eventually find the aircraft. >> let's go to paula newton. in perth. 2:00 in the morning. where you are, we hear about ground-breaking analytical research here and honing in on the search zone. how exactly did they do that? >> reporter: they, once again, went back to those pings from the mr satellites. they had made this calculation, remember, brooke, so many days we were looking at a northern arc and a southern arc. now at the bottom end of the southern, 150 miles, you have the ocean spray on one end, and the hms echo, a british ship on the other end. they will converge on the line. it's a shot in the dark as you said. the u.s. navy commander leading this told me it was a shot in the dark. but at this time they feel the equipment is out there. they will continually look at information, see if they can refine it a little bit more. but right now what they have is a guess.