pinger sound, or ricochet sound. the realtime, the scientists and technicians on the boat will be listening. pinger locaters have been used for years. in 1996, a tpl successfully located the black box for twa flight 100, in shallow waters off new york. investigators used one in 2009 when air france flight 447 went down in the atlantic but found nothing. if they have any luck locating the pinger from flight 370, next they will deploy this autonomous under water vehicle that maps the ocean floor. it will start to run patterns back and forth, shooting sound out the side and taking pictures. and it will show objects, shiny objects, basically, bright objects that could be the plane. right now that is the perfect scenario. but even the head of this search effort seems to be hedging his bets. hopefully, hopefully the
moves at about three knots. that means with about three miles to cover it will take days. it does two things. it gets it down into that level. it also gets it away from a lot of the surface noise, all of the whales, dolphins, fish, they all make sounds. the device can pick up a sound from as far as two miles away. here is why it is so critical to get that towed pinger locater deep down in the ocean. the pinger sound from the black box can get stuck in something called a deep sound channel. about 2,000 to 4,000 feet below the surface. if the sound does get trapped there and bounces around the only way to pick it up may be through one of these towed pinger locaters. seeing the device down there, that will put you in that channel so they can hear the
break. you know, rotating shifts of course. but i m going to jump ahead a little bit and say they have a lot going for them right here with having heard that pinger for so long. and understanding how far away from that pinger could they still have heard that kind of decible. and i don t know what they have received. captain said 30 by ten kilometers. that is a respectable area. a good size, you know, it is large but not too large to search in about a week s time. so that is a very good team out there. they have great technology. he knows what plan he is working by. there is a lot of confidence in what he is doing. does it make sense, david gallow, you said it would take about a week to search the area. i m assuming you would talk about under water vehicles. why not just do that now rather than wait another 15 days for a pinger i m always very anxious to get the vehicles in the water.
carrying the pinger locater. that ship picked up what could have been two separate signals from the black boxes but those pings have not been heard since. and there is a very real danger that the pingers are out of power. now, crews are in a frantic race to keep alive their most promising lead yet. reporter: after another day of searching, crews on board the ocean shield continue to try to find this sound again. the australian defense department released audio of the possible black box signal that the towed pinger detected twice over the weekend. despite a continuous effort to recapture it, still nothing. as the hours pass, we are our optimism is fading away, ever so slightly. reporter: if it is flight 370, black boxes finding it
might be. in this case we had so little information. and almost because of that it forced the clever engineers at inmarsat to come up with the rings, which gave us in a rather amazing way the ability to define locations on the planet where that plane was. and sure enough underneath that last ring we re hearing some pings, apparently. miles, we heard from captain matthews early on in the broadcast at the top of the program talking about giving you know as many as another 15 days or probably 13 days now, sort of a maximum of 45 days on the life of the pinger to continue to search for that sound. do you really think they will go that long to searching for the sound? that seems like a long time to me. listening to van talk about the 7-1 ratio as far as the pinger versus the autonomous under water vehicles. in other words, it would take seven days to cover the same amount you could cover in one day with the pinger.