TAKE OFF V SPEEDS
 

Your all singing all dancing performance program gives you ASSUMED TEMPERATURE, ACCELERATION HEIGHT, and V SPEEDS for your specific weight on the day.

The said program for a given runway flap setting airframe/engine and surface condition has a weight/mass range of minimum say 110,000 kilos up to a maximum of say 200,000 kilos.The airplane structural limit is about say 185,000 kilos.

Today due to a short flight your ACTUAL weight is only 90,000 kilos.Do you use the speeds for 100,000 kilos(bottom of the chart) or the speeds from the QRH/FCOM for the ACTUAL WEIGHT which are up to 15 knots lower?

Why would you have a program that didn't cover the full range of weights that you can operate at?? What would you do on an empty ferry flight??

Doesn't make sense to me.

However, given you parameters I would say use the figures of 100,000, if you can get away and clear obstacles at that weight you can sure do the same 10 tonnes lighter, you'll just have some margin up your sleeve.

15kts for 10T seems quite a lot. True, from performance criteria you could use V1 & V2 for the higher weight. But for Vr, if you try to use a speed 15kts faster than required you might find yourself 'holding' the a/c on the ground as it wants to loose its earthly bonds. Perhaps not a good idea. V1 can then = VR for the actual weight.

What would you do on an empty ferry flight?? By definition a ferry flight is empty, IMHO.

WTF! If Empty or Ferry, Have Some Fun!
 

If it is an empty ferry flight, fault the recorder's breakers, run it up to about 15Kts LESS than max tire speed and then go ZOOM! (Never done it, but did ride through a TO like that in the 70s. It is the ultimate "E" ticket ride, but in today's world, don't get caught.) :D:E

15 knots in excess when extremely light is no big deal. 15 knots slow may be a very big deal.
I seriously doubt V1 is going to be a critical number when that light as long as you're not doing a max power take off. Err on the high side and go have a beer afterwards.

Don't complicate it.

Ever tried an improved speed schedule? On the 737NG it can give you an up to 40kts higher Vr than the non improved one. Not a big deal at all.

Exactly, but if you do find that the old girl wants to get airborne you most definitely should not try to hold her on the ground.