No wreckage from the plane.It was searching in water so rough, so deep,but the towed pinger-locator deployed from the Australian ship 'ocean shield' has detected signals in the Indian Ocean-- consistent with pings from black boxes. Two separate signals have been detected - possibly the plane's data and voice recorders.What happens next? Officials say they have to re-acquire those signals.That means the pinger-locator has to make other passes. First, at least three runs parallel to those it made when it first detected the signals.Then, perpendicular runs, so they can isolate the source and triangulate its position.
Experts caution- the ocean is full of sonar sounds... And there could be false-positives. They say objects from fishing equipment to whales can emit sonar signals. But the frequency of the black-box signals is intended to be unique, 37-point-5 kilohertz- and the operators of the pinger-locator are trained to listen- and watch closely.