5G signals won't interfere with flight operations, telcos reiterate

Senior industry executives say no recent discussions with government on issue of 5G signals interfering with aviation instruments, companies remain open to talks

Telecom companies have reiterated that 5G signals in the allotted frequencies will not interfere with flight operations and discussions on the issue have not been held recently. However, they remain open to talks on codified rules for 5G infrastructure near airports, people in the know said.
 

Sources at the two telecom service providers rolling out 5G — Reliance Jio and Bharti Airtel — said the industry has made sure 5G signals in the C band don’t interfere with flights. Talks on the issue have not taken place recently, they added.
 

“The situation in the US and India are different. We have been clearly saying that here there will be a 500 MHz gap in the frequencies which will safely allow aviation without interference. But if the government wants to codify the rules, we will work with them,” a senior industry executive said.
 

In India, the C-band 5G will be rolled out in the 3.3 GHz to 3.67 GHz frequency range. However, in the US, the operators have used the 3.7 GHz to 3.98 GHz frequencies, which are closer to the radio altimeter frequencies inside the aircraft. Telecom companies have, therefore, argued the C-band 5G frequencies might not affect the altimeter readings at all because of a safe distance between the operating frequencies.

Back and forth

In January 2022, the Federation of Indian Pilots sent a letter raising the issue of possible interference of 5G signals with instruments such as radio altimeters in commercial aircraft. The Directorate General of Civil Aviation (DGCA) had also written to the DoT saying altimeters pick up the faintest of signals from the ground and necessary precautions need to be taken.
 

Altimeters measure altitude above terrain, along with a global positioning system (GPS), to determine the path of aircraft. It helps pilots in situational awareness during low visibility and also provide inputs for onboard systems such as the traffic collision avoidance system by gauging the presence of highrises, mountains, and other obstacles, and the likely flying time.
 

Senior officials from the Department of Telecommunications (DoT) told Business Standard the issue remains under consideration and no final decision has been taken yet on the issue of standard operating practices. “Stakeholder discussions had happened earlier. A decision is yet to be taken,” one official said.
 

“There have been no meetings on this issue recently. Talks may happen as the 5G rollout gains pace nationwide,” another top executive said.
 

Back then, the Cellular Operators’ Association of India, which represents the telecom companies, had said 5G signals will not interfere with aviation technology.
 

Earlier this year, the International Air Transport Association had also flagged the issue, pointing out that some governments have gone for testing to establish sufficient spectrum separation remains between 5G C-band deployments and 4.2-4.4 GHz frequency band used by existing radio altimeters.
 

It has also suggested that national air authorities clearly codify and enforce the maximum power limit for 5G C-band transmission and ensure downward tilting of 5G antennas situated particularly in the vicinity of flight paths. It also called for the establishment of sufficient 5G C-band prohibition and precautionary zones around airports.
 

Restrictions in US
 

Earlier this year, the Federal Aviation Administration (FAA) had in January 2022 released a list of 50 airports that will have buffer zones when telecom companies were scheduled to turn on new 5G service in the C-band.
 

In June, US telecom service providers such as Verizon and AT&T voluntarily agreed to delay some C-Band 5G usage until July 2023 as air carriers work to retrofit airplanes to ensure they will not face interference. This includes radio frequency filters. After initially mandating additional precautions for certain aircraft models, the FAA has progressively given a larger share of the US commercial fleet permission to perform low-visibility landings at many of the airports where 5G C-band will be deployed.
 

The US telecom industry has continued to stress that 5G signals in the C band will not interfere with flight operations in the US given that nations such as France, Spain, Ireland, and Finland have operated 5G in the C-band for several years without consequences.