2026-05-11: Helicopter vibration analysis

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: a. Removing Airworthiness Directive 2020-09-15, Amendment 39-19911 (85 FR 30589, May 20, 2020); and b. Adding the following new airworthiness directive: 2026-05-11 Airbus Helicopters: Amendment 39-23284; Docket No. FAA-2025-5389; Project Identifier MCAI-2024-00716-R. (a) Effective Date This airworthiness directive (AD) is effective April 17, 2026. (b) Affected ADs This AD replaces AD 2020-09-15, Amendment 39-19911 (85 FR 30589, May 20, 2020) (AD 2020-09-15). (c) Applicability This AD applies to Airbus Helicopters Model AS332C, AS332C1, AS332L, and AS332L1 helicopters, certificated in any category, equipped with a dual hoist installation and de-icing system. (d) Subject Joint Aircraft System Component (JASC) Code 1810, Helicopter vibration analysis. (e) Unsafe Condition This AD was prompted by a report of vibrations around the 12 Hz frequency due to the specific helicopter configuration and determination that additional vibration level measurements are necessary. The FAA is issuing this AD to prevent divergent aeromechanic coupling between the helicopter structure and rotor. The unsafe condition, if not addressed, could result in mechanical failure of structural parts 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 without Airbus Helicopters modification 0722907 installed, within 7 days after May 20, 2020 (the effective date of AD 2020-09-15): Remove the removable parts of the dual hoist installation or remove the de-icing system in accordance with the instructions of section 3.B of Airbus Helicopters Emergency Alert Service Bulletin (EASB) AS332 01.00.91, Revision 1, dated December 4, 2019 (EASB AS332 01.00.91 Rev 1), or Section 3.B.2 of Airbus Helicopters EASB AS332 01.00.96, Revision 0, dated December 4, 2019 (EASB AS332 01.00.96), as applicable to the helicopter, except you are not required to contact Airbus Helicopters. (2) For helicopters with Airbus Helicopters modification 0722907 installed, within 110 hours time-in-service (TIS) or 30 days whichever occurs first after the effective date of this AD and thereafter, during the first flight after each time any of the maintenance tasks identified in the COMPLIANCE: MANDATORY section of Airbus Helicopters Alert Service Bulletin ASB AS332-04-00-0001, Issue 002, dated December 4, 2024 (ASB AS332-04-00-0001) is accomplished, perform a vibration level measurement in accordance with paragraphs (g)(2)(i) and (ii) of this AD. (i) With the accelerometer already installed, check the measurement of the vibration level in-flight, at 12 Hz by following figure 1 to paragraph (g)(2)(i) of this AD. The owner/operator (pilot) holding at least a private pilot certificate may perform this check and must enter compliance with these paragraphs into the helicopter maintenance records in accordance with 14 CFR 43.9(a) and 91.417(a)(2)(v). The record must be maintained as required by 14 CFR 91.417, 121.380, or 135.439. Figure 1 to Paragraph (g)(2)(i)-Method of Measurement ER13MR26.003 (ii) Interpret the results in accordance with the instructions in Section 4.4 of ASB AS332-04-00-0001 except you are not required to send any information to Airbus Helicopters. If the vibration level between 11.7 Hz and 12.7 Hz is more than 0.08g (0.40 IPS), before further flight, revise the helicopter configuration by removing the dual hoist system or removing the blade de-icing harnesses in accordance with instructions of section 4.5 through 4.5.2.1 of ASB AS332-04-00-0001. (h) Optional Method of Compliance For helicopters without Airbus Helicopters modification 0722907 installed: Revising the rotorcraft flight manual for your helicopter by inserting the information specified in Appendix 4A, 4B, or 4C of EASB AS332 01.00.96, as applicable to your helicopter model and configuration, and installing a locally made placard on the instrument panel, in accordance with the instructions of section 3.B.1 of EASB AS332 01.00.96, is an acceptable method for compliance with the requirements of paragraph (g)(1) of this AD. (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 responsible Flight Standards 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 responsible Flight Standards Office. (j) Additional Information 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: matthew.t.williams@faa.gov. (k) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) 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. (3) The following material was approved for IBR on April 17, 2026. (i) Airbus Helicopters Alert Service Bulletin ASB AS332-04-00-0001, Issue 002, dated December 4, 2024. (ii) [Reserved] (4) The following material was approved for IBR on May 20, 2020, (85 FR 30589, May 20, 2020). (i) Airbus Helicopters Emergency Alert Service Bulletin AS332 01.00.91, Revision 1, dated December 4, 2019. (ii) Airbus Helicopters Emergency Alert Service Bulletin AS332 01.00.96, Revision 0, dated December 4, 2019. (5) For Airbus 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; or at airbus.com/en/products-services/helicopters/hcare-services/airbusworld. (6) 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. (7) 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 March 4, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-04967 Filed 3-12-26; 8:45 am]BILLING CODE 4910-13-P