Airworthiness Directives; General Electric Company Engines

[Federal Register Volume 90, Number 96 (Tuesday, May 20, 2025)]
[Rules and Regulations]
[Pages 21402-21404]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-09007]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2721; Project Identifier AD-2024-00610-E; 
Amendment 39-23045; AD 2025-10-11]
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 CF6-80E1A2, CF6-80E1A3, 
CF6-80E1A4, and CF6-80E1A4/B 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 June 24, 2025.

ADDRESSES: 
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2024-2721; 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.

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 CF6-
80E1A2, CF6-80E1A3, CF6-80E1A4, and CF6-80E1A4/B engines. The NPRM was 
published in the Federal Register on January 30, 2025 (90 FR 8505). The 
NPRM was prompted by a manufacturer investigation that revealed the 
detection of iron inclusion in an HPT stage 2 disk manufactured from 
the same powder metal material used to manufacture certain HPT stage 1 
and HPT stage 2 disks for GE Model CF6-80E1A2, CF6-

[[Page 21403]]

80E1A3, CF6-80E1A4, and CF6-80E1A4/B 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 showed that 
there were no failed events associated with the discovery of this iron 
inclusion material. However, it was concluded that replacement of the 
affected HPT stage 1 and HPT stage 2 disks is necessary to prevent any 
future failed 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 three commenters. The commenters 
were Delta Air Lines, Inc. (DAL) and two individual commenters. The 
individual commenters supported the NPRM without change. DAL requested 
changes to the proposed AD. The following presents the comments 
received on the NPRM and the FAA's response to each comment.

Request To Expand Applicability and Add Parts Prohibition Requirement

    DAL requested that the FAA revise the proposed AD to add certain 
engine variants to paragraph (c), Applicability, and to add a parts 
installation prohibition to paragraph (g), Required Actions, to prevent 
installation of the removed parts on non-CF6-80E1 engines. DAL noted 
that, according to the engine illustrated parts catalog, the HPT stage 
1 and HPT stage 2 disks on the CF6-80E1 fleet of engines could be 
installed on the CF6-80C2 fleet of engines, specifically on the -B2F, -
B4F, -B6F, -B7F, and -B8F variants. The commenter reasoned that without 
a parts installation prohibition in the proposed AD, the affected parts 
would be eligible for installation on the non-CF6-80E1 engines after 
the required removal action in the AD.
    The FAA disagrees. This AD applies to engine models known to have 
affected parts installed. Paragraph (g) of this AD requires the removal 
of the affected parts from service. Since the FAA and the manufacturer 
know where these parts are, and parts removed from service by AD action 
are not serviceable and not eligible for reinstallation on any engine, 
it is not necessary to revise paragraph (c) of this AD to add engine 
variants and revise paragraph (g) of this AD to prohibit installation 
of the removed parts. The FAA did not change this AD as a result of 
these comments.

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, this 
AD is adopted as proposed in the NPRM. None of the changes will 
increase the economic burden on any operator.

Costs of Compliance

    The FAA estimates that this AD affects one engine installed on an 
airplane of U.S. registry.
    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     $1,228,800 (prorated)      $1,229,480      $1,229,480
                                     per hour = $680.
Replace HPT stage 2 disk..........  8 work-hours x $85     $201,600 (prorated)..         202,280         202,280
                                     per 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 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:

2025-10-11 General Electric Company: Amendment 39-23045; Docket No.

[[Page 21404]]

FAA-2024-2721; Project Identifier AD-2024-00610-E.

(a) Effective Date

    This airworthiness directive (AD) is effective June 24, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) Model CF6-
80E1A2, CF6-80E1A3, CF6-80E1A4, and CF6-80E1A4/B engines with an 
installed high-pressure turbine (HPT) stage 1 disk or HPT stage 2 
disk having a part number (P/N) and serial number (S/N) identified 
in table 1 to paragraph (c) of this AD.

  Table 1 to Paragraph (c)--Affected HPT Stage 1 and HPT Stage 2 Disks
------------------------------------------------------------------------
          Part name                    P/N                   S/N
------------------------------------------------------------------------
HPT stage 1 disk............  1863M36G06            GWN0GP27.
HPT stage 1 disk............  1863M36G06            GWN0GPM8.
HPT stage 1 disk............  1863M36G06            GWN0GP26.
HPT stage 1 disk............  1863M36G06            TMT5SW61.
HPT stage 1 disk............  1863M36G06            TMT5SW59.
HPT stage 1 disk............  1863M36G06            TMT5SW64.
HPT stage 1 disk............  1863M36G06            TMT5SW82.
HPT stage 1 disk............  1863M36G06            GWN0GPMG.
HPT stage 2 disk............  1778M72P05            BTB77100.
HPT stage 2 disk............  1778M72P05            MUNLD123.
HPT stage 2 disk............  1778M72P05            MUNLD122.
HPT stage 2 disk............  1778M72P05            MUN5B794.
HPT stage 2 disk............  1778M72P05            BTB77102.
------------------------------------------------------------------------

(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 and HPT stage 2 disks were subject to 
iron inclusion introduced during the manufacturing process. The FAA 
is issuing this AD to prevent fracture and potential uncontained 
failure of certain HPT stage 1 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

    (1) Before further flight after the effective date of this AD, 
remove any affected HPT stage 1 disk having P/N 1863M36G06 and S/N 
GWN0GP27 from service and replace with a part eligible for 
installation.
    (2) Before further flight after the effective date of this AD, 
remove any affected HPT stage 2 disk having P/N 1778M72P05 and S/N 
BTB77100 from service and replace with a part eligible for 
installation.
    (3) For affected HPT stage 1 disks identified in table 1 to 
paragraph (c) of this AD that are not included in paragraph (g)(1) 
of this AD, at the next piece part exposure or before the affected 
HPT stage 1 disk exceeds 8,600 cycles since new (CSN), whichever 
occurs first after the effective date of this AD, remove the 
affected HPT stage 1 disk from service and replace with a part 
eligible for installation.
    (4) For affected HPT stage 2 disks identified in table 1 to 
paragraph (c) of this AD that are not included in paragraph (g)(2) 
of this AD, at the next piece part exposure or before the affected 
HPT stage 2 disk exceeds 12,000 CSN, whichever occurs first after 
the effective date of this AD, remove the affected HPT stage 2 disk 
from service and replace with a part eligible for installation.

(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 that does not have a P/N and S/N identified in 
table 1 to paragraph (c) of this AD.
    (2) A ``piece part exposure'' is when the affected part is 
removed from the engine and completely disassembled.

(i) Grace Period for HPT Stage 1 Disk Replacement

    For affected HPT stage 1 disks having greater than 8,550 CSN on 
the effective date of this AD, the replacement required by paragraph 
(g)(3) of this AD may be deferred up to 50 flight cycles after the 
effective date 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 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) 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

    None.

    Issued on May 15, 2025.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-09007 Filed 5-19-25; 8:45 am]
BILLING CODE 4910-13-P

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