necessarily following the other? >> reporter: i guess there are a couple of ways you could do this. if you did it manually like that and instantly hit the button that confirms you're making the turn, the plane begins to make that motion immediately. could you sort of set it up with an alternate and then hit it later? yeah, you could do that, too. and remember, there are legitimate reasons to change course. >> absolutely. mechanical failure, weather, a sick passenger, all of those are really good reasons to deviate. >> reporter: so it isn't just the fact that because the plane changed course dramatically that it necessarily means sinister intent. it does look rather odd, though, that you've got a plan in there and you say rather calmly all right good night, that doesn't sound like you're you've got an emergency on board. >> richard, that's what raises questions that the copilot didn't say anything about it when he did communicate. >> what's interesting here about what we're seeing from the flight deck here is this 12