Resolving the safety challenges posed by 5G wireless broadband service to the aviation sector will take years despite progress in recent weeks that prevented major disruptions for the flying public and cargo shippers, airline, manufacturing and union representatives told lawmakers on Thursday.
Developing permanent standards that go beyond the current “Band-Aid” risk mitigation is needed to allow for the safe and efficient functioning of commercial and general aviation aircraft, and retrofitting equipment will take time, the stakeholders said.
“It will likely take years, not days or weeks, to fully and permanently mitigate the interference issues caused by deployment of 5G in the C-band,” Nicholas Calio, president of Airlines for America, said in written testimony to the House Transportation and Infrastructure Committee.
“There is still much work to be done, and we are unfortunately only at the beginning of what is expected to be a long odyssey,” Calio said. “It is imperative that the data sharing, testing and honing of safety assurance tools continues at a rapid pace. The breadth and complexity of the operating changes to the aviation environment caused by these events, along with the impacts on human factors, desperately call for a methodical, predictable and routine set of solutions to stabilize our operating framework.”
Verizon and AT&T last month agreed to delay deploying some 5G wireless stations near airports after the aviation industry and the Federal Aviation Administration warned that C-band signals could interfere with aircraft safety technology, such as radio altimeters that measure the cleared height above ground and are critical to landing in low-visibility and wind-shear conditions.
The FAA said last week it has approved 20 altimeter models and approved 90% of the U.S. commercial fleet for landing in low-visibility approaches where 5G is deployed near airports. Flights at some regional airports have been delayed during poor weather because of 5G concerns.
It also codified manufacturers’ concerns on four fleets of large aircraft — including Boeing 747-8 freighters — that severely limited their operations at airports with 5G flight precautions regardless of weather conditions.
Ever since the Federal Communications Commission announced its intent in 2018 to auction the 5G spectrum, aviation stakeholders have warned about interference that could throw off radio altimeter readings. Other critical instruments, such as auto throttle, heads-up display and power brakes, rely on the altimeter.
Calio faulted the FCC and the FAA for not working together much earlier, before the spectrum auction occurred, to resolve technical issues between the telecommunications and aviation technologies.
“The U.S. aviation industry should not be in this position and the process that led to this operational nightmare should be held up as a cautionary tale of government communication and coordination gone awry. It is not a partisan problem; it is a government process problem that desperately needs to be addressed.
“One can assume there will be 6G, 7G and many other spectrum utilization issues in the future. Those efforts should be seamlessly integrated into the broader economy without causing seismic disruptions to critical industry segments. Unfortunately, there are no easy answers for the current dynamic, but a framework can be put in place to make sure this never happens again to our industry, or any other for that matter,” Calio said.
Committee Chairman Peter DeFazio, D-Ore., singled out the FCC for not devising a safety plan during the Trump administration for the safe deployment of 5G.
“The FCC’s history of subordinating transportation safety to corporate broadband interests has predictably resulted in the current mess we find ourselves in and must change if we hope to avoid a similar result in the future,” he said. “The consequences of getting this right are enormous. We cannot afford to dismiss the aviation industry’s concerns regarding the importance of accurate radio altimeter readings. We must do everything we can to prevent or limit the potential for 5G signals to interfere with these devices.”
Eric Fanning, president of the Aerospace Industries Association representing manufacturers such as Boeing, placed blame on the telecom companies, and the Air Line Pilots Association (ALPA) blasted the FCC for its handling of the matter.
Fanning noted that Verizon and AT&T didn’t start sharing data about near-airport wireless towers until Dec. 21, the same month the FCC licenses allowed service to begin.
“It was an affront to airline pilots when the FCC sold and licensed a section of the C-Band spectrum to wireless companies without heeding — or even acknowledging — our concerns about potential interference with the radar altimeters we use to safely navigate our aircraft. Their stovepiped policymaking process and single-minded focus on doing the bidding of the telecom industry not only put the public at risk, but it has also forced pilots to perform extensive workarounds to ensure the safety of flight — workarounds that we expect will be needed for the foreseeable future,” said ALPA President Joe DePete.
The FAA’s stopgap measures have added another layer of complexity to preflight planning, with crews now expected to know the type of radio altimeter the aircraft is equipped with, applicable airworthiness directives, whether the aircraft/altimeter combination has been issued an alternate method of compliance for the destination airport and whether the airport is still legal, DePete, a former airline captain, said.
Notices to Air Missions (NOTAMS) issued by the FAA — which let pilots know where 5G is present and operations are restricted — are constantly changing because of the 5G deployment, requiring pilots to carefully review them each time even if they’ve seen them before. Alternate compliance methods may only apply to one airport on a trip or specific runways during poor weather at certain airports, and they are only valid for 30 days at a time, he added.
DePete said the 5G deployment has also added to a pilot’s in-flight workload. Changing cloud patterns at destination airports may force more frequent decisions to divert to alternate airports or stay in a holding pattern until conditions are acceptable.
The wireless industry “is confident 5G poses no risk to aviation safety,” said CTIA President Meredith Baker, adding that concerns are based on a flawed industry study and that the FCC had determined that existing rules provided sufficient protection for altimeters.
T-Mobile has been using a different set of mid-band frequencies for its existing 5G network that are not in conflict with frequencies relied on by aircraft equipment.
The aviation representatives dismissed telecom comparisons to successful 5G deployments in other countries, noting that the U.S. aviation system is far more complex and that governments in other countries have mandated restrictions on the power, proximity and orientation of wireless towers near airports.
In Japan, for example, 5G power levels are at least 90% below those permitted in the U.S. and authorities restrict siting of 5G transmitters away from aircraft flight paths, they said.
DeFazio said he still wants to know the precise details of the agreement by AT&T and Verizon to have exclusion zones around airports for six months and how long the current safety mitigations are expected to last. Even if the risk of 5G interference with onboard devices is low, the deadly 737 MAX crashes show that even “low-risk” threats must be taken seriously, he said.
“The FAA is continuing to work with avionics manufacturers to evaluate altimeters and review manufacturer testing data to measure the accuracy, reliability and robustness of each model, including for those used in regional and business aircraft,” Administrator Stephen Dickson told the panel. Some altimeters, especially older models, may not receive approval as compatible with 5G emissions and may need to be replaced, he acknowledged.
The airline and pilot representatives called for legislation requiring the FCC to share information before spectrum decisions are final so airlines can conduct risk analysis and defer to safety regulators, while also giving the FAA override authority on spectrum allocation until safety issues are resolved.
And the Aerospace Industries Association said auction proceeds should be used to help finance new equipment and technology airlines have to adopt to prevent interference from telecom signals.