(NBC News) American crews operating a a high-tech sonar system are working to to home in on pings detected Sunday on the bottom of the Indian Ocean, clear sounds that have re-energized the search for Malaysian Airlines flight 370's black boxes.
Hope is riding on the Australian ship, Ocean Shield and its towed "pinger locator", run by a team from the U.S. Navy.
One ping was heard for two hours, then two more pings were heard when ocean shield towed the locator back at a depth of 1.9 miles.
"Significantly, this would be consistent with transmissions from both the flight data recorder and the cockpit voice recorder," says Angus Houston, head of the Joint Agency Coordination Center overseeing the search.
Data in the boxes will last years, but the "pinger" batteries will soon die, making finding the recorders much harder.
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