words turn off certain functions, but you couldn't turn it off unless you went down below decks and unplugged it. unlike, say, this thing, the transponder. another important device you've heard a lot about. this is what'dize if us on radar. but it does have an on/off switch. a simple one right here. one, two, three clicks and now we're no longer identified on the radar screens. two very different but critical pieces of communication equipment on this aircraft. if they can't be disabled the same way, it means that if they were somebody knew a lot about this plane. back to you. >> thanks to martin savage for that. malaysian authorities say the evidence they have indicates flight 370 was deliberately flown off course but so far there's been no claim of responsibility by any terror group. cnn's security analysts have more on that side of the story.