5G Radio Signal Interference on Aircraft Radio Altimeters

Telecom Operators (Telcos) were authorized by Industry Science & Economic Development Canada (ISED) to begin broadcasting 5G signals in the “C” band of 3.8 Ghz as of May 29, 2024. TC issued global Airworthiness Directive CF-024-14 on May 15, 2024, with an effective date of May 29. 2024. The AD was issued owing to safety concerns of non-tolerant radio altimeters when operating in Canada due to 5G C-band wireless broadband signal interference. Due to the delay by TC in specifying the mandatory modification requirements combined with supply chain problems, a high percentage of commercial aircraft operated in Canada are still considered to have non-tolerant radio altimeters with regards to 5G signal interference. ATAC has been strongly advocating for TC and ISED to advise operators of where these active 5G towers are located, however to date this has not happened. For operators of aircraft without tolerant radio altimeters, operational restrictions are now in place as per the AD and modifications to become tolerant are encouraged as soon as possible in order to regain full aircraft operational capabilities especially for approach and landing during poor visibility. These modifications are expected to be mandated by January 1, 2026.

Report details of any abnormal radio signal interference on radio altimeters to ATAC at laalders@atac.ca as soon as possible after the occurrence so that we can urgently follow up with TC and ISED.