reporting for us, and there is technical difficulty there, and i you can understand. i want to talk about the french prosecutors because they say that the co-pilot deliberately crashed that plane after he locked the pilot out of the plane. and so the fate of the passengers on the plane rested on one switch. kyung lah is looking into that. what have you got for us? >> well, don, the switch is something that exists in every single commercial plane that is flown around the world. >> reporter: he cannot imagine why a pilot would do this. >> terrain terrain. >> reporter: but bugs forsytht knows how. a retired military and commercial pilot, forsyth says he has flown thousands of hours in the a320 airbus. he has used the switch hundreds of times. >> ton lock you pull it up, and hold it, and the light comes on