[Federal Register Volume 88, Number 236 (Monday, December 11, 2023)]
[Rules and Regulations]
[Pages 85836-85838]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-27092]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-1216; Project Identifier AD-2023-00502-E; 
Amendment 39-22614; AD 2023-23-12]
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 all 
CFM International, S.A. (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 (LEAP-1B) engines. This AD was 
prompted by a manufacturer investigation that revealed that certain 
high-pressure turbine (HPT) rotor stage 1 disks (HPT stage 1 disks) and 
a certain compressor rotor stages 6-10 spool were manufactured from 
material suspected to have reduced material properties due to iron 
inclusion. This AD requires replacing certain HPT stage 1 disks and a 
certain compressor rotor stages 6-10 spool. The FAA is issuing this AD 
to address the unsafe condition on these products.

DATES: This AD is effective January 16, 2024.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of January 16, 
2024.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2023-1216; 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 service information identified in this final rule, 
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. It is 
also available at regulations.gov under Docket No. FAA-2023-1216.

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 CFM International, S.A. 
(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. The NPRM published in the Federal Register on 
July 24, 2023 (88 FR 47404). The NPRM was prompted by a manufacturer 
investigation that detected iron inclusion in three non-LEAP-1B HPT 
rotor disks. Further investigation determined that the iron inclusion 
is attributed to deficiencies in the manufacturing process. The 
manufacturer also determined that certain LEAP-1B HPT stage 1 disks and 
a certain compressor rotor stages 6-10 spool manufactured using the 
same process may have reduced material properties and a lower fatigue 
life capability due to iron inclusion, which may cause premature 
fracture and subsequent uncontained failure of certain HPT stage 1 
disks and a certain compressor rotor stages 6-10 spool.
    In the NPRM, the FAA proposed to require replacement of certain HPT 
stage 1 disks and a certain compressor rotor stages 6-10 spool and also 
prohibit installation of an HPT stage 1 disk or compressor rotor stages 
6-10 spool that has a part number and serial number identified in the 
service information onto any engine. The FAA is issuing this AD to 
address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

    The FAA received comments from five commenters. Commenters included 
CFM International, United Air Lines (United), The Boeing Company 
(Boeing), Air Line Pilots Association, International (ALPA) and Lynx 
Air (Lynx). United, Boeing, and ALPA supported the NPRM without change. 
The following presents the comments received on the NPRM from CFM and 
Lynx and the FAA's response to each comment.

Request To Update Service Information

    CFM advised that updated service information for replacement of the 
HPT Stage 1 disks and high-pressure compressor (HPC) Stage 6-10 spool 
has been published. This updated service information provides certain 
corrections, identifies Required by Compliance annotations, and updated 
cost information to adequately address this unsafe condition. CFM 
recommends the latest revision to be utilized in this final rule.
    The FAA agrees with CFM's recommendation to utilize the updated

[[Page 85837]]

service information and has updated this final rule to reflect the 
service information that is to be incorporated by reference in this 
final rule.

Request To Issue Separate AD Actions

    Lynx stated that the reference of HPC Stage 6-10 spool should be 
removed from the manufacturer service information; and additional 
removal instruction should be provided to address the unsafe condition 
as it pertains to this affected part. Lynx pointed out that issuing a 
single AD addressing HPC Stage 6-10 spools and HPT Stage 1 disks, could 
cause a certain level of uncertainty when maintaining maintenance 
records and incorporating these applicable engines into the operator's 
maintenance programs. Lynx suggested separate ADs should be issued to 
minimize the risk of confusion as it pertains to ensuring this unsafe 
condition has been addressed on these engines.
    The FAA disagrees with the request to require the manufacturer to 
revise their service information and issue separate ADs for each 
affected part. Since the applicability, unsafe condition, required 
action, and corrective action, are consistent among the affected parts 
and the FAA has determined that the content of the service bulletin 
addresses the unsafe condition, there is no need for separate service 
bulletins or separate ADs.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for any changes described 
previously, this AD is adopted as proposed in the NPRM. None of the 
changes will increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed CFM Service Bulletin LEAP-1B-72-00-0392-01A-930A-
D, Issue 002, dated September 5, 2023. This service information 
identifies the part numbers and serial numbers of HPT stage 1 disks and 
a compressor rotor stages 6-10 spool with potentially reduced material 
properties and specifies procedures for replacement of these parts. 
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 section.

Costs of Compliance

    The FAA estimates that this AD affects 39 engines installed on 
airplanes of U.S. registry. These 39 engines require replacement of the 
HPT stage 1 disk. The FAA estimates that there are no engines installed 
on airplanes of U.S. registry that require replacement of the 
compressor rotor stages 6-10 spool.
    The FAA estimates the following costs to comply with this AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
              Action                      Labor cost             Parts cost           product        operators
----------------------------------------------------------------------------------------------------------------
Replace HPT stage 1 disk..........  8 work-hours x $85     $215,635 (pro-rated).        $216,315      $8,436,285
                                     per hour = $680.
Replace compressor rotor stages 6-  8 work-hours x $85     $37,660 (pro-rated)..          38,340               0
 10 spool.                           per hour = $680.
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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:

2023-23-12 CFM International, S.A.: Amendment 39-22614; Docket No. 
FAA-2023-1216; Project Identifier AD-2023-00502-E.

(a) Effective Date

    This airworthiness directive (AD) is effective January 16, 2024.

(b) Affected ADs

    None.

(c) Applicability

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

[[Page 85838]]

(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) and a certain compressor rotor stages 6-10 
spool were manufactured from material suspected to have reduced 
material properties due to iron inclusion. The FAA is issuing this 
AD to prevent fracture and subsequent uncontained failure of certain 
HPT stage 1 disks and a certain compressor rotor stages 6-10 spool. 
The unsafe condition, if not addressed, could result in uncontained 
debris release, damage to the engine, and damage to the aircraft.

(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 having a part 
number (P/N) and serial number (S/N) identified in Compliance, 
paragraph 3.E., Tables 1 through 2, of CFM Service Bulletin (SB) 
LEAP-1B-72-00-0392-01A-930A-D, Issue 002, dated September 5, 2023 
(CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 2): At the next piece-
part exposure of the HPT stage 1 disk, or before exceeding the 
applicable cycles since new (CSN) threshold identified in 
Compliance, paragraph 3.E., Tables 1 through 2, of CFM SB LEAP-1B-
72-00-0392-01A-930A-D, Issue 2, 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 flight 
cycles (FCs) from the effective date of this AD; remove the HPT 
stage 1 disk from service and replace with a part eligible for 
installation.
    (2) For engines with an installed compressor rotor stages 6-10 
spool having a P/N and S/N identified in Compliance, paragraph 3.E., 
Table 3, of CFM SB LEAP-1B-72-00-0392-01A-930A-D, Issue 2: At the 
next piece-part exposure of the compressor rotor stages 6-10 spool, 
or before exceeding the applicable CSN threshold identified in 
Compliance, paragraph 3.E., Table 3, of CFM SB LEAP-1B-72-00-0392-
01A-930A-D, Issue 2, 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 compressor rotor stages 6-10 spool 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 or compressor rotor stages 6-10 spool that 
does not have a P/N and S/N identified in Compliance, paragraph 
3.E., Tables 1 through 3 of CFM SB LEAP-1B-72-00-0392-01A-930A-D, 
Issue 2.

(i) Installation Prohibition

    After the effective date of this AD, do not install an HPT stage 
1 disk or compressor rotor stages 6-10 spool that has a P/N and S/N 
identified in Compliance, paragraph 3.E., Tables 1 through 3 of CFM 
SB LEAP-1B-72-00-0392-01A-930A-D, Issue 2 on any engine.

(j) Credit for Previous Actions

    This paragraph provides credit for the actions required by 
paragraph (g) of this AD, if those actions were performed prior to 
the effective date of this AD by following the Accomplishment 
Instructions specified in CFM SB LEAP-1B-72-00-0392-01A-930A-D, 
Issue 001, dated March 7, 2023.

(k) 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)(1) 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.

(l) Related Information

    (1) 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].
    (2) Service information identified in this AD that is not 
incorporated by reference is available at the addresses specified in 
paragraphs (m)(3) and (4) of this AD.

(m) 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-1B-72-00-0392-
01A-930A-D, Issue 002, dated September 5, 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 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 November 20, 2023.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness 
Division, Aircraft Certification Service.
[FR Doc. 2023-27092 Filed 12-8-23; 8:45 am]
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