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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-1885; Project Identifier AD-2023-00995-E]
RIN 2120-AA64
Airworthiness Directives; General Electric Company 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) Model CF34-10E2A1, CF34-10E6,
CF34-10E6A1, CF34-10E7, and CF34-10E7-B engines having certain high-
pressure turbine (HPT) front rotating air seals installed. This
proposed AD was prompted by a report of cracks found in the HPT front
rotating air seal. This proposed AD would require performing repetitive
fluorescent penetrant inspections (FPIs) to detect indications or
linear indications (any indication which is four times longer than the
width of that same indication) in the HPT front rotating air seal and,
if necessary, replacement of the HPT front rotating air seal or HPT
rotor disk with parts eligible for installation as applicable. This
proposed AD also includes an optional terminating action to the
repetitive FPIs. 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
9, 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-2024-1885; 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:
For material identified in this NPRM, contact General
Electric Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513)
552-3272; email: aviation.fleetsupport@ge.com; website: ge.com.
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: Alexei Marqueen, Aviation Safety
Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone:
(781) 238-7178; email: alexei.t.marqueen@faa.gov.
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-2024-1885; Project Identifier
AD-2023-00995-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
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
Alexei Marqueen, 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 received a report of indications found in certain HPT front
rotating air seals at the rabbet surface where the affected part
interacts with the HPT rotor disk tabs. The manufacturer investigated
and determined that the indications were caused by a high edge of
contact stress between the HPT rotor disk and the rabbet surface of the
HPT front rotating air seal. This condition, if not addressed, could
result in uncontained release of the HPT front rotating air seal
or HPT rotor disk, 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 Material Under 1 CFR Part 51
The FAA reviewed GE CF34-10E Service Bulletin 72-0341 R02, dated
September 24, 2021. This material provides procedures for repetitive
FPIs and eddy current inspections of certain HPT front rotating air
seals for indications or linear indications and, if necessary,
replacing the affected HPT front rotating air seals or the HPT rotor
disk with parts eligible for installation. 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
ADDRESSES.
Proposed AD Requirements in This NPRM
This proposed AD would require, at the next piece-part exposure,
repetitive FPIs to detect indications (indications) or linear
indications (any indication which is four times longer than the width
of that same indication) in the HPT front rotating air seal and, if
necessary, replacement of the HPT front rotating air seal or HPT rotor
disk with parts eligible for installation as applicable. Additionally,
replacing the HPT front rotating air seal with an updated design part
constitutes optional terminating action for the repetitive FPI.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 300 engines, installed on airplanes of U.S. registry.
The FAA estimates the following costs to comply with this proposed
AD:
Estimated Costs
|
Action
|
Labor cost
|
Parts cost
|
Cost per
product
|
Cost on
U.S. operators
|
| FPI of the HPT front rotating
air seal |
8 work-hours x $85 per hour =
$680 |
$0
|
$680
|
$204,000
|
The FAA estimates the following costs
to do any necessary
replacements that would be required based on the results of the
proposed inspections. The agency has no way of determining the number
of engines that might need these replacements:
On-Condition Costs
|
Action
|
Labor cost
|
Parts cost
|
Cost per
product
|
| Replace HPT front rotating air
seal |
8 work-hours x $85 per hour =
$680 |
$332,000
|
$332,680
|
| Replace HPT rotor disk |
8 work-hours x $85 per hour =
$680 |
$341,800
|
$342,480
|
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
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]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
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