room with a nice clean whiteboard and going through what we know, what we don't know, what do we do next? it took a lot of thought. it was a long peer. months before we came up with the next plan of what to do. >> reporter: it took 70 days of subsea search missions over years to find that wreckage. in this investigation, the subsea search area could be shifted or expanded perhaps to include the other three pings and using other vehicles to scan the ocean floor. this remis 6000 was used in the search for air france 447 and can go deeper than bluefin. another option, a towed sonar system like the orion which can scan large areas under water. whatever the system, gallo suspects this general part of the ocean to still be the target. >> i don't know how you leave this place before you take that area of the sea floor apart completely. >> the ship used in the subsea search efforts cannot be refueled at sea so will eventual eventually have to return to