Airworthiness Directives; CFM International, S.A. Turbofan Engines, 15896-15899 [2022-05524]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 87, Number 54 (Monday, March 21, 2022)]
[Proposed Rules]
[Pages 15896-15899]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-05524]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2022-0160; Project Identifier AD-2022-00009-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 certain CFM International, S.A. (CFM) LEAP-1A model turbofan 
engines. This proposed AD was prompted by reports of two in-flight 
shutdowns (IFSDs) and subsequent investigation by the manufacturer that 
revealed cracks in the high-pressure turbine (HPT) rotor stage 1 
blades. This proposed AD would require initial and repetitive borescope 
inspections (BSIs) of the HPT rotor stage 1 blades and HPT stator stage 
1 nozzle set. Depending on the results of the BSIs, this proposed AD 
would require either additional BSIs at reduced intervals or 
replacement of the HPT rotor stage 1 blades or HPT stator stage 1 
nozzle set. This proposed AD would also require sending the inspection 
results to CFM if any unserviceable finding is found. 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 May 5, 
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

[[Page 15897]]

p.m., Monday through Friday, except Federal holidays.
    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-2022-0160; 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; 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-2022-0160; Project Identifier 
AD-2022-00009-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 received reports of two single-engine IFSDs on airplanes 
powered by LEAP-1A model turbofan engines, operating extensively in the 
Middle East and North Africa (MENA) region. A post-flight BSI of the 
HPT module revealed that the engine failures were due to cracks in the 
HPT rotor stage 1 blades. After investigation, the manufacturer 
determined that engines operating in the MENA region are susceptible to 
accelerated HPT rotor stage 1 blade deterioration and airfoil distress 
due to the build-up of dust. This unsafe condition, if not addressed, 
could result in failure of the engine, in-flight shutdown, loss of 
thrust control, and loss of 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 Service Bulletin (SB) LEAP-1A-72-00-0461-01A-
930A-D, Issue 002-00, dated December 21, 2021. This SB specifies 
procedures for performing a BSI of the HPT rotor stage 1 blades and HPT 
stator stage 1 nozzle set for LEAP-1A model turbofan engines operating 
in the MENA region, performing all applicable corrective actions, and 
reporting any unserviceable results to CFM. 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 initial and repetitive BSIs of the 
HPT rotor stage 1 blades and HPT stator stage 1 nozzle set and, 
depending on the results of the inspections, additional BSIs at reduced 
intervals or replacement of the HPT rotor stage 1 blades or HPT stator 
stage 1 nozzle set. This proposed AD would also require a BSI of the 
HPT rotor stage 1 blades and HPT stator stage 1 nozzle set installed on 
the sister engine of the same airplane if certain criteria are met. 
This proposed AD would also require sending the inspection results to 
CFM if any unserviceable finding is found.

Differences Between This Proposed AD and the Service Information

    The Accomplishment Instructions, paragraphs 5.E.(1)(g)2 and 
5.E.(1)(g)3, of CFM SB LEAP-1A-72-00-0461-01A-930A-D, Issue 002-00, 
dated December 21, 2021, specify removing one engine if certain 
conditions exist, whereas this proposed AD would require replacement of 
the HPT rotor stage 1 blades or HPT stator stage 1 nozzle set if 
certain conditions exist.

Interim Action

    The FAA considers that this proposed AD would be an interim action. 
The inspection reports that would be required by this proposed AD will 
enable the manufacturer to obtain better insight into the nature, 
cause, and extent of the cracking, and eventually to develop final 
action to address the unsafe condition. Once final action has been 
identified, the FAA might consider additional rulemaking.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 0 engines installed on airplanes of U.S. registry.
    The FAA estimates the following costs to comply with this proposed 
AD:

[[Page 15898]]



                                                 Estimated Costs
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                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
BSI the HPT rotor stage 1 blades and    4 work-hours x $85 per                $0            $340              $0
 HPT stator stage 1 nozzle set.          hour = $340.
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    The FAA estimates the following costs to do any necessary reporting 
and replacements that would be required based on the results of the 
proposed inspections. The agency has no way of determining the number 
of airplanes that might need these replacements.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                   Action                                 Labor cost                Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace the HPT rotor stage 1 blades.......  150 work-hours x $85 per hour =            $988,200      $1,000,950
                                              $12,750.
Replace the HPT stator stage 1 nozzle set..  24 work-hours x $85 per hour =              701,460         703,500
                                              $2,040.
BSI the HPT rotor stage 1 blades and HPT     4 work-hours x $85 per hour = $340.               0             340
 stator stage 1 nozzle set (on the sister
 engine).
Report BSI results to CFM..................  1 work-hour x $85 per hour = $85...               0              85
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Paperwork Reduction Act

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to a penalty for 
failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection of 
information displays a current valid OMB Control Number. The OMB 
Control Number for this information collection is 2120-0056. Public 
reporting for this collection of information is estimated to take 
approximately 1 hour per response, including the time for reviewing 
instructions, searching existing data sources, gathering and 
maintaining the data needed, and completing and reviewing the 
collection of information. All responses to this collection of 
information are mandatory. Send comments regarding this burden estimate 
or any other aspect of this collection of information, including 
suggestions for reducing this burden, to: Information Collection 
Clearance Officer, Federal Aviation Administration, 10101 Hillwood 
Parkway, Fort Worth, TX 76177-1524.

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-2022-0160; Project 
Identifier AD-2022-00009-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by May 5, 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 with an installed high-pressure 
turbine (HPT) rotor stage 1 blade, having part number (P/N) 
2747M92P01, P/N 2553M91G03, P/N 2553M91G05, P/N 2553M91G06, P/N 
2553M91G07, or P/N 2553M91G08 that has accumulated more than 800 
Middle East and North Africa (MENA) takeoffs.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7250, Turbine 
Section.

(e) Unsafe Condition

    This AD was prompted by reports of two in-flight shutdowns and 
subsequent investigation by the manufacturer that revealed cracks in 
the HPT rotor stage 1 blades. The FAA is issuing this AD to prevent 
failure of the HPT rotor stage 1

[[Page 15899]]

blades. The unsafe condition, if not addressed, could result in 
failure of the engine, in-flight shutdown, loss of thrust control, 
and loss of the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

(1) Group 1 Engines: Borescope Inspection (BSI) of HPT Rotor Stage 
1 Blades and HPT Stator Stage 1 Nozzle Set

    For Group 1 engines with an affected HPT rotor stage 1 blade 
installed:
    (i) Within 100 flight cycles (FCs) after accumulating 800 MENA 
takeoffs on the HPT rotor stage 1 blade, before the HPT rotor stage 
1 blade accumulates 1,750 cycles since new (CSN), or within 100 FCs 
after the effective date of this AD, whichever occurs later, perform 
an initial BSI of the HPT rotor stage 1 blades and HPT stator stage 
1 nozzle set in accordance with the Accomplishment Instructions, 
paragraphs 5.E.(1)(c) and 5.E.(1)(d), of CFM Service Bulletin LEAP-
1A-72-00-0461-01A-930A-D, Issue 002-00, dated December 21, 2021 (the 
SB).
    (ii) Thereafter, at intervals not to exceed 150 FCs since the 
last BSI, perform a repetitive BSI of the HPT rotor stage 1 blades 
and HPT stator stage 1 nozzle set in accordance with the 
Accomplishment Instructions, paragraphs 5.E.(1)(c) and 5.E.(1)(d), 
of the SB.

(2) Group 2 Engines: BSI of HPT Rotor Stage 1 Blades and HPT Stator 
Stage 1 Nozzle Set

    For Group 2 engines with an affected HPT rotor stage 1 blade 
installed:
    (i) Within 100 FCs after accumulating 800 MENA takeoffs on the 
HPT rotor stage 1 blade, before the HPT rotor stage 1 blade 
accumulates 2,600 CSN, or within 100 FCs after the effective date of 
this AD, whichever occurs later, perform an initial BSI of the HPT 
rotor stage 1 blades and HPT stator stage 1 nozzle set in accordance 
with the Accomplishment Instructions, paragraphs 5.E.(1)(c) and 
5.E.(1)(d), of the SB.
    (ii) Thereafter, at intervals not to exceed 300 FCs since the 
last BSI, perform a repetitive BSI of the HPT rotor stage 1 blades 
and HPT stator stage 1 nozzle set in accordance with the 
Accomplishment Instructions, paragraphs 5.E.(1)(c) and 5.E.(1)(d), 
of the SB.

(3) BSI Results Disposition

    Based on the results of the BSI required by paragraph (g)(1) or 
(2) of this AD, as applicable, either re-inspect or replace the HPT 
rotor stage 1 blades or HPT stator stage 1 nozzle set using the 
criteria, compliance times, and procedures referenced in the 
Accomplishment Instructions, paragraph 5.E.(1)(f), of the SB.

(4) Conditional Inspection of the Sister Engine on the Same 
Airplane

    (i) Based on the BSI results disposition required by paragraph 
(g)(3) of this AD, if re-inspection or replacement of the HPT rotor 
stage 1 blades or HPT stator stage 1 nozzle set is required within 
50 FCs based on the criteria, compliance times, and procedures 
referenced in the Accomplishment Instructions, paragraph 5.E.(1)(f), 
of the SB, then perform the actions required in paragraph (g)(4)(ii) 
of this AD.
    (ii) Within 5 FCs after performing the inspection required by 
paragraph (g)(1) or (2) of this AD, as applicable, either inspect or 
replace the HPT rotor stage 1 blades or HPT stator stage 1 nozzle 
set on the sister engine using the procedures and compliance times 
in the Accomplishment Instructions, paragraph, 5.E.(1)(g), of the 
SB. Where the SB specifies to remove the engine, this AD requires 
replacement of the HPT rotor stage 1 blades or HPT stator stage 1 
nozzle set, as applicable.

(5) Reporting Requirements

    If, during any inspection required by paragraph (g)(1), (2), 
(3), or (4) of this AD, as applicable, any HPT unserviceable finding 
is found on an engine as identified in the Accomplishment 
Instructions, paragraph 5.E.(1)(f) of the SB, within 30 days of 
performing the inspection, report the HPT unserviceable finding to 
CFM in accordance with the Accomplishment Instructions, paragraph 
5.E.(1)(f)1, of the SB.
    Note 1 to paragraph (g): The Accomplishment Instructions in 
paragraph 5.E.(1)(f) of the SB reference applicable aircraft 
maintenance manual tasks for procedures and compliance times for the 
actions required by paragraphs (g)(3) through (5) of this AD.

(h) Definitions

    (1) Group 1 engines are CFM LEAP-1A29, LEAP-1A29CJ, LEAP-1A30, 
LEAP-1A32, LEAP-1A33, LEAP-1A33B2, and LEAP-1A35A model turbofan 
engines.
    (2) Group 2 engines are CFM LEAP-1A23, LEAP-1A24, LEAP-1A24E1, 
LEAP-1A26, LEAP-1A26CJ, and LEAP-1A26E1 model turbofan engines.
    (3) For the purpose of this AD, a ``MENA takeoff'' is any 
takeoff accomplished in the MENA region, as defined in the Planning 
Information, paragraph 3.D., of the SB.
    (4) For the purpose of this AD, ``sister engine'' refers to the 
other engine installed on the same airplane.

(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 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.

(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; 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 March 10, 2022.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2022-05524 Filed 3-18-22; 8:45 am]
BILLING CODE 4910-13-P