5G-resistant radio altimeters are coming

NEW YORK, U.S. — U.S. airlines have begun installing new radar altimeters immune to interference from 5G transmitters. At the beginning of the year, the airline operators had voiced their concerns that 5G antennas could interfere with airplanes' radio altimeters and other flight systems, which could pose flight safety risks.



The U.S. Federal Aviation Administration (FAA) imposed restrictions on certain types of aircraft and airports, while mobile phone providers At&T and Verizon have not yet been allowed to roll out their 5G services around airports fully.

Radio Altimeters operate in an Aeronautical Radio Navigation Service (ARNS) spectrum allocation in the 4.2-4.4 GHz frequency band. The deployment of 5G for mobile communication devices interferes with frequency bands that so far have been dedicated to the aerospace industry in the U.S. and may potentially affect the accuracy of information from radio altimeters.

The aviation industry along with the FAA are working together with inputs from the telecommunication sector to resolve the 5G interference problem affecting airline operations at hundreds of airports across the U.S. In addition, the FAA issued Airworthiness Directives that can prohibit the certain approach and landing operations at airports where 5G interference could occur.

5G-immune altimeters are now retrofitting the Airbus A320 in the U.S. The French technology company Thales has already equipped 50 aircraft with the improved ERT530R radio altimeter. The manufacturer has so far received 2000 orders for the new altimeters. The new technology was approved by the European Aviation Safety Agency EASA in July. Thales also secured certification for the ERT540R for the A330 and A340. The French developer is the first company to offer 5G-resistant radar altimeters.

Thales' ERT530R and ERT540R altimeters use bandpass radio frequency filtering signals within certain frequencies between 4.2 and 4.4 GHz. Radar altimeters work in this C-band frequency range. Signals above or below, such as those of the 5G C-band between 3.7 and 3.98 GHz, are attenuated.

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