Airlines must get new altimeters to ensure no 5G interference: Telcos

Telecommunications companies are pressing the General Directorate of Civil Aeronautics (DGCA) to impose a sunset clause in which airlines must mandatorily replace their old altimeters with a newer one so that the radiation of 5G spectrum waves in airports do not interfere with the instruments of an aircraft.

The DGCA had ordered a complete blackout of 5G services at airports across the country and areas within a 2.1-kilometre radius due to security concerns. To address this contentious issue, a meeting between stakeholders and the civil aviation regulator was held on Thursday.

The telcos have informed the DGCA that Boeing and Airbus representatives have shared details of what they are doing globally to resolve the issue. For example, the US has given a deadline to replace all older altimeters by May 31 of this year, and replacement of the altimeters is currently underway.

Brazil and some Central American countries have also given a deadline within which old altimeters must be replaced. Indian telcos are urging the government to set a clear deadline for this so that airline companies can execute the replacement.

Currently, replacements are on a first-come, first-served basis.

Airlines have said they can determine the maximum allowable radiation from a tower with 5G radios that would not interfere with older altimeters. To do this, the telcos have to provide them with the details of their 5G antennas, so that it is possible for them to determine the power. A senior executive from a telecommunications company said: “If the DGCA doesn’t give airlines a clear deadline to change altimeters, why should they do it voluntarily? It means the plane will be on the ground for a while and you will lose money.”

The Ministry of Civil Aviation had asked telecommunications companies last year to create a buffer and security zone to ensure mitigation measures when deploying C-band 5G spectrum in and around an airport.

It has told the telecommunications companies that there should be no base station for the 3.3GHz-3.67GHz frequency range within 2,100 meters from both ends of the runway and 910 meters from the center line of the runway. .

In addition, base stations beyond this zone, within a radius of 540 meters, can operate only at lower powers limited to 58 dBm of the same band, and telcos must ensure the downward tilt of these 5G base stations. as long as 5G signals do not interfere. with radio altimeters.

The move, according to the telcos, would essentially mean they would not be able to provide 5G services in the crucial band in and around airports and in nearby residential and commercial areas. They point out that given the high cost of the spectrum they have paid, the telecommunications department should compensate them if they cannot put it to commercial use at airports and nearby areas.

The DGCA directive comes amid global concerns that the 5G band could interfere with aircraft radio altimeters, especially when many aircraft are older. Radio altimeters measure altitude above the ground to determine the path of the aircraft, along with GPS. They also help them measure skyscrapers, mountains, and other obstacles in poor visibility.

But the telecommunications companies argue that the band used by the altimeters is 4.2 GHz and not 3.3-3.67 GHz, which has been auctioned off for 5G services in the country. So there’s a 500 MHz gap, and therefore no real chance of interference, they said. The telecom companies said they had applied to the DGCA to test for any interference as was done in some European countries, but the request was denied.