Families of passengers aboard missing flight MH370 on Wednesday accused Malaysia of withholding crucial satellite data, saying a long-awaited report is incomplete and does not prove the plane crashed in the Indian Ocean.
Authorities on Tuesday released a 47-page summary of communication logs from the Malaysia Airlines plane recorded by British satellite operator Inmarsat, information which relatives and independent experts had demanded.
No wreckage from the jet, which disappeared on March 8 en route from Kuala Lumpur to Beijing with 239 passengers and crew on board, has been found despite a massive international search off western Australia.
Many relatives are frustrated over the lack of progress, and have little faith in the complex process used to form the theory that the plane veered off course for reasons unknown after losing contact, and then crashed into the southern Indian Ocean.
Michael Exner, a US-based satellite engineer and one of the most prominent independent experts to analyse the findings, said Malaysia had failed to provide crucial supporting details together with the Inmarsat logs.
"There is a little bit more new information that may help us. But there is just a very large body of metadata that is missing," he told AFP.
"They are not being transparent," he added. "It may not be possible to draw any conclusions. Why don't they just release all? Why do they hide so much of it?"
Exner said it would take days to properly examine even the limited technical data that had been released.
Steve Wang, a spokesman for a support group of relatives of the flight's 153 Chinese passengers, accused authorities of holding back data.
"We want a complete report releasing all the information on how the theory behind the plane's position was reached, so that we can invite experts to give their independent opinion."
"So much time has passed and nothing has been found, so we doubt that the calculated position of the plane is correct," he said.
Sarah Bajc, the girlfriend of American passenger Philip Wood and a vocal critic of the Malaysian response, said the authorities had chosen to "manage" what they released instead of handing over the original raw data.
"This report is anti-climatic. Our original request for the data was over two months ago... For it to have taken so long to release data that has still been manipulated is just ridiculous," she told AFP.
The Boeing 777's transponder, which relays an aircraft's location, and its Aircraft Communications Addressing and Reporting Systems (ACARS), which transmits information on a plane's mechanical health, appear to have been shut off around the time it went missing.
That forced authorities to piece together a picture of its path from other information including satellite signals, radar data and aircraft performance calculations.
The untested method has left the door open for relatives, already critical of the handling of the Malaysia-led investigation, to suggest that authorities may have got their sums wrong.
In response to the criticism, Malaysia's civil aviation chief Azharuddin Rahman said that any further queries should be directed to Inmarsat.
"There is no plan at this stage to provide any further details on the Inmarsat raw data," he told AFP.
Malaysia has insisted it is doing as much as it possibly can in what is an unprecedented situation.
However, the coalition that has been in power for 57 years has a history of using its entrenched position of power to cover up scandals -- a backdrop that has fuelled the scepticism and conspiracy theories.
Relying in part on the Inmarsat data, officials believe the jet inexplicably veered off its flight path before crashing into the sea, possibly after running out of fuel.
The sketchy data was extrapolated using the Doppler effect -- the change in frequency of waves from a moving object -- to decipher the final flight path.
One phase of the search -- using a mini-submarine to scour the ocean depths -- is set to end this week. The next phase will involve using sophisticated equipment to scan the unmapped ocean bed.
Australia, which is leading the hunt in the Indian Ocean, has committed up to US$84 million towards the search operation over two years.