2026-12362: Airworthiness Directives; Airbus Helicopters

Federal Register, Volume 91 Issue 117 (Thursday, June 18, 2026) [Federal Register Volume 91, Number 117 (Thursday, June 18, 2026)] [Proposed Rules] [Pages 36771-36774] From the Federal Register Online via the Government Publishing Office [www.gpo.gov] [FR Doc No: 2026-12362] ======================================================================= ----------------------------------------------------------------------- DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2026-4657; Project Identifier MCAI-2024-00383-R] RIN 2120-AA64 Airworthiness Directives; Airbus Helicopters

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 AS355E, AS355F, AS355F1, AS355F2, and AS355N helicopters. This proposed AD was prompted by the determination that the tail rotor drive fan wheels (fan wheels) and the impeller second stage have been incorrectly identified during production. This proposed AD would require verifying the serial number and amendment of the log cards of the affected parts, and depending on the findings, performing a one-time borescope inspection to verify consistency between the log cards and the affected parts. Depending on the inspection results, this proposed AD would require replacing or re- identifying certain parts. This proposed AD would also prohibit the installation of certain fan wheels and impeller second stages on any helicopter. The FAA is proposing this AD to address the unsafe condition on these products.

Dates

The FAA must receive comments on this NPRM by August 3, 2026.

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-2026-4657; 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 European Union Aviation Safety Agency (EASA) material identified in this proposed AD, contact EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; phone: +49 221 8999 000; email: [email protected]; 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, Airworthiness Products Section, Operational Safety Branch, 10101 Hillwood Parkway, Fort Worth, TX 76177. For information on the availability of this material at the FAA, call (817) 222-5110.

For Further Information Contact

Andrew Gronau, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7378; 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 using a method listed under ADDRESSES. Include ``Docket No. FAA-2026-4657; Project Identifier MCAI-2024-00383-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. [[Page 36772]] 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 Andrew Gronau, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. 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, issued EASA AD 2024-0127, dated July 3, 2024 (EASA AD 2024-0127) (also referred to as the MCAI), to correct an unsafe condition on Airbus Helicopters Model AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, and AS 355 N helicopters. The MCAI states that it was determined that the fan wheel part number (P/N) 704A33691014 amdt [amendment] C and the impeller second stage P/N 704A33691015 amdt C have been incorrectly identified in production. Incorrect identification may cause the loss of traceability of the affected parts, which could lead to required inspections not being accomplished. The unsafe condition, if not addressed, could lead to undetected fatigue failure of the affected parts and result in loss of control of the helicopter. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-4657. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed EASA AD 2024-0127, which specifies procedures for verifying the helicopter's existing log card to determine whether an affected fan wheel and impeller second stage are installed. Depending on the results, EASA AD 2024-0127 specifies procedures for performing a borescope inspection of the affected parts for further verification and either replacing affected parts or reidentifying the parts and amending their log cards. EASA AD 2024-0127 also prohibits installing an affected fan wheel or impeller second stage 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. FAA's Determination These products have been approved by the civil aviation authority (CAA) 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, that authority 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 2024-0127, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this 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 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 2024-0127 by reference in this FAA final rule. This proposed AD would, therefore, require compliance with EASA AD 2024-0127 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 2024-0127 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 2025-0127. Material required by EASA AD 2024-0127 for compliance will be available at regulations.gov under Docket No. FAA-2026-4657 after the FAA final rule is published. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect four helicopters of U.S. registry. The FAA estimates the following costs to comply with this proposed AD: Estimated Costs ---------------------------------------------------------------------------------------------------------------- Cost per Cost on U.S. Action Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Review log card....................... 1 work-hour x $85 per $0 $85 $340 hour = $85. ---------------------------------------------------------------------------------------------------------------- The FAA estimates the following costs to do any replacements that would be required based on the results of the proposed inspection. The agency has no way of determining the number of helicopters that might need these replacements: [[Page 36773]] On-Condition Costs ---------------------------------------------------------------------------------------------------------------- Cost per Action Labor cost Parts cost product ---------------------------------------------------------------------------------------------------------------- Perform borescope inspection of the fan wheel. 1 work-hour x $85 per hour = $85 0 85 Perform borescope inspection of the impeller 1 work-hour x $85 per hour = $85 0 85 second stage. Replace fan wheel............................. 2 work-hours x $85 per hour = 1,534 1,703 $170. Replace impeller second stage................. 2 work-hours x $85 per hour = 1,219 1,389 $170. Perform balance of tail rotor drive shaft..... 2 work-hours x $85 per hour = 0 170 $170. Re-identify the fan wheel or the impeller 1 work-hour x $85 per hour = $85 0 85 second stage. ---------------------------------------------------------------------------------------------------------------- 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