If you live or work close enough to a major airport, you may not get much benefit from C-Band 5G’s speed upgrades until sometime in 2023.
That was one of few things clarified at a lengthy hearing held Thursday by the House Transportation and Infrastructure Committee.
“5G and aviation can safely coexist,” Steve Dickson, administrator of the Federal Aviation Administration, told the panel, before spending much of the next two hours describing how much more work that safe coexistence will require.
Dickson said he's content with steps taken so far by AT&T and Verizon to avoid possible interference on their initial C-Band 5G service on frequencies from 3.7 to 3.8GHz with radio altimeters that operate from 4.2 to 4.4GHz.
AT&T and Verizon have twice pushed back their C-Band launches and agreed not to deploy C-Band in buffer zones around airports identified by the FAA. The agency also began an intensive testing program that has now certified 90% of the US commercial fleet as safe to operate in low-visibility conditions that would require relying on radio altimeters.
“All parties are working together very effectively at this point,” Dickson said, crediting wireless carriers for providing the government with more detailed information about cell-site location, power strength, and signal shape.
But that leaves some small regional jets, plus many helicopters and business jets and, to a lesser extent, other “general aviation” aircraft, with altimeters still uncertified against C-Band interference.
Dickson suggested some of those altimeters could be fixed with radio-frequency filters, citing “promising discussions” with altimeter manufacturers. But ultimately, the FAA will need to write altimeter performance standards for C-Band resistance, which he said will probably take a year before manufacturers can design new units.
The cost of these upgrades—and who might eat it—barely got discussed.
That means the temporary restrictions AT&T and Verizon announced in January are likely to run more than the announced six months, although Dickson said continued testing could help the FAA “refine what the problem set is” and nibble away at these exclusion zones.
Almost every member of Congress at the hearing had questions about how an interagency coordination process meant to avoid last-minute conflicts could have gone so wrong.
Dickson said wireless carriers did not provide sufficiently detailed technical data until December. Some committee members, meanwhile, blamed extended leadership vacancies during most of the Trump administration at the Commerce Department’s National Telecommunications and Information Administration (NTIA), the agency that’s supposed to help coordinate these efforts. In fewer words: a failure to communicate.
That failure doesn’t seem to have been entirely resolved: The FCC, which ran the C-Band auction that concluded last February, did not participate in the hearing.