Air India flights to US may need radio filters to counter 5G interference

5G issues unlikely to affect domestic airlines & their operations in India

As 5G auctions pick up pace in India, airlines in the US are racing against time to retrofit their aircraft with devices that protect against interference from frequencies that may lead to equipment malfunction.

The Federal Aviation Administration (FAA) last month asked all airlines in the US operating Boeing aircraft to install radio frequency filters before the end of this year on an “expedited basis” to prevent any disaster arising out of interference from 5G frequencies. The move is likely to impact Air India, the only Indian airline flying to the US from India. However, 5G interference-related issues are unlikely to affect domestic airlines and their operations since India is not auctioning the “problematic bandwidth” that has been red flagged by the US regulator. 

It takes just a few hours to install these filters on planes. A response from the spokesperson of the Tata group, the owner of Air India, is awaited.

In January this year, Air India had cancelled eight flights to the US citing “deployment of 5G communications”. The cancelled flights included those connecting New York, Newark, San Francisco and Chicago with New Delhi.

The Directorate General of Civil Aviation (DGCA) had earlier stated that it was closely working with US regulators to find a solution to the threat posed by 5G technologies to planes.

5G frequencies pose dangers to the functioning of radio altimeters on aircraft. These instruments are crucial to gauge the distance of the plane from the ground. Radio altimeters on commercial aircraft operate in the 4.2 to 4.4 GHz band. This is perilously close to the 3.7 to 3.93 GHz band rolled out in the US as part of that country’s 5G auctions last year.

Earlier this year, the FAA had noted, “The receiver on the radio altimeter is typically highly accurate, however, it may deliver erroneous results in the presence of out-of-band radio frequency emissions from other frequency bands. Out-of-band signals could significantly degrade radio altimeter functions during critical phases of flight, if the altimeter is unable to sufficiently reject those signals.” The regulator had estimated that the interference could affect over 10,500 aircraft in the US and across the world.

Airlines operating at US airports where 5G interference is a threat would have to retrofit planes with radio frequency filters. Airlines in India are not required to. That’s because the Indian government is auctioning 5G spectrum in the 3.2 to 3.6 GHz bandwidth. This is lower than the 4.2 to 4.4 GHz band used by aircraft radio altimeters.

Nations like China, which rolled out 5G before much of the world, use the 4.8-to-5 GHz band to provide the service. This is higher than the bandwidth used by aircraft and eliminates the threat to their equipment.