MH370 - Facts at a glance 8 March: Malaysia Airlines Kuala Lumpur-Beijing flight carrying 239 people disappears 
 
 Malaysia Airlines Kuala Lumpur-Beijing flight carrying 239 people disappears Plane's transponder, which communicates with ground radar, was switched off as it left Malaysian airspace 
 
 Satellite 'pings' indicate plane was still flying seven hours after satellite contact was lost 
 
 24 March: Based on new calculations, Malaysian PM says "beyond reasonable doubt" that plane crashed in southern Indian Ocean with no survivors What we know The search for flight MH370 
 
 The Ocean Shield had also spotted an oil slick in the same area where the signals had been heard, ACM Houston said, and a sample was being sent for testing. (U.S. Navy / Getty Images / ) 
 
 BEIJING -- An unmanned underwater vehicle will be deployed to look for missing Malaysia Airlines Flight 370 on the floor of the Indian Ocean, Australian authorities said Monday, and investigators have collected samples from an oil slick discovered in the search area. It should have taken the probe and its operators 24 hours to map the first portion of the search area: 16 hours to map, four hours' travel time to just above the ocean floor and back, and four hours for analysts to examine the data gathered. 'Manageable search area' 
 
 An international search has focused on waters west of the Australian city of Perth, with teams racing against time to detect signals before the flight recorder batteries - which last about one month - run out. Search chief Angus Houston said the Bluefin-21 drone would be sent down as soon as possible to search for wreckage on the sea floor. “It is time to go underwater,” said Air Chief Marshal Angus Houston, who is coordinating the search from Perth, Australia. Monday marked day 38 of the search for the Boeing 777, which disappeared March 8 en route from Kuala Lumpur to Beijing with 239 people aboard. Hide Caption 7 of 43 Photos: The search for MH370 Operators aboard the Australian ship Ocean Shield move Bluefin-21, the U.S. Navy's autonomous underwater vehicle, into position to search for the jet on April 14, 2014. "The experts have therefore determined that the Australian Defence Vessel Ocean Shield will cease searching with the towed pinger locator later today and deploy the... Bluefin-21 as soon as possible.'' Image copyright Getty Images Image caption The Bluefin-21 will search the sea floor for wreckage from flight MH370 
 
 Image copyright Reuters Image caption Up to 12 planes and 15 ships were involved in the search for the plane 
 
 Air Chief Marshal Houston, who heads the joint agency co-ordinating the search effort, said that given no signals had been detected in six days, it was time to go underwater. Hide Caption 38 of 43 Photos: The search for MH370 The rescue vessel sets out from Sanya in the South China Sea on March 9, 2014. Hide Caption 43 of 43 
 
 JUST WATCHED New sonar device seeks plane underwater Replay More Videos ... MUST WATCH New sonar device seeks plane underwater 01:27 
 
 JUST WATCHED Search for MH370 goes underwater Replay More Videos ... MUST WATCH Search for MH370 goes underwater 01:51 
 
 JUST WATCHED Underwater vehicle to search for MH370 Replay More Videos ... MUST WATCH Underwater vehicle to search for MH370 02:31 
 
 Houston cautioned against hopes that the underwater vehicle will find wreckage of the plane, which disappeared on March 8 on a flight between Kuala Lumpur, Malaysia, and Beijing that should have taken about six hours. He warned that the submersible search would be a long, "painstaking" process that might, in the end, yield no results. But he said the area probably has a lot of silt, which can "complicate" the search. Australian officials have said previously that they are confident they are searching in the right area for the missing plane. "It was the site of the highest signal strength or the loudest received signal," Matthews told CNN, referring to the pings detected by a towed pinger locator, a wing-shaped listening device connected to the ship by a cable. Meanwhile, searchers will work to send the oil slick sample, collected Sunday evening, to a laboratory on shore for analysis, Houston said. "I stress the source of the oil has yet to be determined, but the oil slick is approximately 5,500 meters (3.4 miles) downwind ... from the vicinity of the detections of the TPL on Ocean Shield," Houston said. This is an area, Houston said, that is “new to man.” 
 
 Asked if other underwater vehicles besides the Bluefin-21 would be joining the search, Houston indicated that investigators had no plans at this point. "The air and surface search for floating material will be completed in the next two to three days in the area where the aircraft most likely entered the water," Houston said. With six days having passed with no further detection of “pings” from what may have been the plane’s black boxes, searchers on the Australian ship Ocean Shield will cease using the U.S. Navy’s towed pinger locator and deploy the Bluefin-21 underwater search vessel, officials said.
– After six days with no fresh pings detected, the chief of the search for Malaysia Airlines Flight 370 says it's time to go underwater. The Bluefin-21 underwater autonomous vehicle will now be deployed to search for wreckage in an area defined by signals picked up last week that are believed to have been from the missing jet's data recorders, reports the BBC. Search chief Angus Houston says the robotic sub will be in a "reduced and manageable search area on the ocean floor" and, with the data recorders' batteries now almost certainly dead, efforts to detect pings will cease. On its first 24-hour mission, the Bluefin-21 will search an area of around 15 square miles, producing a high-resolution map of the sea floor, the Los Angeles Times reports. Houston warns, however, that the underwater search will be a "slow and painstaking process" with no guarantee of results. The area being searched, he says, is extremely deep—2.8 miles—and is largely unknown terrain "new to man." An oil slick detected on the surface of the area last night, meanwhile, is being analyzed and officials believe it didn't come from any of the search vessels, CNN reports.