# Airworthiness Directives; MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier Inc.) Airplanes
> **Rule** · Final rule. · Published 2025-03-21 · Effective 2025-04-25 · 90 FR 13278
## Document
- **Document number:** 2025-04720
- **Category:** airworthiness
- **Manufacturer:** MHI RJ Aviation ULC (Type Certificate Previously Held by Bombardier Inc.)
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 90 FR 13278
- **Publication date:** 2025-03-21
- **Effective date:** 2025-04-25
- **FAA docket:** Docket No. FAA-2024-1896
## Abstract

The FAA is adopting 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. This AD was prompted by the determination that radio altimeters cannot be relied upon 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 requires 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 issuing this AD to address the unsafe condition on these products.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2025/03/21/2025-04720/airworthiness-directives-mhi-rj-aviation-ulc-type-certificate-previously-held-by-bombardier-inc)
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