Proposed Rule2022-16011
Airworthiness Directives; General Electric Company Turbofan Engines
Primary source
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Published
August 1, 2022
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA proposes to adopt a new airworthiness directive (AD) for certain General Electric Company (GE) CF34-8C and CF34-8E model turbofan engines. This proposed AD was prompted by a report of a crack found on the low-pressure turbine (LPT) stage 5 disk at the forward arm area. This proposed AD would require the removal of the affected LPT stage 5 disk and replacement with a part eligible for installation. The FAA is proposing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 87 Issue 146 (Monday, August 1, 2022)</title>
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[Federal Register Volume 87, Number 146 (Monday, August 1, 2022)]
[Proposed Rules]
[Pages 46906-46908]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2022-16011]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-0977; Project Identifier AD-2022-00419-E]
RIN 2120-AA64
Airworthiness Directives; General Electric Company 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 General Electric Company (GE) CF34-8C and CF34-8E model
turbofan engines. This proposed AD was prompted by a report of a crack
found on the low-pressure turbine (LPT) stage 5 disk at the forward arm
area. This proposed AD would require the removal of the affected LPT
stage 5 disk and replacement with a part eligible for installation. 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
15, 2022.
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://www.regulations.gov">www.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.
For service information identified in this NPRM, contact General
Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513)
552-3272; email: <a href="/cdn-cgi/l/email-protection#58392e31392c313736763e343d3d2c2b2d2828372a2c183f3d763b3735"><span class="__cf_email__" data-cfemail="a3c2d5cac2d7cacccd8dc5cfc6c6d7d0d6d3d3ccd1d7e3c4c68dc0ccce">[email protected]</span></a>; website: <a href="http://www.ge.com">www.ge.com</a>. You
may view this service information at the Airworthiness Products
Section, Operational Safety Branch, FAA, 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 <a href="http://www.regulations.gov">www.regulations.gov</a> by searching
for
[[Page 46907]]
and locating Docket No. FAA-2022-0977; 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: Scott Stevenson, Aviation Safety
Engineer, ECO Branch, FAA, 1200 District Avenue, Burlington, MA 01803;
phone: (781) 238-7132; email: <a href="/cdn-cgi/l/email-protection#adfecec2d9d983e083fed9c8dbc8c3dec2c3edcbcccc83cac2db"><span class="__cf_email__" data-cfemail="1a4979756e6e345734496e7f6c7f746975745a7c7b7b347d756c">[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-2022-0977; Project Identifier
AD-2022-00419-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://www.regulations.gov">www.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 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 Scott
Stevenson, 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 a report of a crack found on an LPT stage 5 disk
at the forward arm area. The manufacturer's analysis revealed that the
crack was due to high-vibratory stress caused by a bladed disk mode
that resulted in the initiation of multiple high cycle fatigue (HCF)
cracks that connected, resulting in a long circumferential crack. As a
result of its analysis, the manufacturer published service information
that specifies procedures for the removal of the affected LPT stage 5
disk, part number (P/N) 4117T14P02, and replacement with an LPT stage 5
disk, P/N 4117T14P03. The replacement LPT stage 5 disk, P/N 4117T14P03,
has a modified geometry (thicker forward arm) that will improve the HCF
capability and reduce the likelihood of a crack. This condition, if not
addressed, could result in failure of the LPT stage 5 disk, loss of
engine thrust control, and reduced control 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
The FAA reviewed GE CF34-8C Service Bulletin (SB) 72-0352 R00,
dated September 20, 2021, and GE CF34-8E SB 72-0240 R00, dated
September 20, 2021. These SBs, differentiated by engine model, describe
procedures for removing and replacing the affected LPT stage 5 disk, P/
N 4117T14P02, with a new LPT stage 5 disk, P/N 4117T14P03.
Proposed AD Requirements in This NPRM
This proposed AD would require the removal of the affected LPT
stage 5 disk and replacement with a part eligible for installation.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 112 engines installed on airplanes of U.S. registry.
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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Remove and replace the LPT stage 5 2 work-hours x $85 $30,500 (pro-rated).. $30,670 $3,435,040
disk. per hour = $170.
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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
[[Page 46908]]
(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:
General Electric Company: Docket No. FAA-2022-0977; Project
Identifier AD-2022-00419-E.
(a) Comments Due Date
The FAA must receive comments on this airworthiness directive
(AD) by September 15, 2022.
(b) Affected ADs
None.
(c) Applicability
This AD applies to General Electric Company CF34-8C1, CF34-8C5,
CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-8E2, CF34-
8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1
model turbofan engines with an installed low-pressure turbine (LPT)
stage 5 disk, part number (P/N) 4117T14P02.
(d) Subject
Joint Aircraft System Component (JASC) Code 7250, Turbine
Section.
(e) Unsafe Condition
This AD was prompted by a report of a crack found on the LPT
stage 5 disk at the forward arm area. The FAA is issuing this AD to
prevent failure of the LPT stage 5 disk. The unsafe condition, if
not addressed, could result in loss of engine thrust control and
reduced control of the airplane.
(f) Compliance
Comply with this AD within the compliance times specified,
unless already done.
(g) Required Actions
During the next piece-part exposure after the affected LPT stage
5 disk accumulates 8,000 cycles since new (CSN), remove the affected
LPT stage 5 disk and replace with a part eligible for installation.
(h) Installation Prohibition
Do not install an affected LPT stage 5 disk with 8,000 CSN or
more into the LPT module of the engine.
(i) Definitions
(1) For the purpose of this AD, a ``part eligible for
installation'' is an LPT stage 5 disk, P/N 4117T14P03, or later
approved P/N.
(2) For the purpose of this AD, ``piece-part exposure'' is when
the LPT module is separated from the engine and the LPT stage 5
blades are removed from the LPT stage 5 disk.
(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: <a href="/cdn-cgi/l/email-protection#6a2b242f472b2e472b2725292a0c0b0b440d051c"><span class="__cf_email__" data-cfemail="98d9d6ddb5d9dcb5d9d5d7dbd8fef9f9b6fff7ee">[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.
(k) Related Information
For more information about this AD, contact Scott Stevenson,
Aviation Safety Engineer, ECO Branch, FAA, 1200 District Avenue,
Burlington, MA 01803; phone: (781) 238-7132; email:
<a href="/cdn-cgi/l/email-protection#b9eadad6cdcd97f497eacddccfdcd7cad6d7f9dfd8d897ded6cf"><span class="__cf_email__" data-cfemail="c291a1adb6b6ec8fec91b6a7b4a7acb1adac82a4a3a3eca5adb4">[email protected]</span></a>.
Issued on July 21, 2022.
Christina Underwood,
Acting Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2022-16011 Filed 7-29-22; 8:45 am]
BILLING CODE 4910-13-P
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