Originally Posted by Microburst2002
High aoa protection pitches the airplane down to prevent aoa from exceeding alpha prot (sidestick neutral)
Not exactly.
During the deceleration to V-alphaprot the airplane is pitching up to maintain lift at decreasing airspeed. The elevator moves NU, the THS follows. That process is arrested at V-alphaprot. The autotrim stops trimming NU, the elevator stops moving NU, the AoA is at Alpha-Prot and stays there, the FPA is level at that point.
As the airspeed continues to reduce below V-alphaprot, the lift reduces as airspeed squared. When lift it is less than weight the airplane starts to descend. It then pitches down to maintain a constant AoA relative to the increasingly downward flight path angle. At some point the trend of decreasing airspeed is reversed, it increases beyond V-alphaprot, lift becomes greater than weight and the flight path starts levelling off. Somewhat later the airspeed trend reverses again and the airspeed reduces through V-alphaprot. That cycle is repeated until the pilot intervenes.