hearing a signal underwater. as you know, the ocean shield towing behind the u.s. navy's pinger locator listened to a signal more than two hours over the weekend and tried again. heard it about 15 minutes, but it's been silent ever since. and so the big push right now is to try to relocate that signal, because what needs to happen is, this pinger locator needs to hear the signal multiple times to be able to get a pretty approximate idea of where debris, where wreckage might be, and right now we just don't have the answers. the area still too big for the other equipment that's in the area to work effectively. >> all right. will ripley, reporting live from perth, australia. let's talk more about this. is all hope lost with now mary schiavo, cnn aviation analyst and cnn inspector general for the department of transportation and peter golts, a cnn analyst and former ntsb managing director. welcome to both of you. >> thank you. >> good to see you. >> nice to see you both. peter, the batteries are likely dying or dead in those black