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 Department of Transportation Federal Aviation Administration 14 CFR Part 39
[Docket No. FAA-2024-2547; Project Identifier AD-2024-00334-E]
RIN 2120-AA64
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for all General Electric Company (GE) Model CT7-2E1 engines. This proposed AD was prompted by a revised analysis using an updated stress model, which calculated that the actual life limit of the CT7-2E1 stage 2 turbine aft cooling plate is less than the current life limit. This proposed AD would require revision of the airworthiness limitations section (ALS) of the existing CT7-2E1 engine maintenance manual (EMM) and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate a reduced life limit for this part. 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 January 21, 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-2024-2547; 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: Barbara Caufield, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7146; email: 
                        *barbara.caufield@faa.gov*.


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-2024-2547; Project Identifier AD-2024-00334-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 Barbara Caufield, 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 This AD was prompted by a revised analysis using an updated stress model, which calculated that the actual life limit of the GE Model CT7-2E1 engine stage 2 turbine aft cooling plate is less than the current life limit. The FAA is issuing this AD to prevent failure of the stage 2 aft turbine cooling plate. The unsafe condition, if not addressed, could result in an uncontained failure, release of high-energy debris, damage to the engine, damage to the airplane, and loss of 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 revision of the ALS of the existing CT7-2E1 EMM and the operator's existing approved maintenance program or inspection program, as applicable, to incorporate a reduced life limit for the stage 2 turbine aft cooling plate part number 5166T27P01. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect eight CT7-2E1 engines installed on airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:
                    ( print page 96619) Estimated Costs
Action
Labor cost
Parts cost
Cost per
                             product
Cost on U.S.
                             operatorsRevise the ALS
1 work-hour × $85 per hour = $85
$0
$85
$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
 1.The authority citation for part 39 continues to read as follows: Authority:
                    49 U.S.C. 106(g), 40113, 44701. § 39.13
 2.The FAA amends § 39.13 by adding the following new airworthiness directive: **General Electric Company:**
                         Docket No. FAA-2024-2547; Project Identifier AD-2024-00334-E. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by January 21, 2025. (b) Affected ADs None. (c) Applicability This AD applies to General Electric Company (GE) Model CT7-2E1 engines. (d) Subject Joint Aircraft System Component (JASC) Code 7200, Engine (Turbine/Turboprop). (e) Unsafe Condition This AD was prompted by a revised analysis using an updated stress model, which calculated that the actual life limit of the CT7-2E1 stage 2 turbine aft cooling plate is less than the current life limit. The FAA is issuing this AD to prevent failure of the stage 2 aft turbine cooling plate. The unsafe condition, if not addressed, could result an uncontained failure, release of high-energy debris, damage to the engine, damage to the airplane, and loss of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions Within 30 days after the effective date of this AD, revise the airworthiness limitations section (ALS) of the existing engine maintenance manual or instructions for continued airworthiness (ICA), and the operator's existing approved maintenance program or inspection program, as applicable, by replacing the 6,100 cycle life limit with the new life limit of 3,100 cycles for the stage 2 aft turbine cooling plate part number 5166T27P01. (h) Provisions for Alternative Actions or Intervals After the action required by paragraph (g) of this AD has been done, no alternative actions, including life limits, are allowed unless they are approved as specified in the provisions of paragraph (i) of this AD. (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. Information may be emailed to: 
                        *AMOC@faa.gov*. (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 Barbara Caufield, Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, WA 98198; phone: (781) 238-7146; email: 
                        *barbara.caufield@faa.gov*. (k) Material Incorporated by Reference None. Issued on November 27, 2024. Suzanne Masterson, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.


[FR Doc. 2024-28436 Filed 12-4-24; 8:45 am] BILLING CODE 4910-13-P