Originally Posted by
porterhouse
If you think about it - the same 'rings' could be generated by millions of trajectories, some probably quite spread out in directions.
I did.
If you knew the accurate groundspeed hour by hour you will finish up with a very narrow probable track band.
As you increase the speed range you will get a wider band.
I presume from successive Doppler they have been able to deduce a reasonable accurate speed range hence the track band was determined and the cessation of transmissions determined the track box length.
As there is uncertainty between transmission cessation and aircraft crash they would attempt to refine the box based on estimated fuel exhaustion. Fuel burn is probably the most problematical of the assumptions, next is the descending flight path once transmissions ceased.
The flight path could be near vertical as some have supposed or a shallow glide in any direction.
And lastly there are the pings.