Airworthiness Directives; Airbus Helicopters

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-5389; Project Identifier MCAI-2024-00716-R]</DEPDOC> <RIN>RIN 2120-AA64</RIN> <SUBJECT>Airworthiness Directives; Airbus Helicopters</SUBJECT> <HD SOURCE="HED">AGENCY:</HD> Federal Aviation Administration (FAA), DOT. <HD SOURCE="HED">ACTION:</HD> Notice of proposed rulemaking (NPRM). <SUM> <HD SOURCE="HED">SUMMARY:</HD> The FAA proposes to supersede Airworthiness Directive (AD) 2020-09-15, which applies to certain Airbus Helicopters Model AS332C, AS332C1, AS332L, and AS332L1 helicopters. AD 2020-09-15 requires removing the removable parts of the dual hoist installation or removing the de-icing system and allows, for certain helicopters, revising the rotorcraft flight manual (RFM) for the helicopter and installing a placard as an optional method of compliance. Since the FAA issued AD 2020-09-15, analysis revealed that additional vibration level measurements are necessary. This proposed AD would retain all the requirements of AD 2020-09-15 and would require for certain helicopters repetitively measuring vibration levels in-flight, and depending on the results, performing corrective actions. The FAA is proposing this AD to address the unsafe condition on these products. </SUM> <EFFDATE> <HD SOURCE="HED">DATES:</HD> The FAA must receive comments on this NPRM by February 2, 2026. </EFFDATE> <HD SOURCE="HED">ADDRESSES:</HD> You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods: • <E T="03">Federal eRulemaking Portal:</E> Go to <E T="03">regulations.gov.</E> Follow the instructions for submitting comments. • <E T="03">Fax:</E> (202) 493-2251. • <E T="03">Mail:</E> U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590. • <E T="03">Hand Delivery:</E> Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. <E T="03">AD Docket:</E> You may examine the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5389; 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. <E T="03">Material Incorporated by Reference:</E> • 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; or at <E T="03">airbus.com/en/products-services/helicopters/hcare-services/airbusworld.</E> • 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 <E T="03">regulations.gov</E> under Docket No. FAA-2025-5389. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Matthew Williams, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4134; email: <E T="03">matthew.t.williams@faa.gov.</E> </FURINF> <SUPLINF> <HD SOURCE="HED">SUPPLEMENTARY INFORMATION:</HD> <HD SOURCE="HD1">Comments Invited</HD> The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2025-5389; Project Identifier MCAI-2024-00716-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 <E T="03">regulations.gov,</E> including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. <HD SOURCE="HD1">Confidential Business Information</HD> 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. <HD SOURCE="HD1">Background</HD> The FAA issued AD 2020-09-15, Amendment 39-19911 (85 FR 30589, May 20, 2020) (AD 2020-09-15), for Airbus Helicopters Model AS332C, AS332C1, AS332L, and AS332L1 helicopters equipped with a dual hoist installation and de-icing system, except those that have Airbus Helicopters modification 0722907 installed in production. AD 2020-09-15 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 2018-0142R1, dated December 9, 2019 (EASA AD 2018-0142R1) to address vibrations around the 12Hz frequency. EASA AD 2018-0142R1 states that during the first flight of an Airbus Helicopters Model AS332L helicopter after a retrofit that re-installed the deicing system, vibrations around the 12Hz frequency were observed. Subsequent flight tests and analysis determined that this vibration is due to the specific helicopter configuration. Factors that contributed to the vibration included simultaneous installation of riveted main frames X3855 and X5295 (pre-Airbus Helicopter modification 0722907), additional weight created by parts of the rotor de-icing system on the main rotor head (the distributor and de-icing harnesses), and removable parts (hoist arm and hoists) of the dual hoist installation. AD 2020-09-15 requires removing the removable parts of the dual hoist installation or removing the de-icing system, and allows, for certain helicopters, revising the RFM for the helicopter and installing a placard as an optional method of compliance. The FAA issued AD 2020-09-15 to address vibrations around the 12Hz frequency. The unsafe condition, if not addressed, could generate divergent aeromechanic coupling between the helicopter structure and the rotor, possibly resulting in mechanical failure of structural parts and loss of control of the helicopter. <HD SOURCE="HD1">Actions Since AD 2020-09-15 Was Issued</HD> Since the FAA issued AD 2020-09-15, EASA issued EASA AD 2024-0100, dated May 10, 2024 (EASA AD 2024-0100), which superseded EASA AD 2018-0142R1. EASA AD 2024-0100 stated that the same occurrence of the 12Hz vibratory condition was reported on a helicopter with Airbus Helicopters modification 0722907 embodied and that it was necessary for all helicopters with this modification to measure vibrations in-flight, interpret the results, and depending on the results, send the vibration levels to Airbus Helicopters or modify the helicopter configuration. After EASA issued EASA AD 2024-0100, EASA superseded EASA AD 2024-0100 and issued EASA AD 2024-0233, dated December 5, 2024 (EASA AD 2024-0233) (also referred to as the MCAI). The MCAI states that since EASA AD 2024-0100 was issued, it was determined that further vibration level measurements were necessary after performing certain maintenance tasks. The MCAI further states that EASA AD 2024-0233 is considered to be an interim action. This condition, if not addressed, could generate divergent aeromechanic coupling between the helicopter structure and the rotor, possibly resulting in mechanical failure of structural parts and loss of control of the helicopter. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-5389. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed Airbus Helicopters Alert Service Bulletin AS332-04-00-0001 Issue 002, dated December 4, 2024 (ASB AS332-04-00-0001), which specifies procedures for installing the accelerometer in the cockpit of the helicopter, repetitively inspecting the vibration level at 12 Hz each time a specific maintenance task is completed, and interpreting the results. Depending on the results of this inspection, ASB AS332-04-00-0001 specifies procedures for corrective actions, which include changing the configuration by either removing the dual hoist system or removing the de-icing harness and contacting Airbus Helicopters for further instructions. This proposed AD would also require Airbus Helicopters Emergency Alert Service Bulletin (EASB) No. 01.00.91 Revision 1 (EASB 01.00.91 Rev 1) for Model AS332C, and AS332C1 helicopters, and EASB No. 01.00.96 Revision 0 (EASB 01.00.96) for Model AS332L and AS332L1 helicopters, both dated December 4, 2019. EASB 01.00.91 Rev 1 specifies pro ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 24k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━