FAA Warning Heeded, Further Testing Warranted

In a surprising turn, Telecom giants AT&T and Verizon have agreed to temporarily pause the rollout of new 5G service, which was set to activate in limited markets on December 5. AT&T has delayed its start to January 5, after receiving a request from the DOT.

Verizon has done a similar pause, but only for the higher frequency ranges in question. Its mid-range frequency bands will go live as planned, since they lack overlap with the aviation frequency range in question.

The move gives a measure of breathing room to an industry figuratively backed against the wall, after multiple warnings from stakeholders of the theoretical negative effects of 5G networks on aeronautical navigation equipment were downplayed and assumed to be overblown by some. The contention lies in the small overlap in frequency use by the newer, higher-speed cellular networks and radar or radio altimeters in use. The similarity in the licensed frequencies, though separate in theory, has led to conjecture that fringe cases, errors, and other non-standard occurrences could produce false and anomalous indications in aircraft indicators.

In the worst-case scenario, an aircraft in poor visibility relying primarily on their radio altimeter could rely on incorrect information about their proximity to ground, which could lead to very deadly outcomes. 

The FAA released a Special Airworthiness Bulletin requesting more testing, specifications, and information about radar altimeters and equipped aircraft, with special guidance for operators and pilots. Telecom industry specialists have maintained that no evidence of interference exists between C-band spectrum and flight equipment, but the FAA takes a different tack. It has been a good example of the difference in aviation's approach to safety, and the FAA's culture of wariness towards new developments.

The adage about regulations being written in blood has sunk deep in the minds of FAA personnel, owing to a level of responsibility that is likely downright alien to those in the internet connectivity game. The FAA has been playing it safe, hoping to prevent even an infinitesimally small chance of damage. 

FMI: www.verizon.com, www.Tmobile.com