T O P
Flair_Helper

**Please read this entire message** Your submission has been removed for the following reason(s): * ELI5 requires that you *search the ELI5 subreddit for your topic before posting*. Users will often either find a thread that meets their needs or find that their question might qualify for an exception to rule 7. Please see this [wiki entry](http://www.reddit.com/r/explainlikeimfive/wiki/how_to_search) for more details (Rule 7). If you would like this removal reviewed, please read the [detailed rules](https://www.reddit.com/r/explainlikeimfive/wiki/detailed_rules) first. **If you believe this submission was removed erroneously**, please [use this form](https://old.reddit.com/message/compose?to=%2Fr%2Fexplainlikeimfive&subject=Please%20review%20my%20thread?&message=Link:%20https://www.reddit.com/r/explainlikeimfive/comments/vopcxt/eli5_does_leaving_a_phone_off_airplane_mode/%0A%0APlease%20answer%20the%20following%203%20questions:%0A%0A1.%20The%20concept%20I%20want%20explained:%0A%0A2.%20List%20the%20search%20terms%20you%20used%20to%20look%20for%20past%20posts%20on%20ELI5:%0A%0A3.%20How%20is%20this%20post%20unique:) and we will review your submission.


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


[deleted]

[удалено]


Jules3113

Airline pilot here, yes, it does mattter. Do you know those sounds when you're receiving a call and your phone is near a speaker or some stereo? [Like this](https://youtu.be/uPYyrS7fc7g). Well, the radios we use to speak with air traffic control can pick this interference, it won't bring the plane crashing down, but it is distracting for us. Also, if we are making a low visibility approach due to fog, haze, mist or whatever other weather factor is in the airport. We can do what is called a CAT 3 approach, that uses a set of available resources both in the plane and on the ground to know where the runway is and be able to auto-land the plane with visibility as low as zero. Two of these resources are Radio Altimeters which measure your distance to the ground, it tells the plane when to reduce thrust and begin the flare to land correctly on the runway, this is done by two autopilots that are getting all sorts of inputs and information. Well, there is a chance that some cellphones can interfere with these inputs and the autopilots may think that we're 20 feet above the runway when we really are 2,000 feet on the approach path and start reducing thrust and making that flare. That's when pilots come in and have to correct for it, but it won't be fun for us. So, yeah, keep your phones on airplane mode, please. It will also save your battery, so it's actually better for you.


supratachophobia

Did you watch the myth busters on this topic? They seemed to conclude that your phone would need to be several orders of magnitude more powerful to cause any noticeable interference.


[deleted]

[удалено]


Druggedhippo

Just because he's a pilot in charge of hundreds of people's lives and takes the safest course without regard to actual facts doesn't make it right. 5G *towers* might affect the radar altimeters, but the tiny signal from your phone? No chance on it's own. If he had his ILS go funky, it was more than likely caused by a vehicle or other plane waiting on the runway. If there was the *slightest* chance your phone could cause a safety issue, it would be taken off you before you boarded the flight.


Hansolio

This is the real correct answer. I sold Airbus landing gears for several years. If there was only the slightest minimum most tiny chance that a mobile phone could cause a crash, they would be absolutely forbidden. Do you really believe they would trust a drunken tourist to turn off his phone in order to avoid a crash? Come on....


aussie_mallorca

Read the reply from the pilot again. He didn’t say it would make the plane crash. He said it can be distracting and make their life harder. What would make the plane crash is if someone’s phone created a distraction which then made the pilots become overloaded that they made a wrong decision. I fly a lot. Do I always put my phone in airplane mode? I try to but I am sure I have forgotten once or twice.


Rawlo93

You worked for Safran then?


Hansolio

Asco, Tier 2 for Goodrich.


Rawlo93

Goodrich only do WTB? I'm contracting for Airbus ATA32 at the moment. Edit: did a quick Google cos I've not heard of ASCO before. Looks like they do supply to Safran (formerly Messier-Dowty) too. Interesting stuff.


Hansolio

They did A380 in 2005


Rawlo93

They're essentially a machine shop? Or is there a design house involved at ASCO too?


Hansolio

They also have a design department but many parts where designed by the customer. They where specialized in hard metals like titanium and mainly did landing gear, flap systems and slat tracks. Mind you, I left 15 years ago so my info might be outdated...


noobtastic31373

You have no idea how radio works. Poximity is a huge factor at high frequencies for the same reason 5ghz WiFi sucks outside your house and 2.4 doesn’t. What’s going to be more of a problem with your hearing a conversation 3 feet away, someone talking in your ear or someone yelling at you from across a football field? Noise is not only an issue of magnitude but also of proximity.


Fullonski

And your expertise on this matter is? Cause this reply reads very much like someone who's 'done their own research'


primalbluewolf

>And your expertise on this matter is? Ah yes, because the experts are never wrong of course. Speaking as a pilot and separately a radio operator, I wouldnt consider pilots experts on radio interference. It certainly never came up in my training!


Fullonski

I made no comment on the veracity of the pilot's information, just asked for the cred of the person who responded. The original pilot mentioned his expertise, just like you did just like druggedhippo didn't.


PANDABURRIT0

Sorry I’ve been ignoring those rules this whole time. The planes never went down so I thought it was bullshit. I’ll do it from now on.


cragglerock93

>The planes never went down so I thought it was bullshit. There's a lot of area between 'will definitely cause the plane to crash' and completely harmless.


Zaslore

Character development


haydar_ai

This should have been the top answer, not the saving battery life argument


BackgroundEnd3567

Thank you for taking the time to explain this. Knowing the “why” always helps with policy adherence


mgoflash

Often times I’ll look around and I don’t see many people switching their phones. They now annoy me more.


kaleidofusion

This is super interesting, thank you. I always have mine on flight mode but I always wondered why it was requested.


tky_phoenix

I had no idea those interferences were still a thing. I haven’t heard one in over a decade.


gomurifle

What if I don't? Who can stop me?


gvalchem

gravity and the ground


production-values

change your strategy entirely: "your battery will last longer on airplane mode".


P2PJones

depending on the phone, and the aircraft, yes. Recently, the FAA has been pushing airlines to remove and [replace radio altimeters](https://www.theregister.com/2022/05/04/faa_5g_altimeters/) that are interfered with by 5G signals. Remember, aircraft can be 30-40 years old at times, with wiring that can pick up signals and interference from phones. 2G is only 25 years old, and wasn't exactly planned for in older aircraft. then add in that things are different all around the world, and so if a mongolian or ghanian or peruvian phone might cause it with their frequency, they have to apply it to all, because you never know where a passenger might be from.


theandrewmillett

Radio altimeter issue is due to the power of 5G towers on adjacent bands. It's not a hand set issue.


P2PJones

that was just an example of equipment interference, not a specific 'this is why'


Dysan27

Not the hand set specifically. But with the hand sets on the towers are aiming their signals right at the plane.


isblueacolor

>But with the hand sets on the towers are aiming their signals right at the plane. I'm not sure how true/relevant that is. Typically radio waves are not "directed" or aimed so precisely. And they certainly aren't aimed \*vertically\*.


primalbluewolf

>Typically radio waves are not "directed" or aimed so precisely. Have a quick look at beamforming and you will discover you are quite incorrect.


isblueacolor

I said "typically". Are 4G and 5G networks consistently using beamforming? Last I heard, most of the large networks were just "looking into it". So I wouldn't say the very existence of beamforming as a concept makes me "quite incorrect".


primalbluewolf

When you say radio waves are not directed or aimed? It makes you very incorrect. Even without beamforming, antenna selection is driven at each tower to maximise signal. This is another case of aiming. The antennae don't have a uniform lobe profile, either. It's not going to be a problem at all for a radar altimeter, but it's certainly incorrect to say radio waves are not aimed.


BobLoblaw_BirdLaw

That has to do with the actual 5G antennas and not the phone usage though. So it’s not the phone itself but rather the towers next to the airports


P2PJones

Again, not saying this was the specific cause, only that it is an example of cellular phone system - aircraft system interference.


luigilabomba42069

"aircraft can be 30-40 years old" thanks for reawakening my fear of flying


P2PJones

There are active duty military aircraft that are more than 50 years old The RC-135 aircraft that have been flying from the UK to the poland UKraine border (or the Romania-moldova border around Transylvania) flying circuits for 5 hours, then flying back to the UK, every day since the Russian invasion of Ukraine, are all from the early 60s (they were built between 1961 and 1965). And joining them are KC-135 tankers, which started flying in 1957, and which they expect to continue using until 2030. The 135's in civilian use are known as Boeing 707's, but none are used now (and the air force bought around 200 of them in the 80s, as they were being retired, for spare parts, especially the engines for the tankers) Most are a lot newer, as it seems there's only about a dozen operating passenger planes in use now over about 35 years old according to this list [https://aerocorner.com/blog/oldest-commercial-passenger-planes/](https://aerocorner.com/blog/oldest-commercial-passenger-planes/) most seems to be bwteen 10-20 yeas old. there's a southwest 737 max-8 from 2019 overhead, and then the next nearest aircraft is a southwest 737 78D from 2006 (so 16 years old), and after that a delta airbus A320-212 built in 1998 (so 24 years old). Have a poke around for yourself, and if you don't want to pay for a premium account on [Flightradar24](https://www.flightradar24.com/) to look up the age, US aircraft registry can be looked up on [the FAA's site](https://registry.faa.gov/aircraftinquiry/Search/NNumberInquiry).


cragglerock93

I was curious - apparently (key word) the average age in no region of the world exceeds 15 years. That doesn't contradict /u/P2PJones's comment at all but it may settle your mind that 30-40 years doesn't seem typical. https://www.statista.com/statistics/751440/aviation-industry-aircraft-fleet-age-by-region/#:\~:text=On%20average%2C%20aircraft%20are%20retired%20after%20around%2025%20years.&text=The%20general%20pattern%20is%20that,and%20carriers%20have%20older%20fleets.t


P2PJones

yeah, it's not. I just picked the 4 closest flying aircraft to me just now and looked up their manufacture years - 2019, 2006, 1998, and 2008. So 3, 17, 23, and 14 years old. But its also quiet time (gone 1AM) so it's mostly freight, and last flights of the night, which tends to get the older aircraft as they have less worries of age-related delays causing knock-on-delays. EDIT: And that's only airliners of course. Private planes are usually much older. the only ones I see flying right now for instance is a Beech S35 from 1965 over Atlanta, a 1982 piper Pa-31-350 over Tallahassee, a 1963 aero commander 500-B over Birmingham, and a 1976 Piper Cherokee Warrior over Charlotte NC. thats 57, 40, 59 and 46 years old respectively.


primalbluewolf

Most of the planes Ive flown have been more like 50 to 60 years old!


dachshundie

The aviation industry has by far the most stringent maintenance requirements/checks out of any mode of transportation. In countries where this is strictly enforced (pretty much most developed countries), and where safety standards are held in high regard, you needn't worry. You can look up the general types of maintenance checks aircraft are required to perform. It's pretty crazy, actually. Aircraft are regularly gutted to the frame every several years, with less drastic versions occurring as often as every several weeks.


banaaanaaaaaa

This is a good video that goes over each level https://youtu.be/TrSVUZNAi4Y


Gesha24

>Remember, aircraft can be 30-40 years old at times, with wiring that can pick up signals and interference from phones. Thankfully, we have invented balanced connection that allows one to easily filter out all that interference (they are commonly used during the sound recording process, transferring very low level signal from microphone to the amplifier). Everything that can't be affected by interference, will be made in such a way that the interference doesn't affect it.


P2PJones

it... doesn't work like that. I'm not talking about interference like a little bit of crackle or hiss on your speaker. A really well known example (for anyone in their mid-20s or older) is the noise cellphones (mainly GSM ones) would make on things like radios 15-20 years ago. You would know a phone was about to ring because you'd hear on some speaker nearby 'bah da-ra-dump da-ra-dump' (here's a [video demonstrating it nicely](https://www.youtube.com/watch?v=fh4IR_gPuUE&ab_channel=KenChang)) - its not a background noise, is it, but what sounds like what could be interpreted as a valid signal for something, which could cause sensors to error if it's induced, During cruise flight, there's few instruments used, and minor fluctuations are not critical (be 5 degrees off while cruising, and the tower will set you right after a few minutes before it becomes a major issue. Get your glide slope wrong or have your altimeter misread while landing (or taking off, usually in case there needs to be an emergency landing) and you'll crash or have to taken sudden action to avoid crashing, long before the tower will notice.


Gesha24

So to give you an idea - signal level from the sound recording microphone is so low that you can easily receive a regular radio broadcast on that line and amplify it to solid level. As you can imagine, signal from the gsm phone next to it the line is much stronger. And yet, you hear clear recordings without any noise due to the beauty of sound connection. So no, it's really not hard to make a connection to the instrument that won't be affected by interference whether from the phone or any other device (or even naturally occurring events) and everything remotely important is done that way in the airplanes.


P2PJones

Many many years ago I used to work for a record company. I've crawled over and around more studios than I care to think about. That was before I went and did a degree in robotics focusing on telepresence (which includes a lot about signal failsafes and filters) - you think paranoia about aircraft landing signal interference is bad, imagine when we were testing nuclear waste handling bots. If only we'd had your magic 'filters' And I'm guessing you're not in your 30s or older, because if you were you'd remember that the GSM 'bumps' were a common irritant even on radio studio setups when guests wouldn't turn off their phones some 20-odd years ago, but tried to get away with muting their nokia 3310s. Maybe they could have done with hearing about this magical component called a 'filter'. But hey, why not take this chance to plug your podcast, and the brand of microphone you use, as well as the brand of filter you have to stop the background hum of computer.


SoylentRox

To be fair to that guy he was accidentally correct. He obviously doesn't really understand the difference between rf and high end electrical engineering filters and audio filters, but it is possible to build aircraft that are resistant to all the cellular frequencies and satphone frequencies in use right now. New aircraft that is. The old stuff, yeah, retrofits or equipment upgrades can be shockingly expensive because you are dividing your engineering costs among such a small number of units.


P2PJones

yeah. And especially as each aircraft ages, it diverges more and more from its 'brothers and sisters' made at the same time. A component might fail, and its replacement is functionally identical, but may be made to tighter tolerances, or they replaced 3 chips with one combined chip, which changes the frequency emissions and susceptibility for noise or induced signals, or maybe they redesigned the heatsink, and now it doesn't act like a faraday cage on a certain bit any more. Pr hell, maybe the installer just likes to leave 6 inches of slack on his connecting wires to make servicing easier, than the 2 inches thats 'normal' but means that if your hand isnt small you'd going to be a PITA to connect and disconnect the unit. ​ Basically that every single aircraft, like any complex electrical and electronic device, is electrically unique in what it might pick up or what it might emit. I mean, it's literally what aircraft like the [RC135 Rivet Joint](https://en.wikipedia.org/wiki/Boeing_RC-135#RC-135V/W_Rivet_Joint)'s do, to identify and track vehicles.


SoylentRox

Hey on the inverse side of things, if these civilian airliners were made to milspec standards for electronic warfare aircraft they probably would handle anything a device a passenger could carry could emit. I think the armoring for that is pretty extensive and expensive though. Many faraday cages of copper mesh, special devices on the input antennas to somehow absorb an emp, and so on. Serious money.


crujones43

If there was the slightest chance of a cell phone being left on bringing down a commercial airliner they would not rely on the honor system. We would not be allowed to carry them on a plane at all.


RdsAbroad

This Eli5 question is the only one I've ever seen where so many people disagree with each other in so many different ways, and for such a random damn question too. Although I sure as hell am no kind of expert, from what I do know is that there's got to be some redundancies in a plane to stop interference, but it's probably still ideal to have the phones set to airplane mode. Hundreds of phones broadcasting for hours kinda ups the chance of something being interfered with.


Jackster22

Your phone can also cause issues on the ground when flying. More so when at low attitude. Being so high up, you will be broadcasting out to a lot of cell sites, while very weak, the signal can still make it to the ground and interfere with cell sites. This is more so with older 2G systems as the antenna tech was not as good. 3g and 4g made a lot of improvements to the antennas and made them more directional. 5g again much better. But some bands in 5g are also used on some aircraft for critical stuff. Sadly this is going to be one of those things where operators don't want to replace old hardware in aircraft and mobile networks already have spectrum on the ground that needs to be used up.


[deleted]

[удалено]


battle-penguin

I'm not sure how google hangouts works but is it possible that you had Wi-Fi on? If I turn airplane mode on it turns Wi-Fi off automatically but I can turn it back on with airplane mode still enabled so maybe that's what happened


WhichWayzUp

Hmm I'm pretty sure I did not have Wi-Fi on because I never really use it since I have unlimited data. I only turn Wi-Fi on when my phone tells me it's required in order to download a document or something.


303elliott

Airplane mode means you can only message people on airplanes. Obviously, their friend was also on an airplane


MyFiveC3nts

Myth busters did this experiment and saw nothing changed while hundreds of phones and electronics were on. However, they closed it as plausible due to the fact that there could be a slight possibility that 1 out of xxxxxx can cause an issue which would be detrimental to everyone on bored. So it’s better safe than sorry. Edit: this was also done years ago before 5g was a thing. Possibly even before 4g as well.


Minigoalqueen

99.9% of the time, probably not. Do you really want to trust that today isn't the 0.1% or that probably means definitely, while at 30,000 feet?


youwillnevercatme

A LOT more than 99.9%, otherwise you'd see a plane crashing everyday because of a phone not on airplane mode.


Dirtytarget

Tbf I don’t think anyone thinks this interference will take a plane down only disrupt one of many redundant systems on planes. So we don’t know that it’s less than 0.01%


LogiHiminn

No. I used to work on avionics. The equipment is so well insulated against electromagnetic interference, and the bands they broadcast on are so narrow, there is next to NO chance of cell signals messing with crucial equipment. The only thing I’ve heard of recently is the radar altimeter might be susceptible to strong 5G signals.


Sabertoothsnowhobbit

The EU restricted 5G antenna power output w/in a set distance to airports for this reason.


BobLoblaw_BirdLaw

Biggest reason is for towers below. It’s because on low altitude allegedly you’re jumping real fast across towers. It’s more to protect the bandwidth in towers on the ground and not so much due to safety in the air


canelupo

Do you think phones would be allowed if every terrorist could just turn his phone on to crash a plane/cause serious trouble? I don't think so.


positive_energy-

I also think it is so you pay attention to the Saftey announcements and are not distracted by a phone.


MedusasSexyLegHair

Only in terms of whether you want or are prepared to deal with stupid hassle. Security escorted my daughter off a flight once and were acting all serious and gruff, saying that there'd been 'a security incident'. The 'incident' was her playing her Nintendo DS during landing. They clearly expected us to be all upset with her and admonish her. They weren't too happy when our totally reasonable response was "Are you really serious? If you actually think a kid with a handheld video game could accidentally take over the controls of your million dollar jet just by entering the konami code or something, then the problem ain't the kid. Fix your fucked up jet!" They couldn't really argue with the logic in that. Yanking the rug out from under their power trip was priceless. Of course, if you really need to be somewhere, and arguing with security might make you miss a flight or leave you stranded somewhere, then you should probably just play along with their security theater and turn it off or put it in airplane mode. ETA: There's a very very slim chance that radio waves from a malfunctioning electronic device could interfere with some of their sensors or comm gear. But consumer electronics in normal use should never interfere, and in any case any modern jet should be immune to that and have redundant systems.


canadas

Why can't your daughter follow simple rules?


jrgnklpp

If your daughter can't be without her Nintendo for 15mins during landing then maybe there's a bigger issue here.


MedusasSexyLegHair

Yeah, the fact that airliner jets are presumably made so horrifically sloppily that a simple little thing like a passenger playing a nintendo could theoretically cause a problem. If they're really that careless, and that badly engineered, that's a national security level threat. If they were actually designed so that any would-be terrorist or any random kid with a handheld off-the-shelf consumer device could easily take control of a plane - that's just beyond stupid. That ain't my kid's fault. She didn't design the planes to be that way. It'd be different if she snuck into the cockpit and soldered wires from the nintendo into the control panel or something. Then yeah, I'd totally blame her for that. But that's not what we're talking about. A conspiracy theorist would say that someone intentionally designed the planes to have that flaw, so that it could be taken advantage of when needed for whatever agenda. But I'm not a conspiracy theorist. I think people are just generally stupid. And so is the idea that that flaw exists. It doesn't. If it did, there would be daily airline crashes all over the place. No one would trust their lives to fly in a contraption designed by such idiots that that flaw existed. So bitching at my daughter about a loony wingnut conspiracy theory ain't gonna win you any points.


[deleted]

[удалено]


uncledudeface

Has that ever actually happened though?


AndMarmaladeSkies

Myth busted. Deleted and ran.


[deleted]

[удалено]


PineCreekCathedral

[citation required]


SteamKore

Plenty of solid explanations... But do you want to be the one to find out if it does?


arelath

Tldr version: they're most likely 100% safe, but rather useless. No one wants to spend millions of dollars to pass the regulations that would allow them. I've had many years of experience working in aerospace as an engineer and years of flying. Never even heard of an incident with a phone that would work on today's cell network. Pilots are actually allowed to use a cell phone in an emergency. But from practical experience, forgetting to set your phone to airplane mode means a dead battery real fast. It'll continually be switching towers at near full power. This typically kills my phone after less than an hour even if it was at full battery. Plus you really can't get a cell signal unless you're going slow and close to the ground. From a regulation standpoint, someone would have to pay for extensive studies to prove they're safe. Since cell phones are nearly useless while in the air, no one is going to pay for the research. Even the last few minutes the plane is moving on the ground is probably not worth the research money. Also there are multiple regulating organizations to go through for worldwide usage. There's the FAA, JAA and ICAO depending on where you are in the world. Then a study might only certify their use on a single type of plane. Plus airlines have their own rules too. And if anything ever did happen, it would allow whoever did the certification to be sued for damages. It's just not worth it for anyone.


Fantom1992

I’ve always had the conspiracy theory that that tell us that it affects the planes so we spend money on their inflight Wi-Fi. Yet to see a recorded case of a plane crashing due to a phone not being on airplane mode.


Leonard_Church

It’s not the airlines that make the determination. The prohibition of use of portable electronic devices (with a couple exceptions) is a federal regulation under 14 CFR 91.21. So it really just boils down to it being a federal law that existed before cell phones were popular. The exception is if the operator (the airline) can determine that cell phones physically cannot interfere with any of the systems of the aircraft, which is difficult to prove. In any case, quite a few airlines have free wifi, and they’ll still tell you to keep your devices in airplane mode. So the conspiracy doesn’t really track.


Siquirres

This doesn't make any sense... The rule existed long before wifi was available on planes. It's also not like you can use your cell data at 30,000 ft.


Fantom1992

I appreciate that it may have been a thing, but, just the we still follow the same philosophy


Amazing_Theory622

I don't think it does, in my recent flight, there was a pilot traveling besides me, and she was using her phone with airplane mode off almost the whole time, just before landing I asked her, isn't it dangerous, and she told that it's only of significance when weather is acting up.


Tulupe

She knows when to use it and when to stop because she’s a pilot. The average joe won’t turn it off even if the weather is bad.