As US telecom carriers plan to switch on 5G signal wireless services across the country by January 2022, the Federal Aviation Administration (FAA) has issued new airworthiness directives to avoid any potential effects on aviation safety equipment.

In a statement released on December 7, 2021, the FAA said that the goal of the directives is to provide a framework and to gather more information to avoid potential effects of 5G. The FAA is working closely with the Federal Communications Commission and wireless companies.

The airworthiness directive is for all transport and commuter category airplanes equipped with a radio (also known as radar) altimeter, and for all helicopters equipped with a radio altimeter / radar. 

The directive forbids pilots from using auto-landing and other certain flight systems at low altitudes where 5G wireless signals could interfere with onboard instruments that measure a plane's distance to the ground.

According to the FAA, 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)

The airworthiness directive also required revision of the limitations section of the existing airplane/aircraft flight manual (AFM) to incorporate limitations prohibiting certain operations requiring radio altimeter data when in the presence of 5G C-Band interference as identified by Notices to Air Missions (NOTAMs). 

The directive affects more than 6,800 US airplanes and dozens of aircraft manufacturers, and more than 1,800 US helicopters.

The FAA said that it is confident that with ongoing collaboration between the Federal Communications Commission and wireless companies, the shared goal of expansion for both 5G and aviation can “co-exist safely”.