determination of V speeds at very low takeoff weight on A320

[speedbird787]

dear capts.

how to determine the V speeds if the takeoff weight is below the last weight row on the RTOW ( weight entry charts)

example: say last weight on the RTOW is 56 .....and in the 5 kt HW colum we have speeds of say 113/125/129........how to determine the v speeds if the take off weight is 54 ......( min speeds being say113/117/128)......

do we decrease 1 kt for every 1000 kg......and if we do that.....we go below the min speeds.......then which speeds are supposed to bre used for take off:rolleyes:

thanks

[cosmiccomet]

According to the 7-FCOM Performance-TAKE OFF
TAKE OFF CHARTS-MTOW CALCULATION (TEMPERATURE ENTRY)
EXTRAPOLATION
For a takeoff weight lower than those displayed on the chart, associated speeds are calculated as follow:

1. For given configuration and wind, note the speeds associated with the takeoff weight in the row displaying the highest permissible temperature.

2. Apply speed corrections provided at the bottom of the RTOW chart to V1, VR and V2 limited to the minimum speeds.