Canada’s Department of Innovation, Science and Economic Development (ISED) has decided to restrict some 5G services because they would interfere with radio altimeters, a crucial part of aircraft navigation systems.
Radio altimeters tell pilots where their planes are relative to Earth. If the radio altimeters are not functioning properly, the aircraft could crash on landing or fly into mountains or hills. No one wants a loved one to be on an airplane with a faulty radio altimeter.
On Thursday, ISED, acting on the results of a study initiated in August, concluded that without further restrictions, 5G services in the 3.45-3.65 GHz band would pose dangers to radio altimeters, which operate in band 4. , 2 – 4.4 GHz.
Canadian restrictions include “exclusion zones” around 26 airports where outdoor 5G base stations would not be allowed to operate, but indoor 5G operations would be allowed. ISED also established “protection zones” where 5G operations would be permitted, with limited power. Additionally, ISDE requires, until it decides otherwise, that 5G antennas tilt downward, rather than horizontally or upward, so as not to interfere with radio altimeters. These restrictions would be in effect until national and international studies have come to a definitive conclusion on the extent of the problem.
ISED’s concerns about potential interference with altimeters by 5G operations in the 3.45 – 3.65 GHz band in Canada emerge the same week that the FCC concluded the auction for licenses in Band 3, 45 – 3.55 GHz in the United States for over $ 20 billion. The FCC order authorizing the auction makes no mention of altimeters, let alone potential interference.
A similar discussion is underway in the United States, following the planned deployment of 5G in the 3.7 – 4.2 GHz section of spectrum known as the C-band, originally scheduled for December 5, now postponed to January 2022. Last year, the Federal Communications Commission auctioned off license rights in C-band to, among others, Verizon, AT&T and T-Mobile to use for 5G services. These companies paid more than $ 80 billion for spectrum that would help provide consumers with faster mobile Internet services. The C band is much closer to the spectrum used for altimeters and therefore the C band would reasonably pose more interference problems than the 3.45 – 3.55 GHz band. The FCC order authorizing the C-band auction mentions altimeters but makes no specific arrangements for them.
ISED’s advice regarding interference with altimeters coincides with a Friday letter to Federal Communications Commission Chairman Jessica Rosenworcel, Chamber of Transport and Infrastructure Chairman Peter DeFazio (D-OR ) and Chairman Rick Larsen (D-WA) of the Aviation Subcommittee. They wrote: “With the FCC administrative process nearing completion, we are now on the verge of a dangerous situation in which flight safety depends on the telecom industry‘s decision on when to turn on its 5G networks. “.
The Federal Aviation Administration warned airlines and aircraft manufacturers in a special airworthiness newsletter on Nov. 2 that 5G transmitters could interfere with radio altimeters. Presidents DeFazio and Larsen called on the FCC to “ban all 5G broadband transmission in the C-band until the FAA has conducted a robust risk assessment and concludes that no mitigation is necessary or that all necessary mitigations are in place ”.
This question, although only now making the headlines, was raised by the FAA over two years ago. Last year, in December 2020, in a letter to the Commerce Department, Assistant Secretary of the United States Department of Transportation Steven Bradbury and FAA Administrator Steve Dickson wrote: “As an executive branch expert on Transportation Safety, the DOT is concerned about the impact on safety may result from FCC’s action. Recent tests and analyzes reveal the potential for harmful interference to radar altimeters installed in thousands of commercial transport aircraft, general aviation aircraft, business jets and helicopters. The Commerce Department has chosen not to place this letter on the FCC file.
The security measures proposed by Canada to protect altimeters against interference from 5G operations in the 3.45 – 3.65 GHz band exceed those of the United States in the 3.45 – 3.55 GHz band or the C band .
It is surprising that the FCC has moved forward with 5G licenses in bands that could cause interference to altimeters due to FAA safety concerns and now despite concerns from Canadian government officials. Should the FCC advise auction bidders that there are potential safety concerns before an auction, or only after an auction when bidders have already engaged tens of billions of dollars in shareholders? These are questions that must be resolved, preferably before an aircraft experiences harmful interference with its radio altimeter.