Phone in Air Plane

There are very good reasons why the air crew always remind passengers that it is strictly forbidden to use cell phone in the cabin of the plane.
Modern aircraft depend greatly on radio waves to perform numerous functions, such as communication with the control tower, navigation and regulation of cabin atmosphere. Radio wave interference from a cell phone can seriously disturb these functions.
You may not be aware that even when your cell phone is on standby is still send out an electromagnetic signal that notifies the cellular networks computer that the phone is active and can be contacted. This signal become stronger when the transmitter at the Base Terminal Station (BTS) communicates with the cell phone to send a voice call or short message (SMS).
Actually, once the aircraft has taken off and approaches its cruising altitude, your cell phone will not work anyway, because the plane is too far from BTS. Furthermore, the plane move so fast that once the phone’s presence has been detected and registered by a cell in the cellular network, the phone is no longer within that cell’s range. Yet if your cell phone is active, it is continually emitting electromagnetic signal that could seriously disrupt the aviation equipment, thereby endangering the lives of hundreds of passengers.
So for your own safety and that of you fellow passengers, you must turn off your cell phone as soon as enter the plane. If you have a phone in your carry-on luggage, check to make sure that it is turned completely off.