if the tail area is cracked off of the plane, off the fuselage, sometimes the black boxes can be broken free and move across the ocean floor in the crash sequence. so the pingers would be the most help but in most cases it s divers that have brought them up. in sounds like a needle in a haystack finding that. david, mary mentioned divers. what else do you think they are doing to try to find the equipment? well, the primary goal right now is to recover any of the deceased victims, although concurrently they are probably listening for it. the underwater locator beacon is not designed to be the first level of search for the aircraft like you tried to make it in 370. it s really designed once the aircraft is under the water, once it is in a mangled mess, that s when it s important to have the underwater beacon