AD 2026-16-11

This AD is effective August 28, 2026.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of August 28, 2026.

The FAA must receive comments on this AD by September 28, 2026.

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to regulations.gov. Follow the instructions for submitting comments.

• Fax: (202) 493-2251.

• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.

• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

AD Docket: You may examine the AD docket at regulations.gov under Docket No. FAA-2026-7235; 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 final rule, the mandatory continuing airworthiness information (MCAI), any comments received, and other information. The street address for Docket Operations is listed above.

Material Incorporated by Reference:

• For Rotax material identified in this AD, contact Rotax, Rotaxstrasse 1, Gunskirchen, Austria; phone: +43 7246 601 0; website: flyrotax.com.

• 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. It is also available at regulations.gov under Docket No. FAA-2026-7235.

Joseph Catanzaro, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590; phone: (516) 228-7366; email: joseph.catanzaro@faa.gov.

The FAA invites you to send any written data, views, or arguments about this final rule. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2026-7235; Project Identifier MCAI-2026-00679-E” at the beginning of your comments. The most helpful comments reference a specific portion of the final rule, 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 this final rule 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 regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this final rule.

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 AD 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 AD, 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 AD. Submissions containing CBI should be sent to Joseph Catanzaro, 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.

The European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued EASA Emergency AD 2026-0121-E, dated June 24, 2026 (EASA Emergency AD 2026-0121-E) (also referred to as the MCAI), to correct an unsafe condition on all Rotax Model 912 F2, 912 F3, 912 F4, 912 iSc2 Sport, 912 iSc3 Sport, 912 S2, 912 S3, 912 S4, 914 F2, 914 F3, and 914 F4 engines; and Model 912 A1, 912 A2, and 912 A3 engines. The MCAI states that the manufacturer reported an occurrence where the propeller gearbox in a recently manufactured engine was found to be missing the oil spray nozzle and the M7 x 16 hexagon screws intended to secure the propeller shaft bearing within the propeller gearbox, which could cause the propeller shaft and its front bearing to slightly move into the gearbox housing. Further investigation determined that these parts had not been installed during production. To address this potential unsafe condition, Rotax published service material that identifies the affected propeller gearboxes and specifies instructions for visual inspection and, if necessary, replacement of the propeller gearbox. This condition, if not addressed, could result in an in-flight loss of engine oil, engine in-flight shutdown, and loss of control of the airplane.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-7235.

The FAA reviewed Rotax Alert Service Bulletin ASB-2026-001R00, dated June 22, 2026. This service material identifies the serial numbers of the affected engines and propeller gearboxes. This service material also specifies procedures for performing a visual inspection of the propeller gearbox to determine if the oil spray nozzle and certain screws are installed and, depending on the results of the inspection, replacement of the propeller gearbox with a serviceable propeller gearbox. 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.

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 is issuing this AD after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

This AD requires a one-time visual inspection of the propeller gearbox to determine if the oil spray nozzle and certain screws are installed and, depending on the results, replacement of the propeller gearbox with a serviceable propeller gearbox. This AD also prohibits the installation of an affected propeller gearbox on any engine unless certain conditions are met.

EASA Emergency AD 2026-0121-E applies to Rotax Model 912 F2, 912 F3, 912 F4, 912 iSc2 Sport, 912 iSc3 Sport, 912 S2, 912 S3, 912 S4, 914 F2, 914 F3, and 914 F4 engines; and Model 912 A1, 912 A2, and 912 A3 engines, all serial numbers. Rotax Model 912 A1, 912 A2, and 912 A3 engines are not type certificated in the United States but are part of the type design for certain aircraft. This AD applies to all Rotax Model 912 F2, 912 F3, 912 F4, 912 iSc2 Sport, 912 iSc3 Sport, 912 S2, 912 S3, 912 S4, 914 F2, 914 F3, and 914 F4 engines; and Model 912 A1, 912 A2, and 912 A3 engines included as part of the type design for Aeromot-Indústria Mecânico-Metalúrgica Ltda Model AMT-200 (Super Ximango); Diamond Aircraft Industries Model HK 36 R “SUPER DIMONA”; Diamond Aircraft Industries GmbH Models HK 36 TC and HK 36 TS; Diamond Aircraft Industries Inc. Model DA20-A1; HOAC-Austria Model DV 20 KATANA; Magnaghi Aeronautica S.p.A Model Sky Arrow 650 TC; and SCHEIBE-Flugzeugbau GmbH Model SF 25C aircraft, as applicable.

Section 553(b) of the Administrative Procedure Act (APA) (5 U.S.C. 551 et seq.) authorizes agencies to dispense with notice and comment procedures for rules when the agency, for “good cause,” finds that those procedures are “impracticable, unnecessary, or contrary to the public interest.” Under this section, an agency, upon finding good cause, may issue a final rule without providing notice and seeking comment prior to issuance. Further, section 553(d) of the APA authorizes agencies to make rules effective in less than thirty days, upon a finding of good cause.

An unsafe condition exists that requires the immediate adoption of this AD without providing an opportunity for public comments prior to adoption. The FAA has found that the risk to the flying public justifies forgoing notice and comment prior to adoption of this rule because the absence of both a properly installed oil spray nozzle and the screws that secure the propeller shaft bearing in the propeller gearbox may allow axial displacement of the propeller shaft bearing during operation. This displacement may lead to loss of engine oil, which could result in engine in-flight shutdown or loss of control of the airplane. Since the FAA has no information pertaining to how quickly this unsafe condition may propagate, the inspection required by this AD must be accomplished before next flight or within 5 hours time-in-service after the effective date of this AD, depending on the condition of the affected engine. This compliance time is shorter than the time necessary for the public to comment and for publication of the final rule. Accordingly, notice and opportunity for prior public comment are impracticable and contrary to the public interest pursuant to 5 U.S.C. 553(b).

In addition, the FAA finds that good cause exists pursuant to 5 U.S.C. 553(d) for making this amendment effective in less than 30 days, for the same reasons the FAA found good cause to forgo notice and comment.

The requirements of the Regulatory Flexibility Act (RFA) do not apply when an agency finds good cause pursuant to 5 U.S.C. 553 to adopt a rule without prior notice and comment. Because the FAA has determined that it has good cause to adopt this rule without prior notice and comment, RFA analysis is not required.

The FAA estimates that this AD affects 180 engines installed on airplanes of U.S. registry.

The FAA estimates the following costs to comply with this AD:

The FAA estimates the following costs to do any necessary replacements that would be required based on the results of the inspection. The agency has no way of determining the number of engines that might need this replacement:

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

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.

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, and

(2) Will not affect intrastate aviation in Alaska.

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive: