5G Rollout on Partial Hold on Aviation Safety Concerns

Wireless service providers AT&T Inc. (T) and Verizon Communications Inc. (VZ) have agreed to delay their plans of rolling out 5G near certain airports as airlines officials and the Federal Aviation Administration (FAA) stated that the new service could affect the safety equipment in some aircraft.

AT&T and Verizon have agreed to postpone turning on some wireless towers near certain airports to avoid disruptions to U.S. flights. President Biden said that this measure will help avoid "potentially devastating disruptions."

According to airport officials, the FAA's safety regulations might require several aircraft to be grounded if the 5G service is rolled out near certain runways. 5G requires radio frequencies that fall within a spectrum called the C-band that is close to the frequencies used in radio altimeters in certain aircraft.

Aircraft altimeters work in frequencies of 4.2-4.4 GHz, which overlap the C-band, whose range is 3.7-4.2 GHz. 5G networks use frequencies in the 3.7-3.98 GHz range that is very close to those used in radio altimeters in airplanes. Since the accuracy of radio altimeters in aircraft ensures their safety, the FAA would require aircraft whose altimeters use the frequencies close to the C-band to stay grounded until new equipment is installed in them.

Select Altimeters and Airports Cleared for 5G

Not every aircraft will need the new fitting. On Jan. 16, 2022, the FAA stated that around 45% of U.S. commercial aircraft could execute low-visibility landings in airports where 5G was planned. The agency also cleared two radio altimeters installed in several planes manufactured by The Boeing Company (BA) and Airbus SE (EADSY) for low-visibility landings in airports with 5G. These models include the Boeing 737, 747, 757, 767, and MD-10/-11, as well as the Airbus A310, A319, A320, A321, A330, and A350.

On Jan. 7, 2022, the FAA also published a list of 50 airports that would need 5G buffers to ensure the safe operations of aircraft in those airports. The list included some of the busiest airports such as Los Angeles International Airport and John F. Kennedy International Airport. Airports in cities where 5G is not being rolled out were left out. The 50 airports were identified using information from aviation leaders, data about airport traffic, average low-visibility days, and geographic location.

Low-visibility landings are permitted in airports that are on the priority list if the aircraft are equipped with altimeters that perform accurately in the 5G C-band environment.

Telecommunications and Aviation Make Competing Bids in National Airspace System

The potential interference in the National Airspace System (NAS) due to simultaneous transmissions in the frequencies used by both mobile telecommunication companies and aviation altimeters has been addressed since 2015, when the World Radio Conference proposed a 3.4-3.7 GHz spectrum for international mobile telecommunications.

Before the auction for 5G started in 2020, the FAA asked for a postponement of the rollout, stating that the "interference can interrupt or significantly degrade radar altimeter functions during critical phases of flight—precluding radar altimeter-based terrain alerts and low-visibility approach and landing operations."

According to the telecommunications industry, the 5G spectrum deployment plans to address concerns that the U.S. has lagged behind China and other countries in this technology. The FAA ruled out any comparison with other countries where 5G has been deployed, citing different conditions in those countries such as lower power levels, different frequencies and proximities to frequencies used by their aircrafts, and a different arrangement of 5G antennas with respect to airfields.

On Dec. 31, 2021, the FAA's letter to AT&T and Verizon requested a two-week postponement of the rollout planned for Jan. 5, 2022, during which the FAA planned to identify priority airports that would require a buffer zone while also approving Alternate Means of Compliance at those airports. The wireless companies have since also committed to restricting the power in their 5G base stations that are in line with airport runways.

Earlier, in a letter on Nov. 24, 2021, Verizon had committed to precautionary measures through July 5, 2022, on top of the spectrum buffer and technical restrictions issued by the Federal Communications Commission. These were found to be inadequate by the Aerospace Industries Association. The new protocol will follow guidelines set by the letter sent by Verizon to the U.S. Department of Transportation on Jan. 2, 2022.

The Impact on the Market

With some airlines cancelling their flights ahead of the 5G launch, the impact of the launch and its delay on the financial markets remains to be seen. The telecommunications companies bid over $80 billion for the C-band spectrum and have invested billions more in developing it. On the other hand, the pandemic-hit aviation industry remains vulnerable, and any hiccup caused on the technology or safety front would only make matters worse.