>> wolf, teams are stretching the boundaries of this technology and they have done it again. the latest signal came from something designed for maritime combat, not search and recovery. they are dropped out of a plane and descend below the surface, open up their payload and hunt for their target. these are not bombs or torpedos, they are called zosonobuoys. >> they deploy a hydrophone. >> a source tells cnn that sonobuoys were dropped from an australian pc-3 orion plane. >> it has saltwater switches that starts activating different deplo deployments. there's a bunch of gear in there. some of it floats to the surface so there's a radio antenna that talks to the aircraft and they