Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all Airbus Helicopters Deutschland GmbH Model MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters. The NPRM was published in the Federal Register on February 26, 2025 (90 FR 10705). The NPRM was prompted by AD 2024-0131, dated July 8, 2024 (EASA AD 2024-0131) (also referred to as the MCAI), issued by EASA, which is the Technical Agent for the Member States of the European Union. The MCAI states there have been reports of significant wear of the spherical bearings of control rod assemblies and pitch link assemblies having part number 105-13122, B623M3001101, D623M3201101, or D623M3201102. This condition, if not detected and corrected, could lead to erroneous pitch and oscillations of the main rotor blades and consequent loss of control of the helicopter. In the NPRM, the FAA proposed to require measuring the radial play of certain spherical bearings of control rod assemblies and pitch link assemblies, reporting the results, and depending on the results, taking corrective action. The NPRM also prohibited installing certain control rod assemblies and pitch link assemblies unless certain requirements are met. The FAA is issuing this AD to address the unsafe condition on these products. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-0214. Discussion of Final Airworthiness Directive Comments The FAA received comments from two commenters. The commenters were an individual and the Air Medical Mechanics Organization (AMMO). The individual commenter expressed support for the proposed AD as written. The following presents the comments received on the NPRM and the FAA's response to the comments. Request To Incorporate Requirements Directly Into the AD AMMO commented that the practice of relying on manufacturer-issued and foreign regulatory documents that are not fully integrated into the rule text creates ambiguity, enforcement concerns, and procedural noncompliance under Section 14 of the Code of Federal Regulations (14 CFR) Part 39 and the Administrative Procedure Act. The commenter requested that the FAA incorporate the complete inspection method, measurable thresholds, and response actions directly into the AD text. The commenter also requested that the FAA provide FAA-originated inspection criteria and field-level illustrations. The FAA disagrees with the request. In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some civil aviation authority ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. This AD incorporates EASA AD 2024-0131 by reference. Incorporation by reference (IBR) allows Federal agencies to comply with the requirement to publish rules in the Federal Register by referring to materials already published elsewhere. The legal effect of IBR is that the material is treated as if it were published in the Federal Register . This AD would, therefore, require compliance with EASA AD 2024-0131 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this AD. The complete inspection method, measurable thresholds, and corrective actions are included in EASA AD 2024-0131 and the material referenced in EASA AD 2024-0131. Material referenced in EASA AD 2024-0131 for compliance will be available at regulations.gov under Docket No. FAA-2025-0214. This material, like any other properly issued rule, has the force and effect of law, thus preventing any ambiguity, enforcement concerns, and procedural noncompliance issues under 14 CFR 39 and the Administrative Procedure Act. In addition, Congress authorized IBR in the Freedom of Information Act (5 U.S.C. 552), in part, to reduce the volume of material published in the Federal Register and the CFR. The FAA has not changed this AD in this regard. Request To Provide Standardized Terminology AMMO stated that certain words used in the EASA AD and the material referenced in the EASA AD are ambiguous and not standardized FAA terminology. It requested that the FAA provide standardized FAA terminology for field-observed symptoms such as "play" or "clicking." The FAA agrees that there could be certain words in the EASA AD and the material referenced in the EASA AD that are ambiguous. In these instances, the FAA writes exceptions to eliminate such ambiguity. For example, the term "play," specified in EASA AD 2024-0131, is subjective. In paragraph (h)(2) of this AD, the FAA specifies that this AD does not adopt paragraph (1) and (2) of EASA AD 2024-0131. This exception removes the ambiguous term "play" from the requirements of this AD. In addition, in paragraph (h)(2) of this AD the FAA requires measurement of the radial play of the two spherical bearings of each affected part. The service bulletin then specifies actions based on the radial play measurements. By requiring these measurements, the term "play" is unambiguous in this AD. The term "clicking" referenced in the service bulletin is not part of the required actions. The FAA has not changed this AD in this regard. Request for Alternate Means of Reporting AMMO claimed that a line mechanic cannot be expected to navigate Original Equipment Manufacturer (OEM) reporting portals and requested that the FAA avoid exclusive reliance on OEM digital platforms for compliance reporting in the proposed AD. The FAA disagrees with the request. EASA AD 2024-0131 identifies the on-line questionnaire referenced in the Alert Service Bulletin (ASB) as an acceptable method to comply with the reporting requirement, but it does not specify that it is the only acceptable method to comply with the reporting requirement. EASA AD 2024-0131 provides the website address for Airbus Helicopters Deutschland GmbH, which identifies contact information for the appropriate service area. The FAA has not changed this AD in this regard. Request To Coordinate With Flight Standards Field Personnel AMMO stated that the FAA did not coordinate with Flight Standards field personnel to validate the AD's practical executability, as required by FAA's internal policy. The commenter suggested that the FAA coordinate the proposed AD with Flight Standards to validate the AD's practical executability. The FAA disagrees with the implication that Flight Standards did not review the proposed AD. The FAA coordinates all AD actions with the appropriate Flight Standards Office before issuance. The FAA has not changed this AD in this regard. Request To Ensure All Referenced Documents Are Available AMMO stated that EASA AD 2024-0131 and Airbus ASB MBB-BK117-62-33-0001 are not FAA-certified documents and are therefore subject to unilateral revision by external entities, not docketed for permanent public access, and inaccessible without subscriptions or OEM login credentials. The commenter requested that the FAA ensure that all referenced documents are docketed, publicly accessible, and version-locked. The FAA disagrees with the commenter's statements about the referenced material. The FAA reviewed EASA AD 2024-0131 and Airbus ASB MBB-BK117-62-33-0001 before issuing the NPRM and found them to be acceptable and locked. After this final rule is published, EASA AD 2024-0131 and the referenced material specified in EASA AD 2024-0131 that is required for compliance will be docketed and publicly accessible as they will be able to be found at regulations.gov by locating Docket No. FAA 2025-0214. Additionally, as stated in the NPRM, 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. The FAA has not changed this AD in this regard. Conclusion These products have been approved by the civil aviation authority 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 reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed EASA AD 2024-0131, which specifies procedures for a one-time inspection of the spherical bearings of the control rod assemblies and pitch link assemblies for radial play and, depending on the results, measuring the radial play of the spherical bearings of the control rod assembly and pitch link assembly. Depending on the measurement results, EASA AD 2024-0131 specifies replacing the control rod end and reporting all measurement results to AH (Airbus Helicopters). 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. Differences Between This AD and the MCAI This AD does not require inspecting the spherical bearings of the control rod assemblies and pitch link assemblies for play as specified in the MCAI since that action is subjective and could vary from mechanic to mechanic. Instead, this AD requires measuring the radial play of the spherical bearings of the control rod assembly and pitch link assembly. This AD also prohibits installing an affected control rod assembly or pitch link assembly unless the radial play of the assembly's two spherical bearings is measured and the radial play of each spherical bearing is equal to or less than 0.10 mm, whereas the MCAI does not require that installation limitation. Interim Action The FAA considers that this AD is an interim action. If final action is later identified, the FAA might consider further rulemaking then. Costs of Compliance The FAA estimates that this AD affects 180 helicopters of U.S. registry. Labor costs are estimated at $85 per hour. Based on these numbers, the FAA estimates the following costs to comply with this AD. Measuring the axial play takes 1 work-hour and reporting the results takes 1 work-hour, for an estimated cost of $170 per helicopter and $30,600 for the U.S. fleet. If required, replacing a control rod or pitch link assembly takes 1 work-hour and parts cost $1,650 for an estimated cost of $1,735 per control rod or pitch link assembly replacement. Paperwork Reduction Act A federal agency may not conduct or sponsor, and a person is not required to respond to, nor shall a person be subject to a penalty for failure to comply with a collection of information subject to the requirements of the Paperwork Reduction Act unless that collection of information displays a currently valid OMB Control Number. The OMB Control Number for this information collection is 2120-0056. Public reporting for this collection of information is estimated to take approximately 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. All responses to this collection of information are mandatory. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to: Information Collection Clearance Officer, Federal Aviation Administration, 10101 Hillwood Parkway, Fort Worth, TX 76177-1524. 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, (2) Will not affect intrastate aviation in Alaska, and (3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. 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: 2025-16-02 Airbus Helicopters Deutschland GmbH: Amendment 39-23099; Docket No. FAA-2025-0214; Project Identifier MCAI-2024-00391-R. (a) Effective Date This airworthiness directive (AD) is effective January 12, 2026. (b) Affected ADs None. (c) Applicability This AD applies to Airbus Helicopters Deutschland GmbH Model MBB-BK 117 C-2 and MBB-BK 117 D-2 helicopters, certificated in any category. Note 1 to paragraph (c): Helicopters with an MBB-BK 117 C-2e designation are Model MBB-BK 117 C-2 helicopters. (d) Subject Joint Aircraft System Component (JASC) Code 6230, Main Rotor Mast/Swashplate. (e) Unsafe Condition This AD was prompted by reports of significant wear of the spherical bearings of the control rod assembly and pitch link assembly. The FAA is issuing this AD to detect and address wear of the spherical bearings of the control rod assembly and pitch link assembly. The unsafe condition, if not addressed, could result in erroneous pitch and oscillations of the main rotor blades, and consequent loss of control of the helicopter. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Requirements 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 AD 2024-0131, dated July 8, 2024 (EASA AD 2024-0131). (h) Exceptions to EASA AD 2024-0131 (1) Where EASA AD 2024-0131 requires compliance in terms of flight hours, this AD requires using hours time-in-service. (2) Instead of complying with paragraphs (1) and (2) of EASA AD 2024-0131, within 100 hours time-in-service after the effective date of this AD, measure the radial play of the two spherical bearings of each affected part, as defined in EASA AD 2024-0131, in accordance with the instructions of the ASB, as defined in EASA AD 2024-0131. (3) Where paragraph (5) of EASA AD 2024-0131 specifies reporting measurement results to AH (Airbus Helicopters) within a certain compliance time, for this AD, report those measurement results at the applicable time specified in paragraph (h)(3)(i) or (ii) of this AD. (i) If the measurement was done on or after the effective date of this AD: Submit the report within 30 days after the measurement. (ii) If the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD. (4) This AD does not adopt the "Remarks" section of EASA AD 2024-0131. (i) Parts Installation Limitation As of the effective date of this AD, do not install an affected part, as defined in EASA AD 2024-0131, on any helicopter unless the radial play of the two spherical bearings of that affected part is measured by following the actions required by paragraph (2) of EASA AD 2024-0131 and the radial play of each spherical bearing is equal to or less than 0.10 mm. (j) 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 (k) 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. (k) Additional Information For more information about this AD, contact Michael Mueller, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (847) 294-7543; email: michael.j.mueller@faa.gov. (l) 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 2024-0131, dated July 8, 2024. (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 this 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 November 19, 2025. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.