Originally Posted by
turbojet28
As far as I understand you are correct in your assumption of the initial calculation done by the box for GS mini, but it will dynamically adjust the target speed as you are flying to account for the headwind component of any gusts. You don’t input the gust into the perf page because that would just lower the “baseline” ground speed, and GS mini would essentially be doing nothing since you would already be at or above it’s computed baseline ground speed.
GS mini is sort of a counterintuitive design in that it will increase target speed (and also thrust, assuming the gust lasts a little while) when encountering a headwind gust.
I think we are somewhat talking about different things. While on the Approach it will constantly adjust the target speed. That's based on wind variations at that spot on the approach (as opposed to gusts, because that refers to surface winds) during that phase. Surface wind gusts as reported by the tower/ATIS are not entered on the PERF page and have no effect on GSmini. During the flare the target will be Vapp, regardless of the wind you entered into the PERF page, and gusts, regardless of direction are completely disregarded. And that is why we add gust correction. It is totally separate from GSmini.
Think we both added things, and yes, agree with that