6 ms·

"Finally, there's the Federal Aviation Administration rule that all electronics, even headphones and e-book readers, have to be turned off during takeoff and la

"Finally, there's the Federal Aviation Administration rule that all electronics, even headphones and e-book readers, have to be turned off during takeoff and landing, allegedly to prevent interference with the plane's navigation systems. But the scientific evidence for this worry is sketchy. Some devices emit signals that could theoretically affect an aircraft's electronics. Yet “there have never been any reported accidents from these kinds of devices on planes,” FAA spokesperson Les Dorr told the New York Times last year. Once again, irrational fear, not solid science, is dictating policy for millions of travelers." Actually, it is based on science. Cell phones flying by overhead while landing or taking off overload cellular base stations. So as a courtesy to cellular phone carriers, airlines require cell phones to be put into "airplane" mode. Digital Communications 101 son.

drcube 14y ago
What does that have to do with ebook readers, mp3 players or laptops?
- dkl 14y ago
  Some of these have cell radios in them.
brk 14y ago
* Cell phones flying by overhead while landing or taking off overload cellular base stations.* [citation needed] I've heard this, as one of many theories, discussed about the rationale for this rule. A plane typically has about 150 passengers and there is a narrow window of time during takeoff and landing when you can actually get cell coverage. I find it hard to believe that with the popularity of cell phones today that the towers would be overloaded by 150 phones (or, let's extrapolate to 1000 phones accounting for the takeoff/landing windows) moving rapidly across a couple of towers.
- mikeash 14y ago
  I believe this dates from the bad old days of analog phones and relatively dumb networks. I've read accounts (reliable? not sure, but believable) of people getting billed several times for a single call made from the air, because multiple cells picked it up and they didn't coordinate among each other. I don't believe this is a problem today. I fly small planes for fun and sometimes use my phone in the air to check weather. The biggest problem is that it doesn't work above about 5,000ft because the signal gets too weak. I never bother to turn my phone off, and neither do most of my pilot friends. I spent about fifteen minutes flying a plane with an instructor friend once while he chatted on the phone with his wife about when we was going to get home!
  - freehunter 14y ago
    I do know of an AT&T tower in my state that is malfunctioning (by my standards) and refuses to release the connection once my phone had established the connection. When I'm driving down the freeway past the tower, my signal strength will get weaker and weaker and then I run into no service, even in great service areas. I have to pull the battery (my iPhone toting friends/family have to power down the phone) before it will recognize it's moved to another tower. Obviously it's a different circumstance, but it's another point of data where cell towers aren't always 100% functional when the target is moving.
    - mikeash 14y ago
      The supposed issue isn't movement, it's that cell towers assume a limited signal range due to terrain, which is no longer true once you're in an airplane and high enough to have a horizon of dozens of miles. Edit: by the way, have you reported the problem to AT&T? I have no idea how responsive they are, but it seems like it could be worthwhile, especially if it's as easy to reproduce the problem as you make it sound.
- kalleboo 14y ago
  The window isn't that narrow, I think it can still pose a problem. Last time I left my phone on by mistake in my bag, when I picked it up I had "Welcome to X country! Your roaming rates here are..." from 3 different countries, none of which were the starting or landing countries.
  - brk 14y ago
    I fly about 50-70K miles in a given year. I never turn my phone fully off, I usually put it in "Airplane mode" after I'm out of the coverage area (to conserve the battery so it's not trying to hunt to unreachable towers). I usually find that the phone has lost a signal well before we've hit the 10,000 ft. altitude where electronic devices are "allowed". Roughly this seems to happen about 8-12 minutes into the flight. I would consider the first 1,500 feet of altitude to be a zone where appearance of cellphones would be considered "normal", so the window in which you're truly in the supposed problem zone is even smaller. I'm not sure that the evidence your phone connected to some random carriers is any evidence that phones in flight could be problematic for modern towers. RF systems are also very interesting... I'm not an RF engineer, but I know enough about it that the cell towers coverage pattern is not spherical with equal coverage in all directions. The antennas would be designed and placed to direct the signals mostly out and to lower elevations, not up. Again, this would limit the chances that phones zooming overheard are appearing to multiple towers simultaneously, or moving tower to tower faster than the billing and tracking systems could manage.
milesskorpen 14y ago
Seeing as the vast majority of travelers only turn off the screens of their devices, I somehow doubt this is the issue.
rogerbinns 14y ago
I'm happy with the devices being turned off as most crashes happen during landing and takeoff. I'd rather people were paying attention to their surroundings, paying attention to the briefings and not having hard metal objects that would seriously hurt people should the plane suddenly decelerate. But if they agree with me then that is the reason they should give.
- mikeash 14y ago
  To at least six digits of accuracy, no airline crashes happen in the US at all these days.
- wonderzombie 14y ago
  At least as far as situational awareness concerned, a decent book is just as impairing for many people. Actually, in that case as well as safety, I don't see much difference between a book and a Kindle. But they can't go and whitelist one device without complaints, can they? Sigh.
  - rogerbinns 14y ago
    I'd rather be hit on the back of the head by a book than a kindle should there be a rapid deceleration! But yes the correct answer is to do a cost benefit analysis.
- yason 14y ago
  All of the 500-800 passengers aboard a B747 or A380 certainly won't all have their cellphones, laptops, tablets, and other devices completely shut. Ever. Some forget it, some don't pay attention, some deliberately leave theirs on. In the average, there are always few devices on. Multiply that by a few hundred takeoffs and landing on a single busy airport. No planes have crashed so far because of that. IIRC, some aerospace manufacturers have stated that they would allow electronic devices being on if only <insert your local aviation control body here> approved. I much more gladly believe the cell tower explanation than any appeal to security.
dinkumthinkum 14y ago
Nonsense. You're coming up with this reason, which is fine, whatever, but it has nothing to do with the issue. The cell phone issue IS because of an alleged safety problem. It's not like the CEO of Delta is doing a "solid" for AT&T. Really? That doesn't even seem serious. Also, many people don't really turn off their cellphones, if this were all the case it seems like we'd all be experiencing some pretty big problems right now making calls.
pavel_lishin 14y ago
> So as a courtesy to cellular phone carriers, airlines require cell phones to be put into "airplane" mode. False - I'm always told to actually turn my device off. Furthermore, why can I leave my cellphone on when I'm traveling via bus, or rail?
- anamax 14y ago
  > Furthermore, why can I leave my cellphone on when I'm traveling via bus, or rail? Neither of them rely on radio for essential communication/navigation. I'm not asserting that electronic devices interfere, just that the possibility of interference distinguishes planes from buses and trains.
  - pavel_lishin 14y ago
    The comment I was replying to said that the only reason is a courtesy to cell carriers, not for the airplane's safety.

drcube 14y ago

What does that have to do with ebook readers, mp3 players or laptops?

dkl 14y ago
Some of these have cell radios in them.

brk 14y ago

* Cell phones flying by overhead while landing or taking off overload cellular base stations.* [citation needed] I've heard this, as one of many theories, discussed about the rationale for this rule. A plane typically has about 150 passengers and there is a narrow window of time during takeoff and landing when you can actually get cell coverage. I find it hard to believe that with the popularity of cell phones today that the towers would be overloaded by 150 phones (or, let's extrapolate to 1000 phones accounting for the takeoff/landing windows) moving rapidly across a couple of towers.

mikeash 14y ago
I believe this dates from the bad old days of analog phones and relatively dumb networks. I've read accounts (reliable? not sure, but believable) of people getting billed several times for a single call made from the air, because multiple cells picked it up and they didn't coordinate among each other. I don't believe this is a problem today. I fly small planes for fun and sometimes use my phone in the air to check weather. The biggest problem is that it doesn't work above about 5,000ft because the signal gets too weak. I never bother to turn my phone off, and neither do most of my pilot friends. I spent about fifteen minutes flying a plane with an instructor friend once while he chatted on the phone with his wife about when we was going to get home!
- freehunter 14y ago
  I do know of an AT&T tower in my state that is malfunctioning (by my standards) and refuses to release the connection once my phone had established the connection. When I'm driving down the freeway past the tower, my signal strength will get weaker and weaker and then I run into no service, even in great service areas. I have to pull the battery (my iPhone toting friends/family have to power down the phone) before it will recognize it's moved to another tower. Obviously it's a different circumstance, but it's another point of data where cell towers aren't always 100% functional when the target is moving.
  - mikeash 14y ago
    The supposed issue isn't movement, it's that cell towers assume a limited signal range due to terrain, which is no longer true once you're in an airplane and high enough to have a horizon of dozens of miles. Edit: by the way, have you reported the problem to AT&T? I have no idea how responsive they are, but it seems like it could be worthwhile, especially if it's as easy to reproduce the problem as you make it sound.
kalleboo 14y ago
The window isn't that narrow, I think it can still pose a problem. Last time I left my phone on by mistake in my bag, when I picked it up I had "Welcome to X country! Your roaming rates here are..." from 3 different countries, none of which were the starting or landing countries.
- brk 14y ago
  I fly about 50-70K miles in a given year. I never turn my phone fully off, I usually put it in "Airplane mode" after I'm out of the coverage area (to conserve the battery so it's not trying to hunt to unreachable towers). I usually find that the phone has lost a signal well before we've hit the 10,000 ft. altitude where electronic devices are "allowed". Roughly this seems to happen about 8-12 minutes into the flight. I would consider the first 1,500 feet of altitude to be a zone where appearance of cellphones would be considered "normal", so the window in which you're truly in the supposed problem zone is even smaller. I'm not sure that the evidence your phone connected to some random carriers is any evidence that phones in flight could be problematic for modern towers. RF systems are also very interesting... I'm not an RF engineer, but I know enough about it that the cell towers coverage pattern is not spherical with equal coverage in all directions. The antennas would be designed and placed to direct the signals mostly out and to lower elevations, not up. Again, this would limit the chances that phones zooming overheard are appearing to multiple towers simultaneously, or moving tower to tower faster than the billing and tracking systems could manage.

milesskorpen 14y ago

Seeing as the vast majority of travelers only turn off the screens of their devices, I somehow doubt this is the issue.

rogerbinns 14y ago

I'm happy with the devices being turned off as most crashes happen during landing and takeoff. I'd rather people were paying attention to their surroundings, paying attention to the briefings and not having hard metal objects that would seriously hurt people should the plane suddenly decelerate. But if they agree with me then that is the reason they should give.

mikeash 14y ago
To at least six digits of accuracy, no airline crashes happen in the US at all these days.
wonderzombie 14y ago
At least as far as situational awareness concerned, a decent book is just as impairing for many people. Actually, in that case as well as safety, I don't see much difference between a book and a Kindle. But they can't go and whitelist one device without complaints, can they? Sigh.
- rogerbinns 14y ago
  I'd rather be hit on the back of the head by a book than a kindle should there be a rapid deceleration! But yes the correct answer is to do a cost benefit analysis.
yason 14y ago
All of the 500-800 passengers aboard a B747 or A380 certainly won't all have their cellphones, laptops, tablets, and other devices completely shut. Ever. Some forget it, some don't pay attention, some deliberately leave theirs on. In the average, there are always few devices on. Multiply that by a few hundred takeoffs and landing on a single busy airport. No planes have crashed so far because of that. IIRC, some aerospace manufacturers have stated that they would allow electronic devices being on if only <insert your local aviation control body here> approved. I much more gladly believe the cell tower explanation than any appeal to security.

dinkumthinkum 14y ago

Nonsense. You're coming up with this reason, which is fine, whatever, but it has nothing to do with the issue. The cell phone issue IS because of an alleged safety problem. It's not like the CEO of Delta is doing a "solid" for AT&T. Really? That doesn't even seem serious. Also, many people don't really turn off their cellphones, if this were all the case it seems like we'd all be experiencing some pretty big problems right now making calls.

pavel_lishin 14y ago

> So as a courtesy to cellular phone carriers, airlines require cell phones to be put into "airplane" mode. False - I'm always told to actually turn my device off. Furthermore, why can I leave my cellphone on when I'm traveling via bus, or rail?

anamax 14y ago
> Furthermore, why can I leave my cellphone on when I'm traveling via bus, or rail? Neither of them rely on radio for essential communication/navigation. I'm not asserting that electronic devices interfere, just that the possibility of interference distinguishes planes from buses and trains.
- pavel_lishin 14y ago
  The comment I was replying to said that the only reason is a courtesy to cell carriers, not for the airplane's safety.