shores of the various islands, heavy metal and pieces of the things that they thought was part of a door but really part of a domestic ladder. things like that are not going to float in the ocean guyer so they need to look for things that sealed cargo containers and pieces of the wing pieces of suitcases, gallie items. those kinds of things would confirm it is where they are searching but there is no chance absolutely no chance that the black boxes can float. they do not and so -- i agree completely with richard. they can learn an awful lot and my guess is how they got the serial numbers. they do use remote sensing cameras on the fiber optics and could have put that in any hold available and see if there's any numbers on inside. probably my best guess as to how they got the serial numbers but i agree completely with richard. it will be very hard to determine why even if they can tell how it went down.