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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2024-2147; Project Identifier MCAI-2022-01515-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 Airbus Helicopters Model EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, and AS 365 N3 helicopters. This proposed AD was prompted by an engine compartment fire where the upper stiffener of the central firewall in the engine compartment was found damaged. This proposed AD would require replacing the aluminum central firewall stiffener with a titanium central firewall stiffener and prohibit installing an aluminum central firewall stiffener. These actions are 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 November 14, 2024.

# 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-2024-2147; 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 EASA AD, 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 this 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 Pkwy., Room 6N-321, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110. The EASA material is also available at regulations.gov under Docket No. FAA-2024-2147.

*Other Related Material:*                         For Airbus Helicopters material identified in this proposed AD, contact Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX 75052; phone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at                         *airbus.com/en/products-services/helicopters/hcare-services/airbusworld*.                    

# FOR FURTHER INFORMATION CONTACT:

                        Hye Yoon Jang, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (206) 231-3758; email:                         *Hye.Yoon.Jang@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                     **ADDRESSES**                    . Include “Docket No. FAA-2024-2147; Project Identifier MCAI-2022-01515-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 Hye Yoon Jang, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (206) 231-3758; email:                     *Hye.Yoon.Jang@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 European Union Aviation Safety Agency AD 2022-0231, dated November 28, 2022 (EASA AD 2022-0231), to correct an unsafe condition on Airbus Helicopters Model EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, and AS 365 N3 helicopters.

                    This proposed AD was prompted by an engine fire where the upper stiffener of the central firewall, made of aluminum, in the engine compartment was found damaged. The FAA is proposing this AD to address failure of                           ( print page 79484)                        a central firewall stiffener made of aluminum, possibly due to its inability to withstand high temperatures of an engine fire and subsequently not seal the engine compartment properly. In the event of an engine fire, the unsafe condition, if not addressed, could result in fire propagating from one engine compartment to the other and subsequent loss of control of the helicopter. See EASA AD 2022-0231 for additional background information.                

You may examine EASA AD 2022-0231 in the AD docket at regulations.gov under Docket No. FAA-2024-2147.

## Related Material Under 1 CFR Part 51

The FAA reviewed EASA AD 2022-0231 which requires replacing aluminum central firewall stiffeners with titanium central firewall stiffeners and prohibits installing an aluminum central firewall stiffener on any helicopter.

                    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.                

## Other Related Material

The FAA reviewed Airbus Helicopters Alert Service Bulletin (ASB) No. AS365-71.00.28 and ASB No. EC155-71A015, each Revision 0 and dated October 25, 2022. This material specifies procedures for replacing the aluminum stiffener on the center firewall with a titanium stiffener.

## 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 EASA AD 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 these same type designs.

## Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified in EASA AD 2022-0231, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this proposed AD.

## 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 2022-0231 by reference in the FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2022-0231 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 2022-0231 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 2022-0231. Material referenced in EASA AD 2022-0231 for compliance will be available at                     *regulations.gov*                     under Docket No. FAA-2024-2147 after the FAA final rule is published.                

## Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 35 helicopters of U.S. Registry. Labor rates are estimated at $85 per work-hour. Based on these numbers, the FAA estimates that operators may incur the following costs in order to comply with this proposed AD.

Replacing the aluminum central firewall stiffener with a titanium central firewall stiffener would take 7 work-hours and parts would cost $1,737 to $2,801 depending on part number for an estimated cost of $2,332 to $3,396 per helicopter and up to $81,620 to $118,860 for the U.S. fleet.

## 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-2024-2147; Project Identifier MCAI-2022-01515-R.                    

## (a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by November 14, 2024.

## (b) Affected ADs

None.

## (c) Applicability

                        This AD applies to Airbus Helicopters Model EC 155B, EC155B1, SA-365N, SA-365N1, AS-365N2, and AS 365 N3 helicopters, certificated in any category.                              ( print page 79485)    

## (d) Subject

Joint Aircraft System Component (JASC) Code 5412, Nacelle/Pylon, Bulkhead/Firewall.

## (e) Unsafe Condition

This AD was prompted by an engine compartment fire where the upper stiffener of the central firewall, made of aluminum, in the engine compartment was found damaged. The FAA is issuing this AD to address failure of a central firewall stiffener made of aluminum, possibly due to its inability to withstand high temperatures of an engine fire and subsequently not seal the engine compartment properly. In the event of an engine fire, the unsafe condition, if not addressed, could result in fire propagating from one engine compartment to the other 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 (EASA) AD 2022-0231, dated November 28, 2022 (EASA AD 2022-0231).

## (h) Exceptions to EASA AD 2022-0231

(1) Where EASA AD 2022-0231 refers to its effective date, this AD requires using the effective date of this AD.

(2) Where EASA AD 2022-0231 refers to flight hours, this AD requires using hours time-in-service.

(3) Where the material referenced in EASA AD 2022-0231 specifies discarding certain parts, this AD requires removing those parts from service.

(4) Where the material referenced in EASA AD 2022-0231 states “If the bracket (f) is in unsatisfactory condition (DETAIL D);” for this AD, replace that text with “Inspect the bracket (f) (DETAIL D) for airworthy condition; for the purpose of this AD, an unairworthy condition may be indicated by corrosion, a crack, or wear. If the bracket (f) is in an unairworthy condition.”

(5) Where the material referenced in EASA AD 2022-0231 states to “Do a check of the cover strip (g) and the fireproof seal (h) to replace if necessary (SECTION B-B);” for this AD, replace that text with “Inspect the cover strip (g) and the fireproof seal (h) for airworthy condition. If the cover strip (g) or the fireproof seal (h) is in an unairworthy condition, remove each unairworthy part from service and replace it with a new (zero total hours time-in-service) part (SECTION B-B).”

(6) This AD does not adopt the “Remarks” section of EASA AD 2022-0231.

## (i) No Reporting Requirement

Although the material referenced in EASA AD 2022-0231 specifies to submit certain information to the manufacturer, this AD does not require that action.

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

                        (1) The Manager, International Validation 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 International Validation Branch, send it to the attention of the person identified in paragraph (k) 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.

## (k) Related Information

                        For more information about this AD, contact Hye Yoon Jang, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (206) 231-3758; email:                         *Hye.Yoon.Jang@faa.gov*.                    

## (l) 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 2022-0231, dated November 28, 2022.

(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 the 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 Pkwy., 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 September 17, 2024.

Victor Wicklund,

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

[FR Doc. 2024-22169 Filed 9-27-24; 8:45 am]

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