A New Zealand Air Force Orion has this morning returned to Perth empty-handed after a second search for a wooden pallet, spotted by a search plane.
And as new French satellite data comes in showing possible debris from the missing Malaysia Airlines Boeing 777, Australian authorities co-ordinating the search in the southern Indian Ocean have asked New Zealand to help analyse imagery from the search.
Flight MH370 went missing over the Gulf of Thailand on March 8 with 239 people aboard, including two New Zealanders. It was on its way from Kuala Lumpur, Malaysia, to Beijing and since then a multinational search effort has been carried out over wide swathes of ocean.
New Zealand Air Force Air Commodore Mike Yardley told Radio NZ the latest search by the New Zealand Orion had returned to Perth about 4.30am (NZ time).
"The weather conditions were not great," he said.
"We had sea fog right down to the surface of the water in half the area, and then 600 foot of cloud in the other half."
The crew had searched for 4½ hours but found nothing significant.
Yardley also said that over the weekend Australia had asked if New Zealand could help with imagery analysis from the search.
"Basically I'm talking about people just looking at video footage and checking and reviewing footage taken from the aircraft, as an example, and seeing whether they can see anything in that footage."
The sighting of a wooden pallet, which was seen with a range of coloured straps attached, raised hopes. While they were commonly used in shipping, they could also be used in cargo containers carried on planes.
The Australian Maritime Safety Authority (AMSA), which is leading the search in waters off Australia, said the aircraft that spotted the pallet was unable to take photos of it, so it sent planes and a ship to try to "re-find" it in an area 2500 kilometres southwest of Perth. An Australian navy ship was also involved in the search.
Meanwhile, France has provided new satellite data showing possible debris from the missing flight plane.
The new information, given to the Malaysian Government and forwarded to searchers in Australia, shows "potential objects" in the same part of the ocean where satellite images previously released by Australia and China showed objects that could be debris from the plane, Malaysia's Ministry of Transport said in a statement without providing further details.
Details on the data were not immediately released.
The statement called the French information "new satellite images", while a statement from France's Foreign Ministry said "radar echoes taken by a satellite" had located floating debris but made no mention of imagery.
AMSA declined to offer details about the French information.
"Any satellite images or other new information that comes to AMSA is being considered in developing the search plans," AMSA said.
But a Malaysian official involved in the search mission said the French data consisted of radar echoes captured on Friday and converted into fuzzy images that located objects about 930 kilometres north of the spots where the objects in the images released by Australia and China were located.
One of the objects located was estimated to be about the same size as an object captured on Tuesday by the Chinese satellite that appeared to be 22 metres by 13m, said the official, who declined to be identified because he isn't authorised to speak to the media.
It was not possible to determine precise dimensions from the French data, the official said.
Meanwhile police in Malaysia have also reportedly seized the personal financial records of all 12 crew members of the flight - including bank statements, mortgage documents and credit card bills.
Detectives also got hold of the mobile and landline phone records of the crew, along with details of their computer use and online habits, British newspaper The Sunday Times reported.
Investigators are treating as potentially significant a two-minute call shortly before take-off to the captain of the missing plane from a mystery woman using a mobile phone number obtained under a false identity.
The Mail Online reported it was one of the last calls made to or from the mobile of Captain Zaharie Ahmad Shah in the hours before his Boeing 777 left Kuala Lumpur.
Anyone buying a pay-as-you-go SIM card in Malaysia must fill out a form giving their identity card or passport number.
In this case, police traced the number to a shop selling SIM cards in Kuala Lumpur.
They found it had been bought "very recently" by someone who gave a woman's name – but was using a false identity.
There has been speculation that Zaharie, 53, was linked to anti-government protest groups in Malaysia.
Everyone else who spoke to the pilot on his phone in the hours before the flight took off has already been interviewed.
Australian Air Force flight Lieutenant Russell Adams told reporters yesterday's search was frustrating because "there was cloud down to the surface and at times we were completely enclosed by cloud".
Speaking at the military base where the planes take off and land on their missions, Adams said nothing of interest to searchers had been found, but the search was worth it because "we might do 10 sorties and find nothing, but on that 11th flight when you find something and you know that you're actually contributing to some answers for somebody".
An official with Malaysia Airlines said on Sunday night that the flight was carrying wooden pallets but provided no further details, including the number of pallets.
When Brazilian searchers in 2009 were looking for debris from Air France Flight 447 after it mysteriously plunged into the Atlantic Ocean, they first found a wooden pallet. The military initially reported that the pallet came from the Air France flight, but backtracked hours later and said the plane had not been carrying any wooden pallets.
The southern Indian Ocean is thought to be a potential area to find the jet because Malaysian authorities have said pings sent by the Boeing 777-200's engines for several hours after it disappeared indicated that the plane ended up in one of two huge arcs: a northern corridor stretching from Malaysia to Central Asia, or a southern corridor that stretches toward Antarctica.
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.
Authorities are considering the possibilities of hijacking, sabotage, terrorism or issues related to the mental health of the pilots or anyone else on board.