Originally Posted by R2000/1830
Vmca, is based on the following:
1)MTOW
That being said, I understand all but #1. Does weight affect Vmca (or Vmcg) I would think it does but I have read otherwise.
MTOW - No.
Vmca is most critical; at MINIMUM weight. This is because the amount of bank into the live engine is limited - by regulation - at 5 degrees.
For a given weight, the sideslip to balance 5 deg bank can be determined; the heavier the aircraft, the more sideslip you need to balance 5 deg bank. Since that sideslip HELPS control the asymettric engine, it follows that the critical case is where the sideslip is minimize, i.e. the lowest weight. Therefore Vmca is highest at the minimum weight.
Vmcg is less clear-cut and one can argue that its pretty much independent of weight. the regs/AC require testing at the weight where Vmcg is critical, but dont specify the weight, so its up to the OEM to convince the NAA that they have the right test conditions.