point the airplane was still flying on the program course. and then at some point there was some malfunction that took out the transponder. and the program route and then the airplane reverted to this other heading select mode. and then went in the other direction. >> okay. let me turn to steve wallace, former faa director of accident investigation. steve wallace, when you hear this, that was a very plausible explanation if that is what happened, one i hadn't heard spelled in such a coherent manner. extremely useful. many people are rushing i think to judge here from a very inexperienced position. when you look at this from an accident investigation point of view, clearly it's a very difficult thing to investigate because they don't seem to really know where this plane may have come down. where would you start from now if you were brought in right now with all the knowledge that you have of this today? where would you start in trying to really find this plane? >> well, piers, i'll start by