Surface Listening Device News Today

Navy, coast guard, et cetera, they have the equipment either on an a surface listening device or a towed array on the ship itself which goes to a depth and listens for the equipment. so its important that they have the equipment that will listen for the specific frequency. >> literally an army of people are looking for any sign, any ping emitted from these flight data recorders. i know its a very large area but are you surprised nothing has been heard as of yet? >> it is surprising. with as many...