Few days ago I was flying by plane and stewards asked us to turn our devices to Airplane Mode. But why is that?
In: Technology
Radio waves can interfere with plane systems, especially the ILS (the instrument landing system, which sends radio signals from the ground to the plane, to help it land in the right spot). Theoretically other systems can be impacted as well, like the radios, but newer planes are more hardened, and newer phones are less powerful from a signal perspective than older analog models.
There are a few other reasons, which are less official, but I think are also reasons the rules persist, despite improved plane and phone technology. Having your phone off, makes you pay more attention to the safety demonstration, and also any emergency crew announcements during takeoff or landing. Also, if phones are put away during taxi and takeoff, there is less risk of them flying around the cabin and hitting other people in the case of a sudden stop or accident.
Basically, a mobile phone is a radio, so it is constantly transmitting and looking for a base station to connect to. Some of the navigation instruments on airplanes can *potentially* be affected by mobile phone signals, which might feed incorrect or contradictory information into the flight computers, which is generally considers to be A Bad Thing. As I understand it, their relatively little proof of this (there’s no accident I know of where passenger’s electronic devices emissions are cited as a factor), but the FAA ordered a ban anyway in the 90s out of an abundance of caution and no one’s overturned it. Its been relaxed somewhat with stuff like Bluetooth and Wi-Fi being allowed at the operators choice.
also, airplane mode will save device battery, as the phone is not burning power screaming into the void, looking for a tower thats too far away to ever hear it.
edited to add: theirs also a secondary issue with hundreds of phones rapidly connecting and dropping of towers on the take-off and approach routes, which is a quality of life issue for those people that the airports might care about, but not a factor in the actual FFA ban that made “airplane mode” a thing to begin with.
Your phone always looks for signal. The further away your phone is from the source of the signal, the more power it needs and the more power the antenna on the ground needs. Airplane mode preserves the batterie of your phone and improves reception for anyone you fly over
Airplane mode disables most if not all transmitters in your phone. They ask you to do this because while it is unlikely there is the extremely tiny possibility that a stray transmission may affect the plane. They used to ask everyone to turn off all electronic devices but now its more a formality since its been a long time since there were any problems. They generally do this at take offs and landings as these are the most dangerous times should a problem occur.
From an old reply to this question:
20 years ago GPS systems were less accurate and more prone to interference, as were basic communications systems, like the radios a pilot used to speak to the ground. The technology at the time (which was 2G, I think) would cause intense blasts of static, like this: [https://www.youtube.com/shorts/rODbnb1_uaE](https://www.youtube.com/shorts/rODbnb1_uaE) The worst case here is that: information from the ground is misheard, information from the ground isn’t heard at all, or information can’t be transmitted to/from the ground in an emergency.
There were at the time conflicting debates about which systems were affected and to what to degree. Obviously, the industry and relevant authorities wouldn’t have wanted to risk any danger to the passengers or crew, so it was easier to simply prohibit use of phones and/or enforce airplane mode rather than identify which planes had what and use different rules for different flights.
Things have now moved on technologically: the phones use a different technology (3/4/5G) as can/do the radio masts that are used to transmit calls/texts. There are even things called picocells which are miniature masts (simplifying here) about the size of a shoebox and can be used on planes to help direct that traffic and reduce interference. The issue however is the same as before: lots of variance in planes and their respective aviation electronics, in addition to the new problem of technology advancing at a pace faster than we can test for issues – in short, it’s still easier (and cheaper!) to have a catch-all rule.
With all that said, we are now technologically far enough away from the issues of 20 years ago that the risk is small enough to allow all phone use (calls/texts) on flights than can install and use these 5G mini-masts onboard. In June of this year the EU opted (or was in the process of last I checked) to legislate this as standard. To actually answer your question, unless you’re on one of these magical 5G planes, there is still some amount of risk to the systems that run the plane, even if it’s small or unlikely.
Edit: “June of this year” would have been 2023, I think. 🙂
Similar questions have been asked in the past. [Here is one answer](https://www.reddit.com/r/explainlikeimfive/comments/9fyxro/eli5_why_do_electronic_devices_phones_laptops_etc/e60noql/) from six years ago.
Airplanes use a ton of radios for various different things. They obviously use radios to talk to air traffic control, but airplanes also use radios to avoid running in to other airplanes, to communicate via satellite to air traffic control on the ground, to broadcast their location to air traffic control, to land safely, and to tell how high they are above the ground.
Back in the 80s when cellphones were brand new, there was a bit of a concern that the radio signals from cellphones could potentially interfere with all the various radio signals that airplanes used, so it was decided that everyone who boards an airplane should turn off their cellphones. For the longest time, this was all that was needed. Cellphones didn’t do much other than make calls, so it was perfectly acceptable to turn off your phone while flying.
Then, phones got the ability to be more than just phones. You could watch movies, you could play games, you could draw, take pictures, etc. The capabilities expanded rapidly! But there was still a lingering fear that cellphones could mess with airplane radios. So, cellphone manufacturers created a switch on phones that said “Turn off all wireless communication features” so that you could still use your cellphone to watch movies, play games, use apps, etc. while you were on an airplane with nothing else to do. Your phone isn’t using radio signals? Then there’s no way it can interfere with the plane’s own radios. They called it “Airplane Mode” because that was the most common situation in which you’d want to keep using your phone without it being able to use any wireless communication systems! The name just stuck over time, and it’s become the catch-all term in technology to describe the act of turning off all wireless communications on a device!
Nowadays, even though we now know that cellphones don’t *really* interfere with the radios that airplanes use, it’s a bit redundant. Although, since your cellphone will constantly be searching for cellphone towers and you’re not likely to get a signal while in the air, using airplane mode helps to save battery when you’re flying and don’t need a connection.
It used to be a cellphone could actually cause errors in the flight equipment. It doesn’t anymore, but there’s two other reasons, why you‘re still asked to do so:
1. a cell phone that has lost its signal will keep searching for it. Its using a lot more energy and a lot more electromagnetism than when it is actually connected. With a whole lot of cellphones in one plane, that would really add up.
2. So people don’t make calls. Can you imagine 200 people in a metal tube calling home at the same time? It would incredibly loud, everyone trying to be audible.
To add to all that, mobile manufactures need to add a mode that allows disabling cellular transmission which you may need for whatever reason.
Imagine your phone is like a super loud, chatty friend who loves to talk to a lot of people at once. Now, think of the airplane as a very important classroom where the pilot and the airplane’s systems need to concentrate very hard to fly the plane safely.
When your phone is not in Airplane Mode, it sends out signals, like shouting really loud. These signals can sometimes mix up the important messages the pilot needs to hear, like if someone shouted in class when the teacher was giving instructions.
Your phone tries to talk to cell towers on the ground to stay connected, just like trying to wave at lots of friends at the same time. When you’re high up in the sky, your phone tries to reach many towers at once, which can cause a big mess and confuse the cell towers.
So, when you turn on Airplane Mode, it’s like telling your phone to take a quiet nap. It stops shouting and waving, making it easier for the airplane to fly safely and for the pilot to concentrate on getting everyone to their destination. Plus, it helps your phone save its battery, just like resting helps you save energy!
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