Airworthiness Directives; CFM International, S.A. Engines, 33211-33215 [2024-09110]

Download as PDF Federal Register / Vol. 89, No. 83 / Monday, April 29, 2024 / Rules and Regulations (g) Required Actions (1) Within 30 months after the effective date of this AD, remove from service an auxiliary motor and pump having part number (P/N) 782655–3 (Aerocontrolex P/N 4122–006009) and replace with an auxiliary motor and pump having P/N 782655–4 (Aerocontrolex P/N 4122–056000) in accordance with the Accomplishment Instructions, paragraphs 3.B., 3.C., and 3.E. of Hamilton Sundstrand Service Bulletin (SB) 14SF–61–168, Revision 1, dated December 21, 2016 (Hamilton Sundstrand SB 14SF–61– 168, Revision 1). (2) After replacement of the auxiliary motor and pump, perform a post-installation system test in accordance with the Accomplishment Instructions, paragraph 3.F. of Hamilton Sundstrand SB 14SF–61–168, Revision 1. (h) Installation Prohibition After the effective date of this AD, do not install an auxiliary motor and pump having P/N 782655–3 (Aerocontrolex P/N 4122– 006009) on any propeller identified in paragraph (c) of this AD. (i) No Return of Parts Where the service information referenced in the Accomplishment Instructions, paragraph 3.B. of Hamilton Sundstrand SB 14SF–61–168, Revision 1, specifies returning certain parts to the manufacturer for modification, this AD does not include that requirement. (j) Credit for Previous Actions You may take credit for the actions required by paragraph (g) of this AD if you performed those actions before the effective date of this AD using Hamilton Sundstrand SB 14SF–61–168, Original Issue, dated December 14, 2016. Issued on March 26, 2024. Victor Wicklund, Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2024–09142 Filed 4–26–24; 8:45 am] BILLING CODE 4910–13–P (k) Alternative Methods of Compliance (AMOCs) DEPARTMENT OF TRANSPORTATION (1) The Manager, East Certification 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 branch office, send it to the attention of the person identified in paragraph (l)(1) of this AD. Information may be emailed to: 9-AVSAIR-BACO-COS@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. Federal Aviation Administration (l) Additional Information khammond on DSKJM1Z7X2PROD with RULES (m) 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 the AD specifies otherwise. (i) Hamilton Sundstrand Corporation Service Bulletin 14SF–61–168, Revision 1, dated December 21, 2016. Note 2 to paragraph (m)(2)(i): Hamilton Sundstrand Corporation is a UTC Aerospace Systems Company. This service information is identified as both Hamilton Sundstrand Corporation and UTC Aerospace Systems. (ii) [Reserved] (3) For service information identified in this AD, contact Hamilton Sundstrand, One Hamilton Road, Windsor Locks, CT 06096– 1010, phone: (877) 808–7575; email: CRC@ collins.com. (4) You may view this service information at 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. (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. (1) For more information about this AD, contact Isabel Saltzman, Aviation Safety Engineer, FAA, 1701 Columbia Avenue, College Park, GA 30337; phone: (781) 238– 7649; email: 9-AVS-AIR-BACO-COS@faa.gov. (2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (m)(3) and (4) of this AD. VerDate Sep<11>2014 15:46 Apr 26, 2024 Jkt 262001 14 CFR Part 39 [Docket No. FAA–2023–1991; Project Identifier AD–2023–00700–E; Amendment 39–22727; AD 2024–07–06] RIN 2120–AA64 Airworthiness Directives; CFM International, S.A. Engines Federal Aviation Administration (FAA), DOT. ACTION: Final rule. AGENCY: The FAA is adopting a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model 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. This AD was prompted by a report of multiple aborted takeoffs and air turn-backs SUMMARY: PO 00000 Frm 00029 Fmt 4700 Sfmt 4700 33211 (ATBs) caused by high-pressure compressor (HPC) stall, which was induced by high levels of nonsynchronous vibration (NSV). Additional manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV. This AD requires initial and repetitive calculations of the levels of NSV, inspection of the stage 2 highpressure turbine (HPT) nozzle assembly honeycomb and HPT stator stationary seal honeycomb and, depending on the results of the calculations and inspections, replacement of certain parts. This AD also requires replacement of certain No. 3 bearing spring finger housings at a certain time. The FAA is issuing this AD to address the unsafe condition on these products. DATES: This AD is effective June 3, 2024. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of June 3, 2024. ADDRESSES: AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA–2023–1991; 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 final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE, Washington, DC 20590. Material Incorporated by Reference: • For service information, 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. • You may view this service information 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: Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain CFM Model LEAP– 1A23, LEAP–1A24, LEAP–1A24E1, E:\FR\FM\29APR1.SGM 29APR1 33212 Federal Register / Vol. 89, No. 83 / Monday, April 29, 2024 / Rules and Regulations LEAP–1A26, LEAP–1A26CJ, LEAP– 1A26E1, LEAP–1A29, LEAP–1A29CJ, LEAP–1A30, LEAP–1A32, LEAP–1A33, LEAP–1A33B2, and LEAP–1A35A engines. The NPRM published in the Federal Register on October 11, 2023 (88 FR 70409). The NPRM was prompted by a manufacturer’s report of three aborted takeoffs and two ATBs caused by HPC stall. Additional manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV, which could induce HPC stall. As a result of its investigation, the manufacturer published service information that specifies procedures for addressing this situation. In the NPRM, the FAA proposed to require repetitive calculations of the levels of NSV and, depending on the results of the calculations, replacement of the No. 3 bearing spring finger housing. The FAA also proposed to require, following the removal and replacement of the No. 3 bearing spring finger housing, inspection of the stage 2 HPT nozzle assembly honeycomb and HPT stator stationary seal honeycomb for rubs and, depending on findings, replacement of the stage 2 HPT nozzle assembly honeycomb and HPT stator stationary seal. This FAA also proposed to require replacement of the No. 3 bearing spring finger housing regardless of calculated level of NSV at a certain time. 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 four commenters. Commenters included the Air Line Pilots Association, International (ALPA), American Airlines (AA), Avianca Airlines (AVA), and CFM International (CFM). ALPA supported the NPRM without change. The following presents the comments received from AA, AVA, and CFM on the NPRM and the FAA’s response to each comment. khammond on DSKJM1Z7X2PROD with RULES Request To Allow Automated Monitoring AA requested that the FAA allow for the use of automated condition monitoring solutions as an alternative to the accomplishment of the manual review every 125 cycles required by paragraph (g)(1) of the proposed AD. AA noted that automated monitoring solutions have already been accepted to replace previously FAA required MRB tasks, and allowing automated condition monitoring will provide a safer, more robust solution that exceeds the VerDate Sep<11>2014 15:46 Apr 26, 2024 Jkt 262001 minimum requirements outlined in CFM Service Bulletin (SB) LEAP–1A– 72–00–0504–01A–930A–D, Issue 001, dated June 14, 2023, and the NPRM. The FAA disagrees with the commenter’s request to add automated monitoring solutions as an alternative in the final rule. However, if any operator prefers to address the unsafe condition by means other than those specified in the referenced service information, they may request approval for an alternative method of compliance (AMOC) in accordance with paragraph (j) of this AD and, if approved, may use it instead of the procedures specified in the service information and the final rule. The FAA did not change this AD as a result of this comment. Request To Include Customer Notification Report (CNR) in AD Avianca requested that the CNR for exceedance of NSV thresholds be included in the NPRM as an additional method of compliance for all operators who have active CFM Diagnostics Monitoring. Avianca noted that under the CFM Diagnostics Program, the parameter NSV TCF Max Vibe Fleeting Event is actively monitored and if any exceedance is detected, a CNR is triggered for NSV exceedance. The FAA disagrees with the commenter’s request to add CNR for NSV thresholds exceedance as an additional method of compliance in the final rule. However, if any operator prefers to address the unsafe condition by means other than those specified in the referenced service information, they may request approval for an AMOC in accordance with paragraph (j) of this AD and, if approved, may use it instead of the procedures specified in the service information and the final rule. The FAA did not change this AD as a result of this comment. Request To Clarify Replacement Language in Summary CFM requested that the FAA update the Summary section of the proposed AD to read: ‘‘This proposed AD would also require replacement of the No. 3 bearing spring finger housing having P/ N 2629M62G01 and a serial number identified in Table 1 of CFM SB LEAP– 1A–72–00–0504–01A–93 0A–D.’’ CFM noted that the focus of the proposed AD should be on NSV monitoring and the actions required when NSV is present. CFM also noted that service bulletins LEAP–1A–72–00–0505–01A–93 0A–D, Issue 001, dated June 05, 2023, and LEAP–1A–72–00–0498–01A–93 0A–D, Issue 001, dated June 05, 2023, include the shop visit workscope recommendations for engines with PO 00000 Frm 00030 Fmt 4700 Sfmt 4700 potential No. 3 bearing spring finger housing wear, regardless of the signs of NSV vibrations. The FAA partially agrees with the request. The FAA agrees to edit the Summary section of this AD to clarify that only certain No. 3 bearing spring finger housings require replacement. The FAA disagrees with the request to specify the part number and serial number of the affected parts in the Summary section of this AD because that level of specificity is not appropriate for the Summary section. The FAA acknowledges the presence of service bulletins LEAP–1A–72–00– 0505–01A–93 0A–D, Issue 001, dated June 05, 2023, and LEAP–1A–72–00– 0498–01A–93 0A–D, Issue 001, dated June 05, 2023, and notes that neither of those SBs are incorporated by reference in this AD. Request To Update Proposed AD Requirements CFM requested that the FAA update the Proposed AD Requirements in This NPRM section to read: ‘‘This proposed AD would also require replacement of the No. 3 bearing spring finger housing having P/N 2629M62G01 and a serial number identified in Table 1 of CFM SB LEAP–1A–72–00–0504–01A–930A–D, regardless of calculated level of NSV, at a certain time.’’ The FAA agrees with the requested language. However, this section is not included in the final rule. Therefore, the FAA did not change this AD as a result of this comment. Request To Update Background and Unsafe Condition CFM requested that the FAA update the Background and Unsafe Condition sections of the proposed AD to include that CFM experience to date has shown that NSV has led to self-recovering HPC stalls. CFM also requested to remove the following portion from paragraph (e): ‘‘The FAA is issuing this AD to prevent HPC stall.’’ CFM acknowledged that the manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV, which could induce HPC stall. The FAA disagrees with the request to include information regarding selfrecovering HPC stalls in this AD. The FAA also disagrees with the requested change to paragraph (e) of this AD. The FAA notes that the field experience to date does not provide conclusive evidence that NSV-induced HPC stalls will always be self-recovering. The FAA did not change this AD as a result of this comment. E:\FR\FM\29APR1.SGM 29APR1 Federal Register / Vol. 89, No. 83 / Monday, April 29, 2024 / Rules and Regulations Request To Update Interim Action CFM requested that the FAA update the Interim Action section of the proposed AD to reflect that this AD is the closing action of paragraph (e) Unsafe Condition of the proposed AD and although there are additional hardware modifications that are being developed by the design approval holder, those modifications are not necessary to address the unsafe condition. The FAA disagrees with this request. Although at this time the required actions of this AD address the unsafe condition, additional hardware modifications, when developed and FAA-approved, could also address the unsafe condition for the long-term. Therefore, the FAA considers that the monitoring and corresponding actions required by this AD would be an interim action to address the unsafe condition, and the FAA may consider additional rulemaking on this subject. The FAA did not change this AD as a result of this comment. Request To Update Service Information Incorporated by Reference khammond on DSKJM1Z7X2PROD with RULES CFM requested that the FAA change the SB referenced in the NPRM from ‘‘LEAP–1A–72–00–0504–01A–930A–D, Issue 001, dated June 14, 2023’’ to ‘‘LEAP–1A–72–00–0504–01A–930A–D, Issue 002, dated October 17, 2023.’’ CFM noted that SB LEAP–1A–72–00– 0504–01A–930A–D, Issue 002, dated October 17, 2023, contains the following revisions that are pertinent to the NPRM; (1) A note that NSV monitoring can be performed on-wing. (2) Correction to data labels used in the alternative procedure for NSV Monitoring with ACMS Takeoff Reports. (3) Correction to vibration units used in the alternative procedure for NSV Monitoring with ACMS Takeoff Reports. The FAA agrees and has updated the service information incorporated by reference from ‘‘LEAP–1A–72–00–0504– 01A–930A–D, Issue 001, dated June 14, 2023’’ to ‘‘LEAP–1A–72–00–0504–01A– 930A–D, Issue 002, dated October 17, 2023.’’ Requiring this updated service bulletin does not increase the scope of the AD or increase the burden on any operator over that already proposed in the NPRM. Request To Remove ‘‘At the Next Piecepart Exposure’’ From Required Actions CFM requested that the FAA remove the reference to ‘‘At the next piece-part exposure’’ in paragraph (g)(5) of the proposed AD. CFM stated that NSV monitoring and actions required when VerDate Sep<11>2014 15:46 Apr 26, 2024 Jkt 262001 NSV is present are the focus of the proposed AD. CFM noted that the statement related to ‘‘At the next piecepart exposure’’ was taken from SB LEAP–1A–72–00–0498–01A–930A–D, Issue 001, dated June 05, 2023, for shop visit work scope recommendations for engines with potential No. 3 bearing spring finger housing wear. CFM also noted that this is already referenced in Chapter 05 of the LEAP–1A Engine Shop Manual LEAP–1A–05–11–03– 01A–0B1B–C. The FAA disagrees with the request because the commenter did not provide an adequate justification for changing the compliance time. The FAA notes that decision to include a mandatory action to remove all affected parts at the next piece-part exposure was not taken from SB LEAP–1A–72–00–0498–01A– 930A–D, Issue 001, dated June 05, 2023. The FAA did not change this AD as a result of this comment. Request To Add Credit for Previous Actions CFM requested that the FAA add the following language to the NPRM to allow customers to take credit for NSV monitoring that was performed prior to the effective date of the proposed AD, in accordance with section 5.A of SB LEAP–1A–72–00–0504–01A–930A–D, Issue 001, dated June 14, 2023; ‘‘Evaluation of the NSV of an engine, accomplished before the effective date of this AD in accordance with the instructions of section 5.A of SB LEAP– 1A–72–00–0504–01A–930A–D original issue (Issue 001) and, as applicable, accomplishment of corrective actions in accordance with the instructions of SB LEAP–1A–72–00–0504–01A–930A–D original issue (Issue 001) are acceptable to comply with the requirements of paragraphs (1) and (2), as applicable, of this AD for that engine (see Note 1 of this AD). Note 1: Evaluation of the NSV of an engine, accomplished in accordance with the instructions of section 5.B (‘Alternative Procedure— NSV Monitoring with ACMS Takeoff Reports’) of SB LEAP–1A–72–00–0504– 01A–930A–D original issue (Issue 001) is not acceptable to comply with the requirements of paragraphs (1) of this AD.’’ The FAA disagrees with the request because the FAA does not believe it is necessary to provide such credit because NSV monitoring is required initially at 125 flight cycles after the effective date of the AD and repetitively at intervals of 125 flight cycles. Therefore, there would be no advantage of taking credit for NSV monitoring done before the effective date of this AD. Once the NSV data calculation PO 00000 Frm 00031 Fmt 4700 Sfmt 4700 33213 exceeds the specified limits, then the affected No. 3 bearing spring finger housing must be removed from the engine and replaced with a part eligible for installation, and the AD applicability no longer applies to that engine. The FAA did not change this AD as a result of this comment. Request To Update Compliance Time for Removal From Service CFM requested that the FAA change compliance time language in paragraph (g)(2) of the proposed AD from, ‘‘within 150 FCs of performing the calculation’’ to ‘‘within 150 FCs of the flight when this threshold is exceeded.’’ CFM noted that there is a discrepancy in the removal compliance time language between the NPRM and CFM SB LEAP– 1A–72–00–0504–01A–930A–D if NSV data exceeds the limits listed in CFM SB LEAP–1A–72–00–0504–01A–930A–D. The FAA agrees to update the language in paragraph (g)(2) of this AD from, ‘‘within 150 FCs of performing the calculation’’ to ‘‘within 150 FCs of the flight when these limits are exceeded.’’ Conclusion The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, and any other changes described previously, 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 The FAA reviewed CFM SB LEAP– 1A–72–00–0504–01A–930A–D, Issue 002, dated October 17, 2023. This service information identifies affected No. 3 bearing spring finger housings and specifies procedures for monitoring NSV during engine operation. This service information also specifies procedures for replacing the No. 3 bearing spring finger housings, inspecting the stage 2 HPT nozzle assembly honeycomb and HPT stator stationary seal honeycomb, and replacing the stage 2 HPT nozzle assembly honeycomb and HPT stator stationary seal. This service information 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. E:\FR\FM\29APR1.SGM 29APR1 33214 Federal Register / Vol. 89, No. 83 / Monday, April 29, 2024 / Rules and Regulations Interim Action The FAA considers this AD to be an interim action. This unsafe condition is still under investigation by the manufacturer and, depending on the results of that investigation, the FAA may consider further rulemaking action. Costs of Compliance The FAA estimates that this AD affects 48 engines installed on airplanes of U.S. registry. The FAA estimates that 33 engines installed on airplanes of U.S. registry require replacement of the No. 3 bearing spring finger housing. The FAA estimates the following costs to comply with this AD: ESTIMATED COSTS Action Labor cost Calculate NSV data ........................................ Replace No. 3 bearing spring finger housing 1 work-hours × $85 per hour = $85 ............... 17 work-hours × $85 per hour = $1,445 ........ The FAA estimates the following costs to do any necessary replacement and inspection that would be required Parts cost based on the results of the calculation. The agency has no way of determining Cost per product $0 64,590 Cost on U.S. operators $85 66,035 $4,080 2,179,155 the number of aircraft that might need these replacements and inspections: ON-CONDITION COSTS Labor cost Inspect stage 2 HPT nozzle assembly honeycomb and HPT stator stationary seal honeycomb. Replace stage 2 HPT nozzle assembly honeycomb ... Replace HPT stator stationary seal ............................. 4 work-hours × $85 per hour = $340 ........................... $0 $340 8 work-hours × $85 per hour = $680 ........................... 8 work-hours × $85 per hour = $680 ........................... 58,536 6,855 59,216 7,535 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. (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: 1. The authority citation for part 39 continues to read as follows: ■ Authority: 49 U.S.C. 106(g), 40113, 44701. 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: VerDate Sep<11>2014 15:46 Apr 26, 2024 Jkt 262001 § 39.13 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: ■ 2024–07–06 CFM International, S.A.: Amendment 39–22727; Docket No. FAA–2023–1991; Project Identifier AD– 2023–00700–E. (a) Effective Date This airworthiness directive (AD) is effective June 3, 2024. PO 00000 Frm 00032 Fmt 4700 Sfmt 4700 Parts cost (b) Affected ADs None. (c) Applicability This AD applies to CFM International, S.A. (CFM) Model 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 with an installed No. 3 bearing spring finger housing having part number (P/N) 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM Service Bulletin (SB) LEAP–1A–72–00–0504–01A–930A–D, Issue 002, dated October 17, 2023 (CFM SB LEAP–1A–72–00–0504–01A–930A–D, Issue 002). (d) Subject Joint Aircraft System Component (JASC) Code 7230, Turbine Engine Compressor Section. PART 39—AIRWORTHINESS DIRECTIVES Regulatory Findings khammond on DSKJM1Z7X2PROD with RULES Cost per product Action (e) Unsafe Condition This AD was prompted by a report of multiple aborted takeoffs and air turn-backs caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration (NSV), and an additional manufacturer investigation that revealed wear on the No. 3 bearing spring finger housing. The FAA is issuing this AD to prevent HPC stall. The unsafe condition, if not addressed, could result in engine power loss at a critical phase of flight such as takeoff or climb, loss of engine thrust control, reduced controllability of the airplane, and loss of the airplane. E:\FR\FM\29APR1.SGM 29APR1 khammond on DSKJM1Z7X2PROD with RULES Federal Register / Vol. 89, No. 83 / Monday, April 29, 2024 / Rules and Regulations (f) Compliance Comply with this AD within the compliance times specified, unless already done. installation, as specified in paragraphs (g)(2)(i) and (g)(5) of this AD, constitutes terminating action for the calculations required by paragraph (g)(1) of this AD. (g) Required Actions (1) Within 125 flight cycles (FCs) after the effective date of this AD and thereafter at intervals not to exceed 125 FCs, calculate the NSV data in accordance with the Accomplishment Instructions, paragraphs 5.A.(1) and 5.A.(3), or 5.B.(1) and 5.B.(3) of CFM SB LEAP–1A–72–00–0504–01A–930A– D, Issue 002. (2) If, during any calculation required by paragraph (g)(1) of this AD, the NSV data exceeds the limits specified in the Accomplishment Instructions, paragraph 5.A.(4)(a)1 or 5.B.(4)(a)1 of CFM SB LEAP– 1A–72–00–0504–01A–930A–D, Issue 002, discontinue the calculations required by paragraph (g)(1) of this AD and within 150 FCs of the flight when these limits are exceeded: (i) Remove from service the No. 3 bearing spring finger housing having P/N 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM SB LEAP–1A– 72–00–0504–01A–930A–D, Issue 002, and replace with a part eligible for installation. (ii) Inspect the stage 2 high-pressure turbine (HPT) nozzle assembly honeycomb for rubs in accordance with the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB LEAP–1A–72–00–0504–01A–930A–D, Issue 002. (iii) Inspect the HPT stator stationary seal honeycomb for rubs in accordance with the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB LEAP–1A–72–00–0504–01A–930A–D, Issue 002. (3) If, during the inspection required by paragraph (g)(2)(ii) of this AD, the stage 2 HPT nozzle assembly honeycomb fails to meet the serviceability criteria referenced in the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB LEAP–1A–72–00–0504–01A–930A–D, Issue 002, before further flight, replace the stage 2 HPT nozzle assembly honeycomb. (4) If, during the inspection required by paragraph (g)(2)(iii) of this AD, the HPT stator stationary seal honeycomb fails to meet the serviceability criteria referenced in the Accomplishment Instructions, paragraphs 5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB LEAP–1A–72–00–0504–01A–930A–D, Issue 002, before further flight, replace the HPT stator stationary seal. (5) At the next piece-part exposure after the effective date of this AD, but before exceeding 9,900 cycles since new, replace the No. 3 bearing spring finger housing having P/ N 2629M62G01 and a serial number identified in Table 1 of CFM SB LEAP–1A– 72–00–0504–01A–930A–D, Issue 002, with a part eligible for installation. (i) Definition For the purpose of this AD, a ‘‘part eligible for installation’’ is a No. 3 bearing spring finger housing that does not have P/N 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM SB LEAP–1A– 72–00–0504–01A–930A–D, Issue 002. (h) Terminating Action Replacement of the No. 3 bearing spring finger housing having P/N 2629M62G01 and a serial number identified in Table 1 or Table 2 of CFM SB LEAP–1A–72–00–0504–01A– 930A–D, Issue 002 with a part eligible for VerDate Sep<11>2014 15:46 Apr 26, 2024 Jkt 262001 (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, AIR–520 Continued Operational Safety Branch, send it to the attention of the person identified in paragraph (k) of this AD and email it to: ANEAD-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. (3) For service information that contains steps that are labeled as Required for Compliance (RC), the following provisions apply. (i) The steps labeled as RC, including substeps under an RC step and any figures identified in an RC step, that are required by paragraph (g) of this AD must be done to comply with this AD. An AMOC is required for any deviations to RC steps required by paragraph (g) of this AD, including substeps and identified figures. (ii) Steps not labeled 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 RC steps, including substeps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition. (k) Additional Information For more information about this AD, 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 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 the AD specifies otherwise. (i) CFM International, S.A. Service Bulletin LEAP–1A–72–00–0504–01A–930A–D, Issue 002, dated October 17, 2023. (ii) [Reserved] (3) For service information, contact CFM International, S.A., GE Aviation Fleet Support, 1 Neumann Way, M/D Room 285, PO 00000 Frm 00033 Fmt 4700 Sfmt 4700 33215 Cincinnati, OH 45215; phone: (877) 432– 3272; email: aviation.fleetsupport@ge.com. (4) You may view this service information at 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. (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-locationsoremailfr.inspection@nara.gov. Issued on March 29, 2024. Victor Wicklund, Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2024–09110 Filed 4–26–24; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2024–0771; Project Identifier AD–2023–01251–E; Amendment 39–22720; AD 2024–06–15] RIN 2120–AA64 Airworthiness Directives; General Electric Company Engines Federal Aviation Administration (FAA), DOT. ACTION: Final rule; request for comments. AGENCY: The FAA is adopting a new airworthiness directive (AD) for certain General Electric Company (GE) Model GE90–110B1 and GE90–115B engines. This AD was prompted by a report of an aborted takeoff due to left engine failure caused by liberation of the interstage high-pressure turbine (HPT) rotor seal rim. This AD requires repetitive ultrasonic inspections (USIs) of the interstage HPT rotor seal for cracks and removal from service if necessary. As a mandatory terminating action to the repetitive USIs of the interstage HPT rotor seal, this AD also requires replacement of the interstage HPT rotor seal. The FAA is issuing this AD to address the unsafe condition on these products. SUMMARY: This AD is effective May 14, 2024. The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of May 14, 2024. The FAA must receive comments on this AD by June 13, 2024. ADDRESSES: You may send comments, using the procedures found in 14 CFR DATES: E:\FR\FM\29APR1.SGM 29APR1

Agencies

[Federal Register Volume 89, Number 83 (Monday, April 29, 2024)]
[Rules and Regulations]
[Pages 33211-33215]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-09110]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1991; Project Identifier AD-2023-00700-E; 
Amendment 39-22727; AD 2024-07-06]
RIN 2120-AA64


Airworthiness Directives; CFM International, S.A. Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain CFM International, S.A. (CFM) Model 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. 
This AD was prompted by a report of multiple aborted takeoffs and air 
turn-backs (ATBs) caused by high-pressure compressor (HPC) stall, which 
was induced by high levels of non-synchronous vibration (NSV). 
Additional manufacturer investigation revealed that wear on the No. 3 
bearing spring finger housing can lead to high levels of NSV. This AD 
requires initial and repetitive calculations of the levels of NSV, 
inspection of the stage 2 high-pressure turbine (HPT) nozzle assembly 
honeycomb and HPT stator stationary seal honeycomb and, depending on 
the results of the calculations and inspections, replacement of certain 
parts. This AD also requires replacement of certain No. 3 bearing 
spring finger housings at a certain time. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective June 3, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of June 3, 
2024.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-1991; 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 final rule, any comments received, and other 
information. The address for Docket Operations is U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
     For service information, contact CFM International, S.A., 
GE Aviation Fleet Support, 1 Neumann Way, M/D Room 285, Cincinnati, OH 
45215; phone: (877) 432-3272; email: [email protected].
     You may view this service information 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: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain CFM Model LEAP-
1A23, LEAP-1A24, LEAP-1A24E1,

[[Page 33212]]

LEAP-1A26, LEAP-1A26CJ, LEAP-1A26E1, LEAP-1A29, LEAP-1A29CJ, LEAP-1A30, 
LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A engines. The NPRM 
published in the Federal Register on October 11, 2023 (88 FR 70409). 
The NPRM was prompted by a manufacturer's report of three aborted 
takeoffs and two ATBs caused by HPC stall. Additional manufacturer 
investigation revealed that wear on the No. 3 bearing spring finger 
housing can lead to high levels of NSV, which could induce HPC stall. 
As a result of its investigation, the manufacturer published service 
information that specifies procedures for addressing this situation. In 
the NPRM, the FAA proposed to require repetitive calculations of the 
levels of NSV and, depending on the results of the calculations, 
replacement of the No. 3 bearing spring finger housing. The FAA also 
proposed to require, following the removal and replacement of the No. 3 
bearing spring finger housing, inspection of the stage 2 HPT nozzle 
assembly honeycomb and HPT stator stationary seal honeycomb for rubs 
and, depending on findings, replacement of the stage 2 HPT nozzle 
assembly honeycomb and HPT stator stationary seal. This FAA also 
proposed to require replacement of the No. 3 bearing spring finger 
housing regardless of calculated level of NSV at a certain time. 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 four commenters. Commenters included 
the Air Line Pilots Association, International (ALPA), American 
Airlines (AA), Avianca Airlines (AVA), and CFM International (CFM). 
ALPA supported the NPRM without change. The following presents the 
comments received from AA, AVA, and CFM on the NPRM and the FAA's 
response to each comment.

Request To Allow Automated Monitoring

    AA requested that the FAA allow for the use of automated condition 
monitoring solutions as an alternative to the accomplishment of the 
manual review every 125 cycles required by paragraph (g)(1) of the 
proposed AD. AA noted that automated monitoring solutions have already 
been accepted to replace previously FAA required MRB tasks, and 
allowing automated condition monitoring will provide a safer, more 
robust solution that exceeds the minimum requirements outlined in CFM 
Service Bulletin (SB) LEAP-1A-72-00-0504-01A-930A-D, Issue 001, dated 
June 14, 2023, and the NPRM.
    The FAA disagrees with the commenter's request to add automated 
monitoring solutions as an alternative in the final rule. However, if 
any operator prefers to address the unsafe condition by means other 
than those specified in the referenced service information, they may 
request approval for an alternative method of compliance (AMOC) in 
accordance with paragraph (j) of this AD and, if approved, may use it 
instead of the procedures specified in the service information and the 
final rule. The FAA did not change this AD as a result of this comment.

Request To Include Customer Notification Report (CNR) in AD

    Avianca requested that the CNR for exceedance of NSV thresholds be 
included in the NPRM as an additional method of compliance for all 
operators who have active CFM Diagnostics Monitoring. Avianca noted 
that under the CFM Diagnostics Program, the parameter NSV TCF Max Vibe 
Fleeting Event is actively monitored and if any exceedance is detected, 
a CNR is triggered for NSV exceedance.
    The FAA disagrees with the commenter's request to add CNR for NSV 
thresholds exceedance as an additional method of compliance in the 
final rule. However, if any operator prefers to address the unsafe 
condition by means other than those specified in the referenced service 
information, they may request approval for an AMOC in accordance with 
paragraph (j) of this AD and, if approved, may use it instead of the 
procedures specified in the service information and the final rule. The 
FAA did not change this AD as a result of this comment.

Request To Clarify Replacement Language in Summary

    CFM requested that the FAA update the Summary section of the 
proposed AD to read: ``This proposed AD would also require replacement 
of the No. 3 bearing spring finger housing having P/N 2629M62G01 and a 
serial number identified in Table 1 of CFM SB LEAP-1A-72-00-0504-01A-93 
0A-D.'' CFM noted that the focus of the proposed AD should be on NSV 
monitoring and the actions required when NSV is present. CFM also noted 
that service bulletins LEAP-1A-72-00-0505-01A-93 0A-D, Issue 001, dated 
June 05, 2023, and LEAP-1A-72-00-0498-01A-93 0A-D, Issue 001, dated 
June 05, 2023, include the shop visit workscope recommendations for 
engines with potential No. 3 bearing spring finger housing wear, 
regardless of the signs of NSV vibrations.
    The FAA partially agrees with the request. The FAA agrees to edit 
the Summary section of this AD to clarify that only certain No. 3 
bearing spring finger housings require replacement. The FAA disagrees 
with the request to specify the part number and serial number of the 
affected parts in the Summary section of this AD because that level of 
specificity is not appropriate for the Summary section. The FAA 
acknowledges the presence of service bulletins LEAP-1A-72-00-0505-01A-
93 0A-D, Issue 001, dated June 05, 2023, and LEAP-1A-72-00-0498-01A-93 
0A-D, Issue 001, dated June 05, 2023, and notes that neither of those 
SBs are incorporated by reference in this AD.

Request To Update Proposed AD Requirements

    CFM requested that the FAA update the Proposed AD Requirements in 
This NPRM section to read: ``This proposed AD would also require 
replacement of the No. 3 bearing spring finger housing having P/N 
2629M62G01 and a serial number identified in Table 1 of CFM SB LEAP-1A-
72-00-0504-01A-930A-D, regardless of calculated level of NSV, at a 
certain time.''
    The FAA agrees with the requested language. However, this section 
is not included in the final rule. Therefore, the FAA did not change 
this AD as a result of this comment.

Request To Update Background and Unsafe Condition

    CFM requested that the FAA update the Background and Unsafe 
Condition sections of the proposed AD to include that CFM experience to 
date has shown that NSV has led to self-recovering HPC stalls. CFM also 
requested to remove the following portion from paragraph (e): ``The FAA 
is issuing this AD to prevent HPC stall.'' CFM acknowledged that the 
manufacturer investigation revealed that wear on the No. 3 bearing 
spring finger housing can lead to high levels of NSV, which could 
induce HPC stall.
    The FAA disagrees with the request to include information regarding 
self-recovering HPC stalls in this AD. The FAA also disagrees with the 
requested change to paragraph (e) of this AD. The FAA notes that the 
field experience to date does not provide conclusive evidence that NSV-
induced HPC stalls will always be self-recovering. The FAA did not 
change this AD as a result of this comment.

[[Page 33213]]

Request To Update Interim Action

    CFM requested that the FAA update the Interim Action section of the 
proposed AD to reflect that this AD is the closing action of paragraph 
(e) Unsafe Condition of the proposed AD and although there are 
additional hardware modifications that are being developed by the 
design approval holder, those modifications are not necessary to 
address the unsafe condition.
    The FAA disagrees with this request. Although at this time the 
required actions of this AD address the unsafe condition, additional 
hardware modifications, when developed and FAA-approved, could also 
address the unsafe condition for the long-term. Therefore, the FAA 
considers that the monitoring and corresponding actions required by 
this AD would be an interim action to address the unsafe condition, and 
the FAA may consider additional rulemaking on this subject. The FAA did 
not change this AD as a result of this comment.

Request To Update Service Information Incorporated by Reference

    CFM requested that the FAA change the SB referenced in the NPRM 
from ``LEAP-1A-72-00-0504-01A-930A-D, Issue 001, dated June 14, 2023'' 
to ``LEAP-1A-72-00-0504-01A-930A-D, Issue 002, dated October 17, 
2023.'' CFM noted that SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, 
dated October 17, 2023, contains the following revisions that are 
pertinent to the NPRM;
    (1) A note that NSV monitoring can be performed on-wing.
    (2) Correction to data labels used in the alternative procedure for 
NSV Monitoring with ACMS Takeoff Reports.
    (3) Correction to vibration units used in the alternative procedure 
for NSV Monitoring with ACMS Takeoff Reports.
    The FAA agrees and has updated the service information incorporated 
by reference from ``LEAP-1A-72-00-0504-01A-930A-D, Issue 001, dated 
June 14, 2023'' to ``LEAP-1A-72-00-0504-01A-930A-D, Issue 002, dated 
October 17, 2023.'' Requiring this updated service bulletin does not 
increase the scope of the AD or increase the burden on any operator 
over that already proposed in the NPRM.

Request To Remove ``At the Next Piece-part Exposure'' From Required 
Actions

    CFM requested that the FAA remove the reference to ``At the next 
piece-part exposure'' in paragraph (g)(5) of the proposed AD. CFM 
stated that NSV monitoring and actions required when NSV is present are 
the focus of the proposed AD. CFM noted that the statement related to 
``At the next piece-part exposure'' was taken from SB LEAP-1A-72-00-
0498-01A-930A-D, Issue 001, dated June 05, 2023, for shop visit work 
scope recommendations for engines with potential No. 3 bearing spring 
finger housing wear. CFM also noted that this is already referenced in 
Chapter 05 of the LEAP-1A Engine Shop Manual LEAP-1A-05-11-03-01A-0B1B-
C.
    The FAA disagrees with the request because the commenter did not 
provide an adequate justification for changing the compliance time. The 
FAA notes that decision to include a mandatory action to remove all 
affected parts at the next piece-part exposure was not taken from SB 
LEAP-1A-72-00-0498-01A-930A-D, Issue 001, dated June 05, 2023. The FAA 
did not change this AD as a result of this comment.

Request To Add Credit for Previous Actions

    CFM requested that the FAA add the following language to the NPRM 
to allow customers to take credit for NSV monitoring that was performed 
prior to the effective date of the proposed AD, in accordance with 
section 5.A of SB LEAP-1A-72-00-0504-01A-930A-D, Issue 001, dated June 
14, 2023; ``Evaluation of the NSV of an engine, accomplished before the 
effective date of this AD in accordance with the instructions of 
section 5.A of SB LEAP-1A-72-00-0504-01A-930A-D original issue (Issue 
001) and, as applicable, accomplishment of corrective actions in 
accordance with the instructions of SB LEAP-1A-72-00-0504-01A-930A-D 
original issue (Issue 001) are acceptable to comply with the 
requirements of paragraphs (1) and (2), as applicable, of this AD for 
that engine (see Note 1 of this AD). Note 1: Evaluation of the NSV of 
an engine, accomplished in accordance with the instructions of section 
5.B (`Alternative Procedure--NSV Monitoring with ACMS Takeoff Reports') 
of SB LEAP-1A-72-00-0504-01A-930A-D original issue (Issue 001) is not 
acceptable to comply with the requirements of paragraphs (1) of this 
AD.''
    The FAA disagrees with the request because the FAA does not believe 
it is necessary to provide such credit because NSV monitoring is 
required initially at 125 flight cycles after the effective date of the 
AD and repetitively at intervals of 125 flight cycles. Therefore, there 
would be no advantage of taking credit for NSV monitoring done before 
the effective date of this AD. Once the NSV data calculation exceeds 
the specified limits, then the affected No. 3 bearing spring finger 
housing must be removed from the engine and replaced with a part 
eligible for installation, and the AD applicability no longer applies 
to that engine. The FAA did not change this AD as a result of this 
comment.

Request To Update Compliance Time for Removal From Service

    CFM requested that the FAA change compliance time language in 
paragraph (g)(2) of the proposed AD from, ``within 150 FCs of 
performing the calculation'' to ``within 150 FCs of the flight when 
this threshold is exceeded.'' CFM noted that there is a discrepancy in 
the removal compliance time language between the NPRM and CFM SB LEAP-
1A-72-00-0504-01A-930A-D if NSV data exceeds the limits listed in CFM 
SB LEAP-1A-72-00-0504-01A-930A-D.
    The FAA agrees to update the language in paragraph (g)(2) of this 
AD from, ``within 150 FCs of performing the calculation'' to ``within 
150 FCs of the flight when these limits are exceeded.''

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, 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

    The FAA reviewed CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, 
dated October 17, 2023. This service information identifies affected 
No. 3 bearing spring finger housings and specifies procedures for 
monitoring NSV during engine operation. This service information also 
specifies procedures for replacing the No. 3 bearing spring finger 
housings, inspecting the stage 2 HPT nozzle assembly honeycomb and HPT 
stator stationary seal honeycomb, and replacing the stage 2 HPT nozzle 
assembly honeycomb and HPT stator stationary seal. This service 
information 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.

[[Page 33214]]

Interim Action

    The FAA considers this AD to be an interim action. This unsafe 
condition is still under investigation by the manufacturer and, 
depending on the results of that investigation, the FAA may consider 
further rulemaking action.

Costs of Compliance

    The FAA estimates that this AD affects 48 engines installed on 
airplanes of U.S. registry. The FAA estimates that 33 engines installed 
on airplanes of U.S. registry require replacement of the No. 3 bearing 
spring finger housing.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Calculate NSV data....................  1 work-hours x $85 per                $0             $85          $4,080
                                         hour = $85.
Replace No. 3 bearing spring finger     17 work-hours x $85 per           64,590          66,035       2,179,155
 housing.                                hour = $1,445.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacement and inspection that would be required based on the results 
of the calculation. The agency has no way of determining the number of 
aircraft that might need these replacements and inspections:

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Inspect stage 2 HPT nozzle assembly honeycomb   4 work-hours x $85 per hour =                 $0            $340
 and HPT stator stationary seal honeycomb.       $340.
Replace stage 2 HPT nozzle assembly honeycomb.  8 work-hours x $85 per hour =             58,536          59,216
                                                 $680.
Replace HPT stator stationary seal............  8 work-hours x $85 per hour =              6,855           7,535
                                                 $680.
----------------------------------------------------------------------------------------------------------------

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

0
1. The authority citation for part 39 continues to read as follows:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13   [Amended]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2024-07-06 CFM International, S.A.: Amendment 39-22727; Docket No. 
FAA-2023-1991; Project Identifier AD-2023-00700-E.

(a) Effective Date

    This airworthiness directive (AD) is effective June 3, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to CFM International, S.A. (CFM) Model 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 with an installed No. 3 bearing 
spring finger housing having part number (P/N) 2629M62G01 and a 
serial number identified in Table 1 or Table 2 of CFM Service 
Bulletin (SB) LEAP-1A-72-00-0504-01A-930A-D, Issue 002, dated 
October 17, 2023 (CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002).

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section.

(e) Unsafe Condition

    This AD was prompted by a report of multiple aborted takeoffs 
and air turn-backs caused by high-pressure compressor (HPC) stall, 
which was induced by high levels of non-synchronous vibration (NSV), 
and an additional manufacturer investigation that revealed wear on 
the No. 3 bearing spring finger housing. The FAA is issuing this AD 
to prevent HPC stall. The unsafe condition, if not addressed, could 
result in engine power loss at a critical phase of flight such as 
takeoff or climb, loss of engine thrust control, reduced 
controllability of the airplane, and loss of the airplane.

[[Page 33215]]

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    (1) Within 125 flight cycles (FCs) after the effective date of 
this AD and thereafter at intervals not to exceed 125 FCs, calculate 
the NSV data in accordance with the Accomplishment Instructions, 
paragraphs 5.A.(1) and 5.A.(3), or 5.B.(1) and 5.B.(3) of CFM SB 
LEAP-1A-72-00-0504-01A-930A-D, Issue 002.
    (2) If, during any calculation required by paragraph (g)(1) of 
this AD, the NSV data exceeds the limits specified in the 
Accomplishment Instructions, paragraph 5.A.(4)(a)1 or 5.B.(4)(a)1 of 
CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, discontinue the 
calculations required by paragraph (g)(1) of this AD and within 150 
FCs of the flight when these limits are exceeded:
    (i) Remove from service the No. 3 bearing spring finger housing 
having P/N 2629M62G01 and a serial number identified in Table 1 or 
Table 2 of CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002, and 
replace with a part eligible for installation.
    (ii) Inspect the stage 2 high-pressure turbine (HPT) nozzle 
assembly honeycomb for rubs in accordance with the Accomplishment 
Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB 
LEAP-1A-72-00-0504-01A-930A-D, Issue 002.
    (iii) Inspect the HPT stator stationary seal honeycomb for rubs 
in accordance with the Accomplishment Instructions, paragraphs 
5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB LEAP-1A-72-00-0504-01A-
930A-D, Issue 002.
    (3) If, during the inspection required by paragraph (g)(2)(ii) 
of this AD, the stage 2 HPT nozzle assembly honeycomb fails to meet 
the serviceability criteria referenced in the Accomplishment 
Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB 
LEAP-1A-72-00-0504-01A-930A-D, Issue 002, before further flight, 
replace the stage 2 HPT nozzle assembly honeycomb.
    (4) If, during the inspection required by paragraph (g)(2)(iii) 
of this AD, the HPT stator stationary seal honeycomb fails to meet 
the serviceability criteria referenced in the Accomplishment 
Instructions, paragraphs 5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB 
LEAP-1A-72-00-0504-01A-930A-D, Issue 002, before further flight, 
replace the HPT stator stationary seal.
    (5) At the next piece-part exposure after the effective date of 
this AD, but before exceeding 9,900 cycles since new, replace the 
No. 3 bearing spring finger housing having P/N 2629M62G01 and a 
serial number identified in Table 1 of CFM SB LEAP-1A-72-00-0504-
01A-930A-D, Issue 002, with a part eligible for installation.

(h) Terminating Action

    Replacement of the No. 3 bearing spring finger housing having P/
N 2629M62G01 and a serial number identified in Table 1 or Table 2 of 
CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002 with a part eligible 
for installation, as specified in paragraphs (g)(2)(i) and (g)(5) of 
this AD, constitutes terminating action for the calculations 
required by paragraph (g)(1) of this AD.

(i) Definition

    For the purpose of this AD, a ``part eligible for installation'' 
is a No. 3 bearing spring finger housing that does not have P/N 
2629M62G01 and a serial number identified in Table 1 or Table 2 of 
CFM SB LEAP-1A-72-00-0504-01A-930A-D, Issue 002.

(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, AIR-520 Continued Operational 
Safety Branch, send it to the attention of the person identified in 
paragraph (k) of this AD and email it to: [email protected].
    (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.
    (3) For service information that contains steps that are labeled 
as Required for Compliance (RC), the following provisions apply.
    (i) The steps labeled as RC, including substeps under an RC step 
and any figures identified in an RC step, that are required by 
paragraph (g) of this AD must be done to comply with this AD. An 
AMOC is required for any deviations to RC steps required by 
paragraph (g) of this AD, including substeps and identified figures.
    (ii) Steps not labeled 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 RC 
steps, including substeps and identified figures, can still be done 
as specified, and the airplane can be put back in an airworthy 
condition.

(k) Additional Information

    For more information about this AD, Mehdi Lamnyi, Aviation 
Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; 
phone: (781) 238-7743; email: [email protected].

(l) 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 the AD specifies otherwise.
    (i) CFM International, S.A. Service Bulletin LEAP-1A-72-00-0504-
01A-930A-D, Issue 002, dated October 17, 2023.
    (ii) [Reserved]
    (3) For service information, contact CFM International, S.A., GE 
Aviation Fleet Support, 1 Neumann Way, M/D Room 285, Cincinnati, OH 
45215; phone: (877) 432-3272; email: [email protected].
    (4) You may view this service information at 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.
    (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/[email protected]">www.archives.gov/federal-register/cfr/[email protected].

    Issued on March 29, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-09110 Filed 4-26-24; 8:45 am]
BILLING CODE 4910-13-P
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.