I am sorry for causing quite a stir with such a simple question. After sifting through opinions, emotions, hearing from owners, and insiders, this is what I have found.
The commotion was caused by your misunderstanding of the 650 lb – whether it was “Useful Load” or “Useful Load with Full Fuel”!!!
Useful Load(approx) = Gross wt minus empty wt
The definition of Useful Load is Gross weight minus empty weight – no approximate to it!!!
The only approximate is that your airplane has not been built and the empty weight will not be known until it is put on the scales and weighed!!!
Remember the the empty weight is for a paticular aircraft and must be adjusted for all additions or subtractions to your a/c (i.e. if you damage your aircraft and have it repaired and the mechanics add 100 lb more to repair the damage than the original construction – then you lost 100 lb of useful load – gross weight - (original empty weight + repair weight).
Current delivered SR-20’s have a useful load of approximately 815-860lbs.(depending on equip)
Cirrus is currently seeking FAA approval to increase the gross wt of the SR-20 by 150-200lbs, without structural or aerodynamic changes. This process requires new testing at the new gross wt. which will produce new performance numbers.
When they succeed, the new useful load will be approximately (965lbs - 1070lbs)
AH…YES… the answer we all are looking for.