Why can't you use cell phones on airplanes?

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There are two reasons that I have heard.

First, as people have mentioned, theoretically, the signal from a cell phone could interupt normal operation of various guidence and communications systems on an airplane. This is a minimal risk as most wires and systems in an airplane are shielded, but when you're 5 miles in the air, why take the risk?

The second reason is to prevent overloading of the cellular system and crashing the system.

When a cell system crashes, it is a major event that requires reports be files explaining what happened to the FCC.

I'll spare you the science behind antenna transmission. A cell antenna's main signal is pointed at the ground, but due to the physics of antenna transmissions, secondary "lobes" are sent in other directions, including up in the air which makes cell calls from planes possible (bad quality, but possible).

A cellular antenna covers roughly a radius of 3 miles or 6 miles across. In most cases, the cell antenna covers a circular area (in theory) and is actually comprised of 3 antennas (some antennas only have 1 antenna and some have 6 antennas, but most have 3), each covering 120 degrees of a circle (I'm getting somewhere with this, I promise).

When you are driving down the road, your call switches between cell sites and even between the three sectors of the antennas. This is called a "handoff".

If you are driving at 60 MPH, it takes you 6 mintues to get across the area of a cell and be handed off to the next cell. Phones typically are in communication with more than one sector of a cell and multiple cells, but for arguements sake, if it takes 6 minutes to drive across an entire cell, i'll say it takes 2 minutes to get out of range of 1 sector of that same cell (remember that 120 degree thing I was mentioning).

A plane cruising at altitude can be going 300 to 500 MPH. For arguements sake, we'll say 400 MPH.

That plane going 400 MPH will go through that same 6 mile area in 54 seconds or 18 seconds per "cell sector".

So in a car, it takes 2 minutes per sector, in a plane, 18 seconds. If one person is making a call from the plane, nothing will happen. A system can have the capability to handle 50000 to 100000 calls at a time. If too many people are making calls from planes and calls being handed off between cell sites at that rate, in theory it could cause the whole cell system to crash.

It is much more complicated than I explained, but that is a summary of why calling from a plane can be bad for a cell system.

The plane phones only talk to a couple of dozen beacons around the US rather than tens of thousands in the case of cell phones.

Plane phones do this in part to prevent rapid handoff between beacons.

ClarkKent (S)

Watch Myth Busters on the Discovery Channel they just did a show on that.

http://www.tv.com/mythbusters/cell-phones-on-planes/episode/661128/summary.html

Bird

The main problem is not a concern for the plane, but a concern for the cell systems themselves. All electrical devices give off magnetic fields that could affect the navigational systems of a plane.

A cell phone can work on a plane, we are just in trouble if everyone uses theirs at the same time.

The cell towers could not keep up with the rapid rate that the calls would jump from one tower to another due to how quickly the plane (and thus the phone) is moving combined with the amount of people on a plane all making those jumps from tower to tower at the same time. The systems today drop enough of the calls they have already.

Keep in mind the number of planes in the air at a time (thousands), thus number of people, and how quickly they are going.

DR. E

because it is against the rules, really cell towers are land based the tower switching can interfer with the freqs on the plane nav systems

spawn_of_cookie_monster

the signal can effect instruments and communications

Lacey B

You cannot use your cell phone in the air b/c 1. it will not work 2. if it is ON it is constantly trying to connect with a tower and may interfere with the flight crews navigational/communication equiptment.

On the ground, you may not use it because the flight attendant have alot of safety information they want you to listen to. Also it is distracting to other passengers.

radiancia

Because apparently like in hospitals it runs the chance of interfering with radar and all sorts of wireless communications on the airplane, but an epsiode of mythbusters said that its probably safe- but you wont catch me taking a chance on anything when Im in an airplane.

aaron a

the pilots wont be able to talk to people at the towers and stuff like that

mr. dorkface

interference.

same goes with hospitals.. banks... you'd be surprised where you shouldn't pop the old cell phone out.

but they do.

Sweet Tooth

Haha, this question reminds of that part on NWA (N*GG*R with attitude) it was a new movie on BET channel, and where this blk woman sassing the airplane worker, and then that blk woman got on her cell phone, and bam, the airplane was going to crash, lol...

Dang, that airplane got spinners!!

Rainy Day Lover <3

because the signal might mess with the crew's communications signals, and they you would crash... not a good idea

maxwell.fisher

safey reasons on the ground for one.... and it can interfear with the communication and navigation equipment onoard the aircraft when used........

A Word In Edgewise

So you don't interfere with crew communications. Your phone might not most times, but what if it did? Is that worth risking?

y que?â™£

cuz youll be sending weird signals to the aliens making them think it coming from the airport forcing the aliens to attack!

tentofield

So the exasperated person sitting next to you doesn't have to listen to your inane conversation and, in a fit of madness, shove the phone up your fundament. No-one needs to make a phone call on an aeroplane and you certainly have no right to annoy your fellow passengers by using one.

The airlines, sensibly, ban all mobile phones on planes to avoid mayhem.

Bunts

Because cell phones not only use radio signals
when they are turned on - even if they are not being used, but so do transmissions on mobiles.
The radio and radar equipment on an aircraft also use radio signals.
Although unlikely, it is possible that the air waves from the mobile could interfere with the aircraft communication or navigation equipment.
Hope this over-simplified answer gives you some idea.

mad manc

you will kiss ur *** goodbye as u hit the ground

dave k

It is like a one in a million chance it would effect the plane, but they say it just in case. The phones today don't really interfere with them anymore.

tmacinac

because when you use your cell phone the signals sent to and back from it, screw up the signals between the plane and traffic control

Jay

People will give you all sorts of answers. Because it interferes with the plane's equipment. Because of a quirk in cell tower technology that causes multiple cell towers to respond and this lets you make free calls. Because they want you to use the expensive air phones.

There have been studies that have shown that a properly working cell phone won't interfere with an airplane.

It's also not true that cell phone's can't deal with the 3-D nature of being ABOVE the towers.

Maybe it's true that it's a plot to force you to use the airphone.

In the end, it's most likely a matter of it POSSIBLY interfering with the aircraft (as someone said, like in a hospital). Why take the risk?

Of course, if a cell phone is dangerous enough to down a plane, why don't they scan for phone in the on-position? I know I've accidentally left my cell phone on and KNOW people do it all the time. No crashes. No pilot coming on and saying "our navigation system is down, please make sure your cell phones are off."

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