Of course, we miss pitch moment curves for the A330 to understand what ND or NU inputs could do. Owain Glyndwr posted a very interesting explanation but I am not convinced the THS was not stalled at 60 deg AoA. We know that the elevator was still working from BEA’s note but perhaps this was due to the elevator presenting a larger frontal area to the airflow in ND position than in NU. The effect of a stalled THS would be a positive slope of the Cm curve in the stalled area, meaning a decreasing downward moment with increasing AoA.
My point was that to maintain 60 deg AoA you need a lot of UP elevator, which takes the THS away from stall. Gums curves and the curves in that NASA report on civil aircraft upset recovery (cited in thread #4 IIRC) show that the THS can stall if DOWN elevator is applied at that sort of AoA but there is no sign of stall with up elevator in either case. To hold 60 deg AoA you need a DOWNLOAD on the THS. What you describe is a stall with a POSITIVE THS load. What I meant was that ND moment can be obtained by reducing the up elevator just as well as applying down elevator - just a different starting point.
Another point where I doubt Owain’s conclusions is the estimation that, at high AoA, the mean aerodynamic center will move longitudinally to the wing center of area, hence behind the CG. Looking at the Viper curves that move apparently occurs at about 60 deg AoA when the curves turn south
As you note, the Viper is a delta wing, and the centre of pressure will be greatly affected by the strong LE vortices a la Concorde. Quite different flow patterns to a high aspect ratio swept wing.
Owain considered the wing only whilst he should consider the wing/body assembly. Adding the fuselage will generally move the mean aerodynamic center forward so I think it is unclear whether the wing/body adds up to or opposes the ND moment of the tail at high AoA.
Not that naive DJ - I did consider the wing body assembly - see my post of 12th July- and the net effect is the way I described it.