```

[Federal Register Volume 89, Number 246 (Monday, December 23, 2024)]
[Proposed Rules]
[Pages 104462-104465]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-30539]

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

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2668; Project Identifier AD-2024-00561-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 supersede Airworthiness Directive (AD) 
2023-09-06, which applies to all CFM International, S.A. Model (CFM) 
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 (LEAP-1A) engines. AD 2023-09-06 requires replacement of 
certain high-pressure turbine (HPT) rotor stage 1 disks (HPT stage 1 
disks), forward outer seals, and compressor rotor stages 6-10 spools. 
AD 2023-09-06 also prohibits installation of an HPT stage 1 disk, 
forward outer seal, or compressor rotor stages 6-10 spool that has a 
part number and serial number identified in the service information 
onto any engine. Since the FAA issued AD 2023-09-06, the manufacturer 
identified additional affected parts that were manufactured from 
material suspected to have reduced material properties due to iron 
inclusion, which prompted this AD. This proposed AD would retain the 
requirements to replace certain HPT stage 1 disks, forward outer seals, 
and compressor rotor stages 6-10 spools and expand the applicability to 
include additional affected parts manufactured from the same material 
suspected to have reduced material properties due to iron inclusion. 
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 February 6, 
2025.

ADDRESSES: You may send comments, using the procedures found in 14 CFR

[[Page 104463]]

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 under 
Docket No. FAA-2024-2668; 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 CFM material identified in this proposed 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.

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 the ADDRESSES section. Include ``Docket No. FAA-2024-2668; 
Project Identifier AD-2024-00561-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 issued AD 2023-09-06, Amendment 39-22429 (88 FR 32092, May 
19, 2023) (AD 2023-09-06), for all CFM Model LEAP-1A engines. AD 2023-
09-06 was prompted by a manufacturer investigation that revealed that 
certain HPT stage 1 disks, forward outer seals, and compressor rotor 
stages 6-10 spools were manufactured from material suspected to have 
reduced material properties due to iron inclusion. AD 2023-09-06 
requires replacement of certain HPT stage 1 disks, forward outer seals, 
and compressor rotor stages 6-10 spools. The agency issued AD 2023-09-
06 to prevent fracture and consequent uncontained failure of certain 
HPT stage 1 disks, forward outer seals, and compressor rotor stages 6-
10 spools.

Actions Since AD 2023-09-06 Was Issued

    Since the FAA issued AD 2023-09-06, further analysis by the 
manufacturer identified additional affected parts that were 
manufactured from material suspected to have reduced material 
properties due to iron inclusion. This condition, if not addressed, 
could result in uncontained debris 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 LEAP-1A-72-00-0507-01A-930A-
D, Issue 001, dated January 24, 2024, which identifies the part numbers 
and serial numbers of HPT stage 1 disks, forward outer seals, and 
compressor rotor stages 6-10 spools with potentially reduced material 
properties and specifies procedures for replacement of these parts.
    This proposed AD would also require the following material, which 
the Director of the Federal Register approved for incorporation by 
reference as of June 23, 2023 (88 FR 32092, May 19, 2023):
     CFM Service Bulletin LEAP-1A-72-00-0470-01A-930A-D, Issue 
003, dated March 3, 2023.
     CFM Service Bulletin LEAP-1A-72-00-0493-01A-930A-D, Issue 
002, dated November 17, 2022.
     CFM Service Bulletin LEAP-1A-72-00-0496-01A-930A-D, Issue 
001, dated March 7, 2023.
    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 retain all of the requirements of AD 2023-
09-06. This proposed AD would require replacement of certain HPT stage 
1 disks, forward outer seals, and compressor rotor stages 6-10 spools. 
This proposed AD would also prohibit installation of an HPT stage 1 
disk, forward outer seal, or compressor rotor stages 6-10 spool that 
has a part number and serial number identified in the material 
incorporated by reference onto any engine.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 42 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

[[Page 104464]]

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
              Action                      Labor cost             Parts cost           product        operators
----------------------------------------------------------------------------------------------------------------
Replace HPT stage 1 disk (42        8 work-hours x $85     $215,635 (pro-rated).        $216,315      $9,085,230
 affected parts).                    per hour = $680.
Replace forward outer seal (24      8 work-hours x $85     $47,500 (pro-rated)..          48,180       1,156,320
 affected parts).                    per hour = $680.
Replace compressor rotor stages 6-  8 work-hours x $85     $37,660 (pro-rated)..          38,340         575,100
 10 spool (15 affected parts).       per hour = $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

    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 that the 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:
0
a. Removing Airworthiness Directive 2023-09-06, Amendment 39-22429 (88 
FR 32092, May 19, 2023); and
0
b. Adding the following new airworthiness directive:

CFM International, S.A.: Docket No. FAA-2024-2668; Project 
Identifier AD-2024-00561-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by February 6, 2025.

(b) Affected ADs

    This AD replaces AD 2023-09-06, Amendment 39-22429 (88 FR 32092, 
May 19, 2023) (AD 2023-09-06).

(c) Applicability

    This AD applies to CFM International, S.A. Model (CFM) 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.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7230, Turbine Engine 
Compressor Section; 7250, Turbine Section.

(e) Unsafe Condition

    This AD was prompted by a manufacturer investigation that 
revealed that certain high-pressure turbine (HPT) rotor stage 1 
disks (HPT stage 1 disks), forward outer seals, and compressor rotor 
stages 6-10 spools were manufactured from material suspected to have 
reduced material properties due to iron inclusion. The FAA is 
issuing this AD to prevent fracture and consequent uncontained 
failure of certain HPT stage 1 disks, forward outer seals, and 
compressor rotor stages 6-10 spools. The unsafe condition, if not 
addressed, could result in uncontained debris 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 engines with an installed HPT stage 1 disk, forward 
outer seal or compressor rotor stages 6-10 spool having a part 
number (P/N) and serial number (S/N) identified in Compliance, 
paragraph 3.E., Tables 1 through 9, of CFM Service Bulletin (SB) 
LEAP-1A-72-00-0496-01A-930A-D, Issue 001, dated March 7, 2023 (CFM 
SB LEAP-1A-72-00-0496-01A-930A-D): At the next piece-part exposure 
of the HPT stage 1 disk, forward outer seal, or compressor rotor 
stages 6-10 spool, as applicable, or before exceeding the applicable 
cycles since new (CSN) threshold identified in Compliance, paragraph 
3.E., Tables 1 through 9, of CFM SB LEAP-1A-72-00-0496-01A-930A-D, 
whichever occurs first after June 23, 2023 (the effective date of AD 
2023-09-06); or if the applicable CSN threshold has been exceeded as 
of June 23, 2023 (the effective date of AD 2023-09-06), within 50 
flight cycles (FCs) from June 23, 2023 (the effective date of AD 
2023-09-06); remove the HPT stage 1 disk, forward outer seal, or 
compressor rotor stages 6-10 spool, as applicable, from service and 
replace with a part eligible for installation.
    (2) For engines with an installed forward outer seal having a P/
N and S/N identified in Compliance, paragraph 3.E., Tables 1 through 
2, of CFM SB LEAP-1A-72-00-0470-01A-930A-D, Issue 003, dated March 
3, 2023 (CFM SB LEAP-1A-72-00-0470-01A-930A-D): At the next piece-
part exposure of the forward outer seal, or before exceeding the 
applicable CSN threshold identified in Compliance, paragraph 3.E., 
Tables 1 through 2, of CFM SB LEAP-1A-72-00-0470-01A-930A-D, 
whichever occurs first after June 23, 2023 (the effective date of AD 
2023-09-06); or if the applicable CSN threshold has been exceeded as 
of June 23, 2023 (the effective date of AD 2023-09-06), within 50 
FCs from June 23, 2023 (the effective date of AD 2023-09-06); remove 
the forward outer seal from service and replace with a part eligible 
for installation.
    (3) For engines with an installed HPT stage 1 disk having a P/N 
and S/N identified in Compliance, paragraph 3.E., Tables 1 through 
2, of CFM SB LEAP-1A-72-00-0493-01A-930A-D, Issue 002, dated 
November 17, 2022 (CFM SB LEAP-1A-72-00-0493-01A-930A-D): At the 
next piece-part exposure of the HPT stage 1 disk, or before 
exceeding the applicable CSN threshold identified in Compliance, 
paragraph 3.E., Tables 1 through

[[Page 104465]]

2, of CFM SB LEAP-1A-72-00-0493-01A-930A-D, whichever occurs first 
after June 23, 2023 (the effective date of AD 2023-09-06); or if the 
applicable CSN threshold has been exceeded as of June 23, 2023 (the 
effective date of AD 2023-09-06), within 50 FCs from June 23, 2023 
(the effective date of AD 2023-09-06), remove the HPT stage 1 disk 
from service and replace with a part eligible for installation.
    (4) For engines with an installed HPT stage 1 disk having a P/N 
and S/N identified in Compliance, paragraph 3.E., Tables 1 through 
2, of CFM SB LEAP-1A-72-00-0507-01A-930A-D, Issue 001, dated January 
24, 2024 (CFM SB LEAP-1A-72-00-0507-01A-930A-D): At the next piece-
part exposure of the HPT stage 1 disk, or before exceeding the 
applicable CSN threshold identified in Compliance, paragraph 3.E., 
Tables 1 through 2, of CFM SB LEAP-1A-72-00-0507-01A-930A-D, 
whichever occurs first after the effective date of this AD; or if 
the applicable CSN threshold has been exceeded as of the effective 
date of this AD, within 50 FCs from the effective date of this AD; 
remove the HPT stage 1 disk from service and replace with a part 
eligible for installation.

 (h) Definition

    For the purpose of this AD, a ``part eligible for installation'' 
is an HPT stage 1 disk, forward outer seal, or compressor rotor 
stages 6-10 spool that does not have a P/N and S/N identified in the 
service information listed in paragraphs (g)(1) through (4) of this 
AD.

(i) Installation Prohibition

    After the effective date of this AD, do not install an HPT stage 
1 disk, forward outer seal, or compressor rotor stages 6-10 spool 
that has a P/N and S/N identified in the service information listed 
in paragraphs (g)(1) through (4) of this AD on any engine.

(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.
    (3) The following material was approved for IBR on [DATE 35 DAYS 
AFTER PUBLICATION OF THE FINAL RULE].
    (i) CFM Service Bulletin LEAP-1A-72-00-0507-01A-930A-D, Issue 
001, dated January 24, 2024.
    (ii) [Reserved]
    (4) The following material was approved for IBR on June 23, 2023 
(88 FR 32092, May 19, 2023).
    (i) CFM Service Bulletin LEAP-1A-72-00-0470-01A-930A-D, Issue 
003, dated March 3, 2023.
    (ii) CFM Service Bulletin LEAP-1A-72-00-0493-01A-930A-D, Issue 
002, dated November 17, 2022.
    (iii) CFM Service Bulletin LEAP-1A-72-00-0496-01A-930A-D, Issue 
001, dated March 7, 2023.
    (5) 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].
    (6) 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.
    (7) 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 December 17, 2024.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-30539 Filed 12-20-24; 8:45 am]
BILLING CODE 4910-13-P
```