Submarine Deployed in Search for Flight 370

The Bluefin-21 is hoisted back on board the Ocean Shield. Photo: U.S. Navy/2014 U.S. Navy

The batteries in the black boxes on Flight 370 were expected to die sometime last week, and since no pings have been detected in six days, the Australian official coordinating the search declared on Monday, "it is time to go underwater." Air Chief Marshal Angus Houston said the Bluefin-21, a 16-foot submersible drone, will be deployed from the Australian ship Ocean Shield on Monday night. The vessel will be deployed for 24 hours at a time to map the ocean floor. An oil slick spotted near the search area on Sunday is being analyzed, but the chance of finding clues on the ocean surface has "greatly diminished," Houston said. "I would caution against raising hopes that the deployment of the underwater vehicle will result in detection of underwater wreckage," he added. "It may not. However, this is the best lead we have."