KUALA LUMPUR, Malaysia (AP) — Search planes sent to find objects in the south Indian Ocean that may be from the missing Malaysia Airlines jet began returning without success Friday, and an Australian official said the hunt would be extended again for another day.
The planes are part of an international effort to solve the nearly 2-week-old aviation mystery by locating two large objects a satellite detected floating off the southwest coast of Australia about halfway to the desolate islands of the Antarctic.
The area in the southern Indian Ocean is so remote is takes aircraft four hours to fly there and four hours back, and leaves them only about two hours to search.
The satellite discovery raised new hope of finding the vanished jet and sent another emotional jolt to the families of the 239 people aboard.
But like the first day of searching Thursday, efforts so far Friday have been fruitless, said John Young, manager of the Australian Maritime Safety Authority's emergency response division.
"Although this search area is much smaller than we started with, it nonetheless is a big area when you're looking out the window and trying to see something by eye," Young said.
"So we may have to do this a few times to be confident about the coverage of that search area," he said.
Five planes were sent out, with the last expected to head back to Perth in western Australia about 1100 GMT, he said.
Young said that although the weather improved from Thursday, there was still some low cloud cover over the search area 2,300 kilometers (1,400 miles) from western Australia. Given that radar did not pick up anything on Thursday, searchers were using their eyes instead of equipment to try and spot the objects, forcing the planes to fly very low over the water.
The aircraft are planning to head back to the search zone on Saturday, but the search area will change slightly depending on water movements overnight, Young said.
AMSA officials are also looking to see if there is any new satellite imagery that can help provide searchers with new or more information, he said.
Speaking at a news conference in Papua New Guinea, Australian Prime Minister Tony Abbott said, "We've been throwing everything we've got at that area to try to learn more about what this debris might be."
He said that the objects "could just be a container that's fallen off a ship — we just don't know."
Abbott spoke with Chinese President Xi Jinping, whom he described as "devastated." Of the 227 passengers on the missing flight, 154 were from China.
"It's about the most inaccessible spot that you could imagine on the face of the earth, but if there is anything down there we will find it. We owe it to the families of those people to do no less," Abbott said.
The development also marked a new phase for the anguished relatives of the passengers, who have been critical of Malaysian officials for what the relatives say has been the slow release of timely information.
In Beijing, relatives met Friday with Malaysian officials at the Lido Hotel, where most have been staying awaiting the latest news. Those who spoke said they had a two-hour briefing about the search but that nothing new was said.
Wang Zhen, son of artist Wang Linshi, said the meeting went smoothly but that there were questions on why Malaysian authorities had provided so much seemingly contradictory information.
Wang said he has hopes his father can be found alive and was praying that the Australian reports turn out to be false. He said he and other relatives are suspicious about what they were being told by the Malaysian side, but are at a loss as to what to do next.
"We feel they're hiding something from us," said Wang, who was filling his days attending briefings and watching the news for updates.
One of the objects on the satellite image was 24 meters (almost 80 feet) long — which is longer than a standard container — and the other was 5 meters (15 feet).
The Norwegian cargo vessel Hoegh St. Petersburg is also in the area and its crew of 20 Filipinos is helping with the search. The ship, which transports cars, was on its way from South Africa to Australia, he said. The Australian Maritime Safety Authority said another commercial ship and an Australian navy vessel were also en route to the search area.
Three Chinese naval ships were heading to the area, along with the icebreaker Snow Dragon, China's state television reported. The icebreaker was in Perth following a voyage to the Antarctica in January, but it wasn't clear when the other ships would get there.
The combination the planes are using of radar to detect objects coupled with low passes over the ocean to identify them visually is crucial because when "radar blips come back it's not always clear what the object is," said Michael Smart, an aerospace engineering professor at Australia's University of Queensland.
"They use the radar to focus and then they go and visually look to see what it is," he said. "The high technology and the low technology are equally important."
The biggest challenges for the searchers are weather conditions in an area known for its storms, he said, though rainy and cloudy weather appeared to be clearing up Friday afternoon. And if the objects are partially submerged as they bob in the ocean that could also affect the planes' radar detection capabilities.
Smart predicted that "it will be just a matter of time before they are found. If they were going to sink they would have already."
The hunt has encountered other false leads. Oil slicks that were seen did not contain jet fuel. A yellow object thought to be from the plane turned out to be sea trash. Chinese satellite images showed possible debris, but nothing was found.
Malaysian authorities have not ruled out any possible explanation for what happened to the jet, but have said the evidence so far suggests it was deliberately turned back across Malaysia to the Strait of Malacca, with its communications systems disabled. They are unsure what happened next.
Police are considering the possibility of hijacking, sabotage, terrorism or issues related to the mental health of the pilots or anyone else on board.
Gelineau reported from Sydney, Australia. Associated Press writers Rod McGuirk and Todd Pitman in Kuala Lumpur; Nick Perry in Wellington, New Zealand; and Christopher Bodeen in Beijing contributed to this report.