does the CAD display not give a consumption rate and fuel time?
There is an option to have that facility, however I don't believe it is fitted/activated as standard on any UK Police/AA 135's.
The 902 we used to have could display the fuel flow rate and there was occasion where I had the display up in order to have a more accurate idea of how much longer we could stay on task before reaching bingo.
However, this all now boils down to the mantra I remember being drummed into us from the start of the IF phase - '
Always Trust Your Instruments'
! 