For all the Airbus drivers, check your gross weight on the lower Ecam against your fuel burn after take off, you may be surprised by how much more than the standard weight (83kgs) the pax and bags really are
(FCOM 1 DSC-22_40-30 P 2/4)
The principle of the speed computation is as follows:
‐ First, the FAC computes VS1G (stall speed). From VS1G it computes the Gross Weight (GW) which is also sent to the Elevator Aileron computers:
• When the aircraft is below 14 500 ft and 250 kt, it computes this from current angle of attack, speed/Mach, altitude, thrust, and CG.
• When the aircraft is above 14 500 ft or 250 kt, it computes this out of the GW, which it has memorized and updated with a fuel consumption model set in the FAC.
Basically, the aircraft reweighs itself once airborne and calculates all the speeds from there, clever french stuff
