Chris Buckley and Nicola Clark, writing for the New York Times:
The plane sent out a series of such messages after civilian radar lost contact, he said. Those messages later stopped, but he declined to specify precisely when or how many messages had been received. Mr. Coiley said Inmarsat was sharing the information with the airline and investigators.
“It does allow us to determine where the airplane is relative to the satellite,” he said of the signal, which he likened to the “noises you might hear when a cellphone sits next to a radio or a television speaker.” He said: “It does allow us to narrow down the position of the aircraft” — at moment when the signal was sent.
Such equipment automatically checks in to satellites, much as a mobile phone would check in to a network after passing through a mountain tunnel, he said. Because the pings go over a measurable distance at a specific angle to one of the company’s satellites, the information can be used to help calculate the trajectory of an aircraft and narrow down its approximate location — though not necessarily its resting point.
I don’t warm to make light of a tragedy, but I’m really looking forward to the film adaptation of the hunt for MH370.