Clipping and highlighting:
The Doppler effect gives a compression of wave fronts when a source is approaching, and a spreading out as it recedes, for example the familiar eeeh-whooosh when a fast moving car goes the other way on the highway.
By applying it to the pings and using the range data given by the intensity of the signal and/or time delays relative to set times, we can credibly construct range and direction of travel, perhaps even work out the speed of approach/recession, which could help reconstruct the path more fully.
South, not North.
Until compelling reason points otherwise, this is the reasonable conclusion, as on a northerly track, all pings would have been receding.
And it did not look to be on track to Australia but the reaches of the southern Indian Ocean.
Unfortunately, this supports the conclusion that this ended in a fatal crash, with no survivors.
Why, is another story.
Maybe there was a hijack and somehow a southern path got plugged into an autopilot that could not be over-ridden (the pilots being by then dead)?
Maybe, willful suicide and mass murder?
We don't know.
Telegraph of the UK summarises:
But we must weep and mourn with those who mourn and seek to comfort them. END