# Airworthiness Directives; BRP-Rotax GmbH & Co KG (Formerly BRP-POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH) Engines
> **Rule** · Final rule; request for comments. · Published 2026-03-04 · Effective 2026-03-19 · 91 FR 10513
## Document
- **Document number:** 2026-04280
- **Category:** airworthiness
- **Manufacturer:** BRP-Rotax GmbH & Co KG (Formerly BRP-POWERTRAIN GMBH & CO KG and Bombardier-Rotax GmbH)
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 91 FR 10513
- **Publication date:** 2026-03-04
- **Effective date:** 2026-03-19
- **FAA docket:** Docket No. FAA-2026-1321
## Abstract

The FAA is adopting a new airworthiness directive (AD) for all BRP-Rotax GmbH & Co KG (Rotax) Model 915 iSc2 C24 and 915 iSc3 C24 engines. This AD was prompted by a report of a certain collar nut that was not installed on the propeller gearbox. This AD requires a visual inspection of the propeller gearbox to determine if a collar nut is installed on the propeller shaft and, if not installed, replacement of the propeller gearbox with a serviceable propeller gearbox. The FAA is issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2026/03/04/2026-04280/airworthiness-directives-brp-rotax-gmbh-and-co-kg-formerly-brp-powertrain-gmbh-and-co-kg-and)
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