Airworthiness Directives; CFM International, S.A. Engines

[Federal Register Volume 90, Number 41 (Tuesday, March 4, 2025)]
[Rules and Regulations]
[Pages 11116-11118]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-03459]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2424; Project Identifier AD-2024-00416-E; 
Amendment 39-22970; AD 2025-04-12]
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, LEAP-1B, and LEAP-
1C engines. This AD was prompted by a manufacturer investigation that 
revealed a quality escape for low-pressure turbine (LPT) disks made 
from forgings with nonconforming grain size. This AD requires removal 
and replacement of the LPT stage 4 and stage 5 disks. The FAA is 
issuing this AD to address the unsafe condition on these products.

DATES: This AD is effective April 8, 2025.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of April 8, 
2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-2424; 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:
    <bullet> 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].
    <bullet> 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-2024-2424.

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, LEAP-1B, and LEAP-1C engines. The NPRM published in the Federal 
Register on November 8, 2024 (89 FR 88681). The NPRM was prompted by a 
report of a quality escape on LPT disks made from forgings with 
nonconforming material grain size on certain CFM Model LEAP-1A and 
LEAP-1B engines. The supplier assessed the duplex micro-structure using 
an arithmetic average grain size instead of considering the coarsest 
grain size. After a re-check of all forgings, the supplier has 
identified a number of parts with a coarse grain size that is below the 
drawing requirement. In the NPRM, the FAA proposed to require removal 
and replacement of the LPT stage 4 and stage 5 disks at the next piece-
part exposure or before exceeding between 2,400 and 19,000 cycles since 
new, depending on the applicable threshold identified in CFM Service 
Bulletin (SB) LEAP-1A-72-00-0519-01A-930A-D, Issue 001-00, dated 
September 18, 2024 (CFM SB LEAP-1A-72-00-0519-01A-930A-D) or CFM SB 
LEAP-1B-72-00-0419-01A-930A-D Issue 001-00, dated September 18, 2024 
(CFM SB LEAP-1B-72-00-0419-01A-930A-D). 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 two commenters. Commenters included 
Air Line Pilots Association, International and The Boeing Company. 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 CFM SB LEAP-1A-72-00-0519-01A-930A-D; CFM SB LEAP-
1B-72-00-0419-01A-930A-D; and CFM SB LEAP-1C-72-00-0100-01A-930A-D, 
Issue 001-00, dated September 18, 2024. This material specifies the 
part numbers and serial numbers of affected LPT disks, and the cycles 
since new thresholds for the replacement of affected LPT disks. These 
documents are distinct because they apply to different engine models. 
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 13 engines installed on 
airplanes of U.S. registry. The FAA estimates that 2 engines will need 
removal and replacement of the LEAP-1A LPT stage 5 disk; 8 engines will 
need removal and replacement of the LEAP-1B LPT stage 5 disk; and 3 
engines will need removal and replacement of the LEAP-1B LPT stage 4 
disk.
    The FAA estimates the following costs to comply with this AD:

[[Page 11117]]



                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
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Remove and replace LEAP-1A LPT stage 5  150 work-hours x $85 per        $225,500        $238,250        $476,500
 disk.                                   hour = $12,750.
Remove and replace LEAP-1B LPT stage 5  150 work-hours x $85 per         205,100         217,850       1,742,800
 disk.                                   hour = $12,750.
Remove and replace LEAP-1B LPT stage 4  150 work-hours x $85 per         442,800         455,550       1,366,650
 disk.                                   hour = $12,750.
----------------------------------------------------------------------------------------------------------------

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(f), 40113, 44701.


Sec.  39.13  [Amended]

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

2025-04-12 CFM International, S.A.: Amendment 39-22970; Docket No. 
FAA-2024-2424; Project Identifier AD-2024-00416-E.

(a) Effective Date

    This airworthiness directive (AD) is effective April 8, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the following CFM International, S.A. (CFM) 
Model engines:
    (1) 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;
    (2) LEAP-1B21, LEAP-1B23, LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-
1B28B1, LEAP-1B28B2, LEAP-1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, LEAP-
1B28BBJ2; and
    (3) LEAP-1C28, LEAP-1C30, and LEAP-1C30B1.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a manufacturer investigation that 
revealed a quality escape for certain low-pressure turbine (LPT) 
disks made from forgings with nonconforming grain size. The FAA is 
issuing this AD to prevent the fracture and uncontained failure of 
certain LPT stage 4 and stage 5 disks. The unsafe condition, if not 
addressed, could result in uncontained part release, damage to the 
engine, and damage to the airplane.

(f) Compliance

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

(g) Required Actions

    (1) For LEAP-1A engines with an installed LPT stage 5 disk 
having a part number (P/N) and serial number (S/N) listed in Table 
1, Table 2, or Table 3 of CFM Service Bulletin (SB) LEAP-1A-72-00-
0519-01A-930A-D, Issue 001-00, dated September 18, 2024 (CFM SB 
LEAP-1A-72-00-0519-01A-930A-D): At the next piece-part exposure of 
the LPT stage 5 disk, or before exceeding the applicable cycles 
since new (CSN) threshold identified in Table 1, Table 2, or Table 3 
of CFM SB LEAP-1A-72-00-0519-01A-930A-D, whichever occurs first 
after the effective date of this AD, remove the LPT stage 5 disk 
from service and replace with a part eligible for installation.
    (2) For LEAP-1B engines with an installed LPT stage 4 disk 
having a P/N and S/N listed in Table 1 of CFM SB LEAP-1B-72-00-0419-
01A-930A-D, Issue 001-00, dated September 18, 2024 (CFM SB LEAP-1B-
72-00-0419-01A-930A-D): At the next piece-part exposure of the LPT 
stage 4 disk, or before exceeding the applicable CSN threshold 
identified in Table 1 of CFM SB LEAP-1B-72-00-0419-01A-930A-D, 
whichever occurs first after the effective date of this AD, remove 
the LPT stage 4 disk from service and replace with a part eligible 
for installation.
    (3) For LEAP-1B engines with an installed LPT stage 5 disk 
having a P/N and S/N listed in Table 2 or Table 3 of CFM SB LEAP-1B-
72-00-0419-01A-930A-D: At the next piece-part exposure of the LPT 
stage 5 disk, or before exceeding the applicable CSN threshold 
identified in Table 2 or Table 3 of CFM SB LEAP-1B-72-00-0419-01A-
930A-D, whichever occurs first after the effective date of this AD, 
remove the LPT stage 5 disk 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 LPT 
stage 5 disk that has a P/N and S/N identified in Table 1, Table 2, 
or Table 3, of CFM SB LEAP-1A-72-00-0519-01A-930A-D, in any LEAP-1A 
engine.
    (2) After the effective date of this AD, do not install an LPT 
stage 4 disk or LPT stage 5 disk that has a P/N and S/N identified 
in Table 1, Table 2, or Table 3, of CFM SB LEAP-1B-72-00-0419-01A-
930A-D in any LEAP-1B engine.
    (3) After the effective date of this AD, do not install an LPT 
stage 5 disk that has a P/N and S/N identified in Table 1 of CFM SB 
LEAP-1C-72-00-0100-01A-930A-D, Issue 001-00, dated September 18, 
2024, in any LEAP-1C engine.

[[Page 11118]]

(i) Definitions

    For the purpose of this AD:
    (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, and LEAP-1A35A 
engines.
    (2) ``LEAP-1B engines'' are CFM Model LEAP-1B21, LEAP-1B23, 
LEAP-1B25, LEAP-1B27, LEAP-1B28, LEAP-1B28B1, LEAP-1B28B2, LEAP-
1B28B2C, LEAP-1B28B3, LEAP-1B28BBJ1, and LEAP-1B28BBJ2 engines.
    (3) ``LEAP-1C engines'' are CFM Model LEAP-1C28, LEAP-1C30, and 
LEAP-1C30B1 engines.
    (4) A ``part eligible for installation'' on a LEAP-1A engine is 
an LPT stage 5 disk that does not have a P/N and S/N identified in 
Table 1, Table 2, or Table 3 of CFM SB LEAP-1A-72-00-0519-01A-930A-
D.
    (5) A ``part eligible for installation'' on a LEAP-1B engine is 
an LPT stage 4 disk or LPT stage 5 disk that does not have a P/N and 
S/N identified in Table 1, Table 2, or Table 3 of CFM SB LEAP-1B-72-
00-0419-01A-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 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 (SB) LEAP-1A-72-00-0519-01A-930A-D, 
Issue 001-00, dated September 18, 2024.
    (ii) CFM SB LEAP-1B-72-00-0419-01A-930A-D, Issue 001-00, dated 
September 18, 2024.
    (iii) CFM SB LEAP-1C-72-00-0100-01A-930A-D, Issue 001-00, dated 
September 18, 2024.
    (3) For CFM material identified in this AD, contact CFM 
International, S.A., GE Aviation Fleet Support, 1 Neumann Way, M/D 
Room 285, Cincinnati, OH 45215; phone: (877) 432-3272; email: 
[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 February 21, 2025.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-03459 Filed 3-3-25; 8:45 am]
BILLING CODE 4910-13-P

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