# Proposed AD FAA-2025-0619: MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier, Inc.) Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2025-13-04
- Products: MHI RJ Aviation ULC
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: April 15, 2025, 90 FR 15664
- Comments due: May 30, 2025
- Became: [AD 2025-13-04](https://openairdocs.org/ad/2025-13-04)
- Docket: FAA-2025-0619 (https://www.regulations.gov/docket/FAA-2025-0619, where comments are filed)
- Project: MCAI-2024-00372-T
- FR document: 2025-06367
- Official PDF: https://openairdocs.org/files/sha256/48/d7/48d75553ad8b1e137db26a9ec1922c6bad2c597993e69efe23b651ed5ccbfba7 (from https://www.govinfo.gov/content/pkg/FR-2025-04-15/pdf/2025-06367.pdf)
- Federal Register: https://www.federalregister.gov/documents/2025/04/15/2025-06367/airworthiness-directives-mhi-rj-aviation-ulc-type-certificate-previously-held-by-bombardier-inc
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADNPRM-2025-06367-00000000000.0001
- Page: https://openairdocs.org/proposed/FAA-2025-0619

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for all MHI RJ Aviation ULC Model CL-600-2C10 (Regional Jet Series 700, 701 & 702), CL-600-2C11 (Regional Jet Series 550), Model CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000). This proposed AD was prompted by an engine indicating and crew alerting system (EICAS) STAB TRIM Caution message that was posted, and subsequent repair that found prematurely worn teeth on a rubber bull gear (RBG) wheel in the horizontal stabilizer trim actuator (HSTA). This proposed AD would require an inspection for part numbers and on-condition replacement of affected RBG wheels and prohibit the installation of affected parts under certain conditions, as specified in a Transport Canada AD, which is proposed for incorporation by reference (IBR). The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Apr 15, 2025: Notice of proposed rulemaking (NPRM). (first notice), FR document 2025-06367, comments due May 30, 2025 (https://www.federalregister.gov/documents/2025/04/15/2025-06367/airworthiness-directives-mhi-rj-aviation-ulc-type-certificate-previously-held-by-bombardier-inc)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.