welcome back. breaking news, the bluefin 21 has nearly completed its 12th mission, 90% of the search zone scanned. and yet another deadend when sheet metal with rivets washed ashore has been ruled out as debris from this plane. it raises the question, is it time to rethink the search vat gee? jean casaras has more now. australia will not rest until we have done everything we humanly can to get to the bottom of this mystery. reporter: it is a mystery no closer to being solved. the bluefin 21 autonomous underwater vehicle has searched the targeted area with no luck. experts are preparing for the next phase of the recovery effort. this requires deep sea ascents. this requires more probably bluefin 21s. this requires probably
90% of the search zone scanned. another dead end. sheet metal with rivets washed ashore and has been ruled out as debris from the plane. it raises the question, is it time to rethink the search vat gee? jean casaras has more now. australia will not rest until we have done everything we humanly can to get to the bottom of this mystery. reporter: it is a mystery no closer to being solved. the bluefin 21 autonomous underwater vehicle has searched the targeted area with no luck. experts are preparing for the next phase of the recovery effort. this requires deep sea ascents. this requires more probably bluefin 21s. this requires probably submersibles that will be very, very expensive. again, there are so many people out there who are interested in coming on board. reporter: with additional countries coming forward to help coordination of this worldwide
date. bluefin-21s seventh mission commenced this morning. if they don t find anything this week, what do they do? do they expand the underwater search area? as investigators they have to keep on looking as long as the weather and safety permits. they will keep mapping out the seabed and keep looking where they think this plane may be. jeffrey, i want to talk about this list of 26 questions from the committee of the flight 370 families. they have drawn up this list. some of the questions, most of them are quite technical. they want the flight logbook. they want to review the jet s maintenance records and listen to the recordings of the pilot s last conversations with air traffic controllers. what is the likelihood they will get any of this and why aren t
cover a much bigger arc, more than 370 miles long. joining us now, steve wallace, fobter director of the fa s investigation office and our information analyst, jeff weiss. great to have you, steve, i think most people would think more is better in this case. wouldn t it make a difference to have more of these underwater vehicles helping out in the search? well, michaela, i would certainly think so. we ve talked about this bluefin-21 covering maybe 15 square miles a day at best. and a couple of descriptions of the search area, one was 370 by 30 miles, whatever it was, about 11,000 square miles. that looks like a couple of years at that rate. i would certainly think more assets. i m more an expert on things that fly in the sky than go under water. i don t know if these bluefin-21s can confuse each other, whether you can operate several of them near each other. i wouldn t know.
i believe they are. and the only thing that i would think would be somewhat better would be to have four, five, or six if they could afford them of the bluefin-21s or other autonomous underwater vehicles so they can search the targeted area much quicker. only having one or two units makes it much more time consuming. colleen, once they bring up the bluefin-21, it takes about four hours to review. walk us through what they do to see if they have spotted something. well, i would actually like to defer to gene because you re talking about image interpretation and often these images don t look like a photograph. and that s that s the key thing to understand. you re looking at returns of sound that is bouncing off the object and coming back and there are big shadows behind the object where the sound doesn t go and there could be those shadows could be hiding something. so what you have to do is you