After the coast of Australia tonight the search for flight 370 is taking a new and perhaps painfully slow turn. The pings believed to have been the real thing now vanishing. What will they do now?... See More
After the coast of Australia tonight the search for flight 370 is taking a new and perhaps painfully slow turn. The pings believed to have been the real thing now vanishing. What will they do now? ABC's Clayton Sandell is there tonight. Reporter: Five weeks searching from planes, ships, even submarines and tonight still not a single sign. They're narrowing in on a 500 mile underwater search zone, but those emergency beingen batteries are fading. This U.S. Navy defensor hasn't detected any signals since Tuesday. When the time is right we'll say the beacons have stopped transmitting. It's time to shift to the short range sonar. Reporter: In its place the automated bluefin 21 will steer itself nearly 15,000 feet deep using sonar to scan cannons and mountains on the sea floor, in sections half a mile wide, and those critical data and cockpit flight data recorders. A task that's slow. Bluefin's top speed, five miles per hour. At that pace and given the size of the search area, this could take months, even years. Tonight solid answers about what happened to this airplane and the people on board are still a long way off. David?
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