Enjoy Christmas travel now, but get ready for flight diversions and cancellations after the holidays. In preparation for the rollout of 5G wireless services by AT&T, Verizon, and T-Mobile on January 5, the Federal Aviation Administration will shortly issue new rules to keep aircraft and passengers safe.
The FAA will prohibit flying to certain airports that are close to 5G transmitters when there is bad weather or low visibility, following two airworthiness directives issued earlier this month, one for transport and commuter planes, and one for helicopters.
The problem: 5G transmitters will adversely affect some radio altimeters, crucial to navigation systems of planes and helicopters. If your plane is flying into bad weather, it might get diverted to another airport, or your flight may get cancelled.
It is not only the FAA that has concerns. On December 17, the European Union Aviation Safety Agency, the European equivalent of the FAA, issued its own Safety Information Bulletin, warning about potential interference in the United States from 5G transmitters; asking for flight crews to be trained to land in cases of unreliable radio altimeters; and calling for crews to report any problems to aircraft manufacturers.
And, as I wrote last month, in November Canada placed restrictions on 5G transmitters. These include “exclusion zones” around 26 airports where outdoor 5G base stations would not be permitted to operate; “protection zones” where 5G operations would operate with restricted power; and a requirement that 5G antennas tilt down, rather than horizontally or upward, so as not to interfere with radio altimeters.
At a December 15 Senate Commerce Committee hearing on airline safety, United Airlines CEO Scott Kirby said, “This is the biggest and most damaging potential issue facing us.”
After spending over $80 billion on spectrum for 5G at the Federal Communications Commission C-Band auction earlier this year, wireless companies were informed by the FAA that using that spectrum to its fullest extent would interfere with radio altimeters. No matter that Uncle Sam should have informed companies in advance. Wireless companies delayed deploying 5G services for a month, and proposed lowering transmitter power for 6 months, but the problem will take longer to repair.
Telecom companies need to recoup their investment. But this issue will not get resolved by January 5, or even by July 5, because airlines and aircraft manufacturers cannot put new radio altimeters in place in 2022.
Some people think that the interference problem is just a matter of swapping out one radio altimeter for another, the way you can take one EZ pass out of a car and put in another. But it is not so simple.
Radio altimeters are tied into planes’ systems, and some newer altimeters control more internal aviation systems than do older altimeters. So it is not even a matter of replacing old altimeters for new ones.
FAA spokesperson Kiva Williams told me, “The FAA approves radar/radio altimeter type designs based on a number of technical standard orders. Altimeters are then manufactured under FAA technical standard order authorizations.”
But all existing radio altimeters are designed to technical standard orders prepared for the current environment, which does not include 5G. No standards exist for the new high-powered terrestrial wireless environment.
An updated technical standard is being developed, but it will not be complete until early 2023. Only after the standard is in place will new equipment be built and certified. And then it will take many more years to install the new equipment.
The new altimeters must not only be resilient to the new environment, but also must remain capable of meeting all of the other performance requirements, including accuracy and integrity.
Manufacturers and the aviation industry must know the worst-case environment from an international perspective. That environment includes not only power levels, direction of the antennas (especially above the horizon) and how close the transmitters will be to aircraft ground and flight operations, but also understanding if there will be additional changes down the road.
New altimeters based on a new 5G standard would normally not be designed, certified, manufactured and available in quantity until 2026 -2027. The process can be accelerated, but it will still take years to reequip all aircraft.
Manufacturers are extremely concerned. Boeing CEO David Calhoun and Airbus CEO Jeffery Knittel wrote to Transportation Secretary Pete Buttegieg saying, in a letter obtained by Reuters, that “5G interference could adversely affect the ability of aircraft to safely operate.”
The wireless industry believes that there are only a few problematic altimeters, including one with a 40-year-old design. But radio altimeters that are most vulnerable to the new environment can also be the best performers for their intended function. While some altimeters are more susceptible than others, no current altimeter and antenna is fully compliant with the new 5G environment that will be in place in January, much less 6 months later when power levels will be raised. All aircraft and helicopters with radio altimeters will remain at risk.
The FAA will need to address hundreds of publicly-owned, but private-use airports, including all military, Coast Guard, Federal, State, and local airports.
Delta Airlines Executive Vice President and Chief of Operations John Laughter said at last week’s hearing, “I do know that the safety concerns with aircraft and aviation are very real, and I also know there is a solution. We have seen it in other countries, with a combination of power adjustments and location, and we could absolutely solve this and live in a world where 5G is available.”
Let’s hope he is right, and that aviation retains its current levels of safety and convenience as solutions are found.
