Electronic devices on board a plane

Could someone please explain to me why you have to shut off not only cell phones, but ALL electronic devices while a plane is taking off or landing?

I guess I can see that a phone emits weak radio signals, and maybe could mess with the navigational system or something, but I just cannot believe that someone using a PDA or MP3 player in the rear of the plane could possibly generate enough output of any kind to adversely affect the flight.

Does anyone know the rationale for this rule?

Situational awareness. If you need to evacuate, it’ll go a lot more smoothly with no distractions, earbuds, tray tables, or seat backs to deal with.

We have dicussed this a bunch of times and it is difficult to come up with an FAA regulation that absolutley prohibits any of this. If you are on any type of private plane or a corporate jet, you can use your cell phone and your electronic devices all you want at any time. The rules mainly come from the airlines themselves although I have heard that the cell phone companies don’t like calls that jump from tower to tower as quickly as they do with flying chatters. It is possible to cuase interference with some instruments with some tyes of electronic devices but it is rare and would only apply to some devices. The airlines just ban them all during landing so there isn’t any question about the matter. They also want people paying attention and shutting everything off so that they can get off the plane with the least fuss possible. Not complying with the rule could be considered interfering with the flight crew which is a serious offense.