PERTH, Australia: The difficult hunt for wreckage from Malaysia Airlines MH370 resumed in the southern Indian Ocean on Wednesday, as a US firm took the first steps towards potentially huge lawsuits on behalf of grieving families.
Despite the vast and remote search area and mountainous seas, Australian Prime Minister Tony Abbott said he was confident that participating countries would recover debris from the Boeing 777 passenger jet that Malaysia has said crashed in the ocean.
But as the search continued, US law firm Ribbeck Law Chartered International said it was getting the ball rolling on a potential "multi-million dollar" legal action against Malaysia Airlines and Boeing, raising the spectre of massive civil lawsuits in the disaster.
"We believe that both defendants named are responsible for the disaster of Flight MH370," the firm said in a statement.
It said it filed a court petition in the US state of Illinois Tuesday seeking documents pertaining to possible manufacturing defects or airline misconduct that may have led to the disaster.
The plane vanished on March 8 with 239 passengers and crew on board, en route from Kuala Lumpur to Beijing.
Malaysian authorities said Monday that satellite data analysis had determined the plane plunged into the southern seas far off western Australia, possibly after running out of fuel.
The gale-force winds, driving rain and high seas that prevented air sorties in the area a day earlier eased Wednesday, and the Australian Maritime Safety Authority (AMSA) said seven aircraft were in the search area, with four more on the way.
The Australian naval vessel HMAS Success had also returned to the zone to search for two objects spotted from the air this week.
AMSA said four Chinese ships had also reached the area, in the quest to find physical proof that the jet went down, and clues about why it veered off course.
Relatives have endured more than a fortnight of agonising uncertainty about the plane's fate and, lacking firm evidence, some still refuse to accept it had crashed.
Two-thirds of the passengers were from China, and relatives there have accused Malaysia of deception and callousness in handling the tragedy.
Scores protested outside Malaysia's embassy in Beijing on Tuesday, scuffling with guards and abusing the ambassador as they demanded to know what happened to their loved ones.
"I still believe in direct evidence like something from the plane, or something like that. If they got something (debris) then maybe I will accept the result," said Steve Wang, whose 57-year-old mother was on board.
Speaking in Canberra ahead of a moment of silence in parliament for victims of the flight, which included six Australians, Abbott said the search would continue until there was no hope of finding anything.
Weather and the crash area's distance from land have foiled efforts to recover objects suspected to be from MH370 despite a number of sightings, but Abbott said "we are confident" that debris will be found.
"The crash zone is about as close to nowhere as it's possible to be, but it's closer to Australia than anywhere else," he said.
Authorities hope to eventually retrieve the "black box" and its precious flight data, believing it could hold clues to what happened.
But experts warned a chain of undersea volcanoes runs directly through the region, creating a rugged ocean floor constantly reshaped by magma flows, which could complicate the already uphill task of finding the black box.
"It's very unfortunate if that debris has landed on the active crest area, it will make life more challenging," Robin Beaman, an underwater geology expert at Queensland's James Cook University, told AFP.
The US Navy has sent a specialised device to help find the black box, along with a robotic underwater vehicle that can scan the ocean's depths.
The black box will emit a locator signal for 30 days once activated by contact with water, giving searchers less than two weeks to find the crash site.
The plane deviated inexplicably off its intended course between Kuala Lumpur and Beijing, flying thousands of kilometres in the wrong direction.
Malaysia believes the plane was deliberately diverted by someone on board. Scenarios include a hijacking, pilot sabotage or a crisis that incapacitated the crew and left the plane to fly on auto-pilot until it ran out of fuel.
Malaysia Airlines said it was "aware" of the US legal action but declined further comment.
Malaysia authorities on Tuesday released more details of the data used to conclude the plane went down in the Indian Ocean.
It said the last complete contact between a satellite that was "pinging" signals to the flight came at 8:11 am Malaysian time (0011 GMT), with another "partial" signal eight minutes later.
The findings, by British satellite communications firm Inmarsat, suggest the plane was still in touch right around the time it would have run out of fuel.
Malaysia has said a precise location where the plane went down could not be determined from the data.