US airline chiefs have warned that the introduction of a new 5G service could cause US commerce to "grind to a halt" due to possibly grounding a significant number of aircraft and might "strand tens of thousands of Americans overseas".
Warnings of an impending "catastrophic" crisis in aviation came in a letter sent to White House National Economic Council director Brian Deese, transportation secretary Pete Buttigieg, Federal Aviation Administration (FAA) administrator Steve Dickson and Federal Communications Commission (FCC) chairwoman Jessica Rosenworcel, Reuters reported Monday.
"Unless our major hubs are cleared to fly, the vast majority of the traveling and shipping public will essentially be grounded," the letter, signed by the chief executives of American Airlines, Delta Air Lines, United Airlines, Southwest Airlines and Jet Blue, as well as freight and parcel carriers UPS and FedEx, said.
They warned new C-Band 5G technology could interfere with critical airplane instruments such as radio altimeters - which judge the distance from the ground to the bottom of the flying vessel - and have an impact on low-visibility operations.
"This means that on a day like yesterday, more than 1,100 flights and 100,000 passengers would be subjected to cancellations, diversions or delays," the letter cautioned, adding a call for urgent action to be taken.
"To be blunt, the nation's commerce will grind to a halt," the executives said.
Airlines for America, the lobbying group that organized the letter, and government agencies were not immediately available for comment.
In a letter dated 4 January, the group thanked Buttigieg, Dickson and Deese for "reaching the agreement with AT&T and Verizon to delay their planned 5G C-band deployment around certain airports for two weeks and to commit to the proposed mitigations".
"Safety is and always will be the top priority of US airlines," it said. "We will continue to work with all stakeholders to help ensure that new 5G service can coexist with aviation safely."
As part of the agreement - which was dated 3 January - AT&T and Verizon agreed to create buffer zones around 50 US airports to reduce interference risks and take other steps to cut potential interference for six months.
But the agreement to delay wider implementation of the technology to 19 January is about to expire. The airlines had requested "that 5G be implemented everywhere in the country except within the approximate 2 miles (3.2 km) of airport runways" at some key airports.
"Immediate intervention is needed to avoid significant operational disruption to air passengers, shippers, supply chain and delivery of needed medical supplies," Reuters reported the letter as saying.
It also warned that flight restrictions will not be limited to poor weather operations.
The airlines urged action to ensure "5G is deployed except when towers are too close to airport runways until the FAA can determine how that can be safely accomplished without catastrophic disruption".
On Sunday, the FAA said it had cleared an estimated 45% of US commercial airplanes to perform low-visibility landings at many airports where 5G C-band will be deployed starting on Wednesday.
The warning follows previous alerts that Medevac helicopters or the aircraft that hospitals and rescue missions may also be affected by the technology.
According to a Bloomberg report, 5G interference on radio altimeters on emergency helicopters could ground operations. The 5G will not necessarily shut down the altimeter, but could cause it to give inaccurate readings.
