Airworthiness Directives: Airbus Helicopters

Airworthiness Directives; Airbus Helicopters

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-2025-5387; Project Identifier MCAI-2024-00399-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 the 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 Matthew Williams, 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

The FAA issued AD 2023-01-04, Amendment 39-22298 (88 FR 6618, February 1, 2023) (AD 2023-01-04), for Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters. AD 2023-01-04 was prompted by an MCAI originated by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA issued AD 2021-0282, dated December 17, 2021 (EASA AD 2021-0282), to address loss of the TRH pitch change control.

AD 2023-01-04 requires, for helicopters with certain part-numbered TRH pitch change units installed, inspecting for correct installation of the nut; marking a 2 to 5 mm wide black paint index mark to identify the position of certain parts; and after the initial marking, repetitively inspecting the alignment of the marking; and additional inspections and corrective actions if necessary. Additionally, AD 2023-01-04 prohibits installing an affected part on a helicopter unless certain requirements are met. The FAA issued AD 2023-01-04 to detect improper installation of the nut and improper alignment of a black index marking.

Actions Since AD 2023-01-04 Was Issued

Since the FAA issued AD 2023-01-04, EASA superseded AD 2021-0282 and issued EASA AD 2021-0282R1, Revision 1, dated July 10, 2024 (EASA AD 2021-0282R1) (also referred to as the MCAI), to address an unsafe condition on all Airbus Helicopters Model AS 350 B, AS 350 BA, AS 350 BB, AS 350 B1, AS 350 B2, AS 350 B3, AS 350 D, AS 355 E, AS 355 F, AS 355 F1, AS 355 F2, AS 355 N, and AS 355 NP helicopters. The MCAI states the manufacturer revised the Airworthiness Limitations Section (ALS), as applicable, which now includes the repetitive black index marking checks (inspections).

Additionally, for this NPRM, the FAA is updating the name of the TRH spider pitch change unit to TRH pitch change unit as defined in the required material. The FAA is issuing this proposed AD to detect improper installation of the nut and improper alignment of a black index marking. The unsafe condition, if not addressed, could result in loss of the TRH pitch change control and consequent loss of control of the helicopter.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-5387.

Relationship Between This Proposed AD and Other Relevant Rulemaking

EASA AD 2021-0282R1 specifies that the manufacturer revised the ALS, for Airbus Helicopters Model AS350 and AS355 helicopters as applicable. The revised ALS for each model now incorporates the periodic black index marking inspections. The FAA is evaluating this issue and may take further rulemaking action to accommodate these ALS amendments.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters Alert Service Bulletin (ASB) No. AS350-05.01.03, and Airbus Helicopters ASB No. AS355-05.00.86, both Revision 0 and dated July 8, 2024, which include Figure 1 that identifies the position of the TRH pitch change unit and of the bearing spacer to be marked with a 2 to 5 mm wide black paint index mark. This material also specifies procedures for inspecting the condition and installation of the nut; and inspecting the application and alignment of the black index mark on the TRH pitch change unit and the bearing spacer.

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 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 and material 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 the same actions as AD 2023-01-04 except it would only require the initial black paint index marking inspection, not the repetitive inspections. Additionally, this proposed AD would prohibit installing an affected part on a helicopter unless certain requirements are met.

Differences Between This Proposed AD and the MCAI

The MCAI applies to Airbus Helicopters Model AS350BB, whereas this proposed AD does not because that model does not have an FAA type certificate.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 972 helicopters of U.S. registry.

The FAA estimates the following costs to comply with this proposed AD.

The FAA estimates the following costs to do any repairs/replacements that would be required based on the results of the inspection. The agency has no way of determining the number of helicopters that might need these repairs or replacements.

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 that the 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.

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

Airbus Helicopters: Docket No. FAA-2025-5387; Project Identifier MCAI-2024-00399-R.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by February 2, 2026.

(b) Affected ADs

This AD replaces AD 2023-01-04, Amendment 39-22298 (88 FR 6618, February 1, 2023).

(c) Applicability

This AD applies to Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, AS350D, AS355E, AS355F, AS355F1, AS355F2, AS355N, and AS355NP helicopters, certificated in any category.

Note 1 to paragraph (c): Helicopters with AS350B3e designation are Model AS350B3 helicopters.

(d) Subject

Joint Aircraft System Component (JASC) Code 6420, Tail rotor head.

(e) Unsafe Condition

This AD was prompted by an occurrence reported where, during an inspection of a tail rotor head (TRH) pitch change unit, excessive play and excessive wear were detected, due to an unwanted rotating motion and updated airworthiness limitations and maintenance tasks. The FAA is issuing this AD to detect improper installation of the pitch change spider nut (nut) and improper alignment of a black index marking. The unsafe condition, if not addressed, could result in loss of the TRH pitch change control and consequent loss of control of the helicopter.

(f) Compliance

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

(g) Required Actions

(1) For helicopters with TRH pitch change unit, part number (P/N) 350A33-2030-00, 350A33-2167-00, or 350A33-2167-01 installed, within 50 hours time-in-service (TIS) after the effective date of this AD, inspect the nut for correct installation. If the nut is missing or loose, before further flight, remove the bearing from the TRH pitch change unit and do the following:

(i) Inspect the TRH pitch change unit for corrosion. If there is any corrosion, before further flight, remove the affected part from service and replace with an airworthy part.

Note 2 to paragraph (g)(1)(i): Airbus Helicopters Mechanical Repair Manual (MRM) AS350 65-20-00-713, dated March 29, 2017, also known as Work Card 65-20-00-713 MRM, and Airbus Aircraft Maintenance Manual (AMM) AS350 65-21-00, 4-9b, dated May 16, 2019, also known as Task 65-21-00, 4-9 AMM, specify disassembly and reassembly information for the TRH pitch change unit.

(ii) Inspect for rotation and wear on the faces of the bushes. For the purposes of this AD, indications of rotation and wear include tearing, peening, metal pick-up, and hammering. If there is any rotation or any wear on the faces of the bushes, before further flight, remove the bushes from service and replace with airworthy bushes.

(iii) Using 5X or higher power magnification, visually inspect the rotating plate and the rotating plate threads for damage. For the purposes of this AD, indications of damage include wear, deformation, stripping, galling, and corrosion. If there is any damage on the rotating plate or the rotating plate threads, before further flight, remove the rotating plate from service and replace with an airworthy rotating plate.

(iv) Identify the position of the TRH pitch change unit (item a) and of bearing spacer (item b) by marking a 2 to 5 mm wide black paint index mark (item C) with black paint as depicted in Figure 1, Section B-B, of Airbus Helicopters Alert Service Bulletin (ASB) No. AS350-05.01.03, (ASB AS350-05.01.03 Rev 1), or Airbus Helicopters ASB No. AS355-05.00.86 (ASB AS355-05.00.86 Rev 1), both Revision 1, and dated July 8, 2024, as applicable to the model helicopter.

(2) Within 10 hours TIS after the initial marking required by paragraph (g)(1)(iv) of this AD, visually inspect the alignment of the marking. An example of a properly aligned marking is depicted in Figure 1, Section B-B of ASB AS350-05.01.03 Rev 1 and ASB AS355-05.00.86 Rev 1, as applicable to the model helicopter. If the black paint index mark (item C) is misaligned, before further flight, inspect the TRH pitch change unit by accomplishing the actions required by paragraphs (g)(1)(i) and (ii) of this AD.

(h) Parts Installation Limitations

As of the effective date of this AD, do not install a TRH pitch change unit P/N 350A33-2030-00, 350A33-2167-00, or 350A33-2167-01 on any helicopter, unless you do the actions required by paragraphs (g)(1)(i) and (ii) of this AD before further flight after installation, and thereafter do the actions required by paragraph (g)(1)(iii) of this AD at the times specified in paragraph (g)(1)(iii) of this AD

(i) Credit for Previous Actions

This paragraph provides credit for the initial inspections and actions required by paragraph (g)(1) of this AD, if those actions were performed before the effective date of this AD using Airbus Helicopters ASB No. AS350-05.01.03, or ASB No. AS355-05.00.86, both Revision 0, and dated December 16, 2021.

(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)(1) of this AD and email 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.

(k) Additional Information

(1) For more information about this AD, contact Matthew Williams, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4134; email: [email protected].

(2) Material identified in this AD that is not incorporated by reference is available at the address specified in paragraph (l)(3) of this AD.

(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) Airbus Helicopters Alert Service Bulletin (ASB) No. AS350-05.01.03, Revision 1, dated July 8, 2024.

(ii) Airbus Helicopters ASB No. AS355-05.00.86 Revision 1, dated July 8, 2024.

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

(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 [email protected] .

[FR Doc. 2025-23100 Filed 12-16-25; 8:45 am]

BILLING CODE 4910-13-P