From Wall Street Journal, 20th March:
March 8th
Within hours of Flight 370's disappearance on March 8, Inmarsat started searching for clues. What little data it had on the short flight before it disappeared was provided to SITA, a Swiss aviation IT company, on the same day, Inmarsat said.
March 9th
Late that weekend, Inmarsat's team delved into its databases to retrieve periodic "pings," akin to digital handshakes between the plane, a satellite and a ground station.
March 10th
Inmarsat Senior Vice President Chris McLaughlin said that on Monday, March 10, it began extrapolating the location of the jetliner using the aircraft's changing angle and distance to the satellite.
March 11th
Mr. McLaughlin said the data was shared the following day (11th) with SITA, which in turn shared it with Malaysian officials.
March 12th
The information was relayed to Malaysian officials by Wednesday, March 12. (March 13th Malaysian time.)
Concerned the data weren't being acted upon quickly enough to help overhaul the search, Inmarsat turned on Wednesday 12th to U.K. security authorities to more quickly disseminate the data.
Malaysia Airlines, in turn, instructed SITA to use the U.K. Air Accidents Investigation Branch as the primary conduit for Inmarsat's data.
March 13th
... ... ...
March 14th
Inmarsat issued the following statement: "Routine, automated signals were registered on the Inmarsat network from Malaysia Airlines flight MH370 during its flight from Kuala Lumpur. This information was provided to our partner SITA, which in turn has shared it with Malaysia Airlines. For further information, please contact Malaysia Airlines."
March 15th
Malaysia's government, concerned about corroborating the data and dealing with internal disagreements about how much information to release, didn't publicly acknowledge Inmarsat's information until March 15.
Comments
It wasn't clear how U.S. officials obtained the initial Inmarsat data, which they analyzed and helped translate into maps. Regardless, people briefed on the probe agree it took longer than expected for the information to spread from engineers and technical experts to policy makers and then back down to officials directing specific elements of the searches.
The disclosures about how the information made its way into the investigation underline how international efforts to find the plane have been repeatedly marred by distrust among the countries involved, confusion in many of Malaysia's public statements, and criticism from many countries that has led some to suspend or change their search efforts in frustration.
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I don't see this as Malaysia impeding useful implementation of the data.
It seems something happened from when Inmarsat asked UK security to help out on the 12th, which seemingly resulted in American agencies doing further analysis on it with the Brits. Those results were not ready to be made public until the 15th. It's a mess, sure, but resulting from so many agencies being involved rather than Malaysian skullduggery.