Why can't you have a cell phone turned on, on the plane?

Answer 1

Because it can affect the airplane electronics

"There is little evidence to support the idea that a single cellphone left on in a piece of carry-on luggage could adversely affect instruments in the cockpit. But if dozens of phones–along with wireless-enabled laptop computers and other power-emitting portable devices–were to be intentionally switched on in flight, the resulting cacophony of electronic noise could cause dangerous levels of interference that would almost certainly send navigation sensors into tailspins under the right circumstances."

Answer 2

Using a wireless phone depends on the activity of the plane. The use of cell phones during flight is banned by the FAA and the FCC. As soon as the plane starts to move, cell-phone use is forbidden. Most of us experience electromagnetic interference on a fairly regular basis. For example:

* If I put my cell phone down on my desk near the computer, I can hear loud static in my computer's speakers every time the phone and the tower handshake. In the same way, my car's tape player produces loud static whenever I make a call on my cell phone.
* When I dial a number on my home's wireless phone, I can hear the number being dialed through the baby monitor.
* It is not uncommon for a truck to go by and have its CB radio overwhelm the FM station I am listening to.
* Most of us have come across motors that cause radio or TV static.

None of these things, technically, should be happening. For example, a truck's CB radio is not transmitting on the FM radio bands, so my radio should never hear CB signals. However, all transmitters have some tendency to transmit at lower power on harmonic side bands, and this is how the FM radio picks up the CB. The same thing holds true for the wireless phone crossing over to the baby monitor. In the case of the cell phone affecting the computer's speakers, the wire to each speaker is acting like an antenna, and it picks up side bands in the audible range.

These are not dire problems -- they are just a nuisance. But notice how common they are. In an airplane, the same phenomena can cause big trouble.

An airplane contains a number of radios for a variety of tasks. There is a radio that the pilots use to talk to ground control and air traffic control (ATC). There is another radio that the plane uses to disclose its position to ATC computers. There are radar units used for guidance and weather detection, and so on. All of these radios are transmitting and receiving information at specific frequencies. If someone were to turn on a cell phone, the cell phone would transmit with a great deal of power (up to 3 watts). If it happens to create interference that overlaps with radio frequencies the plane is using, then messages between people or computers may be garbled. If one of the wires in the plane has damaged shielding, there is some possibility of the wire picking up the phone's signals just like my computer's speakers do. That could create faulty messages between pieces of equipment within the plane.

While most planes have equipment that prevents interference, it is always better safe than sorry.

Answer 3

The cell phone signal is supposed to interfere with the airplane's electronics and communications with the "tower"
However, this topic was on Myth Busters recently and they found the cell phone had no effect on a newer jet on the ground.
I'd still be afraid to use a cell phone on a plane....just in case :)

Answer 4

It affects the radio frequencies and such.

Answer 5

its because of the radio waves or something messing up the guiding system. (Saw it on Mythbusters)