Two naval ships with locator capabilities are searching a 240km underwater path, in the hope of recovering the plane's data recorder that could help investigators unravel the mystery of what happened on March 8, the day the Beijing-bound plane dropped off radar.
Up to 14 planes and nine ships are participating in today's search for the Boeing 777-200.
The British Royal Navy survey ship HMS Echo and the Australian naval supply ship Ocean Shield began searching the ocean's depths today, said retired Air Chief Marshal Angus Houston, the head of the Perth-based Joint Agency Coordination Centre (JACC), said.
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.
But the area of the southern Indian Ocean where British and Australian naval ships are deploying sophisticated listening technology remains nothing more than a guess at where the plane may have hit the water, CNN said.
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 next four days.
Nearly four weeks have passed since the jetliner vanished with 239 people, including five Indians on board.
Investigators are still stumped by the case as there are no signs of debris. The area chosen for the search operation is based on the analysis of radar, satellite and other data that led the investigators to conclude that the flight ended in the southern Indian Ocean.
"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.
"It's on the basis of data that arrived only recently, and it's the best data that is available."
"On best advice, the locator beacon will last about a month before it ceases its transmissions, so we're now getting pretty close to the time when it might expire," he said.
Until searchers can find a confirmed piece of debris from the plane, which would give them a clearer idea of where the main bits of wreckage might be located, there is no certainty of finding the black box.
Until we get conclusive evidence of debris, it is just a guess. Searching with the pinger locator trailing from a ship is painstaking work, a US Navy official quoted as saying by the CNN.
Authorities still have no idea how or why it crashed and warn that unless the black box is found, the mystery may never be solved.
If floating MH370 debris is eventually found, authorities plan to analyse recent weather patterns and ocean currents to determine where the plane went down.
Malaysian Premier Najib Razak, whose government has come under fire for the handling of the probe into the mysterious disappearance of the plane, yesterday flew in here to see search operations.
Australian Prime Minister Tony Abbott today met with staff at the Australian Maritime Safety Authority, which is coordinating the search efforts, and said, "It is probably the most difficult search that's ever been mounted."
"A large aircraft seems like something that would be easy enough to locate but a large aircraft that all but disappeared and disappeared into inaccessible oceans is an extraordinary, extraordinary challenge that you're faced with," he said.
A false alert was experienced yesterday by the JACC.
"False alerts may be experienced from biological sources such as whales or interference from shipping noise," it said.
Malaysia believes the flight was deliberately diverted by someone on board and that satellite data indicates it crashed in the Indian Ocean.
A relative of a passenger aboard Malaysia Airlines Flight MH370 reacts after attending a video conference with the Malaysian government and Malaysia Airlines officials from Kuala Lumpur, at the Lido Hotel in Beijing.The search for the missing Malaysia Airlines Flight 370 resumed on Wednesday, even as senior Australian officials warned that bad weather and a lack of reliable information were seriously impeding efforts to locate the plane's wreckage.(Reuters)