Hi Chris,
the small, electro-mechanical AoA indicator seems to exceed 15 deg occasionally in the video.
I agree. It exceeds 15 momentarilly when he rolls on some bank.
During the steady turn, the AoA gauge then returns to 15 and when he levels the wings again, the AoA shows less than 15. All that is done with full back stick.
In level flight, the system seems to be limiting the AoA shy of Alpha Max - so that some bank can be applied with the same initial pitch attitude without exceeding Alpha Max.
From my FCOM:
• αfloor is activated through the A/THR system, when
α is greater than αfloor (9.5 ° in configuration 0; 15 ° in configuration 1, 2; 14 ° in configuration 3; 13 ° in configuration FULL)
FCOM FCB5 Avoiding Tail strikes; “Assuming an 8 kt speed decrease during flare, and a -1 ° flight path angle at touchdown, the pitch attitude will increase by approximately 4.5 °”
So during the flare, the flight path is changed by +2° (-3° to -1°) for a loss of 8kt. Therefore the angle of attack increases by 2.5° (4.5°-2°) for about 8 kts reduction in speed.
From the diagram, αfloor is about 8 kts from αMax, therefore in CONF 3, αMax would seem to be about 14° + 2.5° = 16.5°