A320 FMGS Question
I have a tech question on the A320 FMGS. The question concerns the EXTRA/TIME section of the FUEL PRED page. I know from the manuals how the EXTRA/TIME is calculated before the engines are started, but how is it calculated during flight? The manuals I have talk about using BLOCK-(TAXI+TRIP+RSV+ALTN+FINAL), but in flight surely it must be based somehow on FOB vs fuel to destination? Any help would be appreciated.