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[Federal Register Volume 90, Number 14 (Thursday, January 23, 2025)]
[Proposed Rules]
[Pages 7998-8001]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-01458]

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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: Supplemental notice of proposed rulemaking (SNPRM).

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SUMMARY: The FAA is revising a notice of proposed rulemaking (NPRM) 
that applied to 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 action revises the NPRM by 
adding Model CF34-10E5 and CF34-10E5A1 engines to the applicability. 
The FAA is proposing this airworthiness directive (AD) to address the 
unsafe condition on these products. Since these actions would impose an 
additional burden over those in the NPRM the agency is requesting 
comments on this SNPRM.

DATES: The FAA must receive comments on this SNPRM by March 10, 2025.

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.

[[Page 7999]]

     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 SNPRM, any comments received, and other 
information. The street address for Docket Operations is listed above.
    Material Incorporated by Reference:
     For GE material identified in this proposed AD, contact 
GE, 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 the ADDRESSES section. 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 again revise the 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 SNPRM.

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 SNPRM 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 SNPRM, 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 SNPRM. 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 issued an NPRM to amend 14 CFR part 39 by adding an AD that 
would apply to GE Model CF34-10E2A1, CF34-10E6, CF34-10E6A1, CF34-10E7, 
and CF34-10E7-B engines with an installed HPT shroud/LPT nozzle 
assembly having part number (P/N) 2205M38G01, 2205M38G02, 2205M38G03, 
2205M38G04, or 2205M38G05. The NPRM published in the Federal Register 
on July 10, 2024 (89 FR 56674). The NPRM was prompted by 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. 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. In the NPRM, the 
FAA proposed to 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.

Actions Since the NPRM Was Issued

    Since the FAA issued the NPRM, the FAA received comments and 
determined that Model CF34-10E5 and CF34-10E5A1 engines were 
inadvertently omitted from the applicability of the NPRM. In addition, 
the Cost of Compliance section was modified to reflect a more accurate 
estimate of the number of affected engines. While the number of 
affected models increased, the number of affected engines is lower than 
previously estimated.

Comments

    The FAA received comments from three commenters. The commenters 
were the Air Line Pilots Association, International (ALPA), Japan 
Airlines, and GE. ALPA supported the NPRM without change. The following 
presents the comments received from Japan Airlines and GE and the FAA's 
response.

Request To Update the Applicability

    Japan Airlines and GE suggested that engine Model CF34-10E5 and 
CF34-10E5A1 be included in the applicability of the NPRM because the 
effectivity of GE CF34-10E Service Bulletin (SB) 72-0351 R01, dated 
July 17, 2019 (GE CF34-10E SB 72-0351 R01) applies to all CF34-10E 
engines with an installed HPT shroud/LPT nozzle assembly having part 
number (P/N) 2205M38G01, 2205M38G02, 2205M38G03, 2205M38G04, or 
2205M38G05.
    The FAA agrees and has revised paragraph (c) of this proposed AD to 
add engine Model CF34-10E5 and CF34-10E5A1.

FAA's Determination

    The FAA is proposing this AD after determining the unsafe condition 
described previously is likely to exist or develop in other products of 
the same type design. Certain changes described above expand the scope 
of the NPRM. As a result, it is necessary to reopen the comment period 
to provide additional opportunity for the public to comment on this 
SNPRM.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed GE CF34-10E SB 72-0351 R01, 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 material 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 the ADDRESSES section.

Proposed AD Requirements in This SNPRM

    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/

[[Page 8000]]

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, affects 221 
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        $150,280
 case inner shell surface.               hour = $680.
Rework of the affected HPT shroud/LPT   8 work-hours x $85 per                 0             680         150,280
 nozzle assembly.                        hour = $680.
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    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
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                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Repair of the combustion case.................  8 work-hours x $85 per hour =                 $0            $680
                                                 $680.
Replacement of the combustion case............  8 work-hours x $85 per hour =            647,000         647,680
                                                 $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-2024-1883; Project 
Identifier AD-2023-01120-E.

 (a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by March 10, 2025.

 (b) Affected ADs

    None.

 (c) Applicability

    (1) This AD applies to General Electric Company (GE) CF34-
10E2A1, CF34-10E5, CF34-10E5A1, 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.

 (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 paragraphs 3.A.(1) 
and (2) of the Accomplishment Instructions in GE CF34-10E Service 
Bulletin (SB) 72-0351 R01, dated July 17, 2019 (GE CF34-10E 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 GE CF34-10E 
SB 72-0351 R01.
    (ii) If any wear or gouges exceed the maximum repairable limit 
in accordance

[[Page 8001]]

with Table 1 of GE CF34-10E 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 
GE CF34-10E 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) Related Information

    For more information about this AD, contact Alexei Marqueen, 
Aviation Safety Engineer, FAA, 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 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) GE CF34-10E Service Bulletin 72-0351 R01, dated July 17, 
2019.
    (ii) [Reserved]
    (3) For GE material identified in this AD, contact GE, 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 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 January 6, 2025.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-01458 Filed 1-22-25; 8:45 am]
BILLING CODE 4910-13-P
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