# Proposed AD FAA-2024-1896: MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier Inc.) Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2025-04-08
- Products: MHI RJ Aviation ULC
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 9, 2024, 89 FR 73009
- Comments due: October 24, 2024
- Became: [AD 2025-04-08](https://openairdocs.org/ad/2025-04-08)
- Docket: FAA-2024-1896 (https://www.regulations.gov/docket/FAA-2024-1896, where comments are filed)
- Project: MCAI-2023-00978-T
- FR document: 2024-20244
- Official PDF: https://openairdocs.org/files/sha256/fb/ca/fbca2f25ea90937272b93458d97d3085c7067489de29ee14e827440b400cbf7e (from https://www.govinfo.gov/content/pkg/FR-2024-09-09/pdf/2024-20244.pdf)
- Federal Register: https://www.federalregister.gov/documents/2024/09/09/2024-20244/airworthiness-directives-mhi-rj-aviation-ulc-type-certificate-previously-held-by-bombardier-inc
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/FR-ADNPRM-2024-20244-00000000000.0001
- Page: https://openairdocs.org/proposed/FAA-2024-1896

## Summary

The FAA proposes to adopt a new airworthiness directive (AD) for certain MHI RJ Aviation ULC Model CL-600-2B19 (Regional Jet Series 100 and 440), CL-600-2C10 (Regional Jet Series 700, 701, and 702), CL- 600-2C11 (Regional Jet Series 550), CL-600-2D15 (Regional Jet Series 705), CL-600-2D24 (Regional Jet Series 900), and CL-600-2E25 (Regional Jet Series 1000) airplanes. AD 2023-10-02 was prompted by the determination that radio altimeters cannot be relied on to perform their intended function if they experience interference from wireless broadband operations in the 3.7-3.98 GHz frequency band (5G C-Band). This AD was prompted by the determination that this interference can also result in certain failure messages being inhibited longer than intended. This proposed AD would require installing a new radio frequency (RF) bandpass filter on the coaxial line between the radio altimeter and the receive antenna in the aft equipment compartment. The FAA is proposing this AD to address the unsafe condition on these products.

## Notices in this docket

- Sep 9, 2024: Notice of proposed rulemaking (NPRM). (first notice), FR document 2024-20244, comments due Oct 24, 2024 (https://www.federalregister.gov/documents/2024/09/09/2024-20244/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.