Hi,
I believe our actual take off weights can be more than we've calculated because of the different standard weights we assume. (20 kgs difference was noted by Genghis).
On A 320 series the VLS is computed by the angle of attack probe & FAC. The FMGC VLS & VAPP is computed using Fuel remaining + the Zero Fuel Weight (entered from Weight & Balance calculation). There is often a difference in the two VLS values of about 3kts when on the approach; i.e. the aircraft's VLS FAC calculation thinks we are heavier than the weight & balance calculation.
If it was just a random error in the way the angle of attack vane is mounted on the aircraft, then we'd see + and - speed differences. I've only ever noticed that we seem to be heavier than we think we are.
Last edited by rudderrudderrat; 28th Mar 2010 at 10:15.
Reason: syntax