Today the Federal Aviation Administration issued a Special Airworthiness Information Bulletin informing airlines and aircraft manufacturers that new 5G transmitters used by wireless providers might have negative effects on planes’ navigation systems. These concerns were raised in 2020 by FAA Administrator Steve Dickson, and should have been publicly discussed at the time.
This Bulletin is issued in response to the Federal Communication Commission’s decision to allow deployment of new 5G transmitters on December 5. The transmitters will start operating in a band of spectrum close to the one used by aircraft for radio altimeters (also known as radar altimeters).
Radio altimeters tell pilots how far planes are above ground; help planes land; and prevent aircraft from crashing into other aircraft and obstacles such as hillsides in darkness and foggy weather. The new 5G rollout is good news for smartphone users but bad news for air travel.
The FCC’s auction of this band of spectrum, in the 3.7 to 4.2 GHz band, known as the C-Band, netted over $80 billion for the U.S. Treasury. Verizon
The FAA bulletin “recommends that radio altimeter manufacturers, aircraft manufacturers, and operators voluntarily provide to federal authorities specific information related to altimeter design and functionality, specifics on deployment and usage of radio altimeters in aircraft, and that they test and assess their equipment in conjunction with federal authorities.”
The object of this information collection is to see what has to be done to keep aircraft safe. Such information collection, its analysis, and potential solutions can take years. Radio altimeters are embedded in planes’ systems, and cannot simply be taken out and swapped for another model as can be done with a car radio.
For now, in an attempt to reduce the negative effects of 5G transmitters on radio altimeters, 5G transmission will only be allowed in the lower 100 MHz of the C-band.
The Federal Aviation Administration and Congress have continued to warn the FCC about the dangers of 5G transmitters on airline safety.
House Transportation and Infrastructure Chairman Peter DeFazio wrote to then-FCC Chairman Ajit Pai in November 2019 and December 2020 laying out the problems. In 2019 Chairman DeFazio wrote, “unless the FCC imposes mitigations that will conclusively prevent adverse effects of aviation safety, I strongly object to the FCC’s proposal to repurpose portions of the 3.7-4.2 GHz spectrum band, or C-band, for 5G wireless purposes.”
Airline industry groups such as the Airline Pilots Association and the Airline Manufacturers Association submitted joint comments warning about dangers to aviation from the spectrum auction. The joint filing stated that “Since 2017, the aviation industry has consistently noted during the Federal Communications Commission (FCC) rulemaking process that deployment of 5G networks in this frequency band may introduce harmful radio frequency (RF) interference to radar altimeters currently operating in the globally-allocated 4.2–4.4 GHz aeronautical band.”
A December 1, 2020, letter from the Deputy Secretary of Transportation, Steve Bradbury, and the Federal Aviation Administrator, Steve Dickson to the National Telecommunications Information Administration at the Department of Commerce expressing concern about airline safety as a result of the then-planned FCC C-Band auction was not publicly-released nor forwarded to the FCC. NTIA would not transmit the letter to the FCC.
The letter, reported in December 2020 by Defense News, warned that the 5G transmitters could interfere with the operations of the Terrain Awareness Operating System, which keeps planes from crashing in dark and foggy conditions. Automatic landing systems such as Autoland would also be affected.
As reported in Defense News, Bradbury and Dickson wrote, “Given the scope of the safety risk, and based upon our current knowledge, it is unclear what measures will be necessary to ensure safe operations in the [National Aerospace System], or how long it will take to implement such measures. Depending upon the results of further analysis, it may be appropriate to place restrictions on certain types of operations, which would reduce access to core airports in the U.S. and, thus, reduce the capacity and efficiency” of commercial aviation.”
By refusing to put the letter in the public record, NTIA withheld important information from the bidders about the potential liabilities associated with the C-Band that might affect the value of the spectrum. If the wireless companies had known that the head of the FAA had concerns about airline safety, they might not have bid as much for the spectrum.
The carefully considered concerns of the FAA about aviation safety should and do have greater weight than objections raised by private industry or even by a congressional committee chairman. Today’s FAA Bulletin is disturbing not merely to the American public but also to businesses that invested tens of billions of dollars in spectrum whose value might be affected. The concerns of the FAA, the expert agency, should have been publicly disseminated a year ago.
