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.
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.
"It is time to go underwater," said Air Chief Marshal Angus Houston, who is coordinating the search from Perth, Australia.
The Bluefin-21, Houston said, will search an area of about 15 square miles on its first 24-hour mission. It takes two hours to get to the sea floor and will search for 16 hours. It takes another two hours to bring the Bluefin-21 to the surface and four hours to download and analyze the data it has collected. The Bluefin-21, which moves at a walking pace, produces a high-resolution, 3-D map of the sea floor.
Meanwhile, searchers will work to send the oil slick sample, collected Sunday evening, to a laboratory on shore for analysis, Houston said. "We don't think it's from the ships" involved in the search, he said.
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. The aircraft's black box batteries have a guaranteed shelf life of 30 days, so hope is dwindling that further transmissions from the transponders will be detected. Four acoustic signals were earlier picked up by the towed pinger locator.
Houston said the air and surface search for floating debris in the area where the plane "most likely" entered the water would be concluded within two to three days. After that, he suggested, the countries involved in the search would need to consult with one another and determine how to proceed. No debris has been found.
Eleven military planes, one civil aircraft and 15 ships were participating in Monday's search about 1,300 miles northwest of Perth.
The ocean where investigators believe the plane went down is extremely deep -- 2.8 miles -- and not much detail is known about the terrain. 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. However, he indicated that if the depth of the ocean proves to exceed 2.8 miles, a different type of vehicle will be necessary because the Bluefin-21 cannot go deeper than that.