Originally Posted by
silvertate
It was the realisation that the aircraft was flying lower.
The resulting faster IAS, slower TAS, and thus slower groundspeed - and the resulting shorter range - meant that the search location had to move along the last ping-ring towards the northeast. Simple, really.
What we don't yet know, is why they suddenly realised that the aircraft flew at low-level.
P.S. If someone can post the fuel-burn/altitude tables for 1,000' and 10,000', it would be fairly easy to calculate roughly how low it flew.
I think the reasoning was the reverse. Assume last ping was at out-of-fuel. That gives a fuel burn rate which can then be reverse looked up to find the cruise levels/speeds that would result in that burn rate now fit those speeds/levels to the several INMARSAT rings the one that most closely fits tells you where on the final ring the aircraft was out-of-fuel. Use simulation of aircraft behavior when fuel is out at that level/speed, then generate a new search area. Pingo
