85 per hour = $680
$47,500 (pro-rated)
48,180
1,156,320Replace compressor rotor stages 6-10 spool (15 affected parts)
8 work-hours × $85 per hour = $680
$37,660 (pro-rated)
38,340
575,100
 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 The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 the proposed regulation: (1) Is not a “significant regulatory action” under Executive Order 12866, (2) Would not affect intrastate aviation in Alaska, and (3) Would 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 Proposed Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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
 2.The FAA amends § 39.13 by: a.Removing Airworthiness Directive 2023-09-06, Amendment 39-22429 ( 88 FR 32092, May 19, 2023); and b.Adding the following new airworthiness directive: **CFM International, S.A.:**
                         Docket No. FAA-2024-2668; Project Identifier AD-2024-00561-E. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by February 6, 2025. (b) Affected ADs This AD replaces AD 2023-09-06, Amendment 39-22429 (88 FR 32092, May 19, 2023) (AD 2023-09-06). (c) Applicability This AD applies to CFM International, S.A. Model (CFM) LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP-1A26, LEAP-1A26CJ, LEAP-1A26E1, LEAP-1A29, LEAP-1A29CJ, LEAP-1A30, LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A 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 (HPT stage 1 disks), forward outer seals, and compressor rotor stages 6-10 spools were manufactured from material suspected to have reduced material properties due to iron inclusion. The FAA is issuing this AD to prevent fracture and consequent uncontained failure of certain HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-10 spools. The unsafe condition, if not addressed, could result in uncontained debris release, damage to the engine, and damage to the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) For engines with an installed HPT stage 1 disk, forward outer seal or compressor rotor stages 6-10 spool having a part number (P/N) and serial number (S/N) identified in Compliance, paragraph 3.E., Tables 1 through 9, of CFM Service Bulletin (SB) LEAP-1A-72-00-0496-01A-930A-D, Issue 001, dated March 7, 2023 (CFM SB LEAP-1A-72-00-0496-01A-930A-D): At the next piece-part exposure of the HPT stage 1 disk, forward outer seal, or compressor rotor stages 6-10 spool, as applicable, or before exceeding the applicable cycles since new (CSN) threshold identified in Compliance, paragraph 3.E., Tables 1 through 9, of CFM SB LEAP-1A-72-00-0496-01A-930A-D, whichever occurs first after June 23, 2023 (the effective date of AD 2023-09-06); or if the applicable CSN threshold has been exceeded as of June 23, 2023 (the effective date of AD 2023-09-06), within 50 flight cycles (FCs) from June 23, 2023 (the effective date of AD 2023-09-06); remove the HPT stage 1 disk, forward outer seal, or compressor rotor stages 6-10 spool, as applicable, from service and replace with a part eligible for installation. (2) For engines with an installed forward outer seal having a P/N and S/N identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1A-72-00-0470-01A-930A-D, Issue 003, dated March 3, 2023 (CFM SB LEAP-1A-72-00-0470-01A-930A-D): At the next piece-part exposure of the forward outer seal, or before exceeding the applicable CSN threshold identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1A-72-00-0470-01A-930A-D, whichever occurs first after June 23, 2023 (the effective date of AD 2023-09-06); or if the applicable CSN threshold has been exceeded as of June 23, 2023 (the effective date of AD 2023-09-06), within 50 FCs from June 23, 2023 (the effective date of AD 2023-09-06); remove the forward outer seal from service and replace with a part eligible for installation. (3) For engines with an installed HPT stage 1 disk having a P/N and S/N identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1A-72-00-0493-01A-930A-D, Issue 002, dated November 17, 2022 (CFM SB LEAP-1A-72-00-0493-01A-930A-D): At the next piece-part exposure of the HPT stage 1 disk, or before exceeding the applicable CSN threshold identified in Compliance, paragraph 3.E., Tables 1 through 
                        ( print page 104465)
                        2, of CFM SB LEAP-1A-72-00-0493-01A-930A-D, whichever occurs first after June 23, 2023 (the effective date of AD 2023-09-06); or if the applicable CSN threshold has been exceeded as of June 23, 2023 (the effective date of AD 2023-09-06), within 50 FCs from June 23, 2023 (the effective date of AD 2023-09-06), remove the HPT stage 1 disk from service and replace with a part eligible for installation. (4) For engines with an installed HPT stage 1 disk having a P/N and S/N identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1A-72-00-0507-01A-930A-D, Issue 001, dated January 24, 2024 (CFM SB LEAP-1A-72-00-0507-01A-930A-D): At the next piece-part exposure of the HPT stage 1 disk, or before exceeding the applicable CSN threshold identified in Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1A-72-00-0507-01A-930A-D, 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 stage 1 disk from service and replace with a part eligible for installation. (h) Definition For the purpose of this AD, a “part eligible for installation” is an HPT stage 1 disk, forward outer seal, or compressor rotor stages 6-10 spool that does not have a P/N and S/N identified in the service information listed in paragraphs (g)(1) through (4) of this AD. (i) Installation Prohibition After the effective date of this AD, do not install an HPT stage 1 disk, forward outer seal, or compressor rotor stages 6-10 spool that has a P/N and S/N identified in the service information listed in paragraphs (g)(1) through (4) of this AD on any engine. (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 local Flight Standards District Office, as appropriate. If sending information directly to the manager of AIR-520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k) 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. (k) Additional Information 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.* (l) 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 Service Bulletin LEAP-1A-72-00-0507-01A-930A-D, Issue 001, dated January 24, 2024. (ii) [Reserved] (4) The following material was approved for IBR on June 23, 2023 (88 FR 32092, May 19, 2023). (i) CFM Service Bulletin LEAP-1A-72-00-0470-01A-930A-D, Issue 003, dated March 3, 2023. (ii) CFM Service Bulletin LEAP-1A-72-00-0493-01A-930A-D, Issue 002, dated November 17, 2022. (iii) CFM Service Bulletin LEAP-1A-72-00-0496-01A-930A-D, Issue 001, dated March 7, 2023. (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 December 17, 2024. Suzanne Masterson, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.


[FR Doc. 2024-30539 Filed 12-20-24; 8:45 am] BILLING CODE 4910-13-P