Every one of us has been told to put our phone in Airplane Mode while flying. But why? There’s a belief that a phone’s signal can interfere with important electrical or telecommunications systems in the cockpit, and results in the plane crash.
If anything, a mobile that hasn’t been switched to flight mode may just annoy pilots and air traffic controllers with an unpleasant sound.
It’s the same kind of noise that can be heard over speakers if a mobile is nearby and it’s due to the phone’s powerful radio emissions.