Why 5G wireless service is causing turbulence for US airlines
Carriers worry over interference with altimeters, but telecoms groups say there is no safety problem
The highly technical realms of wireless technology and avionics exploded into a furore in the US this week, after airlines warned of chaos if telecoms groups launched new 5G networks as planned on Wednesday.
5G will offer mobile phone users superfast connections and is expected to hasten the digitisation of many industries. But airlines have raised concerns over potential interference with their instrument systems.
AT&T and Verizon, the telecoms groups, on Tuesday said they had voluntarily agreed to scale back 5G near certain airport runways while pushing ahead with nationwide rollouts. The moves eased the showdown with the airline industry.
But not entirely: later on Tuesday, Delta Air Lines said it was planning for possible cancellations “caused by the deployment of new 5G service in the vicinity of dozens of US airports”.
How did the US reach this cliffhanger over 5G technology that already exists in other countries served by airlines? Here are some answers.
Why are airlines worried about 5G in the US?
Airlines warn that the technology could interfere with sensitive equipment, notably altimeters, which use radio frequencies to measure how high an aircraft is flying and provide data to critical equipment including the autopilot. They are particularly crucial for landings in inclement weather.
5G networks in the US operate using frequencies in the same radio spectrum, known as the C-band.
The aviation industry believes this is a safety problem. The Federal Aviation Administration has cleared less than half of the domestic commercial aircraft fleet to perform low-visibility landings at many airports where the 5G C-band will be deployed. On January 7 the regulator delineated so-called buffer zones around 50 airports — including those around the hubs of New York City, Chicago, Dallas and Los Angeles — to turn off 5G wireless transmitters close to runways for six months.
Airlines argue these buffer zones do not go far enough, and have called on the government to block 5G masts within two miles of runways at some airports.
What changed this week?
Airlines on Monday said the problem presented by 5G was worse than their executives expected, threatening to ground thousands of passenger and cargo flights. “Multiple modern safety systems on aircraft will be deemed unusable,” US airline executives wrote in a letter to the FAA and Federal Communications Commission on Monday.
United Airlines has said it is particularly concerned about three Boeing planes — the 787, 777 and 737 — whose altimeters it said would be “compromised”. United and American Airlines said they were preparing to curtail flights if Wednesday’s planned 5G launch went ahead.
Ultimately, AT&T said it agreed to “temporarily defer turning on” some 5G towers around “certain airport runways”, while Verizon said it would limit its launch “around airports”.
Why is this not a problem in other countries?
Many other countries have introduced 5G. A key difference is that the radio frequency band allocated for 5G in the US is closer to the bandwidth used in avionics than in other regions including Europe.
The FAA has also pointed to other differences, including 5G power levels, the tilt of aerials and the placement of aerials in relation to airfields.
The European Union Aviation Safety Agency said it “is not aware of any in-service incidents caused by 5G interference” and that data received from aircraft manufacturers “offers no conclusive evidence for immediate safety concerns”.
Concerns over interference have been discussed for years in the US, according to the FAA. Tom Wheeler, a visiting fellow at the Brookings Institution and former chair of the FCC, said confusion over allocating the airwaves showed “a lack of leadership” in Washington.
“The Trump administration had no . . . unified spectrum policy; as a result, policy ended up being made by individual agencies,” he wrote in a November blog post.
What do telecoms companies say?
The US telecoms industry has insisted there is no safety problem, that their equipment will not interfere with aircraft and points to the fact that 40 countries have already safely adopted 5G. AT&T and Verizon had already delayed their full 5G launches twice since early December.
CTIA, the telecoms trade body, has accused the aviation industry of “spread[ing] incorrect information about 5G and airline safety”, and argues that the delay to building the 5G network is harming US competitiveness.
How have federal officials responded?
Joe Biden, US president, hailed AT&T and Verizon on Tuesday for “allow[ing] aviation operations to continue without significant disruption”.
Yet pressure remained on the White House to find a long-term solution, as telecoms companies left it unclear how long they would further delay service near airports.
As well, the FAA had not lifted its directives to restrict flights as of Tuesday afternoon. Those directives officially govern aviation operations, said one industry official, and leaving them in place “could lead to cancellations”.
An official at the FCC, whose regulatory purview includes the spectrum, said that no other aviation regulator has put in place similar flight restrictions to the FAA.
Jessica Rosenworcel, FCC chair, said in a statement: “The FAA has a process in place to assess altimeter performance in the 5G environment and resolve any remaining concerns. It is essential that the FAA now complete this process with both care and speed.”