"Greg Esres" wrote in message
...
Still, all this is of only academic interest. The one thing that IS
known is that the control surfaces must be protected at VA, and that
won't scale UP from published Va. Agreed?

No. Just because Part 23 doesn't stipulate that at a lower weight, a lower
airspeed must be used to ensure not overstressing the airplane in
turbulence, that does not mean that the maximum speed at which you can fly
and be assured of not overstressing the airplane does not go down as weight
is reduced.

Put another way: the minimum airspeed at which a given load factor can be
achieved before stalling the aircraft is positively correlated with weight
(i.e. it goes down as weight goes down, and goes up as weight goes up).
This is *known*. The fact that it's not stated in Part 23 does not make it
any less known.

Even your control surface tangent isn't really relevant to this particular
thread since you are intentionally limiting your comments to a single
weight. Again, just because Part 23 only requires a number to be defined at
a specific weight, that does not automatically mean that the number doesn't
exist at a different weight, nor does it necessarily mean that number is the
same at a different weight.

The definition of Va in Part 23 is clear. It has nothing to do with control
surfaces and everything to do with stall speed and load factor. Just
because Va is only used again within Part 23 for some other use, that does
not change the nature of the calculation. It is commonly understood that,
even though by definition Va exists only for a specific weight, that for the
purposes of flying, one needs to adjust the "operational Va" according to
weight if one expects to remain within the certificated load limits.

Pete