Australian officials coordinating international efforts to find the missing Malaysian airliner moved the search area in the southern Indian Ocean on Friday, after new calculations on the plane's speed.
Flight MH370 vanished on 8 March with 239 people on board, deviating inexplicably off its intended course between Kuala Lumpur and Beijing, and flying thousands of kilometres in the wrong direction.
Ten aircraft, including a New Zealand Orion, were scheduled to fly out from Perth to the new area on Friday, about 1800km west of the Australian city and 1100km north of where searchers had been concentrating for more than a week.
The shift in the search area, moving it further than the distance between London and Berlin, followed analysis of radar data from Malaysia showing the Boeing 777 had travelled faster, and so would have run out of fuel quicker, than previously thought.
The new search area is larger at 319,000 square kilometres - roughly the size of Poland - but closer to the West Australian city, allowing aircraft to spend longer on site by shortening travel times. It is also vastly more favourable in terms of the weather, as it is out of the deep sea region known as the Roaring 40s for its huge seas and frequent storm-force winds, Reuters reports.
"I'm not sure that we'll get perfect weather out there, but it's likely to be better more often than what we've seen in the past," John Young, general manager of the emergency response division of Australian Maritime Safety Authority (AMSA), told reporters on Friday, adding that the previous search site was being abandoned for a more "credible lead".
Satellite orbits are being changed to take photographs of the new search zone. A flotilla of Australian and Chinese ships would take longer to shift north, however, with the Australian naval ship the HMAS Success not due to arrive until Saturday morning.
The US Navy said on Friday it was sending a second P8-Poseidon, its most advanced maritime surveillance aircraft, to help. The US has also sent a device that can be towed behind a ship to pick up faint pings from the plane's black box voice and data recorders, but time is running out as the black box has limited battery life.
The latest twist underscores the perplexing and frustrating hunt for evidence in the near three-week search. It comes less than a day after the latest reports of sightings of possible wreckage, captured by Thai and Japanese satellites in roughly the same frigid expanse of sea as earlier images reported by France, Australia and China.
On Thursday, Thailand's space agency reported satellite images showing 300 items floating in the southern Indian Ocean, ranging from two to 15 metres in size, that could be debris from the ill-fated flight. That discovery was reported less than 24 hours after the Malaysian government revealed 122 objects had been seen about 2557km from Perth, ranging in length from one metre to 23 metres.
Potential debris has also been seen from search aircraft, but none has been picked up or confirmed as the wreckage of Flight MH370.
Officials believe someone on board may have shut off the plane's communications systems before flying it thousands of kilometres off course, where it crashed into the ocean in one of the world's most isolated and forbidding regions.
Theories range from a hijacking to sabotage or a possible suicide by one of the pilots, but investigators have not ruled out technical problems.
The prolonged and so far fruitless search and investigation have taken a toll, with dozens of distraught relatives of 150 Chinese passengers clashing with police and accusing Malaysia of "delays and deception".
Chinese insurance companies have started paying compensation to the families of passengers, some of the firms and state media said.