A deep-sea drone completed its much-anticipated first full scan of the seabed in the remote Indian Ocean, the team looking for a missing Malaysian jetliner said on Thursday, as an air and surface search became less likely to yield results.
Footage from a U.S. Navy deep-sea drone is fast becoming the most important tool for a multinational team searching for Malaysia Airlines flight MH370, which disappeared from radar screens on March 8 with 239 people aboard.
A sample taken from an oil slick in the same area, some 2,000 km (1,240 miles) west of the Australian city of Perth, was determined not to be related to the plane. Authorities believe the area where the oil slick was found is most likely where the missing jet hit the ocean after disappearing.
A series of "pings'' recorded this month have led searchers
to the remote stretch of ocean in the belief that the signals may have come from the plane's black box recorders.
However, with no pings received in more than a week and the black box's battery now 10 days past its approximate expiry date, authorities are relying on the drone.
Earlier, Australian Prime Minister Tony Abbott told the Wall Street Journal if the so-called Bluefin-21 submarine does not find any wreckage by then, authorities will stop, regroup, and reconsider how to proceed.
The Australian agency coordinating the search said Thursday the vehicle completed its first full 16-hour mission after two previous missions were cut short because of technical problems.
The Bluefin-21 has so far searched 90 square kilometers of the ocean bed, but authorities say they have found "no significant detection" in the sonar data collected.
U.S. Navy officials had previously warned it could take up to two months for the submarine to scan the current 600-square kilometer search area.
Meanwhile, 12 aircraft and 11 ships were involved Thursday in the search for floating debris from the missing Boeing 777. Australian officials have warned this effort will soon be called off, since no debris has been found since the plane went missing more than five weeks ago
It is unclear how authorities will proceed if the surface search is called off and the robotic submarine does not locate any underwater wreckage.
It has been more than a week since authorities last detected a signal they believe came from a locator beacon on the plane's flight data recorder. The recorder's batteries are now presumed to have run out of power.
The "black box" signals helped narrow the search area considerably. But search crews are still dealing with a target area more that 40,000 kilometers in size.
The Malaysia Airlines jet, carrying 239 people, vanished while en route from Kuala Lumpur to Beijing.
Malaysian officials think the plane was intentionally diverted. But they have refused to rule out other possibilities, including a massive mechanical malfunction.
Some information for this report provided by Reuters and AP .