[Federal Register Volume 90, Number 116 (Wednesday, June 18, 2025)]
[Rules and Regulations]
[Pages 25884-25887]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-11206]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-2712; Project Identifier AD-2024-00145-E;
Amendment 39-23066; AD 2025-12-08]
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 CF34-8C1, CF34-8C5, CF34-
8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-8E2, CF34-8E2A1, CF34-
8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 engines. This AD
was prompted by a predicted reduction in the cyclic life of the
combustion chamber assembly (CCA) forward flange. This AD requires
fluorescent penetrant inspections (FPIs) of the CCA for any indications
and replacement if necessary. The FAA is issuing this AD to address the
unsafe condition on these products.
DATES: This AD is effective July 23, 2025.
ADDRESSES:
AD Docket: You may examine the AD docket at regulations.gov under
Docket No. FAAFAA-2024-2712; 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 CF34-
8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, CF34-8C5B1, CF34-
8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-
8E6A1 engines. The NPRM was published in the Federal Register on
December 27, 2024 (89 FR 105483). The NPRM was prompted by a predicted
reduction in the cyclic life of the CCA forward flange. In the NPRM,
the FAA proposed to require FPIs of the CCA for any indications and
replacement if necessary. 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), Fuji Dream
Airlines, Horizon Air, and Japan Airlines. The following presents the
comments received on the NPRM and the FAA's response to each comment.
Support for the NPRM
ALPA expressed support for the proposed AD.
Request for Clarification of Procedures for FPI of the CCA
Fuji Dream Airlines and Horizon Air requested that the FAA clarify
the procedure for the FPI of the CCA in the NPRM. Fuji Dream Airlines
proposed that the FAA revise paragraphs (g)(3) and (5) of the proposed
AD to include reference to Paragraph 3., ``Accomplishment
Instructions'' of GE CF34-8E Service Bulletin (SB) 72-A0250, dated May
1, 2024 (GE SB 72-
[[Page 25885]]
A0250, dated May 1, 2024), in order to accomplish the requested
clarification. Horizon Air proposed that the FAA revise paragraph (h)
of the proposed AD to include reference to the associated subtask in
the CF34-8E Engine Manual.
The FAA disagrees with the requests. The required actions of this
AD do not deviate from the procedures contained in either reference
regarding FPI of the CCA forward flange and, therefore, the FAA does
not consider additional service material references to be necessary.
The FAA has not changed this AD as a result of this comment.
Request To Include Service Material
Japan Airlines requested that the FAA include GE SB 72-A0250, dated
May 1, 2024, as the appropriate source of service material for
accomplishing the actions required by the proposed AD.
The FAA disagrees with the request. As stated previously, the
required actions of this AD do not deviate from the procedures
contained in GE SB 72-A0250, dated May 1, 2024, regarding FPI of the
CCA forward flange and, therefore, the FAA does not consider additional
service material references to be necessary. The FAA has not changed
this AD as a result of this comment.
Request To Allow Multiple FPIs
Fuji Dream Airlines requested that the FAA revise paragraph (g)(3)
of the proposed AD to allow for multiple FPIs. Fuji Dream Airlines
mentioned that GE SB 72-A0250, dated May 1, 2024, includes a note which
specifies that multiple FPIs are permitted.
The FAA agrees with the request and has revised paragraph (g)(4) of
this AD to include the following statement: Multiple FPIs of the
forward flange prior to the 25,000 part cycles since new (PCSN)
threshold are permitted. However, the affected CCA must be removed from
service and replaced no later than 15,000 cycles from the last
inspection performed before the 25,000 PCSN threshold.
Request To Clarify Definition of ``Engine Shop Visit''
Horizon Air requested that the FAA clarify the definition of
``engine shop visit'' in paragraph (h)(3) of the proposed AD, which
discussed the induction of an engine into the shop for maintenance
involving the separation of major mating engine case flanges and
included two exceptions; one for engine flanges separated solely for
transportation, and the other for engine flanges separated solely for
replacement of the fan or propulsor, both without subsequent
maintenance. Horizon Air also stated that no definition is specified
for what constitutes a ``fan'' or ``propulsor,'' and that replacement
of the fan or propulsor could be construed as ``subsequent
maintenance.'' Additionally, Horizon Air mentioned that the GE Model
CF34 engine is not typically separated at the engine flanges for
transportation and proposed an alternative definition of ``engine shop
visit.''
The FAA agrees with the request for the reasons provided and has
revised the definition of ``engine shop visit'' to the following: An
``engine shop visit'' is the induction of an engine into the shop for
maintenance involving the separation of pairs of major mating engine
flanges.
Request To Align Compliance Time of the NPRM With Certain Service
Material
Japan Airlines requested that the FAA align the compliance time
threshold for the required actions of the proposed AD with the
threshold stated in GE SB 72-A0250, dated May 1, 2024. Japan Airlines
pointed out that some engines, due to the difference in compliance time
threshold of the NPRM, would belong to different groups with different
required actions than if the threshold specified in GE SB 72-A0250,
dated May 1, 2024, were to be used. Fuji Dream Airlines also expressed
support for this request.
The FAA disagrees with the request. The FAA acknowledges that the
PCSN are going to be different based on the AD compliance time
threshold, and that some parts may be subject to different requirements
as a result. However, in developing an appropriate compliance time, the
FAA considered the safety implications, parts availability, and normal
maintenance schedules for timely accomplishment of the required
actions. In consideration of all of these factors, the FAA determined
that the compliance time threshold, as proposed, is appropriate, while
still maintaining an adequate level of safety. If additional data are
presented that would justify a different compliance threshold, the FAA
may consider further rulemaking on this issue. The FAA has not changed
this AD as a result of this comment.
Request To Clarify Replacement of the CCA
Japan Airlines requested that the FAA clarify the requirement for
replacement of the CCA with part number (P/N) 4180T27G07, P/N
4180T27G08, or a later approved P/N. Japan Airlines asked if it is
acceptable to replace the CCA with part numbers other than those
specified in the proposed AD if the CCA must be replaced for reasons
other than the requirements of paragraph (g) of the proposed AD.
The FAA agrees to clarify. If the CCA must be replaced for reasons
other than the requirements of paragraph (g) of this AD, it is
acceptable to replace it with part numbers other than those specified
in this AD. However, if the replacement CCA has a part number that is
affected by this AD, then the requirements of this AD will apply to the
replacement CCA. The FAA has not changed this AD as a result of this
comment.
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.
Costs of Compliance
The FAA estimates that this AD affects 2,988 engines installed on
airplanes of U.S. registry.
The FAA estimates the following costs to comply with this AD:
Estimated Costs
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Cost per Cost on U.S.
Action Labor cost Parts cost product operators
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FPI the CCA forward flange............ 8 work-hours x $85 per $0 $680 $2,031,840
hour = $680.
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The FAA estimates an average CCA utilization of 2,143 part cycles
per year. Based on this life estimate, the FAA is providing an
estimated annual cost to replace these parts. The FAA estimates that
369 affected engines will require
[[Page 25886]]
CCA replacement at 28,500 PCSN, 855 affected engines will require CCA
replacement at 25,500 PCSN, and 1,764 affected engines will require CCA
replacement at 40,000 PCSN. The following summarizes the costs of the
proposed AD over the analysis timeframe, for the 12 years spanning
2024-2036. The cost of early CCA removals, required by this AD,
analyzed over 2024 through 2036, are $265 million at a 2% financial
discount rate.
On-Condition Costs
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Cost on U.S.
Cost per operators
Action Labor cost Parts cost product annualized (2%
discount rate)
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Replace the CCA (prorated part cost).. 8 work-hours x $85 per $646,900 $647,580 $24,544,532
hour = $680.
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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:
2025-12-08 General Electric Company: Amendment 39-23066; Docket No.
FAA-2024-2712; Project Identifier AD-2024-00145-E.
(a) Effective Date
This airworthiness directive (AD) is effective July 23, 2025.
(b) Affected ADs
None.
(c) Applicability
This AD applies to the following General Electric Company (GE)
Model engines:
(1) CF34-8C1, CF34-8C5, CF34-8C5A1, CF34-8C5A2, CF34-8C5A3, and
CF34-8C5B1 engines with an installed combustion chamber assembly
(CCA) having part number (P/N) 4145T11G08, 4145T11G10, 4180T27G02,
4180T27G04, or 4923T82G02; and
(2) CF34-8E2, CF34-8E2A1, CF34-8E5, CF34-8E5A1, CF34-8E5A2,
CF34-8E6, and CF34-8E6A1 engines with an installed CCA having P/N
4145T11G08, 4145T11G09, 4180T27G01, or 4180T27G03.
(d) Subject
Joint Aircraft System Component (JASC) Code 7240, Turbine Engine
Combustion Section.
(e) Unsafe Condition
This AD was prompted by a predicted reduction in the cyclic life
of the CCA forward flange. The FAA is issuing this AD to prevent
failure of the CCA. The unsafe condition, if not addressed, could
result in failure of the CCA before reaching the published life
limit, uncontained release of the CCA, 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) For affected Group 1 engines with an installed CCA having
less than 15,000 part cycles since new (PCSN) as of the effective
date of this AD, before the accumulation of 28,500 PCSN, remove the
CCA from service and replace with P/N 4180T27G08 or a later approved
P/N.
(2) For affected Group 2 engines with an installed CCA having
less than 15,000 PCSN as of the effective date of this AD, before
the accumulation of 25,500 PCSN, remove the CCA from service and
replace with P/N 4180T27G07 or a later approved P/N.
(3) For affected Group 1 and 2 engines with an installed CCA
having between 15,000 PCSN and 24,999 PCSN as of the effective date
of this AD, before the accumulation of 25,000 PCSN, perform a
fluorescent penetrant inspection (FPI) on the forward flange of the
CCA for any indications.
(4) If no indications are found during the FPI required by
paragraph (g)(3) of this AD, within 15,000 part cycles from the date
of the FPI, remove the CCA from service and replace with P/N
4180T27G07, 4180T27G08, or a later approved P/N, as applicable.
Multiple FPIs of the forward flange prior to the 25,000 PCSN
threshold are permitted. However, the affected CCA must be removed
from service and replaced no later than 15,000 cycles from the last
inspection performed before the 25,000 PCSN threshold.
(5) For affected Group 1 and 2 engines with an installed CCA
having more than 25,000 PCSN as of the effective date of this AD, at
the next engine shop visit after the effective date of this AD,
perform an FPI on the forward flange of the CCA for any indications.
(6) If no indications are found during the FPI required by
paragraph (g)(5) of this AD, within 15,000 part cycles from the date
of the FPI and not to exceed 41,100 PCSN, remove the CCA from
service and replace with P/N 4180T27G07, 4180T27G08, or a later
approved P/N, as applicable.
(7) If an indication is found during any FPI required by
paragraph (g)(3) or (5) of this AD, before further flight, remove
the CCA from service and replace with P/N 4180T27G07,
[[Page 25887]]
P/N 4180T27G08, or a later approved P/N, as applicable.
(h) Definitions
For the purpose of this AD:
(1) ``Group 1 engines'' are GE Model CF34-8C1, CF34-8C5, CF34-
8C5A1, CF34-8C5A2, CF34-8C5A3, and CF34-8C5B1 engines.
(2) ``Group 2 engines'' are GE Model CF34-8E2, CF34-8E2A1, CF34-
8E5, CF34-8E5A1, CF34-8E5A2, CF34-8E6, and CF34-8E6A1 engines.
(3) An ``engine shop visit'' is the induction of an engine into
the shop for maintenance involving the separation of pairs of major
mating engine flanges.
(i) Installation Prohibition
After the effective date of this AD, do not reinstall any CCAs
that were removed as a result of paragraphs (g)(1), (2), (4), (6),
and (7) of this AD in any engine.
(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 the 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 June 13, 2025.
Peter A. White,
Deputy Director, Integrated Certificate Management Division, Aircraft
Certification Service.
[FR Doc. 2025-11206 Filed 6-17-25; 8:45 am]
BILLING CODE 4910-13-P