[Federal Register Volume 89, Number 132 (Wednesday, July 10, 2024)]
[Proposed Rules]
[Pages 56674-56676]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-14873]


 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
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 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
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 

  Federal Register / Vol. 89, No. 132 / Wednesday, July 10, 2024 / 
Proposed Rules  

[[Page 56674]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-1883; Project Identifier AD-2023-01120-E]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all General Electric Company (GE) Model CF34-10E2A1, CF34-10E6, 
CF34-10E6A1, CF34-10E7, and CF34-10E7-B engines with certain part-
numbered high-pressure turbine (HPT) shroud/low pressure turbine (LPT) 
nozzle assemblies installed. This proposed AD was prompted by a report 
of failed retention features of the inner and outer support air ducts 
(commonly referred to as spoolies) discovered during engine 
disassembly. This proposed AD would require a visual inspection of the 
combustion case for wear and gouges, repair if necessary, and rework of 
the affected HPT shroud/LPT nozzle assemblies. 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 August 26, 
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-2024-1883; 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 GE service information, 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 service information that is incorporated 
by reference 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-2024-1883; Project Identifier 
AD-2023-01120-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 from the manufacturer that during 
disassembly, the retention features of the inner and outer support air 
ducts on GE Model CF34-10E series engines were found to have failed. 
The retention features include a retaining ring, which becomes 
plastically deformed during installation. Vibrations loosen the 
retaining ring until it disengages. With the retaining ring disengaged, 
the outer support air duct has no radial constraint, and releases and 
migrates due to gravity, impacting the inner wall of the combustion 
case causing case wall damage. If this damage has been repaired in the 
past and after the repair the support air duct liberates and causes 
more damage, then the remaining wall thickness is not sufficient to 
sustain the loading from a fan-blade-out or other extreme event. This 
condition, if not addressed, could result in the inner surface of the 
combustion case having reduced load carrying capability for fan blade 
out or other extreme event with possible engine separation and loss of 
the airplane.

[[Page 56675]]

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 GE Service Bulletin (SB) 72-0351 R01, dated July 
17, 2019, which provides instructions for a visual inspection of the 
combustion case for wear and gouges, repair if necessary, and rework of 
the affected HPT shroud/LPT nozzle assemblies. This service bulletin 
also introduces a new HPT shroud/LPT nozzle assembly P/N 2205M38G07 
with welded retaining rings. 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 requires a visual inspection of the combustion 
case for wear and gouges, repair if necessary, and rework of the 
affected HPT shroud/LPT nozzle assemblies to add a positive retention 
of the support air duct.

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
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Visual inspection of the combustion     8 work-hours x $85 per                $0            $680        $204,000
 case inner shell surface.               hour = $680.
Rework of the affected HPT shroud/LPT   8 work-hours x $85 per                 0             680         204,000
 nozzle assembly.                        hour = $680.
----------------------------------------------------------------------------------------------------------------

    The FAA estimates the following costs to do any necessary repairs 
that would be required based on the results of the proposed inspection. 
The agency has no way of determining the number of engines that might 
need these repairs.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Repair the combustion case....................  8 work-hours x $85 per hour =                 $0            $680
                                                 $680.
Replace the combustion case...................  8 work-hours x $85 per hour =            647,000         647,680
                                                 $680.
----------------------------------------------------------------------------------------------------------------

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-2024-1883; Project 
Identifier AD-2023-01120-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by August 26, 2024.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) Model CF34-
10E2A1, CF34-10E6, CF34-10E6A1, CF34-10E7, and CF34-10E7-B engines 
with an installed high-pressure turbine (HPT) shroud/low-pressure 
turbine (LPT) nozzle assembly having part number (P/N) 2205M38G01, 
2205M38G02, 2205M38G03, 2205M38G04, or 2205M38G05.

[[Page 56676]]

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a report of failed retention features of 
the inner and outer support air ducts (commonly referred to as 
spoolies) discovered during engine disassembly. The FAA is issuing 
this AD to prevent failure of the combustion case. The unsafe 
condition, if not addressed, could result in the inner surface of 
the combustion case having reduced load carrying capability for fan 
blade out or other extreme event with possible engine separation and 
loss of the airplane.

(f) Compliance

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

(g) Required Actions

    (1) At the next engine shop visit after the effective date of 
this AD, do a visual inspection of the combustion case inner shell 
surface for wear and gouges in accordance with paragraph 3.A.(1) and 
(2) of the Accomplishment Instructions of GE CF34-10E Service 
Bulletin (SB) 72-0351 R01, dated July 17, 2019 (SB 72-0351 R01).
    (i) If any wear or gouges are found during any inspection 
required by paragraph (g)(1) of this AD, before further flight, 
repair the combustion case in accordance with Table 1 of SB 72-0351 
R01.
    (ii) If any wear or gouges exceed the maximum repairable limit 
in accordance with Table 1 of SB 72-0351 R01, before further flight, 
remove the combustion case from service.
    (2) At the next engine shop visit after the effective date of 
this AD, rework the affected HPT shroud/LPT nozzle assembly, in 
accordance with paragraph 3.B. of the Accomplishment Instructions of 
SB 72-0351 R01.

(h) Definition

    For the purpose of this AD, an ``engine shop visit'' is defined 
as when the HPT shroud/LPT nozzle assembly or the HPT rotor disk is 
removed from the engine.

(i) 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 (j) 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) Additional 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].

(k) 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) General Electric Company (GE) CF34-10E Service Bulletin 72-
0351 R01, dated July 17, 2019.
    (ii) [Reserved]
    (3) For GE service information, 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 service information that is incorporated 
by reference 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.
    (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 1, 2024.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2024-14873 Filed 7-9-24; 8:45 am]
BILLING CODE 4910-13-P