Citing FCOM 1.27.20 P2:
“When angle of attack protection is active, THS is limited between setting at entry in protection and 2° nose down (i.e. further nose up trim cannot be applied).”
This makes sense since AoA protection is to prevent stall and doesn’t need more nose up trim.
Question is: Why is THS allowed unrestricted nose up move in ALT law when the stall alarm is active? Is there a logical answer to this?
Had the AoA parameter value that triggered the stall alarm simultaneously preclude more nose up THS, the AoA would probably not have reached 30 + deg, whatever the pilot was trying to do. Elevator alone efficiency is limited .