Proposed Rule2023-22373
Airworthiness Directives; CFM International, S.A. Engines
Primary source
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Published
October 11, 2023
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for certain CFM International, S.A. (CFM) Model 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 engines. This proposed AD was prompted by a report of multiple aborted takeoffs and air turn-backs (ATBs) caused by high-pressure compressor (HPC) stall, which was induced by high levels of non-synchronous vibration (NSV). Additional manufacturer investigation revealed that wear on the No. 3 bearing spring finger housing can lead to high levels of NSV. This proposed AD would require initial and repetitive calculations of the levels of NSV, inspection of the stage 2 high- pressure turbine (HPT) nozzle assembly honeycomb and HPT stator stationary seal honeycomb and, depending on the results of the calculations and inspections, replacement of certain parts. This proposed AD would also require replacement of the No. 3 bearing spring finger housing. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 88 Issue 195 (Wednesday, October 11, 2023)</title>
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[Federal Register Volume 88, Number 195 (Wednesday, October 11, 2023)]
[Proposed Rules]
[Pages 70409-70412]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2023-22373]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2023-1991; Project Identifier AD-2023-00700-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-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
engines. This proposed AD was prompted by a report of multiple aborted
takeoffs and air turn-backs (ATBs) caused by high-pressure compressor
(HPC) stall, which was induced by high levels of non-synchronous
vibration (NSV). Additional manufacturer investigation revealed that
wear on the No. 3 bearing spring finger housing can lead to high levels
of NSV. This proposed AD would require initial and repetitive
calculations of the levels of NSV, inspection of the stage 2 high-
pressure turbine (HPT) nozzle assembly honeycomb and HPT stator
stationary seal honeycomb and, depending on the results of the
calculations and inspections, replacement of certain parts. This
proposed AD would also require replacement of the No. 3 bearing spring
finger housing. 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 November
27, 2023.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
<bullet> Federal eRulemaking Portal: Go to <a href="http://regulations.gov">regulations.gov</a>. Follow
the instructions for submitting comments.
<bullet> Fax: (202) 493-2251.
<bullet> 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.
<bullet> 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 <a href="http://regulations.gov">regulations.gov</a> by
searching for and locating Docket No. FAA-2023-1991; 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:
<bullet> For service information identified in this NPRM, contact
CFM International, S.A., GE Aviation Fleet Support, 1 Neumann Way, M/D
Room 285, Cincinnati, OH 45215; phone: (877) 432-3272; email:
<a href="/cdn-cgi/l/email-protection#b5d4c3dcd4c1dcdadb9bd3d9d0d0c1c6c0c5c5dac7c1f5d2d09bd6dad8"><span class="__cf_email__" data-cfemail="6d0c1b040c19040203430b010808191e181d1d021f192d0a08430e0200">[email protected]</span></a>.
<bullet> 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, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone:
(781) 238-7743; email: <a href="/cdn-cgi/l/email-protection#87eae2efe3eea9ebe6eae9feeec7e1e6e6a9e0e8f1"><span class="__cf_email__" data-cfemail="9ef3fbf6faf7b0f2fff3f0e7f7def8ffffb0f9f1e8">[email protected]</span></a>.
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-2023-1991; Project Identifier
AD-2023-00700-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
<a href="http://regulations.gov">regulations.gov</a>, 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
[[Page 70410]]
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 engine manufacturer of three aborted
takeoffs and two ATBs caused by HPC stall. Additional manufacturer
investigation revealed that wear on the No. 3 bearing spring finger
housing can lead to high levels of NSV, which could induce HPC stall.
As a result of its investigation, the manufacturer published service
information that specifies procedures for addressing this situation.
This condition, if not addressed, could result in engine power loss at
a critical phase of flight such as takeoff or climb, loss of engine
thrust control, reduced controllability of the airplane, 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-72-00-0504-01A-
930A-D, Issue 001, dated June 14, 2023. This service information
identifies affected No. 3 bearing spring finger housings and specifies
procedures for monitoring NSV during engine operation. This service
information also specifies procedures for replacing the No. 3 bearing
spring finger housings, inspecting the stage 2 HPT nozzle assembly
honeycomb and HPT stator stationary seal honeycomb, and replacing the
stage 2 HPT nozzle assembly honeycomb and HPT stator stationary seal.
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 repetitive calculations of the
levels of NSV and, depending on the results of the calculations,
replacement of the No. 3 bearing spring finger housing. This proposed
AD would require, following the removal and replacement of the No. 3
bearing spring finger housing, inspection of the stage 2 HPT nozzle
assembly honeycomb and HPT stator stationary seal honeycomb for rubs
and, depending on findings, replacement of the stage 2 HPT nozzle
assembly honeycomb and HPT stator stationary seal. This proposed AD
would also require replacement of the No. 3 bearing spring finger
housing, regardless of calculated level of NSV, at a certain time.
Interim Action
The FAA considers that this proposed AD would be an interim action.
The design approval holder is currently developing a modification to
address this issue. The FAA may consider additional rulemaking on this
subject.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 48 engines installed on airplanes of U.S. registry. The FAA
estimates that 33 engines installed on airplanes of U.S. registry would
require replacement of the No. 3 bearing spring finger housing.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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Calculate NSV data.................... 1 work-hour x $85 per $0 $85 $4,080
hour = $85.
Replace No. 3 bearing spring finger 17 work-hours x $85 per 64,590 66,035 2,179,155
housing. hour = $1,445.
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The FAA estimates the following costs to do any necessary
replacement and inspection that would be required based on the results
of the proposed calculation. The agency has no way of determining the
number of aircraft that might need these replacements and inspections:
On-Condition Costs
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Cost per
Action Labor cost Parts cost product
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Inspect stage 2 HPT nozzle assembly honeycomb 4 work-hours x $85 per hour = $0 $340
and HPT stator stationary seal honeycomb. $340.
Replace stage 2 HPT nozzle assembly honeycomb. 8 work-hours x $85 per hour = 58,536 59,216
$680.
Replace HPT stator stationary seal............ 8 work-hours x $85 per hour = 6,855 7,535
$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
[[Page 70411]]
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-2023-1991; Project
Identifier AD-2023-00700-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by November 27, 2023.
(b) Affected ADs
None.
(c) Applicability
This AD applies to CFM International, S.A. (CFM) Model 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 engines with an installed No. 3 bearing
spring finger housing having part number (P/N) 2629M62G01 and a
serial number identified in Table 1 or Table 2 of CFM Service
Bulletin (SB) LEAP-1A-72-00-0504-01A-930A-D, Issue 001, dated June
14, 2023 (CFM SB LEAP-1A-72-00-0504-01A-930A-D).
(d) Subject
Joint Aircraft System Component (JASC) Code 7230, Turbine Engine
Compressor Section.
(e) Unsafe Condition
This AD was prompted by a report of multiple aborted takeoffs
and air turn-backs caused by high-pressure compressor (HPC) stall,
which was induced by high levels of non-synchronous vibration (NSV),
and an additional manufacturer investigation that revealed wear on
the No. 3 bearing spring finger housing. The FAA is issuing this AD
to prevent HPC stall. The unsafe condition, if not addressed, could
result in engine power loss at a critical phase of flight such as
takeoff or climb, loss of engine thrust control, reduced
controllability of the airplane, and loss of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
(1) Within 125 flight cycles (FCs) after the effective date of
this AD and thereafter at intervals not to exceed 125 FCs, calculate
the NSV data in accordance with the Accomplishment Instructions,
paragraphs 5.A.(1) and 5.A.(3), or 5.B.(1) and 5.B.(3) of CFM SB
LEAP-1A-72-00-0504-01A-930A-D.
(2) If, during any calculation required by paragraph (g)(1) of
this AD, the NSV data exceeds the limits specified in the
Accomplishment Instructions, paragraph 5.A.(4)(a)1 or 5.B.(4)(a)1 of
CFM SB LEAP-1A-72-00-0504-01A-930A-D, discontinue the calculations
required by paragraph (g)(1) of this AD and within 150 FCs of
performing the calculation:
(i) Remove from service the No. 3 bearing spring finger housing
having P/N 2629M62G01 and a serial number identified in Table 1 or
Table 2 of CFM SB LEAP-1A-72-00-0504-01A-930A-D and replace with a
part eligible for installation.
(ii) Inspect the stage 2 high-pressure turbine (HPT) nozzle
assembly honeycomb for rubs in accordance with the Accomplishment
Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB
LEAP-1A-72-00-0504-01A-930A-D.
(iii) Inspect the HPT stator stationary seal honeycomb for rubs
in accordance with the Accomplishment Instructions, paragraphs
5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB LEAP-1A-72-00-0504-01A-
930A-D.
(3) If, during the inspection required by paragraph (g)(2)(ii)
of this AD, the stage 2 HPT nozzle assembly honeycomb fails to meet
the serviceability criteria referenced in the Accomplishment
Instructions, paragraphs 5.A.(4)(a)3b1) or 5.B.(4)(a)3b1) of CFM SB
LEAP-1A-72-00-0504-01A-930A-D, before further flight, replace the
stage 2 HPT nozzle assembly honeycomb.
(4) If, during the inspection required by paragraph (g)(2)(iii)
of this AD, the HPT stator stationary seal honeycomb fails to meet
the serviceability criteria referenced in the Accomplishment
Instructions, paragraphs 5.A.(4)(a)3b2) or 5.B.(4)(a)3b2) of CFM SB
LEAP-1A-72-00-0504-01A-930A-D, before further flight, replace the
HPT stator stationary seal.
(5) At the next piece-part exposure after the effective date of
this AD, but before exceeding 9,900 cycles since new, replace the
No. 3 bearing spring finger housing having P/N 2629M62G01 and a
serial number identified in Table 1 of CFM SB LEAP-1A-72-00-0504-
01A-930A-D with a part eligible for installation.
(h) Terminating Action
Replacement of the No. 3 bearing spring finger housing having P/
N 2629M62G01 and a serial number identified in Table 1 or Table 2 of
CFM SB LEAP-1A-72-00-0504-01A-930A-D with a part eligible for
installation, as specified in paragraphs (g)(2)(i) and (g)(5) of
this AD, constitutes terminating action for the calculations
required by paragraph (g)(1) of this AD.
(i) Definition
For the purpose of this AD, a ``part eligible for installation''
is a No. 3 bearing spring finger housing that does not have P/N
2629M62G01 and a serial number identified in Table 1 or Table 2 of
CFM SB LEAP-1A-72-00-0504-01A-930A-D.
(j) 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 branch office, send it to
the attention of the person identified in paragraph (k) of this AD
and email it to: <a href="/cdn-cgi/l/email-protection#266768630b67620b676b69656640474708414950"><span class="__cf_email__" data-cfemail="d899969df5999cf59995979b98beb9b9f6bfb7ae">[email protected]</span></a>.
(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.
(3) For service information that contains steps that are labeled
as Required for Compliance (RC), the following provisions apply.
(i) The steps labeled as RC, including substeps under an RC step
and any figures identified in an RC step, that are required by
paragraph (g) of this AD must be done to comply with this AD. An
AMOC is required for any deviations to RC steps required by
paragraph (g) of this AD, including substeps and identified figures.
(ii) Steps not labeled as RC may be deviated from using accepted
methods in accordance with the operator's maintenance or inspection
program without obtaining approval of an AMOC, provided the RC
steps, including substeps and identified figures, can still be done
as specified, and the airplane can be put back in an airworthy
condition.
[[Page 70412]]
(k) Related 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: <a href="/cdn-cgi/l/email-protection#1f727a777b7631737e727166765f797e7e31787069"><span class="__cf_email__" data-cfemail="5439313c303d7a3835393a2d3d143235357a333b22">[email protected]</span></a>.
(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-72-00-0504-
01A-930A-D, Issue 001, dated June 14, 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:
<a href="/cdn-cgi/l/email-protection#7d1c0b141c09141213531b111818090e080d0d120f093d1a18531e1210"><span class="__cf_email__" data-cfemail="c7a6b1aea6b3aea8a9e9a1aba2a2b3b4b2b7b7a8b5b387a0a2e9a4a8aa">[email protected]</span></a>.
(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: <a href="/cdn-cgi/l/email-protection#2b4d59054245585b4e485f4244456b454a594a054c445d"><span class="__cf_email__" data-cfemail="d4b2a6fabdbaa7a4b1b7a0bdbbba94bab5a6b5fab3bba2">[email protected]</span></a>, or go to: <a href="http://www.archives.gov/federal-register/cfr/ibr-locations.html">www.archives.gov/federal-register/cfr/ibr-locations.html</a>.
Issued on October 3, 2023.
Ross Landes,
Deputy Director for Regulatory Operations, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2023-22373 Filed 10-10-23; 8:45 am]
BILLING CODE 4910-13-P
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