Malaysia Airlines Flight 370 was "highly likely" to have been on autopilot as it flew into the southern Indian Ocean, Australian officials said Thursday, divulging new details about the missing plane's probable fate.
The comments were made during a news conference to announce a southward shift 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.
But the officials said they weren't sure exactly when the autopilot had been turned on.
And they declined to talk about the causes behind the errant flight path, saying those are questions for the Malaysian authorities in charge of the overall investigation.
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The 850 square kilometers scanned off the coast of western Australia in the hunt for a missing Malaysia Airlines plane are not the "final resting place of MH370," the agency leading the search said Thursday.
The search area is where four acoustic pings originally thought to be from the black boxes of the Boeing 777 were heard in early April.
"The Australian Transport Safety Bureau (ATSB) has advised that the search in the vicinity of the acoustic detections can now be considered complete and in its professional judgment, the area can now be discounted as the final resting place of MH370," a statement from the Joint Agency Coordination Centre said.
Unlikely to be from Flight 370
Hours earlier, a U.S. Navy official told CNN that the pings at the center of the search for the past seven weeks are no longer believed to have come from the plane's black boxes.
The acknowledgment came Wednesday as searchers wrapped up the first phase of their effort in the southern Indian Ocean floor without finding any wreckage from the jetliner.
Authorities now almost universally believe the pings did not come from the onboard data or cockpit voice recorders but instead came from some other man-made source unrelated to the jetliner that disappeared on March 8, according to Michael Dean, the Navy's deputy director of ocean engineering.
If the pings had come from the recorders, searchers would have found them, he said.
Dean said "yes" when asked if other countries involved in the search had reached the same conclusions.
"Our best theory at this point is that (the pings were) likely some sound produced by the ship ... or within the electronics of the Towed Pinger Locator," Dean said.
The pinger locator was used by searchers to listen for underwater signals.
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Data from communications between satellites and missing Malaysia Airlines Flight 370 was released Tuesday, more than two months after relatives of passengers say they requested that it be made public.
Malaysian authorities published a 47-page document containing hundreds of lines of communication logs between the jetliner and the British company Inmarsat's satellite system.
The information provided isn't the whole picture but is "intended to provide a readable summary of the data communication logs," the notes at the start of the document say.
Some passengers' families, unsatisfied by official explanations of the plane's fate, say they want an independent analysis of the complex information, a process that could take some time.
"The first thing we're going to expect feedback on is does the data look right," said Sarah Bajc, whose partner, Philip Wood, was on the missing jet. "Is it as complete as we're being led to believe it is?"
She said, though, that she was "annoyed" that Inmarsat and Malaysian authorities hadn't released the raw data in its entirety.
"I see no reason for them to have massaged this before giving it to us," she said.
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It sounds like standard radio chatter between an airplane and ground control, mostly repeating the identifying number of the flight.
But the recording that Malaysian officials played for the first time in public in a Beijing conference room on Tuesday is purportedly the last known words of Malaysia Airlines Flight 370 before it disappeared on March 8.
"Malaysia three-seven-zero contact Ho Chi Minh 120.9, good night," says a voice identified by Malaysian officials as that of a radar controller in Kuala Lumpur, the Malaysian capital.
"Good night Malaysian three-seven-zero," answers a male voice believed to be a crew member on the plane.
Malaysian officials released the audio recording more than 50 days after the plane disappeared, in a long-awaited briefing before scores of relatives of the flight's Chinese passengers.
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The hunt for Malaysia Airlines Flight 370 has penetrated beneath the waves as searchers race to catch pings from the missing plane's flight data recorders before they fall silent.
But the area of the southern Indian Ocean where British and Australian naval ships are deploying sophisticated listening technology remains nothing more than an educated guess at where the plane may have hit the water.
The British Royal Navy survey ship HMS Echo and the Australian naval supply ship Ocean Shield began searching the ocean's depths along a single 240-kilometer (150-mile) track Friday, said retired Air Chief Marshal Angus Houston, the head of the Australian agency coordinating the search efforts.
The Ocean Shield is equipped with high-tech gear borrowed from the United States: the TPL-25, a giant underwater microphone that will listen for the pings from the flight data recorders, and the Bluefin-21, an underwater robot that can scour the ocean bed for signs of wreckage. The HMS Echo also has advanced sensor equipment.
Time is running out in the efforts to detect the pings as the batteries that power the recorders' beacons are expected to expire in the coming days.
"If they do find it, I think it'll be remarkable," said Bill Schofield, an Australian scientist who worked on developing flight data recorders.
Nearly four weeks have passed since the jetliner vanished with 239 people on board. With investigators still apparently stumped by the case, information in the flight recorders could help them unravel the mystery of what happened the night the plane dropped off radar.
But there are no new clues behind the area where the underwater search is concentrated. It's based on the same kind of analysis of radar, satellite and other data that investigators have used to determine a series of shifting search areas in recent weeks.
"The area of highest probability as to where the aircraft might have entered the water is the area where the underwater search will commence," Houston said at a news conference Friday. "It's on the basis of data that arrived only recently, and it's the best data that is available."
Despite better weather, the first of five search planes dispatched to look for floating debris that could be related to missing Malaysia Airlines Flight 370 returned to base Friday without spotting anything of note.
The surveillance planes are looking for two objects photographed by a commercial satellite on Sunday bobbing in the remote and treacherous waters of the southern Indian Ocean off the west coast of Australia.
Aircraft and a merchant ship scoured the area Thursday, but found nothing in a search hindered by poor weather.
Flight 370 vanished 14 days ago with 239 people aboard, and the announcement Thursday by Australian officials that they had spotted something raised hopes of a breakthrough in the frustrating search.
On Friday, Australian Prime Minister Tony Abbott defended the decision to announce the find, saying that Australia owes it to families f those missing "to give them information as soon as it's to hand, and I think I was doing that yesterday in the Parliament."
But he reiterated a warning that two objects spotted by satellite in a remote area of the southern Indian Ocean, which are now being sought by aircraft and ships, may not be related to the search for the plane.
"It could just be a container that has fallen off a ship," he said during a visit to Papua New Guinea. "We just don't know."
His words have focused worldwide attention on Australia's part in the massive international hunt for the jetliner, which disappeared March 8 over Southeast Asia with 239 people on board.
Almost two weeks after the Boeing 777-200 dropped off radar screens, authorities still don't know why it veered dramatically off course or where it ended up.
Because of the "anxiety and apprehension" experienced by relatives of the people aboard the plane, Abbott said
Search teams that flew over the area where the two objects are thought to be located drew a blank Thursday, with poor visibility reported. Flights to the zone by long-range reconnaissance planes resumed Friday, Australian authorities said.
The search area, thousands of kilometers southwest of Perth, the main city on Australia's west coast, is "about the most inaccessible spot you could imagine on the face of the earth," Abbott said.