Here is why the 5G roll out in the US became a major problem for international airlines

The US should learn from Europe and South Korea, where lower 5G frequencies are used, experts say

US telecom companies AT&T and Verizon began 5G service in the US on Wednesday without major disruptions to flights after the launch of the new wireless technology was scaled back. AFP

Major international airlines were caught off guard by safety concerns triggered by a major C-band fifth-generation (5G) wireless roll out in the US, sending them scrambling to alter flight plans or cancel them altogether.

Potential 5G interference could affect altitude readings on some jets, the US Federal Aviation Administration said on Monday, with airlines saying the Boeing's 777 was among the models affected. And despite an announcement by US wireless carriers AT&T and Verizon that they would suspend the 5G roll out near airports, several airlines still cancelled flights or switched aircraft models.

However, there was ample time to have the issue resolved before the situation worsened at the 11th-hour, analysts said.

"It feels like this is a very last-minute, 11th-hour type of issue, but the reality is that discussions ... have been on-going for the past 12 months without resolution. And now that it is making headlines, it is competing narratives, some of which haven’t been very well told," Jason Leigh, research manager and mobile operator research at the International Data Corporation, told The National.

"Boeing has indicated there is an issue with altimeters in their 777, but hasn’t been able to say why this is only an issue for US airports and not airports in other countries where the same mid-band spectrum has been deployed," Mr Leigh said.

Aircrafts' radio altimeters can operate at the same frequencies as 5G networks. The problem resides in the use of spectrum bands used for radio signals. Radio altimeters on aircraft give precise readings of the height above the ground on approach and help with automated landings, as well as verifying the plane has landed before allowing reverse thrust.

Altimeters operate in the 4.2 GHz to 4.4 GHz range and the concern is that the auctioned frequencies in the US – 3.7 GHz to 3.98 GHz – sit too close to this range.

A number of major airlines announced plans to switch away from Boeing 777 and Boeing 747-8 aircraft, including Emirates, All Nippon Airways, Japan Airlines and Lufthansa.

"Our technical team is committed to working closely with airlines, radio altimeter suppliers, telecommunications companies and the FAA on a data-driven solution for the long-term that ensures all commercial airplane models can operate safely as 5G is deployed in the US," a Boeing spokesperson told The National.

Katell Thielemann, a vice president and analyst at research firm Gartner, said the higher the frequency in the spectrum, the faster the service would be. Wireless providers would want to operate at higher frequencies in order to get full value from 5G.

"Every country deploys 5G in different ways and in the US, the 5G bands operate very close to the radio altimeters. In other countries, 5G is used at lower frequencies, so it is not so close to the frequencies used by altimeters," Ms Thielemann said.

"On the safety front, the concern is that possible interference will prevent use of altimeters and other systems, which could be an issue particularly in low visibility landings," Ms Thielemann said.

"On the co-ordination front, failure to find a solution ahead of time now means that the 5G carriers, the FCC that controls US spectrum, the FAA in charge of aviation safety, the US Department of Transportation, airplane manufacturers such as Boeing, airlines such as Emirates and airport operators all need to come together."

The FAA found that 50 US airports are especially vulnerable to the 5G risk. Boston Logan International Airport, the 16th-busiest in the US, and Rhode Island's T.F. Green International Airport, are not on the list.

It is unclear why those airports were not on the FAA's list, but a factsheet on the agency's website said: “In addition to asking for input from the aviation community, the FAA selected the airports based on their traffic volume, the number of low-visibility days and geographic location factored into the selection.”

On Thursday the UAE Telecommunications and Digital Government Regulatory Authority said the problem "is exclusively related to the US airports ... as new spectrum frequencies have been allocated to 5G that differ from the frequencies designated for use in our region, and there is no disruption or interference in the UAE between 5G networks and air navigation systems".

The European Union Aviation Safety Agency echoed the same and said it is not aware of any in-service incidents caused by 5G interference and "until the 5G initiation in the US, the technical data received from EU manufacturers offers no conclusive evidence for immediate safety concerns at this time".

'Call it what you like'

The situation is "one of the most delinquent, utterly irresponsible issue subjects, call it what you like, I've seen in my aviation career", Tim Clark, president of Dubai's Emirates, told CNN.

"Somebody should have told them at the time – that the risks and the dangers they placed in certain frequency uses around field, airfields and metropolitan fields that should have been done at the time."

Emirates suspended some flights on Wednesday, including to Boston, Chicago, Dallas Fort Worth, Houston, Miami, Newark, Orlando, San Francisco and Seattle. However, on Thursday the carrier said it was resuming service to all nine US destinations by Saturday after telecommunication operators decided to delay the roll out of 5G networks around US airports.

The International Air Transport Association welcomed the decisions by AT&T and Verizon to delay the rollout of C-band 5G near airports, but urged stakeholders to share the needed technical information and work together to reach a successful implementation plan.

"Any mitigation measures to ensure safe flying must be operationally viable. To that end, Iata urges the US FCC to recognise the needs and recommendations of the aviation community in deploying C-band 5G," it said.

This situation in the US isn't the case in other regions in the world – and it all boils down to simple technical details, and not doing what the US did.

In 2019, the EU set standards for mid-range 5G frequencies in a 3.4 GHz to 3.8 GHz range, a lower frequency than the service set to be rolled out in the US. The bandwidth has been auctioned on the continent and is in use in many of the bloc's 27 member states without any issues so far.

"At this stage, no risk of unsafe interference has been identified in Europe," the European Union Aviation Safety Agency said on December 17.

France, for instance, uses the 3.6 GHz to 3.8 GHz spectrum, a good distance from 4.2 GHz to 4.4 GHz used for altimeters in the US. The European country's power level for 5G is also much lower than what is authorised in America.

Antennaes around 17 major French airports have also been required to be tilted away from flight paths to minimise the risk of interference, the agency's director of spectrum planning, Eric Fournier, told CNN.

Verizon and AT&T have argued that C-band 5G has been deployed in about 40 other countries without aviation interference issues, and they have agreed to use buffer zones around airports in the US, similar to those used in France, for six months to reduce interference risks.

In South Korea, the 5G frequency is at the 3.42-3.7 GHz band, and there has been no reported interference since the commercialisation of the 5G standard was introduced in April 2019.

"[US] mobile operators have not done a good job of articulating the harm that they would incur by not deploying C-band 5G around airport footprints, or the economic harm of operating C-band 5G antennaes at reduced power levels, which is purported to be the solution in some other countries," the International Data Corporation’s Mr Leigh said.

Linus Bauer, head of Bauer Aviation Advisory, said: “Although we can't ignore such potential threats to the safety of aviation ... poor coordination and cooperation among the government, federal agencies, scientists and the industry have led to that chaos we've been witnessing to date.”

Sweden's Ericsson, one of the world's biggest makers of telecommunication equipment and which is helping Canadian telecom firms build their 5G network, said it was working with customers and the FCC to understand the FAA’s concerns around C-band deployments.

"It is essential that all the proper information be provided by the aviation community so that fact-based decisions can be determined. None of the nearly 40 countries that have deployed 5G base stations in the C-band have reported harmful interference with aviation equipment," a spokesperson told The National.

California-based network gear maker Cisco declined to comment for this story.

The current challenge between the airlines and telecom providers can be resolved by upgrading the altimeters to avoid any potential interference, Algirde Pipikaite, the World Economic Forum's cyber security strategy lead, said.

"A two-way communication between the industry leaders and a clear plan towards it will provide solutions. This escalation once again proves that a multi-stakeholder approach involving public and private sector leaders is essential when introducing new technology and addressing a diverse set of safety and security concerns," she said.

The business impact on aviation is probably no different than any other system-wide flight delays or cancellation events, such as those caused by weather or computer glitches. The only difference is that it can be longer, Mr Leigh said.

"For businesses that are looking to leverage 5G – and many don’t care or aren’t knowledgeable about the nuances between the low/mid/high band spectrums that underpin 5G – as long as they aren’t immediately adjacent to an airport, they can continue their exploration, development and integration of 5G in their business operations," he said.

The situation is a reminder of the exponential promise and complexity of emerging technologies, Ms Thielemann said.

"5G promises to unleash higher speed for communications as well as an increasing number of cyber-physical systems connecting to each other in all aspects of our daily lives. But it also comes with security and safety considerations that impact multiple stakeholders in multiple industries," she said.