can be erroneous and if there are buoys in the water, they would know what the currents are doing. that would help them in determining where to position the ship. >> this is a flight data recorder that i have here on the desk. i want to play for you and our viewers right now the audio sound, the pinger that it emits for 30 days after it goes into the water. listen to this. all right. that could be picked up for a couple of miles? >> yes. it's really distinct underwater and you can recognize it easily. >> let's say it's down 13 or 14,000 feet down. that's a couple miles right there. if you're on top of the indian