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

Telecom companies are pushing the Directorate General of Civil Aviation (DGCA) to impose a sunset clause in which airlines must replace outdated altimeters with the newest one so that airwave radiation from the 5G spectrum at airports does not interfere with aircraft instruments.

The Directorate General of Civil Aviation had imposed a complete blackout of 5G services at airports across the country and areas within a radius of 2.1 kilometers due to safety concerns. To deal with this contentious issue, a meeting was held between stakeholders and the Civil Aviation Regulatory Authority on Thursday.

The telecom companies told the Directorate General of Civil Aviation that representatives of Boeing and Airbus have shared details of what they are doing globally to resolve the issue. For example, the United States has given a deadline to replace all old altimeters by May 31 of this year, and altimeters are currently being replaced.

Brazil and some Central American countries have also given a timeline for when outdated altimeters must be replaced. Indian telecom companies are urging the government to set a clear deadline for this, so that the aircraft companies can implement the replacement.

At present, substitutions are made on a first-come, first-served basis.

Aircraft companies said they can determine the maximum radiation allowable from a tower equipped with 5G radios that will not interfere with older altimeters. For this purpose, telecom companies have to provide them with the details of their 5G antennas, so that they can determine the power. A senior executive at a telecom company said, “If airlines are not given a clear deadline for changing altimeters by the Directorate General of Civil Aviation, why would they do it voluntarily? This means the plane will be idle for a while and lose money.”

The Ministry of Civil Aviation had asked telecom companies last year to create a buffer and safety zone to ensure mitigation measures during the implementation of C-band 5G spectrum in and around the airport.

Telecom companies have been told that there should be no base station for the 3.3GHz-3.67GHz frequency band at 2100 meters from both ends of the runway and 910 meters from the center line of the runway.

Also, base stations outside this area, within a radius of 540 meters, can only operate at lower power limited to 58 dBm of the same band, and telecom companies must ensure that these 5G base stations are tilted to the extent that their signals do not overlap. The fifth generation with radio altimeters.

The move, according to the carriers, essentially means that they will not be able to provide 5G services on the critical band in and around airports and in nearby residential and commercial areas. They pointed out that due to the high cost of spectrum they paid, the Telecom Department should compensate them if they are not able to use it for commercial use in airports and nearby areas.

The directive from the DGCA comes amid global concerns that 5G band could interfere with aircraft radio altimeters, especially when many aircraft are old. Radio altimeters measure altitude over terrain to determine the aircraft’s course, along with a Global Positioning System (GPS). It also helps them measure heights, mountains and other obstacles in low visibility.

But telecom companies argue that the band used by altimeters is 4.2GHz, not 3.3-3.67GHz, which has been auctioned off for 5G services in the country. So there’s a 500MHz gap, so there’s really no chance of any interference, they said. The telecommunications companies said that they had asked the Directorate General of Civil Aviation to test whether there was any interference, as happened in some European countries, but the request was rejected.