Document ID: FAA-2021-1183-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: CFM International, S.A. Turbofan Engines
Posted Date: 2022-01-18T05:00Z

[Federal Register Volume 87, Number 11 (Tuesday, January 18, 2022)]
[Proposed Rules]
[Pages 2563-2566]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-00509]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-1183; Project Identifier AD-2021-01193-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 model 
turbofan engines. This proposed AD was prompted by the detection of 
melt-related freckles in the billet, which may reduce the life of 
certain compressor rotor stages 6-10 spools, high pressure turbine 
(HPT) rotor interstage seals, HPT rotor stage 2 disks, low pressure 
turbine (LPT) stage 1 disks, LPT stage 2 disks, LPT stage 3 disks, and 
LPT stage 4 disks. This proposed AD would require revising the 
airworthiness limitations section (ALS) of the applicable CFM LEAP-1A 
Engine Shop Manual (ESM) and the operator's existing approved 
continuous airworthiness maintenance program (CAMP) to incorporate 
reduced life limits for these parts. This proposed AD would also 
require the removal of certain LPT stage 4 disks identified by serial 
number (S/N) prior to their new life limits. 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 March 4, 
2022.

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 https://www.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.

[[Page 2564]]

    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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-1183; 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.

FOR FURTHER INFORMATION CONTACT: Mehdi Lamnyi, Aviation Safety 
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803; 
phone: (781) 238-7743; fax: (781) 238-7199; 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-2021-1183; Project Identifier 
AD-2021-01193-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.
    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 
https://www.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 melt-
related freckles in the billet, which may reduce the life of certain 
compressor rotor stages 6-10 spools, HPT rotor interstage seals, HPT 
rotor stage 2 disks, LPT stage 1 disks, LPT stage 2 disks, LPT stage 3 
disks, and LPT stage 4 disks (life-limited parts (LLPs)). Through the 
manufacturer's investigation, it was determined that these LLPs may 
have subsurface anomalies that developed during the manufacturing 
process, resulting in a lower life capability. As a result of its 
investigation, the manufacturer determined the need to reduce the life 
limits of these LLPs. To reflect these reduced life limits, the 
manufacturer revised the CFM ALS, Chapter 05 of CFM LEAP 1A ESM. 
Additionally, the manufacturer published service information that 
specifies procedures for the removal and replacement of these LLPs 
before reaching their new life limits.
    The FAA is proposing to require operators to update the ALS of the 
applicable CFM LEAP-1A ESM, with the reduced life limits for these 
LLPs. The FAA is also proposing to require operators to remove certain 
LPT stage 4 disks identified by S/N before reaching their new life 
limits. The LPT stage 4 disks, identified by S/N in Figure 1 to 
paragraph (g)(2) of this proposed AD, were discovered by the 
manufacturer after publication of the ALS updates. 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.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed CFM High Pressure Compressor Rotor Life Limits 
LEAP 1A-05-11-02-01A-0B1B-C, Issue 010-00, dated September 15, 2021 
(CFM LEAP 1A-05-11-02-01A-0B1B-C); CFM High Pressure Turbine Rotor Life 
Limits LEAP 1A-05-11-03-01A-0B1B-C, Issue 007-00, dated September 15, 
2021 (CFM LEAP 1A-05-11-03-01A-0B1B-C); and CFM Low Pressure Turbine 
Rotor Life Limits LEAP 1A-05-11-04-01A-0B1B-C, Issue 009-00, dated June 
1, 2021 (LEAP 1A-05-11-04-01A-0B1B-C). CFM LEAP 1A-05-11-02-01A-0B1B-C, 
CFM LEAP 1A-05-11-03-01A-0B1B-C, and CFM LEAP 1A-05-11-04-01A-0B1B-C 
provide the new life limits for the LLPs. 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.

Other Related Service Information

    The FAA reviewed CFM LEAP 1A-05-11-02-01A-0B1B-C, Issue 009-00, 
dated July 26, 2021; and CFM LEAP 1A-05-11-03-01A-0B1B-C, Issue 006-00, 
dated July 26, 2021. This service information provides the new life 
limits for the LLPs.
    The FAA also reviewed CFM Service Bulletin (SB) LEAP-1A-72-00-0413-
01A-930A-D, Issue 004-00, dated December 11, 2021 (CFM SB LEAP-1A-72-
00-0413-01A-930A-D). CFM SB LEAP-1A-72-00-0413-01A-930A-D specifies 
procedures for removing and replacing the LLPs, and provides new life 
limits for certain S/Ns of the LLPs.

Proposed AD Requirements in This NPRM

    This proposed AD would require revising the ALS of the CFM LEAP-1A 
ESM, as applicable to each affected engine model, and the operator's 
existing approved CAMP to incorporate reduced life limits for certain 
LLPs. This proposed AD also requires replacement of two LPT stage 4 
disks.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 256 engines installed on airplanes of U.S. registry. The FAA 
estimates that 256 engines installed on airplanes of U.S. registry 
would require revising the ALS of the CFM LEAP-1A ESM and the 
operator's existing approved CAMP. The FAA estimates that zero 
airplanes of

[[Page 2565]]

U.S. registry would require replacement of the LPT stage 4 disk.
    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
----------------------------------------------------------------------------------------------------------------
Revise ALS of Engine Manual and the  1 work-hour x $85 per hour               $0             $85         $21,760
 operator's existing approved CAMP.   = $85.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to replace the LPT stage 4 
disk:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
               Action                         Labor cost            Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Replace LPT Stage 4 disk...........  225 work-hours x $85 per           $129,000        $148,125              $0
                                      hour = $19,125.
----------------------------------------------------------------------------------------------------------------

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-2021-1183; Project 
Identifier AD-2021-01193-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by March 4, 2022.

(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, and JASC Code 7250, Turbine Section.

(e) Unsafe Condition

    This AD was prompted by the detection of melt-related freckles 
in the billet, which may reduce the life of certain compressor rotor 
stages 6-10 spools, high pressure turbine (HPT) rotor interstage 
seals, HPT rotor stage 2 disks, low pressure turbine (LPT) stage 1 
disks, LPT stage 2 disks, LPT stage 3 disks, and LPT stage 4 disks. 
The FAA is issuing this AD to prevent the failure of the high-
pressure compressor, HPT rotor, and LPT rotor. The unsafe condition, 
if not addressed, could result in release of uncontained debris, 
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) Within 60 days after the effective date of this AD, revise 
the airworthiness limitations section (ALS) of the applicable CFM 
LEAP-1A Engine Shop Manual (the ESM) and the operator's existing 
approved continuous airworthiness maintenance program (CAMP) by 
incorporating the following service information:
    (i) CFM High Pressure Compressor Rotor Life Limits LEAP 1A-05-
11-02-01A-0B1B-C, Issue 010-00, dated September 15, 2021; and
    (ii) CFM High Pressure Turbine Rotor Life Limits LEAP 1A-05-11-
03-01A-0B1B-C, Issue 007-00, dated September 15, 2021; and
    (iii) CFM Low Pressure Turbine Rotor Life Limits LEAP 1A-05-11-
04-01A-0B1B-C, Issue 009-00, dated June 1, 2021.
    (2) Before the LPT stage 4 disk, P/N 362-039-520-0, with serial 
numbers identified in Figure 1 to paragraph (g)(2) of this AD 
(Figure 1) accumulates the cycles in Figure 1, or within 100 cycles 
after the effective date of this AD, whichever occurs later, remove 
the affected LPT stage 4 disk from service and replace with a part 
eligible for installation.

[[Page 2566]]

[GRAPHIC] [TIFF OMITTED] TP18JA22.000

(h) Credit for Previous Actions

    (1) You may take credit for the action required by paragraph 
(g)(1)(i) of this AD if the following service information was 
incorporated into the ALS of the applicable ESM and the operator's 
existing approved CAMP prior to the effective date of this AD: CFM 
High Pressure Compressor Rotor Life Limits LEAP 1A-05-11-02-01A-
0B1B-C, Issue 009-00, dated July 26, 2021.
    (2) You may take credit for the action required by paragraph 
(g)(1)(ii) of this AD if the following service information was 
incorporated into the ALS of the applicable ESM and the operator's 
existing approved CAMP prior to the effective date of this AD: CFM 
High Pressure Turbine Rotor Life Limits LEAP 1A-05-11-03-01A-0B1B-C, 
Issue 006-00, dated July 26, 2021.

(i) 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 (j)(1) of this AD. You may email your 
request 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.

(j) Related Information

    (1) 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; fax: (781) 238-7199; 
email: [email protected].
    (2) 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]. You may view this referenced 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.

    Issued on January 7, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-00509 Filed 1-14-22; 8:45 am]
BILLING CODE 4910-13-P