>> that the plane turned immediately after the transponder went off is completely inexplicable and very worrisome. >> peter goelz is a former managing director of the ntsb. >> we don't know whether this was done voluntarily, whether it was done under duress. we simply have no idea. >> no idea what really happened, but goelz sees a red flag. >> it was completely out of the ordinary that there was no distress call. that the turn takes place and there's absolute silence, it means that somebody on that plane redirected it to a new course heading and they were not telling anyone. >> not telling anyone and never checking in with vietnam air traffic control. >> the fact that the westerly turn happens at the point of handover between malaysia and