Malaysia's government and satellite firm Inmarsat on Tuesday released the data used to determine the path of missing flight MH370, responding to calls from passengers' relatives for greater transparency.
The data from satellite communications with the Malaysia Airlines plane, which runs to 47 pages in a report prepared by Inmarsat, features hourly "handshakes" - or network log-on confirmations - after the aircraft disappeared from civilian radar screens on March 8.
Families of passengers are hoping that opening up the data to analysis by a wider range of experts can help verify the plane's last location, nearly three months after the Boeing 777 with 239 passengers and crew disappeared.
Separately, Australian investigators said the plane was likely running out of fuel when it stopped communicating with the satellite.
In a new analysis of available information, the Australian Transportation Safety Bureau said the final "handshake" was "consistent with the satellite communication equipment on the aircraft powering up following a power interruption," adding: "The interruption in electrical supply may have been caused by fuel exhaustion."
It added that calculations based on the amount of fuel on board were consistent with the jet running out of fuel at the point where the final "handshake" occurred.
An international investigation team, led by Malaysia, has concluded that the jet flew south after it was last spotted on Malaysian military radar and ended up in the southern Indian Ocean off western Australia.
This conclusion is based on calculations derived largely from the satellite communication data. Release of that data had become a rallying cry for many of the families, who have accused the Malaysian government of holding back information.
"When we first asked for the data it was more than two months ago. I never dreamed it would be such an obstacle to overcome," Sarah Bajc, the American partner of a passenger, told Reuters from Beijing.
Based on Inmarsat's and other investigators' analysis of the data, the aircraft is believed to have gone down in the Indian Ocean, off western Australia.
Malaysian investigators suspect someone shut off MH370's data links making the plane impossible to track, but investigators have so far turned up nothing suspicious about the crew or passengers.
In the hours after the aircraft disappeared, an Inmarsat satellite picked up a handful of handshake "pings", indicating the plane continued flying for hours after leaving radar.
The dense technical data released on Tuesday details satellite communications from before MH370's take-off on a Saturday morning at 12:41 a.m. local time to a final, "partial handshake" transmitted by the plane at 8:19 a.m. The data includes a final transmission from the plane 8 seconds later, after which there was no further response.
The data also featured two "telephony calls" initiated from the ground at 4.39 a.m. and 7.13 a.m. that went unanswered by the plane.
Bajc said experts on flight tracking, who have been advising the families, would now be able to analyse the data to see if the search area could be refined and determine if Inmarsat and other officials had missed anything.
But she complained that Tuesday's report was missing data that had been removed to improve readability, as well as comparable records from previous flights on MH370's route that the families had requested.
"Why couldn't they have submitted that?" she said. "It only makes sense if they are hiding something."
Malaysian officials were not immediately available to answer questions on the data.
Michael Exner, a satellite engineer who has been researching the calculations, said the data was unlikely to give any new insight. "There are probably two or three pages of important stuff, the rest is just noise," he told The Associated Press. "It doesn't add any value to our understanding."
Duncan Steel, a British scientist and astronomer, said some of the data "may" explain the belief that the aircraft went south rather than north, but that further confirmation would take a day or so. But he too was disappointed. "One can see no conceivable reason that the information could not have been released nine or 10 weeks ago. Even now, there are many, many lines of irrelevant information in those 47 pages," he told AP.
Reuters and The Associated Press contributed to this report.
First published May 26 2014, 9:53 PM