Thanks Don,
That nails it in line with what OK465 has been telling us all along?
My (perhaps simplistic) understanding has always been that Alpha-Prot and Alpha-MAX relate to the flight control laws, whereas Alpha-Floor is purely an A/THR mode, albeit an extremely powerful one at low altitudes.***
AFAIK, Alpha-Floor is always higher than Alpha-Prot. As you know, it has always been necesssary to inhibit Alpha-Floor below a certain height on landing (IIRC, 50R on the A320, but I see 100R on the big 'buses), although it was widely thought that one fellow captain did not take that into account during his cavalier fly-by at Habsheim...
Quote from OK465:
Well I'll tell ya folks, even if you pitch up from 35000 feet and 265 KCAS to 20 degrees nose high with idle thrust, the lowest Mach you will see before 'prot' finally gets the nose down is about 0.58....no alpha floor.
YES...!
***(by edit)
You may not be aware that AI originally introduced Alpha-Floor on the A310 in 1983. The A310 has conventional flying controls (except for the roll-spoilers, which are FBW). So, on the A310 and A300-600, you have to push very hard if Alpha-Floor engages...