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[Federal Register Volume 90, Number 19 (Thursday, January 30, 2025)]
[Proposed Rules]
[Pages 8505-8507]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-01728]

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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]
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 CF6-80E1A2, CF6-80E1A3, 
CF6-80E1A4, and CF6-80E1A4/B 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-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 NPRM, any comments received, and other 
information. The street address for Docket Operations is listed above.

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-2024-2721; 
Project Identifier AD-2024-00610-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 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, CF6-80E1A3, 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 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 
certain 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.

Proposed AD Requirements in This NPRM

    This proposed AD would require replacement of affected HPT stage 1 
and HPT stage 2 disks with parts eligible for installation. Because 
affected operators are already aware of the proposed corrective action 
and have already performed the actions proposed in this AD, the FAA has 
determined that the compliance time to replace the affected HPT stage 1 
and HPT stage 2 disks before further flight is appropriate.

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 the following costs to comply with this proposed 
AD:

[[Page 8506]]

                                                 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

    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-2024-2721; Project 
Identifier AD-2024-00610-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 (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.

[[Page 8507]]

    (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 January 21, 2025.
Suzanne Masterson,
Deputy Director, Integrated Certificate Management Division, Aircraft 
Certification Service.
[FR Doc. 2025-01728 Filed 1-29-25; 8:45 am]
BILLING CODE 4910-13-P
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