Genghis, Gedifroggy,
We have two threads running here. One is, what do we teach for the JAR exams?, and the other is, what do we need to know to feel confident in our teaching?
The first is easy. As I said, the JAR ATPL question bank has a very simple definition of Va, and supplementary questions seem to be limited to how Va changes when Vs1g changes, usually because of a change of mass.
The second problem is more difficult. First, I would hold, in the real world, that Va does not change with change of mass, as it is a design speed, a standard to use in stress calculations. It is a worst case, and fixed. You could say that the speed at which you could deploy full control and remain inside the structural limits would change with mass, but Va is allways Va.
Anyway, to get 2.5g in a level turn you would need over 60º bank, and the aircraft would have been shouting "bank angle, bank angle" at you long before that. It pure pitch manoeuvres it is difficult to see where you would be pulling to the stall above Va, except in a complete upset at high speed, and in any case the control laws will be protecting you.
So the exact definition of Va is academic as far as the JAR exams are concerned. Equally so with
Vb.
Vb is a design speed, and is not Vra. Vc, likewise, is not your cruising speed, and is probably going to be more or less Vmo/Mmo. Vd can entirely theoretical. Design speeds are for designers. Pilots use Flap and gear placard speeds, Vra and Vmo/Mmo. Designers use stress diagrams, pilots use buffet boundary charts.
So, I lke to know exactly what the JAR rules say, but I don't teach them. I teach how to read and use the charts and information that will come out in the operating manual when th designers have finished designing and the certification guys have certified the aircraft.
Gedifroggy, e-mail me at
[email protected] if you want to carry on with this. Genghis, interesting proposal. I should warn you that Alex doesn't pay me much, and I'm his father! E-mail us with your contact address please.
Dick W