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[Federal Register Volume 89, Number 234 (Thursday, December 5, 2024)]
[Proposed Rules]
[Pages 96618-96619]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-28436]

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 89, No. 234 / Thursday, December 5, 2024 / 
Proposed Rules

[[Page 96618]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-2547; Project Identifier AD-2024-00334-E]
RIN 2120-AA64

Airworthiness Directives; General Electric Company Engines

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: [email protected].

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:

[[Page 96619]]

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                     Cost per      Cost on U.S.
                Action                         Labor cost           Parts cost        product        operators
----------------------------------------------------------------------------------------------------------------
Revise the ALS........................  1 work-hour x $85 per                 $0             $85            $680
                                         hour = $85.
----------------------------------------------------------------------------------------------------------------

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

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:

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: [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 Barbara Caufield, 
Aviation Safety Engineer, FAA, 2200 South 216th Street, Des Moines, 
WA 98198; phone: (781) 238-7146; email: [email protected].

(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
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