Major international airlines have cancelled flights heading to the U-S or taken their Boeing 7-77 jets off those routes over concerns new 5-G mobile phone service could interfere with aircraft technology.
Some airlines say they were warned the planes are particularly affected by the service that uses a segment of the radio spectrum close to that used by radio altimeters, which measure the height of aircraft above the ground and help pilots land in low visibility.
The U-S will allow planes with accurate, reliable altimeters to operate around high-power 5-G, but planes with older altimeters will not be allowed to make landings under low-visibility conditions.