Airworthiness Directives; CFM International, S.A. Engines

Published date11 October 2023
Record Number2023-22373
Citation88 FR 70409
CourtFederal Aviation Administration
SectionProposed rules
Federal Register, Volume 88 Issue 195 (Wednesday, October 11, 2023)
[Federal Register Volume 88, Number 195 (Wednesday, October 11, 2023)]
                [Proposed Rules]
                [Pages 70409-70412]
                From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
                [FR Doc No: 2023-22373]
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                DEPARTMENT OF TRANSPORTATION
                Federal Aviation Administration
                14 CFR Part 39
                [Docket No. FAA-2023-1991; Project Identifier AD-2023-00700-E]
                RIN 2120-AA64
                Airworthiness Directives; CFM International, S.A. Engines
                AGENCY: Federal Aviation Administration (FAA), DOT.
                ACTION: Notice of proposed rulemaking (NPRM).
                -----------------------------------------------------------------------
                SUMMARY: The FAA proposes to adopt 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 proposed 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 proposed AD would require 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
                proposed AD would also require replacement of the No. 3 bearing spring
                finger housing. 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 November
                27, 2023.
                ADDRESSES: You may send comments, using the procedures found in 14 CFR
                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 by
                searching for and locating 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 NPRM, any comments
                received, and other information. The street address for Docket
                Operations is listed above.
                 Material Incorporated by Reference:
                 For service information identified in this NPRM, 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:
                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 ADDRESSES. Include ``Docket No. FAA-2023-1991; Project Identifier
                AD-2023-00700-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 amend
                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
                [[Page 70410]]
                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 was notified by the engine manufacturer 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.
                This 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.
                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.
                Related Service Information Under 1 CFR Part 51
                 The FAA reviewed CFM Service Bulletin (SB) LEAP-1A-72-00-0504-01A-
                930A-D, Issue 001, dated June 14, 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 ADDRESSES.
                Proposed AD Requirements in This NPRM
                 This proposed AD would 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. This proposed
                AD would 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 proposed AD
                would also require replacement of the No. 3 bearing spring finger
                housing, regardless of calculated level of NSV, at a certain time.
                Interim Action
                 The FAA considers that this proposed AD would be an interim action.
                The design approval holder is currently developing a modification to
                address this issue. The FAA may consider additional rulemaking on this
                subject.
                Costs of Compliance
                 The FAA estimates that this AD, if adopted as proposed, would
                affect 48 engines installed on airplanes of U.S. registry. The FAA
                estimates that 33 engines installed on airplanes of U.S. registry would
                require replacement of the No. 3 bearing spring finger housing.
                 The FAA estimates the following costs to comply with this proposed
                AD:
                 Estimated Costs
                ----------------------------------------------------------------------------------------------------------------
                 Cost per Cost on U.S.
                 Action Labor cost Parts cost product operators
                ----------------------------------------------------------------------------------------------------------------
                Calculate NSV data.................... 1 work-hour 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 proposed 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
                [[Page 70411]]
                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 this 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
                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:
                CFM International, S.A.: Docket No. FAA-2023-1991; Project
                Identifier AD-2023-00700-E.
                (a) Comments Due Date
                 The FAA must receive comments on this airworthiness directive
                (AD) by November 27, 2023.
                (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 001, dated June
                14, 2023 (CFM SB LEAP-1A-72-00-0504-01A-930A-D).
                (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.
                (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.
                 (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, discontinue the calculations
                required by paragraph (g)(1) of this AD and within 150 FCs of
                performing the calculation:
                 (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 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.
                 (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.
                 (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, 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, 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 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 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.
                (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 the branch office, 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.
                [[Page 70412]]
                (k) Related 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: [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 001, dated June 14, 2023.
                 (ii) [Reserved]
                 (3) For service information 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:
                [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 service information that is incorporated
                by reference at the National Archives and Records Administration
                (NARA). For information on the availability of this material at
                NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.
                 Issued on October 3, 2023.
                Ross Landes,
                Deputy Director for Regulatory Operations, Compliance & Airworthiness
                Division, Aircraft Certification Service.
                [FR Doc. 2023-22373 Filed 10-10-23; 8:45 am]
                BILLING CODE 4910-13-P
                

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