Airworthiness Directives; Airbus Helicopters

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-1108; Project Identifier MCAI-2025-00428-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) 2020-24-07, which applies to certain Airbus Helicopters Model AS350B3, EC130B4, and EC130T2 helicopters. AD 2020-24-07 requires modifying and inspecting the pilot's and co-pilot's throttle twist grip (twist grip) for proper operation. Since the FAA issued AD 2020-24-07, Airbus Helicopters developed another modification of the twist grip and additional corrective actions for helicopters already modified. This proposed AD was prompted by reports of the engine remaining in idle when the twist grip was turned from the “IDLE” mode to the “FLIGHT” mode. This proposed AD would retain the actions required by AD 2020-24-07 and mandate an additional modification, which would constitute terminating action for the repetitive inspections. This proposed AD would also expand the helicopter applicability, propose additional requirements for certain helicopters, and would prohibit installing affected microswitches or an affected twist grip with the affected microswitch. 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 August 4, 2025. </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-2025-1108; 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 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: <E T="03">ADs@easa.europa.eu;</E> website: <E T="03">easa.europa.eu.</E> You may find this material on the EASA website at <E T="03">ad.easa.europa.eu.</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-2025-1108. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Zain Jamal, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7264; email: <E T="03">zain.jamal@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-2025-1108; Project Identifier MCAI-2025-00428-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 Zain Jamal, 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 2020-24-07, Amendment 39-21337 (85 FR 78954, December 8, 2020) (AD 2020-24-07), for Airbus Helicopters Model AS350B3 helicopters with an ARRIEL 2B1 engine with the two-channel Full Authority Digital Engine Control (FADEC) and with new twist grip modification (MOD) 073254 or with an ARRIEL 2D engine installed; Model EC130B4 helicopters with an ARRIEL 2B1 engine with the two-channel FADEC and with new twist grip MOD 073773 installed; and Model EC130T2 helicopters with an ARRIEL 2D engine installed. AD 2020-24-07 was prompted by MCAI originated by EASA, which is the Technical Agent for the Member States of the European Union. EASA issued EASA AD 2017-0059, dated April 6, 2017 (EASA AD 2017-0059), to correct an unsafe condition identified, as the microswitches in the engine “IDLE”/“FLIGHT” control system could be affected by the corrosive effects of a salt-laden atmosphere. AD 2020-24-07 requires repetitively inspecting the wiring, performing an insulation test, inspecting the pilot and copilot twist grip controls, and testing the pilot and copilot twist grip controls for proper functioning. The FAA issued AD 2020-24-07 to prevent the failure of one of the microswitches, 53Ka, 53Kb, or 65K, which can prevent switching from “IDLE” mode to “FLIGHT” mode during autorotation training making it impossible to recover from a practice autorotation and compelling the pilot to continue the autorotation to the ground. This condition could result in unintended touchdown to the ground at a flight-idle power setting during a practice autorotation, damage to the helicopter, and injury to occupants. <HD SOURCE="HD1">Actions Since AD 2020-24-07 Was Issued</HD> Since the FAA issued AD 2020-24-07, EASA superseded AD 2017-0059 and issued EASA AD 2023-0133, dated July 5, 2023 (EASA AD 2023-0133). EASA AD 2023-0133 states that Airbus Helicopters developed MOD 074782, introducing a new engine power control assembly with microswitches 53Ka, 53Kb and 65K, and mandating installation of a serviceable assembly, while prohibiting installation of an affected microswitch on any helicopter. EASA AD 2023-0133 also expands the applicability to all serial numbers of Airbus Helicopters Model AS 350 B3, EC 130 B4, and EC 130 T2 helicopters. EASA then superseded AD 2023-0133 and issued EASA AD 2023-0187, dated October 27, 2023 (EASA AD 2023-0187). EASA AD 2023-0187 states that errors were found in the modification installation procedure and requires amending the modification instructions and additional work for certain helicopters already modified. EASA then superseded AD 2023-0187 and issued EASA AD 2023-0187R1, dated March 20, 2025 (EASA AD 2023-0187R1) (also referred to as the MCAI), to correct an unsafe condition for all Airbus Helicopters Model AS 350 B3, EC 130 B4, and EC 130 T2 helicopters. The MCAI states that the salt-laden atmospheric condition definition should be re-formulated, adjusting to the less restrictive description provided in the applicable aircraft maintenance manual. The FAA did not issue an AD corresponding to EASA AD 2023-0133 and EASA AD 2023-0187. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-1108. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed EASA AD 2023-0187R1, which specifies procedures for modifying the twist grip operational logic on helicopters with MOD 074263 installed. EASA AD 2023-0187R1 also specifies procedures for repetitively inspecting for no marks, residue, or corrosion and testing the “IDLE” and “FLIGHT” controls on the pilot's and copilot's twist grips on helicopters with MOD 074699 installed. Additionally, EASA AD 2023-0187R1, specifies procedures for installing MOD 074782 on helicopters if an affected microswitch is installed, which would constitute terminating action for the repetitive inspections. For those helicopters with MOD 074782 installed, EASA AD 2023-0187R1 specifies accomplishing a one-time inspection of the installation of the microswi ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 23k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━