Air traffic audio reveals likely cause of mysterious U.S dysfunction . Aircraft N900NK that crashed into ocean We've just published air traffic control audio and analysis of what happened to the private turbo prop aircraft that crashed yesterday after the pilot became nonresponsive. The transcript of the audio is certainly demonstrated below, and you will hear the entire audio in this YouTube video. It's very clear from the audio that the pilot lost consciousness a while after noticing a problem that prompted him to try a descent to 18,000 feet. He never completed the descent, however, and he appeared to be experiencing confusion - - a common sign of hypoxia .