Groundspeed Mini (A320)
 

Hi all,
query about the groundspeed mini logic.

Does the logic aim to reduce to VAPP at a certain point during the approach at any point late in the approach? Or, in the event of certain conditions would it maintain say (VAPP+15) commanded by GS Mini right down to the flare.

couldn’t find any ref in FCOM regarding this, seen a few people suggest an altitude on these forums but can’t find anything to support their case.
I understand that the purpose of G/S mini is to just add speed to manage the energy, and the purpose is to provide the lowest possible safe approach speed… however in the event that it does keep say vapp+15 right down to landing, does this not technically invalidate landing performance?

thanks all.

GS mini remains active all the way to touchdown. If the wind you entered in the FMC is accurate, then there logically would be no additive to Vapp on touchdown as the (Current headwind component-TWR headwind component) would be the same and equal 0. As your headwind decreases the lower you get, the less active GS mini will become in this case.

If however you enter an erroneous wind, say 220/10 where the actual wind on the runway is 220/20, then GS mini will keep your speed higher than Vapp till touchdown as it is still anticipating a drop of 10 knots. Which is a big gotcha!

Regarding whether your landing performance is valid…

If you have a greater headwind than expected your ground speed mini will be higher potentially all the way to touchdown. However your ground speed (and therefore kinetic energy) will be as planned so your performance will stand.