in my company we use the old system of loadsheet and perf booklet to do our calculations and then cross check what the fmc is saying and if they are within 1 kt we line select the fmc speeds,if not we go with the book figures.
so i stand by my gross error check and it hasn't let me down to date, and besides when the weight v spd check starts to differ greatly we take an extra minute to have another check to insure flaps/weights/runway etc.... are all correct.
automation is nice but what did we do before we had it??????
