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[Federal Register Volume 90, Number 20 (Friday, January 31, 2025)]
[Proposed Rules]
[Pages 8687-8690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-02016]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0015; Project Identifier AD-2024-00615-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 GEnx-1B64, GEnx-1B64/
P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, GEnx-1B70, 
GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-1B70/P2, GEnx-
1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/75/P2, GEnx-1B76/
P2, GEnx-1B76A/P2, and GEnx-2B67/P engines. This proposed AD was 
prompted by a manufacturer investigation that revealed certain high-
pressure turbine (HPT) stage 1 and HPT stage 2 disks were manufactured 
from powder metal material suspected to contain iron inclusion. This 
proposed AD would require replacement of affected HPT stage 1 and HPT 
stage 2 disks with parts 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 March 17, 
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.
     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-2025-0015; 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

[[Page 8688]]

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-2025-0015; 
Project Identifier AD-2024-00615-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 revise 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 was notified by the manufacturer of the detection of iron 
inclusion in a turbine disk manufactured from the same powder metal 
material used to manufacture certain HPT stage 1 and HPT stage 2 disks 
for GE Model GEnx-1B64, GEnx-1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-
1B67/P1, GEnx-1B67/P2, GEnx-1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, 
GEnx-1B70/P1, GEnx-1B70/P2, GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/
P1, GEnx-1B74/75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, and GEnx-2B67/P 
engines. Further investigation by the manufacturer determined that the 
iron inclusion is attributed to deficiencies in the manufacturing 
process and may cause reduced material properties and a lower fatigue 
life capability, which may result in premature fracture and uncontained 
failure. The manufacturer also informed the FAA that additional risk 
assessments determined that there were no failed events associated with 
the discovery of this iron inclusion material on these engines, but 
concluded that replacement of the affected HPT stage 1 and HPT stage 2 
disks is necessary to prevent any future failed events. The exposure of 
HPT stage 1 and HPT stage 2 disks to iron inclusion, if not addressed, 
could result in uncontained debris release, 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.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed GE GEnx-1B Service Bulletin 72-0542 R00, dated 
April 15, 2024 (GE GEnx-1B SB 72-0542 R00). The FAA also reviewed GE 
GEnx-2B Service Bulletin 72-0471 R00, dated April 15, 2024. This 
material specifies the affected part numbers, serial numbers, and 
cyclic removal thresholds for the HPT stage 1 and HPT stage 2 disks. 
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 the ADDRESSES section.

Proposed AD Requirements in This NPRM

    This proposed AD would require replacement of certain HPT stage 1 
disks and HPT stage 2 disks. Depending on the part numbers and serial 
numbers of the affected HPT stage 1 disks and HPT stage 2 disks, this 
NPRM proposes to require these actions to be accomplished at the next 
piece-part exposure after the effective date of this proposed AD or 
before the affected HPT stage 1 disks and HPT stage 2 disks reach the 
cyclic removal threshold of up to 10,100 cycles since new.

Differences Between This Proposed AD and the Referenced Material

    GE GEnx-1B SB 72-0542 R00 uses the terms ``HPT rotor stage 1 disk'' 
and ``HPT rotor stage 2 disk,'' while this proposed AD uses the terms 
``HPT stage 1 disk'' and ``HPT stage 2 disk.''

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect one engine installed on an airplane of U.S. registry. The FAA 
estimates that no engines installed on airplanes of U.S. registry would 
require replacement of the HPT stage 2 disk.
    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
----------------------------------------------------------------------------------------------------------------
Replace HPT stage 1 disk........  8 work-hours x $85  $757,416 (prorated)............   $758,096        $758,096
                                   per hour = $680.
Replace HPT stage 2 disk........  8 work-hours x $85  278,101 (prorated).............    278,781               0
                                   per hour = $680.
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[[Page 8689]]

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-2025-0015; Project 
Identifier AD-2024-00615-E.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by March 17, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company Model GEnx-1B64, 
GEnx-1B64/P1, GEnx-1B64/P2, GEnx-1B67, GEnx-1B67/P1, GEnx-1B67/P2, 
GEnx-1B70, GEnx-1B70/75/P1, GEnx-1B70/75/P2, GEnx-1B70/P1, GEnx-
1B70/P2, GEnx-1B70C/P1, GEnx-1B70C/P2, GEnx-1B74/75/P1, GEnx-1B74/
75/P2, GEnx-1B76/P2, GEnx-1B76A/P2, and GEnx-2B67/P engines with at 
least one of the following installed:
    (1) High Pressure Turbine (HPT) stage 1 disk having part number 
(P/N) 2383M83G03 and a serial number (S/N) listed in Table 1 of GE 
GEnx-1B Service Bulletin 72-0542 R00, dated April 15, 2024 (GE GEnx-
1B SB 72-0542 R00);
    (2) HPT stage 2 disk having P/N 2300M84P02 and a S/N listed in 
Table 2 of GE GEnx-1B SB 72-0542 R00;
    (3) HPT stage 1 disk having P/N 2383M83G03 and a S/N listed in 
Table 1 of GE GEnx-2B Service Bulletin 72-0471 R00, dated April 15, 
2024 (GE GEnx-2B SB 72-0471 R00); or
    (4) HPT stage 2 disk having P/N 2300M84P02 and a S/N listed in 
Table 2 of GE GEnx-2B SB 72-0471 R00.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by a manufacturer investigation that 
revealed certain HPT stage 1 disks and HPT stage 2 disks were 
manufactured from powder metal material suspected to contain iron 
inclusion. The FAA is issuing this AD to prevent premature fracture 
and uncontained failure. The unsafe condition, if not addressed, 
could result in uncontained debris release, 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

    At the applicable time specified in paragraphs (g)(1) through 
(4) of this AD, remove each affected HPT stage 1 disk and HPT stage 
2 disk from service and replace with a part eligible for 
installation.
    (1) For engines identified in paragraph (c)(1) of this AD, at 
the next piece-part exposure after the effective date of this AD or 
before the affected HPT stage 1 disk exceeds the cyclic removal 
threshold listed in Table 1 of GE GEnx-1B SB 72-0542 R00, whichever 
occurs first.
    (2) For engines identified in paragraph (c)(2) of this AD, at 
the next piece-part exposure after the effective date of this AD or 
before the affected HPT stage 2 disk exceeds the cyclic removal 
threshold listed in Table 2 of GE GEnx-1B SB 72-0542 R00, whichever 
occurs first.
    (3) For engines identified in paragraph (c)(3) of this AD, at 
the next piece-part exposure after the effective date of this AD or 
before the affected HPT stage 1 disk exceeds the cyclic removal 
threshold listed in Table 1 of GE GEnx-2B SB 72-0471 R00, whichever 
occurs first.
    (4) For engines identified in paragraph (c)(4) of this AD, at 
the next piece-part exposure after the effective date of this AD or 
before the affected HPT stage 2 disk exceeds the cyclic removal 
threshold listed in Table 2 of GE GEnx-2B SB 72-0471 R00, whichever 
occurs first.

(h) Definitions

    For the purpose of this AD:
    (1) A ``part eligible for installation'' is any HPT stage 1 disk 
or HPT stage 2 disk with a P/N and S/N that is not listed in Table 1 
or Table 2 of either GEnx-1B SB 72-0542 R00 or GEnx-2B SB 72-0471 
R00.
    (2) A ``piece-part exposure'' is when the affected HPT stage 1 
disk or HPT stage 2 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 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 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 GEnx-1B Service Bulletin (SB) 72-0542 R00, dated April 
15, 2024.
    (ii) GE GEnx-2B SB 72-0471 R00, dated April 15, 2024.

[[Page 8690]]

    (3) For GE 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 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 27, 2025.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-02016 Filed 1-30-25; 8:45 am]
BILLING CODE 4910-13-P
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