After a week of optimism over four underwater signals believed to be coming from the missing Malaysian plane, the sea has gone quiet and Australia's leader is warning that the massive search will likely be long.
No new electronic pings have been heard since April 8, and the batteries powering the locator beacons on the jet's black box recorders may already be dead. They only last about a month, and that window has already passed. Once officials are confident no more sounds will be heard, a robotic submersible will be sent down to slowly scour for wreckage across a vast area in extremely deep water.
"No one should underestimate the difficulties of the task still ahead of us,'' Prime Minister Tony Abbott said in Beijing on Saturday, the last day of his China trip.
Abbott appeared to couch his comments from a day earlier, when he met with Chinese President Xi Jinping to brief him on the search for the Malaysia Airlines flight, which was carrying 239 people _ most of them Chinese _ when it disappeared March 8 en route from Kuala Lumpur, Malaysia to Beijing.
After analyzing satellite data, officials believe the plane flew off course for an unknown reason and went down in the southern Indian Ocean off Australia's west coast.
Abbott expressed confidence that the signals heard by an Australian ship, which is towing a U.S. Navy device that listens for flight recorder pings, were coming from the missing Boeing 777's black boxes. But he said the fading batteries were making the job much harder. Recovering the plane's flight data and cockpit voice recorders is essential for investigators to try to piece together what happened to Flight 370.
"There's still a lot more work to be done and I don't want anyone to think that we are certain of success, or that success, should it come, is going to happen in the next week or even month. There's a lot of difficulty and a lot of uncertainty left in this,'' he said.
In Malaysia, Defense Minister Hishammuddin Hussein on Saturday refuted a front-page report in a local newspaper, the New Strait Times, that a signal from the mobile phone of co-pilot Fariq Abdul Hamid was picked up by a telecommunications tower near the Malaysian city of Penang shortly before the plane disappeared from radar. The newspaper report said the signal ended abruptly before contact was established.
Hishammuddin, who is also the acting