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[Federal Register Volume 90, Number 22 (Tuesday, February 4, 2025)]
[Rules and Regulations]
[Pages 8889-8891]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-02204]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2325; Project Identifier AD-2024-00412-E; 
Amendment 39-22927; AD 2025-01-03]
RIN 2120-AA64

Airworthiness Directives; CFM International, S.A. Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain CFM International, S.A. (CFM) Model LEAP-1A and LEAP-1C 
engines. This AD was prompted by an investigation of an in-flight shut 
down event that revealed the aft arm of the high-pressure turbine (HPT) 
rotor interstage seal had failed. This AD requires removal from service 
and replacement of the HPT rotor interstage seal for LEAP-1A engines. 
Since the HPT rotor interstage seal part number is interchangeable 
between LEAP-1A and LEAP-1C engines, this AD also prohibits 
installation of these affected parts onto any LEAP-1A or LEAP-1C 
engine. The FAA is issuing this AD to address the unsafe condition on 
these products.

DATES: This AD is effective March 11, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of March 11, 
2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-2325; 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 CFM material identified in this AD, contact CFM, 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 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. It is also available at 
regulations.gov under Docket No. FAA-2024-2325.

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-
1A and LEAP-1C engines. The NPRM published in the Federal Register on 
October 2, 2024 (89 FR 80155). The NPRM was prompted by a report of an 
in-flight shutdown caused by turbine blades that had broken and metal 
that entered the exhaust. A manufacturer investigation later revealed 
that the aft arm of the HPT rotor interstage seal had failed due to a 
non-conforming surface condition in the fillet area coupled with 
higher-than-expected operating stress due to friction. In the NPRM, the 
FAA proposed to require removal from service and replacement of the HPT 
rotor interstage seal. Since the HPT rotor interstage seal part number 
is interchangeable between LEAP-1A and LEAP-1C engines, the NPRM also 
proposed to prohibit installation of these affected parts onto any 
LEAP-1A or LEAP-1C engine. 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 Airline Pilots Association 
International (ALPA), StandardAero, an individual commenter, and an 
anonymous commenter. All commenters supported the NPRM without change.

Conclusion

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

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed the following CFM material:
     CFM Service Bulletin (SB) LEAP-1A-72-00-0525-01A-930A-D, 
Issue 002-00, dated June 28, 2024, which provides the serial numbers 
(S/Ns) of the affected HPT rotor interstage seals for LEAP-1A engines.
     CFM SB LEAP-1C-72-00-0124-01A-930A-D, Issue 001-00, dated 
September 5, 2024, which provides the S/Ns of the affected HPT rotor 
interstage seals that are excluded from installation onto LEAP-1C 
engines.
    This material also includes instructions for removal and 
installation of the HPT rotor interstage seal. This material is 
reasonably available because the interested parties have access to it 
through their normal course of business or by the means identified in 
the ADDRESSES section.

Costs of Compliance

    The FAA estimates that this AD affects 56 engines installed on 
airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this AD:

[[Page 8890]]

                                                 Estimated costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace HPT rotor interstage seal.....  12 work-hours x $85 per         $195,000        $196,020     $10,977,120
                                         hour = $1,020.
----------------------------------------------------------------------------------------------------------------

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:

2025-01-03 CFM International, S.A.: Amendment 39-22927; Docket No. 
FAA-2024-2325; Project Identifier AD-2024-00412-E.

(a) Effective Date

    This airworthiness directive (AD) is effective March 11, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the following CFM International, S.A. (CFM) 
engines:
    (1) 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.
    (2) Model LEAP-1C28, LEAP-1C30, and LEAP-1C30B1 engines.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by an investigation of an in-flight shut 
down event that revealed the aft arm of the high-pressure turbine 
(HPT) rotor interstage seal had failed. The FAA is issuing this AD 
to prevent failure of the HPT rotor interstage seal. The unsafe 
condition, if not addressed, could result in failure of one or more 
engines, loss of thrust control, and loss of the airplane.

(f) Compliance

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

(g) Required Actions

    (1) For LEAP-1A engines having an HPT rotor interstage seal 
installed with a part number (P/N) and serial number (S/N) listed in 
Table 1 of CFM Service Bulletin (SB) LEAP-1A-72-00-0525-01A-930A-D, 
Issue 002-00, dated June 28, 2024 (CFM SB LEAP-1A-72-00-0525-01A-
930A-D Issue 002-00), at the next engine shop visit or before 
exceeding the applicable cyclic threshold in table 1 to paragraph 
(g)(1) of this AD, whichever occurs first after the effective date 
of this AD, remove the affected HPT rotor interstage seal from 
service and replace with a part eligible for installation.

  Table 1 to Paragraph (g)(1)--Removal Thresholds for Each Engine Model
------------------------------------------------------------------------
              Engine model                   Removal cyclic threshold
------------------------------------------------------------------------
LEAP-1A23, LEAP-1A24, LEAP-1A24E1, LEAP- 11,100 cycles since new (CSN)
 1A26, LEAP-1A26E1, LEAP-1A29, LEAP-      accumulated on the affected
 1A30, LEAP-1A32, LEAP-1A33, LEAP-        part.
 1A33B2, and LEAP-1A35A.
LEAP-1A26CJ and LEAP-1A29CJ............  9,700 CSN accumulated on the
                                          affected part.
------------------------------------------------------------------------

    (2) For LEAP-1A engines having an HPT rotor interstage seal 
installed with a P/N and S/N listed in Table 2 of CFM SB LEAP-1A-72-
00-0525-01A-930A-D Issue 002-00, at the next piece part exposure or 
before exceeding the applicable cyclic threshold in table 1 to 
paragraph (g)(1) of this AD, whichever occurs first after the 
effective date of this AD, remove the affected HPT rotor interstage 
seal from service and replace with a part eligible for installation.

(h) Installation Prohibition

    (1) After the effective date of this AD, do not install an HPT 
rotor interstage seal having a P/N and S/N listed in Table 1 or 
Table 2 of CFM SB LEAP-1A-72-00-0525-01A-930A-D Issue 002-00, in any 
LEAP-1A engine.
    (2) After the effective date of this AD, do not install an HPT 
rotor interstage seal having a P/N and S/N listed in Table 1 of CFM 
SB LEAP-1C-72-00-0124-01A-930A-D, Issue 001-00, dated September 5, 
2024, in any LEAP-1C engine.

(i) Definitions

    For the purpose of this AD:

[[Page 8891]]

    (1) ``LEAP-1A engines'' are 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, LEAP-1A35A 
engines.
    (2) ``LEAP-1C engines'' are CFM Model LEAP-1C28, LEAP-1C30, and 
LEAP-1C30B1 engines.
    (3) A ``part eligible for installation'' is any HPT rotor 
interstage seal having a P/N and S/N that is not listed in Table 1 
or Table 2 of CFM SB LEAP-1A-72-00-0525-01A-930A-D Issue 002-00.
    (4) An ``engine shop visit'' is the induction of an engine into 
the shop for maintenance involving the separation of major mating 
engine flanges, except for the separation of engine flanges solely 
for the purposes of transportation without subsequent engine 
maintenance.
    (5) A ``piece-part exposure'' is when the HPT rotor interstage 
seal is separated from the HPT rotor assembly.

(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: [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.

(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: [email protected].

(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.
    (i) CFM Service Bulletin LEAP-1A-72-00-0525-01A-930A-D, Issue 
002-00, dated June 28, 2024.
    (ii) CFM Service Bulletin LEAP-1C-72-00-0124-01A-930A-D, Issue 
001-00, dated September 5, 2024.
    (3) For CFM material identified in this AD, contact CFM, 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 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.
    (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 [email protected].

    Issued on January 30, 2025.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-02204 Filed 2-3-25; 8:45 am]
BILLING CODE 4910-13-P
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