Explained: Why major airlines suffered disruptions due to US 5G 'nightmare'
Multiple airlines had their services affected on Wednesday, with dozens of flights getting cancelled or rescheduled, as the on-off rollout of 5G mobile in the United States triggered what an airline pilot called a “nightmare” of scheduling for carriers coming to terms with rapidly changing airplane restrictions.
A dispute between airlines and telecom companies in the US has been going on for weeks now over the speed of deployment of 5G mobile services in the country.
US airlines and the Federal Aviation Administration (FAA) have said frequencies and transmission strength being deployed in the country could interfere with the precise height readings needed for bad-weather landings on some jetliners. The tensions have also been mirrored by regulators of other economically sensitive industries.
What caused the latest outage?
A decision by two US wireless carriers – AT&T and Verizon Communications – to delay switching on the powerful new 5G telecom masts near key airports came too late to avoid a ripple of cancellations on Wednesday.
Airlines across Asia and several in the Middle East and Europe said they were cancelling some flights or switching models, with much of the initial disruption hitting the Boeing 777, for decades a workhorse of long-distance air travel.
Dubai's Emirates, the largest user of the Boeing mini-jumbo, kicked off a slew of industry cancellations or aircraft changes late on Tuesday, saying it would suspend nine US routes.
Why are airlines afraid?
The C-Band frequencies used for 5G networks are close to those used by the altimeters of airplanes.
US telecom operators were allocated frequencies between 3.7 and 3.98 gigahertz for their 5G networks -- a right that cost the companies tens of billions of dollars.
But the aviation sector is concerned that the frequencies used by the mobile companies are too close for comfort to those used by aircraft's radio altimeters, which operate between 4.2 and 4.4 GHz.
Altimeters measure the distance between an aircraft and the ground, a vital instrument when landing at night or during bad weather.
"The concern is that the smaller gap between the upper 5G frequency in the US and these frequencies is small enough to potentially cause interference as aircraft are on approach to land," Nigel Linge, a telecommunications professor at the University of Salford in the UK, told AFP.
What have US authorities decided?
Aircraft makers Airbus and Boeing had voiced concerns about the potential risks of interferences to the US transportation secretary in December.
The 5G rollout was then delayed until January 19 following a request from the Federal Aviation Administration (FAA) to ensure the system is safe.
"If there's the possibility of a risk to the flying public, we are obligated to restrict the relevant flight activity until we can prove it is safe," the FAA says on its website.
The FAA approved two models of radio altimeters and gave the green light to 48 of the 88 US airports most directly linked to 5G risks.
Other countries at risk?
The concerns are confined to the United States.
"It's not a global or European issue. It's really an issue specific to the use of 5G and its rollout in the United States in terms of frequency bands and power," Airbus chief Guillaume Faury said earlier this month.
In Europe, 5G networks were given C-Band frequencies ranging between 3.4 and 3.8 GHz, thus providing more distance to those used by aircraft.
"Europe has been transmitting 5G on their frequencies for many months and no reports of problems have been made in respect of airlines," Linge said.
South Korea, a leader in the new-generation mobile technology, gave 5G networks a ceiling of 3.7 GHz.
But the US telecom industry's lobby group, CTIA, has pointed to another example: Japan, where 5G networks have been given a frequency spectrum as high as 4.1 GHz.
"There have been no claims of interference" in Japan, the CTIA has said.
What are the measures to mitigate risks?
In France, buffer zones were created around 17 large airports, restricting the strength of 5G signals and ensuring mobile base station antennas do not broadcast upwards, according to French authorities.
The areas extend several kilometres from landing trips.
The FAA says the mitigation measures in the US are partly similar to those in France, with "significant differences".
The buffer zones for US airports only protect the last 20 seconds of flight, compared to 96 seconds in France, according to the FAA.
The temporary lower power levels in the United States are 2.5 times higher than in France. And in the United States, mobile base station antennas are not required to be tilted downward, the FAA says.
(Information sourced from Reuters and AFP)
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