investigation, there's no evidence one way or the other. >> but there would be piles of evidence if acars hadn't stopped transmitting. >> you'd know the air condition of the engines, the route it was taking, the altitudes it was taking. we would know exactly the state of that aircraft. >> just the kind of information someone taking over a plane wouldn't want anyone to know. >> if you were doing something nefarious, then switching off acars would be a crucial part of making the plane go dark. >> the plane was dark and silent. there was still no check-in with vietnam air traffic call, a call former pilot nick huslon has made thousands of times. >> you have to be like a drunk