Malaysia Airlines Flight 370 likely flew into the southern Indian Ocean on autopilot with an unresponsive crew , Australian authorities said Thursday , divulging new details about what they believe happened during the missing plane 's final hours . The information emerged as officials announced a southward shift , as expected , in the underwater search for the Boeing 777 , which disappeared March 8 with 239 people on board . Searchers have found no trace of the jetliner or its passengers , making the case probably the biggest mystery in aviation history and leaving the families of those on board bereft of answers . The Australian officials said they believe the plane was on autopilot throughout its journey over the Indian Ocean until it ran out of fuel . They cited the straight track on which the aircraft flew , according to electronic `` handshakes '' it periodically exchanged with satellites . `` It is highly , highly likely that the aircraft was on autopilot , otherwise it could not have followed the orderly path that has been identified through the satellite sightings , '' Australian Deputy Prime Minister Warren Truss told reporters in Canberra . Unresponsive crew ? In a report explaining the change in search area , Australian authorities suggested that Flight 370 's crew may have been in an `` unresponsive '' state , possibly caused by a lack of oxygen . That scenario `` appeared to best fit the available evidence for the final period of MH370 's flight , '' the report said , citing previous air accidents in which crews had been rendered unresponsive by a lack of oxygen , also known as hypoxia . But it cautioned that the assumption was `` made for the purposes of defining a search area and there is no suggestion that the investigation authority will make similar assumptions . '' The Australian officials declined to talk about the causes behind Flight 370 's errant flight path , saying those are questions for the Malaysian authorities in charge of the overall investigation . And they said they were n't sure exactly when the autopilot had been turned on . 'Most likely place ' Their disclosure that a computer rather than a human was most likely steering the plane during its final hours adds a little more detail to the largely obscured picture of what took place that March night . But the key questions of why the passenger jet flew dramatically off its intended route -- from Kuala Lumpur , Malaysia , to Beijing -- and where exactly it ended up remain unanswered . The next phase of the underwater search aims to resolve at least one of those issues . Truss said an international team of experts had chosen the 60,000-square-kilometer zone , an area roughly the size of West Virginia , after going over all the available data . `` This site is the best available and most likely place where the aircraft is resting , '' he said . He warned , though , that the operation to comb the sea floor in the area , which has never been fully mapped , would be `` very challenging and complex . '' `` We could be fortunate and find it in the first hour , or the first day , '' he said . `` But it could take another twelve months . '' Biggest search in history . The hunt for the plane has already become `` biggest search operation in history , covering 4.5 million square kilometers of ocean surface , '' Truss said . During the early phase of the search , aircraft and ships scoured vast stretches of the surface of the southern Indian Ocean but found no debris from Flight 370 . Pings initially thought to be from the missing plane 's flight recorders led to a concentrated underwater search that turned up nothing . Last week , a group of independent experts -- using satellite data publicly released in May -- said it thought the missing aircraft was hundreds of miles southwest of the previous underwater search site . Doubts among families . `` It is encouraging that the Australian leadership has taken a very methodical and rigorous approach to redefining the search area , but is it still different than some of the other outside experts had defined , '' said Sarah Bajc , whose partner , Philip Wood , was on board the missing plane . She said she could n't reconcile the differences between the analyses . `` We do n't trust that the officials are being forthright with the information , '' she said . The next underwater search will be broadly in an area where planes and vessels had already looked for debris on the surface of the water , Truss said . It 's roughly 1,800 kilometers off the coast of Western Australia . Two ships have already started mapping the ocean floor of the area , a process that will take about three months . The underwater search , which will rely on the ships ' maps , is expected to begin in August . It will be led by a private contractor that Australian authorities will appoint . Malaysia will contribute equipment to the search effort , including vessels and towed sonar systems , Truss said . For families of the missing , a hole in the clouds , an empty space on earth .
Crew may have been in an `` unresponsive '' state , Australian authorities say . The crew was found unconscious and unresponsive, but the ship is still afloat after being towed to a nearby port for repairs. The next phase of the search will move to an area farther south in the Indian Ocean . The area is the `` most likely place where the aircraft is resting , '' an Australian official says .