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 Model EC 155B and EC 155B1 helicopters. The NPRM was published in the Federal Register on July 2, 2025 (90 FR 28913). The NPRM was prompted by AD 2024-0173, dated September 4, 2024 (EASA AD 2024-0173) (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 that during tests concerning jettisoning of windows on a Model EC 155 helicopter, it was identified that the required forces to jettison the windows exceed the maximum jettisoning effort requirements. The MCAI also states that Airbus Helicopters developed a modification of the jettisonable windows to address this unsafe condition. In the NPRM, the FAA proposed to require replacement of the jettisonable windows and seals on the sliding doors and fixed panels on the left-hand and right-hand sides. The FAA also proposed the installation of new labels. The FAA is issuing this AD to prevent the inability to jettison the window(s) during an emergency. The unsafe condition, if not addressed, could result in a reduced capability to evacuate helicopter occupants during an emergency and consequent injury to helicopter occupants. You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-1350. Discussion of Final Airworthiness Directive Comments The FAA received comments from two anonymous commenters that were unrelated to the actions proposed in the NPRM or that did not make a request that the FAA can act on. These comments are outside the scope of this AD. 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 2024-0173, which specifies procedures for replacement of the jettisonable windows and seals on the sliding doors and fixed panels on the left-hand and right-hand sides. The MCAI also specifies procedure for installation of new labels on the sliding doors and fixed panels. 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. Costs of Compliance The FAA estimates that this AD affects 16 helicopters of U.S. registry. The FAA estimates the following costs to comply with this AD. Estimated Costs Action Labor cost Parts cost Cost per product Cost on U.S. operators Replace windows and seals and install labels 48 work-hours × $85 per hour = $4,080 Up to $53,553 Up to $57,633 Up to $922,128. 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: 2025-24-01 Airbus Helicopters: Amendment 39-23196; Docket No. FAA-2025-1350; Project Identifier MCAI-2024-00510-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 Model EC 155B and EC 155B1 helicopters, certificated in any category. (d) Subject Joint Aircraft System Component (JASC) Code 5620, Passenger Compartment Windows; 5630, Door Windows. (e) Unsafe Condition This AD was prompted by a determination that the required forces to jettison the windows exceed the maximum jettisoning effort requirements and the development of a modification of the jettisonable windows. The FAA is issuing this AD to prevent the inability to jettison the window(s) during an emergency. The unsafe condition, if not addressed, could result in a reduced capability to evacuate helicopter occupants during an emergency and consequent injury to helicopter occupants. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Requirements Except as specified in paragraphs (h) and (i) of this AD: Comply with all required actions and compliance times specified in, and in accordance with European Union Aviation Safety Agency AD 2024-0173, dated September 4, 2024 (EASA AD 2024-0173). (h) Exceptions to EASA AD 2024-0173 (1) Where EASA AD 2024-0173 refers to its effective date, this AD requires using the effective date of this AD. (2) Where EASA AD 2024-0173 refers to flight hours, this AD requires using hours time-in-service (TIS). (3) This AD does not adopt the "Remarks" section of EASA AD 2024-0173. (i) No Reporting Requirement Although the material referenced in EASA AD 2024-0173 specifies to submit certain information to the manufacturer, this AD does not include that requirement. (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 Adam Hein, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (316) 946-4116; email: adam.hein@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 2024-0173, dated September 4, 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.