Airlines vs 5G: What are the concerns? Airbus and Boeing have raised a warning

tech.hindustantimes.com:

Airlines have voiced concern that the rollout of 5G mobile technology in the United States could cause potentially dangerous interference with aircraft systems. Verizon and AT&T were activating their networks on Wednesday but agreed to delay their rollout near airports.

Here are some key questions about the issue:

The C-Band frequencies used for 5G networks are close to those used by the altimeters of airplanes.

US telecom operators were allocated frequencies between 3.7 and 3.98 gigahertz for their 5G networks -- a right that cost the companies tens of billions of dollars.

But the aviation sector is concerned that the frequencies used by the mobile companies are too close for comfort to those used by aircraft's radio altimeters, which operate between 4.2 and 4.4 GHz.

Altimeters measure the distance between an aircraft and the ground, a vital instrument when landing at night or during bad weather.

"The concern is that the smaller gap between the upper 5G frequency in the US and these frequencies is small enough to potentially cause interference as aircraft are on approach to land," Nigel Linge, telecommunications professor at the University of Salford in the UK, told AFP

Aircraft makers Airbus and Boeing voiced concerns about the potential risks of interferences to the US transportation secretary in December.

The 5G rollout was then delayed until January 19 following a request from the Federal Aviation Administration to ensure the system is safe.

"If there's the possibility of a risk to the flying public, we are obligated to restrict the relevant flight activity until we can prove it is safe," the FAA says on its website.

The FAA approved two models of radio altimeters and gave the greenlight to 48 out of 88 US airports most