[Federal Register Volume 89, Number 217 (Friday, November 8, 2024)]
[Proposed Rules]
[Pages 88681-88683]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-25869]



[[Page 88681]]

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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]
RIN 2120-AA64


Airworthiness Directives; CFM International, S.A. Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for certain CFM International, S.A. (CFM) Model LEAP-1A, LEAP-1B, and 
LEAP-1C engines. This proposed 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 
proposed AD would require removal and replacement of the LPT stage 4 
and stage 5 disks. 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 December 
23, 2024.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
    <bullet> Federal eRulemaking Portal: Go to regulations.gov. Follow 
the instructions for submitting comments.
    <bullet> Fax: (202) 493-2251.
    <bullet> 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.
    <bullet> Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-2424; 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 NPRM, any comments received, and other 
information. The street address for Docket Operations is listed above.
    Material Incorporated by Reference:
    <bullet> For CFM material identified in this proposed 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: 
<a href="/cdn-cgi/l/email-protection#d3b2a5bab2a7babcbdfdb5bfb6b6a7a0a6a3a3bca1a793b4b6fdb0bcbe"><span class="__cf_email__" data-cfemail="96f7e0fff7e2fff9f8b8f0faf3f3e2e5e3e6e6f9e4e2d6f1f3b8f5f9fb">[email protected]</span></a>.
    <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.

FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aviation Safety 
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: 
(781) 238-7743; email: <a href="/cdn-cgi/l/email-protection#87eae2efe3eea9ebe6eae9feeec7e1e6e6a9e0e8f1"><span class="__cf_email__" data-cfemail="5b363e333f3275373a363522321b3d3a3a753c342d">[email protected]</span></a>.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    The FAA invites you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2024-2424; 
Project Identifier AD-2024-00416-E'' at the beginning of your comments. 
The most helpful comments reference a specific portion of the proposal, 
explain the reason for any recommended change, and include supporting 
data. The FAA will consider all comments received by the closing date 
and may revise this proposal because of those comments.
    Except for Confidential Business Information (CBI) as described in 
the following paragraph, and other information as described in 14 CFR 
11.35, the FAA will post all comments received, without change, to 
regulations.gov, including any personal information you provide. The 
agency will also post a report summarizing each substantive verbal 
contact received about this NPRM.

Confidential Business Information

    CBI is commercial or financial information that is both customarily 
and actually treated as private by its owner. Under the Freedom of 
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public 
disclosure. If your comments responsive to this NPRM contain commercial 
or financial information that is customarily treated as private, that 
you actually treat as private, and that is relevant or responsive to 
this NPRM, it is important that you clearly designate the submitted 
comments as CBI. Please mark each page of your submission containing 
CBI as ``PROPIN.'' The FAA will treat such marked submissions as 
confidential under the FOIA, and they will not be placed in the public 
docket of this NPRM. Submissions containing CBI should be sent to Mehdi 
Lamnyi, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des 
Moines, WA 98198. Any commentary that the FAA receives which is not 
specifically designated as CBI will be placed in the public docket for 
this rulemaking.

Background

    The FAA received 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.
    This condition, if not addressed, could result in uncontained part 
release, damage to the engine, and damage to the airplane.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed CFM Service Bulletin (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); 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); 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.

Proposed AD Requirements in This NPRM

    This proposed AD would 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 SB LEAP-1A-72-00-0519-01A-930A-D 
or CFM SB LEAP-1B-72-00-0419-01A-930A-D.

[[Page 88682]]

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 13 engines installed on airplanes of U.S. registry.
    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
----------------------------------------------------------------------------------------------------------------
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      150.00 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

    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-2024-2424; Project 
Identifier AD-2024-00416-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by December 23, 2024.

(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

[[Page 88683]]

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.

(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 (l) of this AD and email to: <a href="/cdn-cgi/l/email-protection#02434f4d41426463632c656d74"><span class="__cf_email__" data-cfemail="3e7f73717d7e585f5f10595148">[email protected]</span></a>.
    (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: <a href="/cdn-cgi/l/email-protection#6a070f020e0344060b070413032a0c0b0b440d051c"><span class="__cf_email__" data-cfemail="cca1a9a4a8a5e2a0ada1a2b5a58caaadade2aba3ba">[email protected]</span></a>.

(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: 
<a href="/cdn-cgi/l/email-protection#2445524d45504d4b4a0a4248414150575154544b56506443410a474b49"><span class="__cf_email__" data-cfemail="2c4d5a454d58454342024a404949585f595c5c435e586c4b49024f4341">[email protected]</span></a>.
    (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 <a href="/cdn-cgi/l/email-protection#771105591e1904071214031e1819371916051659101801"><span class="__cf_email__" data-cfemail="c7a1b5e9aea9b4b7a2a4b3aea8a987a9a6b5a6e9a0a8b1">[email protected]</span></a>.

    Issued on November 4, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-25869 Filed 11-7-24; 8:45 am]
BILLING CODE 4910-13-P


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