Background The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain Piaggio Model P-180 airplanes. The NPRM was published in the Federal Register on September 5, 2025 (90 FR 42862). The NPRM was prompted by AD 2025-0102, dated May 5, 2025 (EASA AD 2025-0102) (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 leakage from the flexible hydraulic hoses was reported on a Model P-180 airplane. A subsequent investigation revealed that the failure of the HPP electrical motor caused an anomalous current to return through the HPP body, resulting in electrical arcing. This arcing, which occurred as the HPP body was in contact with a flexible steel braided hose, punctured the flexible hydraulic hose. Additionally, the improper installation of the HPP, specifically the incorrect routing of the hydraulic flexible lines according to the airplane maintenance manual, contributed to the incident. This condition, if not detected and corrected, could lead to leaks developing in the flexible hydraulic hoses, which could result in loss of the hydraulic system or fire in the HPP area. In the NPRM, the FAA proposed to require replacing the affected flexible hydraulic hoses. The FAA also proposed to prohibit the installation of affected flexible hydraulic hoses on any airplane. The FAA is issuing this AD to address the unsafe condition on these products. Comments The FAA received comments from two individual commenters who supported the NPRM without change. The FAA received an additional comment from an individual commenter. The following presents the comment received on the NPRM and the FAA's response to that comment. Request To Revise Applicability An individual commenter stated that select Piaggio airframes have faulty flexible hydraulic hoses; therefore, the AD should be expanded to include all airplanes with a similar hose design. The FAA infers that the commenter requested that the proposed AD be revised to expand the applicability to include all Piaggio Model P-180 airplanes, regardless of serial number. The FAA disagrees with the inferred request to expand the applicability of this AD. This AD applies to airplanes known to have affected parts installed and is being issued to correct a specific known unsafe condition on the affected airplanes. The manufacturer has provided the serial number ranges listed in paragraph (c) of this AD, which account for all affected hydraulic flexible hoses in service. The FAA has not changed this AD as a result of this comment. Explanation of Change To Type Certificate Holder Name The FAA has revised the applicability of this AD to identify the type certificate holder's name as published in the most recent type certificate data sheet for the affected models. 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. This AD is adopted as proposed in the NPRM. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed Piaggio Aerospace Service Bulletin 80-0497, Revision 0, dated March 5, 2025 (Piaggio SB 80-0497, Revision 0). This material specifies procedures for replacing the affected flexible hydraulic hoses with new flexible hydraulic hoses that have a non-metallic and non-conductive abrasion sleeve covering the steel braid, which will provide electrical insulation that can prevent arcing and electrostatic discharge in case of accidental contact between the flexible hydraulic hoses and HPP body. This material is reasonably available because the interested parties have access to it through their normal course of business or by means identified in the ADDRESSES section. Costs of Compliance The FAA estimates that this AD affects 107 airplanes 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 flexible hydraulic hoses 22 work-hours × $85 per hour = $1,870 $1,241 $3,111 $332,877 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: 2025-26-05 Baykar Piaggio Aerospace S.p.A. (Type Certificate Previously Held by Piaggio Aviation S.p.A.): Amendment 39-23227; Docket No. FAA-2025-2272; Project Identifier MCAI-2025-00818-A. (a) Effective Date This airworthiness directive (AD) is effective February 17, 2026. (b) Affected ADs None. (c) Applicability This AD applies to Baykar Piaggio Aerospace S.p.A. (type certificate previously held by Piaggio Aviation S.p.A.) Model P-180 airplanes, manufacturer serial numbers 1002, 1004 through 1234, and 3001 through 3018, certificated in any category. (d) Subject Joint Aircraft System Component (JASC) Code 2910, Hydraulic System, Main. (e) Unsafe Condition This AD was prompted by a report of leakage from the flexible hydraulic hoses connected to the hydraulic pump package (HPP). The FAA is issuing this AD to prevent contact between the flexible hydraulic hoses and the HPP body, which could result in leaks developing in the flexible hydraulic hoses. The unsafe condition, if not addressed, could result in loss of the hydraulic system or fire in the HPP area. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Action For airplanes with flexible hydraulic hoses part number (P/N) AS117-04-0205 or P/N 98E0520FAMA000W (landing gear (LG) up and LG down lines); or flexible hydraulic hoses P/N MS8006G207AL or P/N 99G0530FDFD000W (return line) installed: Within 660 hours time-in-service after the effective date of this AD, replace the affected flexible hydraulic hoses in accordance with part 2. B. and 2. C. of the Accomplishment Instructions of Piaggio Aerospace Service Bulletin 80-0497, Revision 0, dated March 5, 2025. (h) Installation Prohibition After the effective date of this AD, do not install flexible hydraulic hoses with P/N AS117-04-0205 or P/N 98E0520FAMA000W (LG up and LG down lines); or flexible hydraulic hoses P/N MS8006G207AL or P/N 99G0530FDFD000W (return line) on any airplane. (i) Alternative Methods of Compliance 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 (j) of this AD and email to: AMOC@faa.gov. 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. (j) 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. (k) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference (IBR) 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) Piaggio Aerospace Service Bulletin 80-0497, Revision 0, dated March 5, 2025. (ii) [Reserved] (3) For Piaggio Aerospace material identified in this AD, contact Baykar Piaggio Aerospace S.p.A., P180 Customer Support, via Pionieri e Aviatori d'Italia, snc-16154 Genoa, Italy; phone: +39 331 679 74 93; email: technicalsupport@piaggioaerospace.it. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. 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 December 30, 2025. Christopher R. Parker, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service.