[Federal Register Volume 89, Number 142 (Wednesday, July 24, 2024)]
[Proposed Rules]
[Pages 59860-59862]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-16061]


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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: ge.com">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: [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-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

[[Page 59861]]

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
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                                                                                 Cost per        Cost on U.S.
               Action                      Labor cost          Parts cost        product           operators
----------------------------------------------------------------------------------------------------------------
FPI of the HPT front rotating air    8 work-hours x $85                 $0             $680            $204,000
 seal..                               per hour = $680.
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    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
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                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Replace HPT front rotating air seal...........  8 work-hours x $85 per hour =           $332,000        $332,680
                                                 $680.
Replace HPT rotor disk........................  8 work-hours x $85 per hour =           $341,800        $342,480
                                                 $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 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:

General Electric Company: Docket No. FAA-2024-1885; Project 
Identifier AD-2023-00995-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 9, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) Model CF34-
10E2A1, CF34-10E6, CF34-10E6A1, CF34-10E7, CF34-10E7-B engines with 
an installed high-pressure turbine (HPT) front rotating air seal 
having a part number (P/N) 1865M49P04, 2448M30P02, or 2448M30P03.

[[Page 59862]]

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of cracks found in the HPT 
rotating air front seal. The FAA is issuing this AD to detect 
indications and linear indications (any indication which is four 
times longer than the width of that same indication) of the HPT 
front rotating air seal. The FAA is issuing this AD to prevent 
failure of the HPT front rotating air seal or HPT rotor disk. The 
unsafe 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.

(f) Compliance

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

(g) Required Actions

    (1) At the next piece-part exposure of the HPT rotor assembly 
and each piece-part exposure thereafter, after the effective date of 
this AD, perform a fluorescent penetrant inspection (FPI) of the HPT 
front rotating air seal for indications or linear indications in 
accordance with paragraphs 3.B.(1)(a) through (f), of GE CF34-10E 
Service Bulletin (SB) 72-0341 R02, dated September 24, 2021 (CF34-
10E SB 72-0341 R02).
    (2) If during any FPI required by paragraph (g)(1) of this AD, 
there are any indications greater than 0.015 in. (0.38mm) or any 
linear indications, before further flight, remove the HPT front 
rotating air seal from service and replace with a part eligible for 
installation, in accordance with paragraphs 3.B.(1)(g) and (h) of 
CF34-10E SB 72-0341 R02.
    (3) If during any FPI required by paragraph (g)(1) of this AD, 
there are any indications that extends beyond the rabbet diameter M, 
as specified in paragraph 3.B.(1)(i), Figure 1, and Figure 4 (Sheet 
2) of CF34-10E SB 72-0341 R02, before further flight remove the HPT 
rotor disk from service and replace with a part eligible for 
installation, in accordance with paragraph 3.B.(1)(i)2 of CF34-10E 
SB 72-0341 R02.

(h) Optional Terminating Action

    Replacing the HPT front rotating air seal with an HPT front 
rotating air seal having P/N 2929M57P01 constitutes terminating 
action for the inspections required by paragraph (g)(1) of this AD.

(i) Definitions

    (1) For the purpose of this AD, a ``piece-part exposure'' is 
when the HPT front rotating air seal is disassembled from the HPT 
rotor assembly.
    (2) For the purpose of this AD, a ``linear indication'' is any 
indication whose length is at least four times greater than its 
width.
    (3) For the purpose of this AD, a ``part eligible for 
installation'' is defined as the following, as applicable:
    (i) An HPT front rotating air seal that is eligible for 
installation is an HPT front rotating air seal having P/N 
1865M49P04, P/N 2448M30P02, or P/N 2448M30P03 that has passed the 
inspection required by paragraph (g)(1) of this AD, or an HPT front 
rotating air seal having P/N 2929M57P01.
    (ii) An HPT rotor disk that is eligible for installation is an 
HPT rotor disk having P/N 1865M51P03 or P/N 1865M51P04 that has not 
been removed from service as a result of the actions required by 
paragraph (g)(3) of this AD.

(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 AIR-520 Continued 
Operational Safety Branch, send it to the attention of the person 
identified in paragraph (k) 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.

(k) Related Information

    For more information about this AD, contact Alexei Marqueen, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7178; email: [email protected].

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the material listed in this 
paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this material as applicable to do the actions 
required by this AD, unless the AD specifies otherwise.
    (i) General Electric Company CF34-10E Service Bulletin 72-0341 
R02, dated September 24, 2021.
    (ii) [Reserved]
    (3) For material identified in this AD, contact General Electric 
Company, 1 Neumann Way, Cincinnati, OH 45215; phone: (513) 552-3272; 
email: ge.com">aviation.fleetsupport@ge.com; website: ge.com.
    (4) You may view this material 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 material at the National Archives and 
Records Administration (NARA). For information on the availability 
of this material at NARA, visit www.archives.gov/federal-register/cfr/ibr-locations or email [email protected].

    Issued on July 8, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-16061 Filed 7-23-24; 8:45 am]
BILLING CODE 4910-13-P