Such as A/t will kick in if speed drops to vref
- not Vref, but some function of Vs. The system is incidence driven and therein, I believe, lies the years of confusion over 'alpha floor' which is as I understand it is an AB 'copyright' term.
As far as I have been able to ascertain it works on 1.3Vs, but I have not found more than informed opinion to support this. Whatever it is or is called, it is designed to protect against excessive AoA.
It may be of interest to study Vref, particularly at F40, where you will find 1.3Vs is remarkably close to 1.3Vs at some weights. I used to disconnect A/T when flying my (usually precise
) 'Vref over the threshold' at F40 to avoid interference.