Airworthiness Directives; General Electric Company Engines

[Federal Register Volume 90, Number 41 (Tuesday, March 4, 2025)]
[Rules and Regulations]
[Pages 11120-11122]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-03383]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2540; Project Identifier AD-2024-00343-E; 
Amendment 39-22974; AD 2025-05-02]
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 CT7-5A2, CT7-5A3, CT7-7A, 
CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, CT7-9C3, CT7-9D, and CT7-9D2 
engines. This AD was prompted by the manufacturer's determination that 
certain GE Model CT7 fleets have affected cooling plates installed that 
do not meet lifing guidelines. This AD requires replacement of the 
stage 1 turbine forward cooling plate and the stage 2 turbine aft 
cooling plate. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective April 8, 2025.

ADDRESSES: AD Docket: You may examine the AD docket at regulations.gov 
under Docket No. FAA-2024-2540; 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: Sungmo Cho, Aviation Safety Engineer, 
FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-
7241; 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 CT7-
5A2, CT7-5A3, CT7-7A, CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, CT7-
9C3, CT7-9D, and CT7-9D2 engines. The NPRM published in the Federal 
Register on November 26, 2024 (89 FR 93228). The NPRM was prompted by 
the manufacturer's determination that certain GE Model CT7 fleets have 
affected cooling plates installed that do not meet lifing guidelines. 
In the NPRM, the FAA proposed to require replacement of the stage 1 
turbine forward cooling plate and the stage 2 turbine aft cooling 
plate. The FAA is issuing this AD to address the unsafe condition on 
these products.

Discussion of Final Airworthiness Directive

Comments

    The FAA received one comment from the Airline Pilots Association, 
International. The commenter supported the NPRM without change.

Conclusion

    The FAA reviewed the relevant data, considered the comments 
received, and determined that air safety requires adopting the 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.

Costs of Compliance

    The FAA estimates that this AD affects 228 engines installed on 
airplanes 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 stage 1 turbine forward       8 work-hours x $85 per          $88,360          $89,040      $20,301,120
 cooling plate and stage 2 turbine     hour = $680.
 aft cooling plate.
----------------------------------------------------------------------------------------------------------------

    The above costs presume that the installed engine requires 
replacement of both the stage 1 turbine forward cooling plate and stage 
2 turbine aft cooling plate. It is possible that only one of these 
needs replacement, thus reducing the cost of this AD.

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.

[[Page 11121]]

    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:

2025-05-02 General Electric Company: Amendment 39-22974; Docket No. 
FAA-2024-2540; Project Identifier AD-2024-00343-E.

(a) Effective Date

    This airworthiness directive (AD) is effective April 8, 2025.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to General Electric Company (GE) Model CT7-5A2, 
CT7-5A3, CT7-7A, CT7-7A1, CT7-9B, CT7-9B1, CT7-9B2, CT7-9C, CT7-9C3, 
CT7-9D, and CT7-9D2 engines with an installed stage 1 turbine 
forward cooling plate having part number (P/N) 6064T08P01; or with 
an installed stage 2 turbine aft cooling plate having P/N 6064T07P05 
or P/N 6068T36P01.

(d) Subject

    Joint Aircraft System Component (JASC) Code 7200, Engine 
(Turbine/Turboprop).

(e) Unsafe Condition

    This AD was prompted by the manufacturer's determination that 
certain GE Model CT7 fleets have affected cooling plates installed 
that do not meet lifing guidelines. The FAA is issuing this AD to 
prevent the failure of the stage 1 turbine forward cooling plate and 
stage 2 turbine aft cooling plate. The unsafe condition, if not 
addressed, could result in uncontained engine failure and damage to 
the airplane.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    Within the compliance times specified in paragraphs (g)(1) 
through (3) of this AD, replace the affected stage 1 turbine forward 
cooling plate or stage 2 turbine aft cooling plate, as applicable, 
with a replacement P/N eligible for installation, in accordance with 
table 1 to the introductory text of paragraph (g) of this AD:

                Table 1 to the Introductory Text of Paragraph (g)--Cooling Plate Replacement P/Ns
----------------------------------------------------------------------------------------------------------------
          Engine group                  Part name                  Affected P/N               Replacement P/N
----------------------------------------------------------------------------------------------------------------
1...............................  Stage 1 turbine        6064T08P01......................  6064T08P04.
                                   forward cooling
                                   plate.
1...............................  Stage 2 turbine aft    6064T07P05......................  6064T07P07.
                                   cooling plate.
1...............................  Stage 2 turbine aft    6068T36P01......................  6068T36P04.
                                   cooling plate.
2...............................  Stage 1 turbine        6064T08P01......................  6064T08P03 or
                                   forward cooling                                          6064T08P04.
                                   plate.
2...............................  Stage 2 turbine aft    6064T07P05......................  6064T07P07.
                                   cooling plate.
2...............................  Stage 2 turbine aft    6068T36P01......................  6068T36P04.
                                   cooling plate.
----------------------------------------------------------------------------------------------------------------

    (1) For Group 1 engines with an affected part installed, replace 
the affected part at the next exposure of the gas generator stator 
assembly that occurs after the effective date of this AD.
    (2) For Group 2 engines with an affected part installed having 
7,000 part cycles since new (PCSN) or less as of the effective date 
of this AD, replace the affected part at the next exposure of the 
gas generator stator assembly or within 2,000 flight cycles (FCs) 
but before reaching 7,500 PCSN, whichever occurs first after the 
effective date of this AD.
    (3) For Group 2 engines with an affected part installed having 
more than 7,000 PCSN as of the effective date of this AD, replace 
the affected part at the next exposure of the gas generator stator 
assembly or within 500 FCs, whichever occurs first after the 
effective date of this AD.

(h) Definitions

    For the purpose of this AD:
    (1) ``Group 1 engines'' are GE Model CT7-5A2, CT7-5A3, CT7-9B, 
CT7-9B1, CT7-9B2, CT7-9D, and CT7-9D2 engines.
    (2) ``Group 2 engines'' are GE Model CT7-7A, CT7-7A1, CT7-9C, 
and CT7-9C3 engines.
    (3) ``Exposure of the gas generator stator assembly'' is when 
the gas generator rotor and stator assembly are separated from the 
combustor module.

(i) 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 (j) 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.

(j) Additional Information

    For more information about this AD, contact Sungmo Cho, Aviation 
Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; 
phone: (781) 238-7241; email: [email protected].

(k) Material Incorporated by Reference

    None.


[[Page 11122]]


    Issued on February 25, 2025.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-03383 Filed 3-3-25; 8:45 am]
BILLING CODE 4910-13-P

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