Originally Posted by
RatherBeOnATrain
The air in the atmosphere moves relative to the ground (ocean surface), so there are two "speeds" to calculate: Airspeed (speed of 777 relative to the air) and Groundspeed (speed of 777 relative to the ground).
Airspeed is a function of the fuel burn rate while the Groundspeed is what they need in order to calculate where the flight ended. (Groundspeed multiplied by the time flown will give the distance to the point where the flight ended.)
My reading of the updates is that the recalculations found a higher air speed and lower ground speed than originally calculated.
(I suspect that air and ground speed data from the search planes' flights gave them data about wind patterns, data that they did not have when they did the earlier calculations.)
True enough, and I suspect you are correct - as a pilot I found both pretty important. And in a very light plane one could go at a very low groundspeed with heavy headwinds, and really consume fuel.
And yep, the over-the horizon was not in position to "see" MH370 at the time, nor can I believe the Australians
ever go play games 1,000 miles southwest for several days merely to
pretend it didn't (though theoretically, it could have detected the aircraft flying over the "top half" of its coverage, Indonesia - northwest Australia). (Didn't know the Phase 2 was operating!)