[Federal Register Volume 89, Number 145 (Monday, July 29, 2024)]
[Proposed Rules]
[Pages 60838-60841]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-16473]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1898; Project Identifier AD-2023-01013-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-1B engines. This 
proposed AD was prompted by a report of a quality escape involving 
certain high-pressure compressor (HPC) stage 2 seals manufactured 
without detailed finish machining, which could result in deeper rubs 
and mechanical damage to the seal teeth of the stage 3-4 compressor 
rotor blisk (stage 3-4 blisk) of the mating compressor rotor during 
initial operation. This proposed AD would require a visual inspection 
of the HPC stage 2 seal, a visual inspection of the forward arm seal 
teeth of the stage 3-4 blisk, an eddy current inspection (ECI) of the 
forward arm seal teeth of the stage 3-4 blisk, and replacement of the 
HPC stage 2 seal and the stage 3-4 blisk, if necessary. 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 September 
12, 2024.

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 under 
Docket No. FAA-2024-1898; 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

[[Page 60839]]

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 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 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-2024-1898; 
Project Identifier AD-2023-01013-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 was notified by the manufacturer of a quality escape 
involving certain HPC stage 2 seals installed on certain 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. The suspect HPC stage 2 seals were 
manufactured without detailed finish machining, which could result in 
deeper rubs and mechanical damage to the seal teeth of the stage 3-4 
blisk of the mating compressor rotor during initial operation, which 
could lead to failure of the stage 3-4 blisk. This condition, if not 
addressed, could result in uncontained part 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 Material Under 1 CFR Part 51

    The FAA reviewed CFM International, S.A. Service Bulletin LEAP-1B-
72-00-0394-01A-930A-D, Issue 002-00, dated January 23, 2024, which 
specifies procedures for an on-wing borescope inspection (BSI) of the 
honeycomb structure of the affected stage 2 seals and rotating seal 
teeth coating condition and provides instructions for determining the 
serviceability of affected components that fail the BSI. This material 
also specifies procedures for an in-shop visual inspection of the HPC 
stage 2 seal and the forward arm seal teeth of the stage 3-4 blisk, an 
ECI of the forward arm seal teeth of the stage 3-4 blisk, and 
replacement of the HPC stage 2 seal and the stage 3-4 blisk. 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 a visual inspection of the HPC stage 
2 seal and the forward arm seal teeth of the stage 3-4 blisk, an ECI of 
the forward arm seal teeth of the stage 3-4 blisk, and replacement of 
the HPC stage 2 seal and the stage 3-4 blisk, if necessary.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 31 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
----------------------------------------------------------------------------------------------------------------
Visual inspection of HPC stage 2 seal.  1 work-hour x $85 per                 $0             $85          $2,635
                                         hour = $85.
Visual inspection of stage 3-4 blisk..  1 work-hour x $85 per                  0              85           2,635
                                         hour = $85.
ECI of stage 3-4 blisk................  4 work-hours x $85 per                 0             340          10,540
                                         hour = $340.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary 
replacements that would be required based on the results of the 
proposed inspection. The agency has no way of determining the number of 
engines that might need these replacements:

[[Page 60840]]



                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replacement of HPC stage 2 seal...............  8 work-hours x $85 per hour =            $55,312         $55,992
                                                 $680.
Replacement of stage 3-4 blisk................  8 work-hours x $85 per hour =            518,500         519,180
                                                 $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-2024-1898; Project 
Identifier AD-2023-01013-E.

 (a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 12, 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 having an engine serial number (ESN) identified in Table 1 
to paragraph (c) of this AD.

                                    Table 1 to Paragraph (c)--Applicable ESNs
----------------------------------------------------------------------------------------------------------------
         ESN                    ESN                    ESN                    ESN                    ESN
----------------------------------------------------------------------------------------------------------------
             60A635                 60A647                 60A662                 60A678                60A691
             60A639                 60A650                 60A663                 60A679                60A696
             60A642                 60A653                 60A669                 60A682                60A702
             60A643                 60A655                 60A670                 60A686    ....................
             60A644                 60A656                 60A671                 60A687    ....................
             60A645                 60A660                 60A673                 60A689    ....................
             60A646                 60A661                 60A676                 60A690    ....................
----------------------------------------------------------------------------------------------------------------

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of a quality escape involving 
certain high-pressure compressor (HPC) stage 2 seals manufactured 
without detailed finish machining, which could result in deeper rubs 
and mechanical damage to the seal teeth of the stage 3-4 compressor 
rotor blisk (stage 3-4 blisk) of the mating compressor rotor during 
initial operation. The FAA is issuing this AD to prevent uncontained 
failure of the stage 3-4 blisk. The unsafe condition, if not 
addressed, could result in uncontained part 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) Before accumulating 2,900 cycles since new (CSN) or within 
10 flight cycles after the effective date of this AD, whichever 
occurs later, perform the following:
    (i) A visual inspection of the HPC stage 2 seal in accordance 
with the Accomplishment Instructions, paragraph 5.B.(3) of CFM 
Service Bulletin (SB) LEAP-1B-72-00-0394-01A-930A-D, Issue 002-00, 
dated January 23, 2024 (CFM SB LEAP-1B-72-00-0394-01A-930A-D, Issue 
002-00).
    (ii) A visual inspection of the forward arm seal teeth of the 
stage 3-4 blisk in accordance with the Accomplishment Instructions, 
paragraph 5.B.(4) of CFM SB LEAP-1B-72-00-0394-01A-930A-D, Issue 
002-00.
    (iii) An eddy current inspection of the forward arm seal teeth 
of the stage 3-4 blisk in accordance with the Accomplishment 
Instructions, paragraph 5.B.(5) of CFM SB LEAP-1B-72-00-0394-01A-
930A-D, Issue 002-00.
    (2) If, during the inspection required by paragraph (g)(1)(i) of 
this AD, any of the HPC stage 2 seal segments fail to meet the 
serviceability criteria specified in the Accomplishment 
Instructions, paragraph

[[Page 60841]]

5.B.(3) of CFM SB LEAP-1B-72-00-0394-01A-930A-D, Issue 002-00, 
before further flight, remove the unserviceable HPC stage 2 seal 
segments from service.
    (3) If, during the inspections required by paragraphs (g)(1)(ii) 
and (iii) of this AD, the stage 3-4 blisk fails to meet the 
serviceability criteria specified in the Accomplishment 
Instructions, paragraph 5.B.(6) of CFM SB LEAP-1B-72-00-0394-01A-
930A-D, Issue 002-00, before further flight:
    (i) Remove the stage 3-4 blisk from service;
    (ii) Remove all four HPC stage 2 seal segments from service; and
    (iii) Replace the stage 3-4 blisk in accordance with the 
Accomplishment Instructions, paragraph 5.B.(7)(a) of CFM SB LEAP-1B-
72-00-0394-01A-930A-D, Issue 002-00.
    (4) If, during the actions required by paragraphs (g)(2) and (3) 
of this AD, the HPC stage 2 seal is removed, before further flight, 
replace the HPC stage 2 seal in accordance with the Accomplishment 
Instructions, paragraph 5.B.(7)(b) of CFM SB LEAP-1B-72-00-0394-01A-
930A-D, Issue 002-00.

(h) 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 (i) 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.

(i) 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].

(j) 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 International, S.A. Service Bulletin LEAP-1B-72-00-0394-
01A-930A-D, Issue 002-00, dated January 23, 2024.
    (ii) [Reserved]
    (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 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 July 23, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-16473 Filed 7-26-24; 8:45 am]
BILLING CODE 4910-13-P