AD 2026-07-12 ACTIVE

The FAA is adopting a new airworthiness directive (AD) for certain Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, and AS350D helicopters. This AD was prompted by a report of a gap between the bolted assemblies under the attachment fittings of the main gearbox (MGB) suspension bars. This AD requires replacing any affected front and rear attachment fittings, screws, nuts and washers of the MGB suspension bars, and prohibits installing any affected parts unless they are new (never previously installed) parts. The FAA is issuing this AD to address the unsafe condition on these products.

Final rule; request for comments.

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2026-07-12 Airbus Helicopters: Amendment 39-23308; Docket No. FAA-2026-3479; Project Identifier MCAI-2026-00085-R. (a) Effective Date This airworthiness directive (AD) is effective April 29, 2026. (b) Affected ADs None. (c) Applicability This AD applies to all Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, and AS350D helicopters, certificated in any category, that were delivered before January 1, 2026. Note 1 to paragraph (c): Helicopters with AS350B3e designation are Model AS350B3 helicopters. (d) Subject Joint Aircraft System Component (JASC) Code 6330, Main rotor transmission mount. (e) Unsafe Condition This AD was prompted by a report of a gap between the bolted assemblies under the attachment fittings of the main gearbox (MGB) suspension bars. The FAA is issuing this AD to prevent structural failure of the MGB attachment screws. The unsafe condition, if not addressed, could result in detachment of the MGB suspension bars with consequent loss of control of the helicopter. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with European Union Aviation Safety Agency (EASA) AD 2026-0021, dated January 29, 2026 (EASA AD 2026-0021). (h) Exceptions to EASA AD 2026-0021 (1) Where EASA AD 2026-0021 refers to its effective date, this AD requires using the effective date of this AD. (2) Where EASA AD 2026-0021 requires compliance in terms of flight hours, this AD requires using hours time-in-service. (3) Where EASA AD 2026-0021 defines "affected part", this AD requires replacing that definition with "Front and rear attachment fittings, screws, nuts and washers of the MGB suspension bars, having a part number as defined in Airbus Helicopters Emergency Alert Service Bulletin (EASB) AS350-63-31-0001 Issue 002, dated January 22, 2026 (EASB AS350-63-31-0001, Issue 002). The part number is identified as "Reference" in EASB AS350-63-31-0001, Issue 002, as applicable to the part". (4) This AD does not adopt paragraphs (1), (2), (3), (4), (6), and (7) of EASA AD 2026-0021. (5) Where paragraph (5) of EASA AD 2026-0021 specifies "before next flight after having accomplished the actions as required by paragraph (1), (3), or (4) of this AD, as applicable,", this AD requires replacing that text with "Within the compliance time as specified in Table 1 of EASA AD 2026-0021, as applicable, after the effective date of this AD". (6) Where the material referenced in EASA AD 2026-0021 specifies "discard", this AD requires replacing that text with "remove from service". (7) This AD does not adopt the "Remarks" section of EASA AD 2026-0021. (i) 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 (j) 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. (j) Additional Information For more information about this AD, contact Matthew Bloomer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7524; email: matthew.g.bloomer@faa.gov. (k) 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 2026-0021, dated January 29, 2026. (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 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 April 6, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-07168 Filed 4-13-26; 8:45 am]BILLING CODE 4910-13-P

Comments Invited The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under ADDRESSES . Include "Docket No. FAA-2026-3479; Project Identifier MCAI-2026-00085-R" at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, 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 final rule 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 final rule. 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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Matthew Bloomer, 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, has issued EASA AD 2026-0021, dated January 29, 2026 (EASA AD 2026-0021) (also referred to as the MCAI), to correct an unsafe condition on Airbus Helicopters Model AS 350 B, AS 350 BA, AS 350 BB, AS 350 B1, AS 350 B2, AS 350 B3, and AS 350 D helicopters, all serial numbers, delivered before January 1, 2026 (date of EASA Form 52, or equivalent statement of conformity). The MCAI states there was a report of occurrences of a gap between bolted assemblies under the attachment fittings of the MGB suspension bars. The MCAI also states that after investigations it was determined that this unsafe condition could impact the safe life limit of the MGB fittings and bolts. This condition, if not addressed, could lead to structural failure of the MGB attachment screws, which could result in detachment of the MGB suspension bars with consequent loss of control of the helicopter. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-3479. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed EASA AD 2026-0021, which specifies procedures for certain helicopters, performing a torque check of the nuts of each MGB attachment fitting. EASA AD 2026-0021 also specifies procedures for certain helicopters, performing a sealing compound check in the inspection areas as defined in EASA AD 2026-0021 and, depending on the inspection results, performing a torque check of the nuts of the MGB attachment fitting, measuring the flatness of the MGB deck, measuring the plays of the assembly between the reinforcement plate and shim, measuring the cumulative thickness of the assembly between the reinforcement plate and shim, and reporting results to Airbus Helicopters. Additionally, EASA AD 2026-0021 specifies procedures for replacing the front and rear attachment fittings, screws, nuts and washers of the MGB suspension bars with new (never previously installed) parts. EASA AD 2026-0021 also prohibits installing any affected front and rear attachment fittings, screws, nuts and washers on any helicopter unless they are new (never previously installed) parts. 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 AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. AD Requirements This AD requires accomplishing the actions specified in EASA AD 2026-0021, described previously, as incorporated by reference, except for any differences identified as exceptions in the regulatory text of this AD. See "Differences Between this AD and the MCAI" for a discussion of the general differences included in this AD. Differences Between This AD and the MCAI The MCAI applies to Airbus Helicopters Model AS350BB helicopters, whereas this AD does not because that model does not have an FAA type certificate. The MCAI requires replacing affected parts after having accomplished certain inspections as defined in EASA AD 2026-0021, whereas this AD requires those actions before exceeding certain compliance times as specified in Table 1 of EASA AD 2026-0021. The MCAI requires performing a torque check and performing a sealing compound check in certain inspection areas as defined in EASA AD 2026-0021 and, depending on the inspection results, performing corrective actions, whereas this AD does not require those actions and only requires replacing the affected parts before exceeding certain compliance times as defined in EASA AD 2026-0021. The MCAI also requires reporting results to Airbus Helicopters, whereas this AD does not require reporting. Interim Action The FAA considers that this AD is an interim action. If final action is later identified, the FAA might consider additional rulemaking. 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, EASA AD 2026-0021 is incorporated by reference in this AD. This AD requires compliance with EASA AD 2026-0021 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. Using common terms that are the same as the heading of a particular section in EASA AD 2026-0021 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 2026-0021. Material required by EASA AD 2026-0021 for compliance will be available at regulations.gov under Docket No. FAA-2026-3479 after this AD is published. Justification for Immediate Adoption and Determination of the Effective Date Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq. ) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for "good cause," finds that those procedures are "impracticable, unnecessary, or contrary to the public interest." Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause. An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because the occurrence of a gap between bolted assemblies under the attachment fittings of the MGB suspension bars has an impact on the safe life limit of fittings and bolts, which are critical parts to the helicopter. This unsafe condition poses a significant risk of structural failure to the attachment screws, as failure of these parts could occur earlier than previously expected, which could lead to detachment of the MGB suspension bars. Further, the compliance requirement for replacing any affected parts is within 10 hours time-in-service (TIS) after the effective date of this AD, for all helicopters that have accumulated 35,950 hours TIS or more. There are currently helicopters on the U.S. registry that are approaching or exceeding the 35,950 hours TIS threshold. Consequently, these helicopters are subject to the 10-hour compliance timeframe, which is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable pursuant to 5 U.S.C. 553(b). In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment. Regulatory Flexibility Act The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required. Costs of Compliance The FAA estimates that this AD affects 903 helicopters of U.S. registry. The FAA estimates the following costs to comply with this AD: Estimated Costs Action Labor cost Parts cost Cost per product Cost on U.S. operators Replace front and rear attachment fittings 8 work-hour × $85 per hour = $680 * $13,800 $14,480 $13,075,440 * The labor cost is for two front and two rear attachment fitting 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 This AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD: (1) Is not a "significant regulatory action" under Executive Order 12866, and (2) Will not affect intrastate aviation in Alaska. List of Subjects in 14 CFR Part 39 Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. The Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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 [Amended] 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2026-07-12 Airbus Helicopters: Amendment 39-23308; Docket No. FAA-2026-3479; Project Identifier MCAI-2026-00085-R. (a) Effective Date This airworthiness directive (AD) is effective April 29, 2026. (b) Affected ADs None. (c) Applicability This AD applies to all Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, and AS350D helicopters, certificated in any category, that were delivered before January 1, 2026. Note 1 to paragraph (c): Helicopters with AS350B3e designation are Model AS350B3 helicopters. (d) Subject Joint Aircraft System Component (JASC) Code 6330, Main rotor transmission mount. (e) Unsafe Condition This AD was prompted by a report of a gap between the bolted assemblies under the attachment fittings of the main gearbox (MGB) suspension bars. The FAA is issuing this AD to prevent structural failure of the MGB attachment screws. The unsafe condition, if not addressed, could result in detachment of the MGB suspension bars with consequent loss of control of the helicopter. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions Except as specified in paragraph (h) of this AD: Comply with all required actions and compliance times specified in, and in accordance with European Union Aviation Safety Agency (EASA) AD 2026-0021, dated January 29, 2026 (EASA AD 2026-0021). (h) Exceptions to EASA AD 2026-0021 (1) Where EASA AD 2026-0021 refers to its effective date, this AD requires using the effective date of this AD. (2) Where EASA AD 2026-0021 requires compliance in terms of flight hours, this AD requires using hours time-in-service. (3) Where EASA AD 2026-0021 defines "affected part", this AD requires replacing that definition with "Front and rear attachment fittings, screws, nuts and washers of the MGB suspension bars, having a part number as defined in Airbus Helicopters Emergency Alert Service Bulletin (EASB) AS350-63-31-0001 Issue 002, dated January 22, 2026 (EASB AS350-63-31-0001, Issue 002). The part number is identified as "Reference" in EASB AS350-63-31-0001, Issue 002, as applicable to the part". (4) This AD does not adopt paragraphs (1), (2), (3), (4), (6), and (7) of EASA AD 2026-0021. (5) Where paragraph (5) of EASA AD 2026-0021 specifies "before next flight after having accomplished the actions as required by paragraph (1), (3), or (4) of this AD, as applicable,", this AD requires replacing that text with "Within the compliance time as specified in Table 1 of EASA AD 2026-0021, as applicable, after the effective date of this AD". (6) Where the material referenced in EASA AD 2026-0021 specifies "discard", this AD requires replacing that text with "remove from service". (7) This AD does not adopt the "Remarks" section of EASA AD 2026-0021. (i) 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 (j) 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. (j) Additional Information For more information about this AD, contact Matthew Bloomer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7524; email: matthew.g.bloomer@faa.gov. (k) 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 2026-0021, dated January 29, 2026. (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 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 April 6, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.

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-2026-3479; 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 final rule, 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 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 regulations.gov under Docket No. FAA-2026-3479.

Matthew Bloomer, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7524; email: matthew.g.bloomer@faa.gov .