Question: VS and G

[zodiac1214]

It looks like we are using the G/VS before touch down?
say touchdown is at T1, we pick up G/VS from T0? is that right?

also
static void update_landing_result() { int changed = 0; if (landing_vspeed > last_vspeed) { landing_vspeed = last_vspeed; changed = 1; } if (landing_G < lastG) { landing_G = lastG; changed = 1; } if (changed || landMsg[0][0]) { int w = print_landing_message(); if (w > window_width) { window_width = w; force_widget_visible (window_width); XPSetWidgetGeometry(main_widget, win_pos_x, win_pos_y, win_pos_x + window_width, win_pos_y - WINDOW_HEIGHT); } } }

what if last_vspeed is lower than previously recorded but last G is lower? now we have VS from one timestamp and G from another? Should it be G/VS at touchdown point? i am not sure if i am wrong here or it was done intentionally for a reason. Like why we need to keep updating this if we know the touch down point? The landing G/VS should be what is at touchdown point?

[hotbso]

No and yes. Look what happens during and after touchdown:
tire deflection, strut compression come in while aerodynamic lift diminishes or even collapses.

In that phase vy goes down while g goes up. So normally you have max vy at around touchdown while max g is more at the end of the strut compression phase.

So depending of the ground/aerodynamics dynamics vy can still go up after touchdown.
Image that you come in extremely shallow scratching the runway meaning vy == 0. Then cut power. The struts compress and you have vy >0 after touchdown.