5G phones may cause radalt problems

News & Press: Aviation

10 January 2022 (0 Comments)

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The CAA, FAA and others have alerted operators to the danger of the 5G telecomms system interfering with radio/radar altimeter (radalt) systems.

Radalts are used in aircraft for the likes of autoland, automatic pilots, terrain awareness, Ground Proximity Warning Systems (GPWS) and Traffic Collision Avoidance Systems (TCAS). They are basically downward-looking very accurate radars.

Radalts operate in the range 4.2-4.4 GHz, with 5G frequencies already in use or up for auction currently covering 3.3-4.2 GHz. With possible interference from out-of-band frequencies, the European Organisation for Civil Aviation Equipment (EUROCAE) and Radio Technical Commission for Aeronautics (RTCA) are attempting to ensure compatibility within the adjacent-band spectrum environment.

The CAA advises the following actions to operators:

- Ensure crews are aware of implications of possible malfunctions.
- Look out for possible NOTAMS.
- Ensure especially that mobile phones are in ‘flight mode’.
- Report all malfunctions.
- Be aware that operations could be impacted.
- Don’t assume that malfunctions are due to 5G.

Further details from the CAA
and FAA