[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]
-----------------------------------------------------------------------
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.
-----------------------------------------------------------------------
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