[Federal Register Volume 88, Number 57 (Friday, March 24, 2023)]
[Proposed Rules]
[Pages 17753-17755]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-05862]



[[Page 17753]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2023-0653; Project Identifier AD-2023-00280-E]
RIN 2120-AA64


Airworthiness Directives; CFM International, S.A. Turbofan 
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 all CFM International, S.A. (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) 
model turbofan engines. This proposed 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 
stages 6-10 compressor rotor spools were manufactured from material 
suspected to have reduced material properties due to iron inclusion. 
This proposed AD would require replacement of certain HPT stage 1 
disks, forward outer seals, and stages 6-10 compressor rotor spools. 
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 April 24, 
2023.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
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 by 
searching for and locating Docket No. FAA-2023-0653; 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 service information identified in this NPRM, contact 
CFM International, S.A., Aviation Operations Center, 1 Neumann Way, M/D 
Room 285, Cincinnati, OH 45125; 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.

FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
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 ADDRESSES. Include ``Docket No. FAA-2023-0653; Project Identifier 
AD-2023-00280-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 amend 
this proposal because of those comments.
    The FAA has been informed that CFM has done some outreach with 
affected operators regarding the proposed corrective actions for this 
unsafe condition. As a result, affected operators are already aware of 
the proposed corrective actions and, in some cases, have already begun 
planning for replacement of certain HPT stage 1 disks, forward outer 
seals, and stages 6-10 compressor rotor spools. Therefore, the FAA has 
determined that a 30-day comment period is appropriate given the 
particular circumstances related to the proposed correction of this 
unsafe condition.
    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, ECO Branch, FAA, 1200 District 
Avenue, Burlington, MA 01803. 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 was notified by the manufacturer of the detection of iron 
inclusion in three non-LEAP-1A HPT rotor disks. Further investigation 
by the manufacturer determined that the iron inclusion is attributed to 
deficiencies in the manufacturing process. The investigation by the 
manufacturer also determined that certain CFM LEAP-1A HPT stage 1 
disks, forward outer seals, and stages 6-10 compressor rotor spools 
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, forward outer seals, and stages 6-10 
compressor rotor spools. This condition, if not addressed, could result 
in uncontained debris release, damage to the engine, and damage to the 
aircraft.

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.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed the following service information issued by CFM, 
which identify the part numbers and serial numbers of HPT stage 1 
disks, forward outer seals, and stages 6-10 compressor rotor spools 
with potentially

[[Page 17754]]

reduced material properties and specify procedures for replacement of 
these parts. These documents are distinct since they apply to different 
engine serial numbers.
     Service Bulletin LEAP-1A-72-00-0470-01A-930A-D, Issue 003, 
dated March 3, 2023.
     Service Bulletin LEAP-1A-72-00-0493-01A-930A-D, Issue 002, 
dated November 17, 2022.
     Service Bulletin LEAP-1A-72-00-0496-01A-930A-D, Issue 001, 
dated March 7, 2023.
    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.

Proposed AD Requirements in This NPRM

    This proposed AD would require replacement of certain HPT stage 1 
disks, forward outer seals, and stages 6-10 compressor rotor spools. 
This proposed AD would also prohibit installation of an HPT stage 1 
disk, forward outer seal, or stages 6-10 compressor rotor spool that 
has a part number and serial number identified in the service 
information onto any engine.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 38 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
----------------------------------------------------------------------------------------------------------------
Replace HPT stage 1 disk (38     8 work-hours x     $215,635 (pro-rated)........        $216,315      $8,219,970
 affected parts).                 $85 per hour =
                                  $680.
Replace forward outer seal (24   8 work-hours x     $47,500 (pro-rated).........          48,180       1,156,320
 affected parts).                 $85 per hour =
                                  $680.
Replace stages 6[dash]10         8 work-hours x     $37,660 (pro-rated).........          38,340         575,100
 compressor rotor spool (15       $85 per hour =
 affected parts).                 $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

    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-2023-0653; Project 
Identifier AD-2023-00280-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by April 24, 2023.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to CFM International, S.A. (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 model turbofan 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 HPT stage 1 disks, forward outer seals, and 
stages 6-10 compressor rotor 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 subsequent 
uncontained failure of certain high-pressure turbine (HPT) stage 1 
disks, forward outer seals, and stages 6-10 compressor rotor spools. 
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, forward 
outer seal, or stages 6-10 compressor rotor 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 stages 6-10 
compressor rotor

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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 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, forward outer seal, or 
stages 6-10 compressor rotor 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 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 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 2, of CFM SB LEAP-1A-72-00-0493-
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 stages 6-10 
compressor rotor spool that does not have a P/N and S/N identified 
in the service information listed in paragraphs (g)(1) through (3) 
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 stages 6-10 compressor rotor spool 
that has a P/N and S/N identified in the service information listed 
in paragraphs (g)(1) through (3) of this AD on any engine.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, ECO 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 
certification office, 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) Related Information

    For more information about this AD, contact Mehdi Lamnyi, 
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue, 
Burlington, MA 01803; 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 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-1A-72-00-0470-
01A-930A-D, Issue 003, dated March 3, 2023.
    (ii) CFM International, S.A. Service Bulletin LEAP-1A-72-00-
0493-01A-930A-D, Issue 002, dated November 17, 2022.
    (iii) CFM International, S.A. Service Bulletin LEAP-1A-72-00-
0496-01A-930A-D, Issue 001, dated March 7, 2023.
    (3) For service information identified in this AD, contact CFM 
International, S.A., Aviation Operations Center, 1 Neumann Way, M/D 
Room 285, Cincinnati, OH 45125; 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 service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on March 17, 2023.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2023-05862 Filed 3-23-23; 8:45 am]
BILLING CODE 4910-13-P