How 5G Wireless Service Puts Airplanes at Risk – An Electrical Engineer Explains

[sun rise]

This article explains the technical reasons why there's a dispute about 5G versus airlines in clear language

How 5G Wireless Service Puts Airplanes at Risk – An Electrical Engineer Explains

...if an altimeter interprets a signal from a wireless carrier as the rebounded signal from the ground, it may think that the ground is closer than it is and prematurely try to lower the landing gear and do the other maneuvers that are needed to land an aircraft. If interference with wireless carrier signals corrupts and garbles the altimeter’s radio signals, the altimeter may not recognize the rebounded signal and thus be unable to figure out how close to the ground the plane is.

The portions of the radio frequency spectrum used by airplanes and cellphone carriers are different. The problem is that airplane altimeters use the 4.2 to 4.4 gigahertz range, while the recently sold – and previously unused – C-band spectrum for wireless carriers ranges from 3.7 to 3.98 gigahertz. It turns out the 0.22 gigahertz difference between the signals may not be quite enough to be absolutely sure that a cellphone carrier signal will not be mistaken for or corrupt an altimeter’s signal.

The telecommunication industry has argued that the gap of 0.22 gigahertz is enough and there will be no interference. The airline industry has been more cautious. Even if the risk is very small, I believe the consequences of a plane crash are enormous.

 

[Twilight Hue]

All it takes is one plane crash. There, continue on with it as if it's a fluke once the newsworthyness dies out.

The bigger company gets the prize.

 

[ChristineM]

Perhaps part of the reason why phones should not be used on planes.

 

[exchemist]

This article explains the technical reasons why there's a dispute about 5G versus airlines in clear language

How 5G Wireless Service Puts Airplanes at Risk – An Electrical Engineer Explains

...if an altimeter interprets a signal from a wireless carrier as the rebounded signal from the ground, it may think that the ground is closer than it is and prematurely try to lower the landing gear and do the other maneuvers that are needed to land an aircraft. If interference with wireless carrier signals corrupts and garbles the altimeter’s radio signals, the altimeter may not recognize the rebounded signal and thus be unable to figure out how close to the ground the plane is.

The portions of the radio frequency spectrum used by airplanes and cellphone carriers are different. The problem is that airplane altimeters use the 4.2 to 4.4 gigahertz range, while the recently sold – and previously unused – C-band spectrum for wireless carriers ranges from 3.7 to 3.98 gigahertz. It turns out the 0.22 gigahertz difference between the signals may not be quite enough to be absolutely sure that a cellphone carrier signal will not be mistaken for or corrupt an altimeter’s signal.

The telecommunication industry has argued that the gap of 0.22 gigahertz is enough and there will be no interference. The airline industry has been more cautious. Even if the risk is very small, I believe the consequences of a plane crash are enormous.

However, Europe has managed it without any trouble.

Here is an article on the subject: How Europe rolled out 5G without hurting aviation - CNN

I'm far from expert on this stuff but key differences seem to be:

- In the EU, the top end of the 5G spectrum is 3.8GHz, whereas in the US the telecoms companies have been allowed to buy the right to go up to 3.98GHz, halving the safety margin (Aircraft altimeter systems use a range of 4.2-4.4 GHz.)

- In the EU the power of the transmitters is lower than allowed in the US.

- In the EU the aviation authorities have insisted that transmitters near airfields direct the beam so that it does not point at the flight paths.

European managed airlines like British Airways, Lufthansa and Emirates are cancelling flights to the US because they can't be sure they are safe, whereas they happily fly into EU airports in countries where 5G is already being rolled out.

So this looks as if the US aviation regulators were either not on the ball or have been unable to get their voice heard.

 

[Shadow Wolf]

All it takes is one plane crash. There, continue on with it as if it's a fluke once the newsworthyness dies out.

The bigger company gets the prize.

Is that why the Concorde was grounded? That literally only took one wreck and now they aren't used anymore.

 

[9-10ths_Penguin]

This article explains the technical reasons why there's a dispute about 5G versus airlines in clear language

How 5G Wireless Service Puts Airplanes at Risk – An Electrical Engineer Explains

...if an altimeter interprets a signal from a wireless carrier as the rebounded signal from the ground, it may think that the ground is closer than it is and prematurely try to lower the landing gear and do the other maneuvers that are needed to land an aircraft. If interference with wireless carrier signals corrupts and garbles the altimeter’s radio signals, the altimeter may not recognize the rebounded signal and thus be unable to figure out how close to the ground the plane is.

The portions of the radio frequency spectrum used by airplanes and cellphone carriers are different. The problem is that airplane altimeters use the 4.2 to 4.4 gigahertz range, while the recently sold – and previously unused – C-band spectrum for wireless carriers ranges from 3.7 to 3.98 gigahertz. It turns out the 0.22 gigahertz difference between the signals may not be quite enough to be absolutely sure that a cellphone carrier signal will not be mistaken for or corrupt an altimeter’s signal.

The telecommunication industry has argued that the gap of 0.22 gigahertz is enough and there will be no interference. The airline industry has been more cautious. Even if the risk is very small, I believe the consequences of a plane crash are enormous.

Last weekend's Skeptics Guide to the Universe touched on this. Sounds like a decent workaround would be to prohibit 5G towers (or maybe just prohibit ones that operate in that problematic frequency range?) within a certain radius around airports with ILS approaches.

 

[Brickjectivity]

The telecommunication industry has argued that the gap of 0.22 gigahertz is enough and there will be no interference. The airline industry has been more cautious. Even if the risk is very small, I believe the consequences of a plane crash are enormous.

The telecommunications industry knows that if there is a crash it is the airlines which will be held accountable not the telecoms.

 

[9-10ths_Penguin]

The telecommunications industry knows that if there is a crash it is the airlines which will be held accountable not the telecoms.

I think the odds are remote that this would result in a crash.

If it does turn out that 5G messes with radar altimeters, this will definitely create headaches for the airlines, but this will be addressed by:

- flight crews being vigilant and ready to switch off their autoland systems and land manually at the first hint of any problems.

- in cases where visibility is so bad that they'd need to use autoland to land (i.e. the pilots can't see for a manual landing), they'll reduce their weather threshold where they'd still operate a scheduled flight. This will mean more delayed and cancelled flights. In rare cases when visibility gets bad quickly and unexpectedly, you'll see diversions to alternate airports more often.

Definitely a headache for the airlines, but I'm not sure it's a safety problem.

 

[sun rise]

The telecommunications industry knows that if there is a crash it is the airlines which will be held accountable not the telecoms.

Given the number of times businesses have ignored "clear and present" dangers for short term profit is very very long. I don't expect rational behavior.

 

[exchemist]

Given the number of times businesses have ignored "clear and present" dangers for short term profit is very very long. I don't expect rational behavior.

Dat wot we have regulator for, innit?

 

[crossfire]

I think the odds are remote that this would result in a crash.

If it does turn out that 5G messes with radar altimeters, this will definitely create headaches for the airlines, but this will be addressed by:

- flight crews being vigilant and ready to switch off their autoland systems and land manually at the first hint of any problems.

- in cases where visibility is so bad that they'd need to use autoland to land (i.e. the pilots can't see for a manual landing), they'll reduce their weather threshold where they'd still operate a scheduled flight. This will mean more delayed and cancelled flights. In rare cases when visibility gets bad quickly and unexpectedly, you'll see diversions to alternate airports more often.

Definitely a headache for the airlines, but I'm not sure it's a safety problem.

We have been having heavy fog here lately, so almost all of the flights out of the small airport, Paine Field, Everett (next to the Everett Boeing plant) were canceled.
Fog and 5G cancel air travel at Paine Field

 

[Revoltingest]

I think the odds are remote that this would result in a crash.

The odds of any crash are remote.
The degree of remoteness is the issue, & that isn't known yet.

- flight crews being vigilant and ready to switch off their autoland systems and land manually at the first hint of any problems.

This increases the danger. Take off & landing are
the most dangerous parts of any flight. Automation
reduces flight crew workload, which can be demanding.

- in cases where visibility is so bad that they'd need to use autoland to land (i.e. the pilots can't see for a manual landing), they'll reduce their weather threshold where they'd still operate a scheduled flight. This will mean more delayed and cancelled flights. In rare cases when visibility gets bad quickly and unexpectedly, you'll see diversions to alternate airports more often.

That would be an unacceptable major reduction of service
that would increase cost & passenger inconvenience.

Definitely a headache for the airlines, but I'm not sure it's a safety problem.

That's yet to be established.