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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2025-0007; Project Identifier MCAI-2023-00998-R]
          - 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                               ( print page 5749)                            Airbus Helicopters Model SA341G and SA342J helicopters. This proposed AD was prompted by reports of corrosion on the contact surfaces of the tail rotor inclined and horizontal drive shaft flanges. This proposed AD would require repetitively inspecting the inclined and horizontal drive shaft flanges and, depending on the results, replacing the inclined or horizontal drive shaft. This proposed AD would also prohibit installing certain inclined and horizontal drive shafts unless certain requirements are met, as specified in a European Union Aviation Safety Agency (EASA) AD, which is proposed for incorporation by reference. The FAA is proposing this AD to address the unsafe condition on these products.                    

# DATES:

The FAA must receive comments on this NPRM by March 3, 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-2025-0007; 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, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.                    

*Material Incorporated by Reference:*
      - For EASA material identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: ADs@easa.europa.eu;                          website:                          easa.europa.eu.                          You may find the EASA material on the EASA website at                          ad.easa.europa.eu. 
      - You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. It is also available at regulation.gov                          under Docket No. FAA-2025-0007.                    

# FOR FURTHER INFORMATION CONTACT:

                        Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4152; email:                         *Evan.P.Weaver@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-2025-0007; Project Identifier MCAI-2023-00998-R” 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 amend 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 Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4152; email:                     *Evan.P.Weaver@faa.gov.*                     Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.                

## Background

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2023-0168, dated August 31, 2023 (EASA AD 2023-0168) (also referred to as the MCAI), to correct an unsafe condition on all Airbus Helicopters Model SA 341 G and SA 342 J (Gazelle) helicopters. The MCAI states that there have been several reports of corrosion on the contact surfaces of the tail rotor inclined and horizontal drive shaft flanges. More detailed non-destructive testing indicated pitting corrosion on the mating faces of several flanges and further investigation revealed various regions of intergranular failure beneath the surface of corrosion pits. The unsafe condition, if not addressed, could result in the failure of the tail rotor drive and subsequent loss of control of the helicopter.

The FAA is issuing this proposed AD to address the unsafe condition on these products.  

                    You may examine the MCAI in the AD docket at                     *regulations.gov*                     under Docket No. FAA-2025-0007.                

## Material Incorporated by Reference Under 1 CFR Part 51

                    The FAA reviewed EASA AD 2023-0168, which requires repetitively inspecting the flanges of certain part-numbered inclined and horizontal drive shafts for corrosion. If corrosion is found, EASA AD 2023-0168 requires replacing the affected inclined or horizontal drive shaft. EASA AD 2023-0168 also prohibits installing an affected inclined or horizontal drive shaft on any helicopter unless it is a serviceable part as defined within. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the                     **ADDRESSES**                     section.                

## FAA's Determination

These products have been approved by the aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, it has notified the FAA of the unsafe condition described in the MCAI referenced above. 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 accomplishing the actions specified in EASA AD 2023-0168, described previously, as incorporated by reference, except for any differences                           ( print page 5750)                        identified as exceptions in the regulatory text of this proposed AD and except as discussed under “Differences Between This NPRM and the MCAI.”                

## Explanation of Required Compliance Information

                    In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority (CAA) ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, the FAA proposes to incorporate EASA AD 2023-0168 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2023-0168 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2023-0168 does not mean that operators need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,” compliance with this AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA AD 2023-0168. Material required by EASA AD 2023-0168 for compliance will be available at                     *regulations.gov*                     under Docket No. FAA-2025-0007 after the FAA final rule is published.                

## Differences Between This NPRM and the MCAI

The material referenced in the MCAI specifies sending corroded parts to Airbus Helicopters, whereas this proposed AD would not require that action.

## Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 63 helicopters of U.S. registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates the following costs to comply with this proposed AD.

Visually inspecting the inclined and horizontal drive shaft flanges would take 4 work-hours for an estimated cost of $340 per helicopter and $21,420 for the U.S. fleet, per inspection cycle. If required, replacing the inclined or horizontal drive shaft would take 4 work-hours and parts would cost $17,900 (inclined drive shaft) or $35,500 (horizontal drive shaft), for an estimated cost of $18,240 or $35,840 per helicopter.

## 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: 

**Airbus Helicopters:**                         Docket No. FAA-2025-0007; Project Identifier MCAI-2023-00998-R.                    

## (a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by March 3, 2025.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to Airbus Helicopters Model SA341G and SA342J helicopters, certificated in any category.

## (d) Subject

Joint Aircraft System Component (JASC) Code 6510, Tail Rotor Drive Shaft.

## (e) Unsafe Condition

This AD was prompted by reports of corrosion on the contact surfaces of the tail rotor inclined and horizontal drive shaft flanges. The FAA is issuing this AD to detect and address corrosion on the inclined and horizontal drive shaft flanges. The unsafe condition, if not addressed, could result in the failure of the tail rotor drive and subsequent loss of control of the helicopter.

## (f) Compliance

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

## (g) Requirements

Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with, European Union Aviation Safety Agency AD 2023-0168, dated August 31, 2023 (EASA AD 2023-0168).

## (h) Exceptions to EASA AD 2023-0168

(1) Where EASA AD 2023-0168 requires compliance in terms of flight hours, this AD requires using hours time-in-service.

(2) Where EASA AD 2023-0168 refers to its effective date, this AD requires using the effective date of this AD.

(3) Where the material referenced in paragraph (2) of EASA 2023-0168 specifies sending corroded inclined or horizontal drive shaft to Airbus Helicopters, this AD does not require that action.

(4) This AD does not adopt the “Remarks” section of EASA AD 2023-0168.

## (i) No Reporting Requirement

Although the material referenced in EASA AD 2023-0168 specifies to submit certain information to the manufacturer, this AD does not require that action.

## (j) Special Flight Permits

Special flight permits are prohibited.

## (k) Alternative Methods of Compliance (AMOCs)

                        (1) The Manager, International Validation Branch, FAA, has the authority to approve                               ( print page 5751)                            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 International Validation Branch, send it to the attention of the person identified in paragraph (l) of this AD and email 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.

## (l) Additional Information

                        For more information about this AD, contact Evan Weaver, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4152; email:                         *Evan.P.Weaver@faa.gov.*

## (m) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) European Union Aviation Safety Agency (EASA) AD 2023-0168, dated August 31, 2023.

(ii) [Reserved]

                        (3) For EASA material identified in this AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email:                         *ADs@easa.europa.eu;*                         website:                         *easa.europa.eu.*                         You may find this EASA material on the EASA website at                         *ad.easa.europa.eu.*

(4) You may view this material at the FAA, Office of the Regional Counsel, Southwest Region, 10101 Hillwood Parkway, Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.

                        (5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit                         *www.archives.gov/​federal-register/​cfr/​ibr-locations*                         or email                         *fr.inspection@nara.gov.*

Issued on January 13, 2025.

Victor Wicklund,

Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2025-01100 Filed 1-16-25; 8:45 am]

BILLING CODE 4910-13-P