2024-27664. Airworthiness Directives; General Electric Company Engines.

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Replace stage 1 turbine forward cooling plate and stage 2 turbine aft cooling plate	8 work-hours × $85 per hour = $680	$88,360	$89,040	$20,301,120

The above costs presume that the installed engine would require 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 would need replacement, thus reducing the cost of the proposed 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.

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

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive:

General Electric Company: Docket No. FAA-2024-2540; Project Identifier AD-2024-00343-E.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by January 10, 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. ( print page 93230)

(g) Required Actions

(1) Within the compliance times specified in paragraphs (g)(1)(i) through (iii) 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 paragraph (g)(1) of this AD:

(i) 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.

(ii) 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.

(iii) 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.

Table 1 to Paragraph (g) (1): Cooling Plate Replacement P/Ns

Engine group	Part name	Affected P/N	Replacement P/N
1	Stage 1 turbine forward cooling plate	6064T08P01	6064T08P04
1	Stage 2 turbine aft cooling plate	6064T07P05	6064T07P07
1	Stage 2 turbine aft cooling plate	6068T36P01	6068T36P04
2	Stage 1 turbine forward cooling plate	6064T08P01	6064T08P03 or 6064T08P04
2	Stage 2 turbine aft cooling plate	6064T07P05	6064T07P07
2	Stage 2 turbine aft cooling plate	6068T36P01	6068T36P04