2026-04-02: Turbine Engine Reduction Gear

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 39.13 by adding the following new airworthiness directive: 2026-04-02 BRP-Rotax GmbH & Co KG (formerly BRP-POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH): Amendment 39-23261; Docket No. FAA-2026-1321; Project Identifier MCAI-2025-01769-E. (a) Effective Date This airworthiness directive (AD) is effective March 19, 2026. (b) Affected ADs None. (c) Applicability This AD applies to all BRP-Rotax GmbH & Co KG (formerly BRP-POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH) (Rotax) Model 915 iSc2 C24 and 915 iSc3 C24 engines. (d) Subject Joint Aircraft System Component (JASC) Code 7210, Turbine Engine Reduction Gear. (e) Unsafe Condition This AD was prompted by a report of a certain collar nut that was not installed on the propeller gearbox. The FAA is issuing this AD to detect and correct a collar nut that was not installed on the propeller gearbox. The unsafe condition, if not addressed, could result in an in-flight engine failure and loss of propeller retention, possibly resulting in loss of control of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Definition For the purpose of this AD: (1) A "serviceable gearbox" is a propeller gearbox that meets one of the conditions in paragraphs (g)(1)(i) through (iv) of this AD. (i) A propeller gearbox having Part Number 686790 that has passed the inspection required by paragraph (h)(1) of this AD. (ii) A propeller gearbox manufactured after November 18, 2025. (iii) A propeller gearbox that was overhauled after November 18, 2025. (iv) A propeller gearbox having a serial number that is not listed in paragraph 4) Appendix, of Rotax Alert Service Bulletin ASB-915 i-021R1/ASB-916 i-009R1, Revision 1, dated November 27, 2025 (published as a single document) (Rotax ASB-915 i-021R1/ASB-916 i-009R1). (2) An "affected propeller gearbox" is a propeller gearbox that is listed in paragraph 4) Appendix, of Rotax ASB-915 i-021R1/ASB-916 i-009R1. (h) Required Actions (1) Before further flight after the effective date of this AD and thereafter before further flight after installation of an affected propeller gearbox, do a visual inspection of the propeller gearbox for a collar nut installed on the propeller shaft in accordance with the Accomplishment/Instructions, paragraph 3.5.1) of Rotax ASB-915 i-021R1/ASB-916 i-009R1. (2) If, during the inspection required by paragraph (h)(1) of this AD, any propeller gearbox is found without the collar nut installed on the propeller shaft, replace the propeller gearbox with a serviceable propeller gearbox and perform a test run in accordance with paragraphs (3.5.2) and (3.6) of Rotax ASB-915 i-021R1/ASB-916 i-009R1. (i) Exception to the Referenced Material Where Rotax ASB-915 i-021R1/ASB-916 i-009R1 specifies "If contamination is found, contact your local ROTAX Authorized Distributors or their independent Service Centers," this AD requires, before further flight, accomplishing further action in accordance with a method approved by the Manager, International Validation Branch, FAA; European Union Aviation Safety Agency (EASA); or Rotax' EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature. (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: [email protected]. (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 David Bergeron, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (860) 386-1805; email: [email protected] . (l) 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) BRP-Rotax GmbH & Co KG Alert Service Bulletin ASB-915 i-021R1/ASB-916 i-009R1, Revision 1, dated November 27, 2025 (published as a single document). (ii) [Reserved] (3) For Rotax material identified in this AD, contact Rotax, Rotaxstrasse 1, Gunskirchen, Austria; phone: +43 7246 601 0; website: www.flyrotax.com. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 1200 District Avenue, Burlington, MA 01803. 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 [email protected] . Issued on February 10, 2026. Steven W. Thompson, Acting Deputy Director, Compliance & Airworthiness Division, Aircraft Certification Service. [FR Doc. 2026-04280 Filed 3-3-26; 8:45 am]BILLING CODE 4910-13-P