Airworthiness Directives; General Electric Company Engines

[Federal Register Volume 91, Number 1 (Friday, January 2, 2026)]
[Rules and Regulations]
[Pages 16-18]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-24173]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-1364; Project Identifier AD-2024-00613-E; 
Amendment 39-23215; AD 2025-25-07]
RIN 2120-AA64


Airworthiness Directives; General Electric Company Engines

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain General Electric Company (GE) Model GE90-90B, GE90-94B, GE90-
110B1, and GE90-115B engines. This 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 AD requires replacement of 
affected HPT stage 1 and HPT stage 2 disks with parts eligible for 
installation. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective February 6, 2026.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of February 6, 
2026.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-1364; 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 final rule, any comments received, and other 
information. The address for Docket Operations is U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.
    Material Incorporated by Reference:
    <bullet> 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.

[[Page 17]]

    <bullet> 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. It is also available at 
regulations.gov under Docket No. FAA-2025-1364.

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:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 by adding an AD that would apply to certain GE Model GE90-
90B, GE90-94B, GE90-110B1, and GE90-115B engines. The NPRM was 
published in the Federal Register on July 29, 2025 (90 FR 35642). The 
NPRM was prompted by 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 GE90-90B, GE90-
94B, GE90-110B1, and GE90-115B engines. Further investigation by the 
manufacturer revealed 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 revealed that 
there were no incidents of premature fracture and uncontained failure 
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 failure events. In 
the NPRM, the FAA proposed to require replacement of affected HPT stage 
1 and HPT stage 2 disks with parts eligible for installation. The FAA 
is issuing this AD to address the unsafe condition on these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from four commenters. The commenters were 
the Air Line Pilots Association, International (ALPA), The Boeing 
Company (Boeing), FedEx Express (FedEx), and GE Aerospace. The ALPA, 
Boeing, and FedEx supported the NPRM without change. The following 
presents the comment received on the NPRM and the FAA's response to the 
comment.

Request To Correct Part Numbers

    GE Aerospace requested that the FAA revise the part number in Table 
1 to Paragraph (c) of the proposed AD for serial numbers GWN0NJ92, 
GWN0NJ94, and GWN0NK87 from ``1865M13G08'' to ``1865M13G07.'' GE 
Aerospace noted that GE GE90-100 Service Bulletin 72-0926, Revision 01, 
dated December 22, 2023, lists the current part numbers for affected 
disks, and they have been confirmed with product support engineering.
    The FAA agrees and has updated the part number in Table 1 to 
Paragraph (c) of this AD as requested.

Conclusion

    The FAA reviewed the relevant data, considered any comments 
received, and determined that air safety requires adopting this AD as 
proposed. Accordingly, the FAA is issuing this AD to address the unsafe 
condition on these products. Except for minor editorial changes, and 
any other changes described previously, this AD is adopted as proposed 
in the NPRM. None of the changes will increase the economic burden on 
any operator.

Material Incorporated by Reference Under 1 CFR Part 51

    The FAA reviewed GE GE90-100 Service Bulletin 72-0926, Revision 01, 
dated December 22, 2023. 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.

Costs of Compliance

    The FAA estimates that this AD affects two engines installed on 
airplanes of U.S. registry. The FAA estimates that one engine installed 
on an airplane of U.S. registry will require replacement of the HPT 
stage 1 disk, and one engine installed on an airplane of U.S. registry 
will require replacement of the HPT stage 2 disk. The FAA estimates the 
following costs to comply with this 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 per  $932,136 (prorated)...     $932,816        $932,816
                                      hour = $680.
Replace HPT stage 2 disk...........  8 work-hours x $85 per  $186,406 (prorated)...      187,086         187,086
                                      hour = $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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Will not affect intrastate aviation in Alaska, and
    (3) Will not have a significant economic impact, positive or 
negative, on a substantial number of small entities

[[Page 18]]

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 Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 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:

2025-25-07 General Electric Company: Amendment 39-23215; Docket No. 
FAA-2025-1364; Project Identifier AD-2024-00613-E.

(a) Effective Date

    This airworthiness directive (AD) is effective February 6, 2026.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to the following General Electric Company (GE) 
Model engines:
    (1) GE90-90B and GE90-94B engines with a high pressure turbine 
(HPT) stage 1 disk having a part number and serial number identified 
in table 1 to paragraph (c) of this AD installed; and
    (2) GE90-110B1 and GE90-115B engines with an HPT stage 1 disk or 
HPT stage 2 disk having a part number and serial number identified 
in table 1 to paragraph (c) of this AD or Table 1 or Table 2 of GE 
GE90-100 Service Bulletin (SB) 72-0926, Revision 01, dated December 
22, 2023 (GE GE90-100 SB 72-0926, Revision 01), installed.

       Table 1 to Paragraph (c)--Affected HPT Stage 1 and 2 Disks
------------------------------------------------------------------------
           Part name                  Part No.            Serial No.
------------------------------------------------------------------------
HPT Stage 1 Disk..............  1847M95G01           GWN05K5J
HPT Stage 1 Disk..............  1847M95G01           GWN05K5M
HPT Stage 1 Disk..............  1847M95G01           GWN05NP6
HPT Stage 1 Disk..............  1865M13G08           GWN10N9A
HPT Stage 1 Disk..............  1865M13G07           GWN0NJ92
HPT Stage 1 Disk..............  1865M13G07           GWN0NJ94
HPT Stage 1 Disk..............  1865M13G07           GWN0NK87
HPT Stage 1 Disk..............  1865M13G08           GWN0RJ4G
HPT Stage 1 Disk..............  1865M13G08           GWN0WPEC
HPT Stage 2 Disk..............  1865M14P04           TMT4RK67
HPT Stage 2 Disk..............  1865M14P04           TMT4RG10
HPT Stage 2 Disk..............  1865M14P04           TMT4RG11
------------------------------------------------------------------------

(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 of the HPT stage 1 disks and HPT stage 2 
disks. 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 times specified in paragraphs (g)(1) through 
(3) 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 HPT stage 1 disks and HPT stage 2 disks with a part 
number and serial number identified in table 1 to paragraph (c) of 
this AD, before further flight.
    (2) For HPT stage 1 disks with a part number and serial number 
identified in Table 1 of GE GE90-100 SB 72-0926, Revision 01, that 
are not identified in table 1 to paragraph (c) of this AD, at the 
next piece-part exposure or before exceeding 4,650 cycles since new 
(CSN), whichever occurs first.
    (3) For HPT stage 2 disks with a part number and serial number 
identified in Table 2 of GE GE90-100 SB 72-0926, Revision 01, that 
are not identified in table 1 to paragraph (c) of this AD, at the 
next piece-part exposure or before exceeding 11,300 CSN, whichever 
occurs first.

(h) Grace Period for HPT Stage 1 Disk Replacement

    For affected HPT stage 1 disks having greater than 4,650 CSN on 
the effective date of this AD, the replacement required by paragraph 
(g)(2) of this AD may be deferred up to 50 flight cycles after the 
effective date of this AD.

(i) Definitions

    (1) For the purpose of this AD, a ``part eligible for 
installation'' is any HPT stage 1 disk or HPT stage 2 disk having a 
part number and serial number that is not identified in table 1 to 
paragraph (c) of this AD or Table 1 or Table 2 of GE GE90-100 SB 72-
0926, Revision 01.
    (2) For the purpose of this AD, a ``piece-part exposure'' is 
when the affected HPT stage 1 disk or HPT stage 2 disk is removed 
from the engine and completely disassembled.

(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 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]. 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) 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].

(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) GE GE90-100 Service Bulletin 72-0926, Revision 01, dated 
December 22, 2023.
    (ii) [Reserved]
    (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 December 8, 2025.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-24173 Filed 12-31-25; 8:45 am]
BILLING CODE 4910-13-P

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