.. I think that we need a bit more of the question before we can come up with a convincing answer ...
Possibly The Don is thinking about a situation where, on a shortish runway for the Type, the weight is down anyway due to the declared lengths and the V1 becomes limiting due to rated thrust considerations (ie Vmcg) while trying to fit the ASDR within the ASDA. In such a case it is typical to see a lower than optimum weight due to ASDA considerations while there is plenty of spare distance for TORA/TODA at the weight in question. The trick is to find a way to reduce the V1 to reduce the ASDR which may provide a few more kilos ...
Especially if the takeoff may be unbalanced then use of a derate (as opposed to a flex or reduced) thrust may provide a reduction in Vmcg and, in turn, may permit a lower V1 resulting in a better ASDR-limited weight provided that the TORA/TODA considerations are OK at the higher weight .... all a case of juggling the oranges and lemons to get the best weight on the day.
Last edited by john_tullamarine; 3rd Aug 2003 at 08:51.