Airworthiness Directives; Airbus Helicopters

DEPARTMENT OF TRANSPORTATION <SUBAGY>Federal Aviation Administration</SUBAGY> <CFR>14 CFR Part 39</CFR> <DEPDOC>[Docket No. FAA-2025-0922; Project Identifier MCAI-2024-00650-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) 2021-26-07, which applies to all Airbus Helicopters Model EC120B helicopters. AD 2021-26-07 requires performing repetitive inspections of the tail rotor (TR) hub body and, depending on the inspection results, replacing certain parts, and accomplishing further inspections. AD 2021-26-07 also requires for certain helicopters removing from service any bolt, washer, and nut installed on the TR hub body at certain life limits and replacing them with airworthy parts and accomplishing further inspections. Additionally, AD 2021-26-07 prohibits the installation of a certain part-numbered TR hub body unless certain requirements are met. Since the FAA issued AD 2021-26-07, it was determined that modifying the link of the TR hub body and splined flange by adding red paint marks is necessary to enable the detection of any loss of tightening torque. This proposed AD would require the same repetitive inspections and corrective actions as AD 2021-26-07 and would require modification of the link of the TR hub body, which would be a terminating action for the repetitive inspections. The proposed AD would also require repetitive inspections of the red paint line added during the modification of the link of the TR hub body for alignment. 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 11, 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-2025-0922; 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 proposed 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: <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-2025-0922. <FURINF> <HD SOURCE="HED">FOR FURTHER INFORMATION CONTACT:</HD> Camille Seay, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (817) 222-5149; email: <E T="03">camille.l.seay@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 using a method listed under the <E T="02">ADDRESSES</E> section. Include “Docket No. FAA-2025-0922; Project Identifier MCAI-2024-00650-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 Camille Seay, 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 2021-26-07, Amendment 39-21866 (86 FR 72829, December 23, 2021) (AD 2021-26-07), for Airbus Helicopters Model EC120B helicopters. AD 2021-26-07 was prompted by European Union Aviation Safety Agency (EASA) AD 2021-0069, dated March 11, 2021 (EASA AD 2021-0069), issued by EASA, which is the Technical Agent for the Member States of the European Union, to address loss of tightening torque in the interface between the TR hub body and splined flange, which creates the risk of crack initiation from a fretting area located on the TR hub body and splined flange or on the TR hub body and flange bolts. AD 2021-26-07 requires performing repetitive inspections of the TR hub body for a crack, and depending on the inspection results, removing the affected parts from service and inspecting the TR spline flange and, depending on those inspection results, removing an affected splined flange from service. AD 2021-26-07 also requires, for certain helicopters, removing from service any bolt, washer, and nut installed on the TR hub body that has exceeded a certain life limit, and thereafter removing these parts from service within specific intervals and accomplishing further inspections and corrective actions. Additionally, AD 2021-26-07 prohibits installing a certain part-numbered TR hub body unless certain requirements are met. The FAA issued AD 2021-26-07 to detect cracking and fretting, which if not addressed, could result in potential loss of the TR drive and consequent loss of yaw control of the helicopter. <HD SOURCE="HD1">Actions Since AD 2021-26-07 Was Issued</HD> Since the FAA issued AD 2021-26-07, EASA superseded EASA AD 2021-0069 with EASA AD 2024-0209, dated October 28, 2024 (EASA AD 2024-0209) (also referred to as the MCAI), to address an unsafe condition on all Airbus Helicopters Model EC 120 B helicopters. The MCAI states that, Airbus Helicopters developed a modification, which consists of adding a line of red paint on each bolt and each nut of the link between the TR hub and the splined flange. The MCAI further states that an Airworthiness Limitations Section task was published for checking alignment of the marks. The FAA is proposing this AD to detect cracking and fretting of the TR hub body, which, if not addressed, could lead to loss of the TR drive, and consequent loss of yaw control of the helicopter. You may examine the MCAI in the AD docket at <E T="03">regulations.gov</E> under Docket No. FAA-2025-0922. <HD SOURCE="HD1">Material Incorporated by Reference Under 1 CFR Part 51</HD> The FAA reviewed Airbus Helicopters Emergency Alert Service Bulletin 05A020, Revision 3, dated September 19, 2024 (EASB 05A0020 Rev 3), which specifies procedures for repetitive inspections of the TR hub body for cracks and the TR spline flange for cracks and fretting and the appropriate corrective actions to include replacing the hub body and the splined flange. EASB 05A0020 Rev 3 also excludes helicopters that have complied with Airbus Helicopters Alert Service Bulletin EC120-64-21-0001, Issue 001, dated September 19, 2024 (ASB EC120-64-21-0001) from its effectivity and limits the effectivity for “non installed equipment or parts”. The FAA also reviewed ASB EC120-64-21-0001, which specifies procedures for inspecting the torque applied on the nut of the link between the TR hub and the splined flange, and depending on the inspection results, applying torque and replacing parts. ASB EC120-64-21-0001 also specifies procedures for applying a red paint line on the screw, nut, washer, TR hub, and splined flange. 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 <E T="02">ADDRESSES</E> section. <HD SOURCE="HD1">FAA's Determination</HD> Th ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ Preview showing 10k of 25k characters. Full document text is stored and available for version comparison. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━