Fourteen aviation organizations urged lawmakers to protect frequencies used for aeronautical purposes from potential interference from 5G telecommunications applications. The organizations wrote key House and Senate leaders expressing concern about the FCC’s decision to make the frequency spectrum from 3.7 to 3.98 GHz available for flexible use, including for 5G telecommunications applications. This move came despite aviation industry warnings that 5G application in the 3.7 to 3.98 GHz frequency band could interfere with radar altimeters operating in the globally-allocated 4.2 to 4.4 GHz aeronautical band.

An RTCA study found “a major risk” that the 5G telecommunications systems would cause harmful interference to radar altimeters on all types of civil aircraft, they said.

“The results of the study performed clearly indicate that this risk is widespread and has the potential for broad impacts to aviation operations in the U.S., including the possibility of catastrophic failures leading to multiple fatalities, in the absence of appropriate mitigations,” the organizations said in the November 17 letter. The peer-reviewed RTCA report has been the most comprehensive analysis to date, they said.

“We are concerned that without congressional intervention…decisions will be made with a frightening lack of understanding of aviation requirements,” said the groups, representing airlines, business and general aviation, manufacturers, controllers, and other aspects of the industry.