User Sidestick_n_Rudder posted on PPRuNe (emphasis mine):
Vs1g is the lowest speed, at which the airplane can maintain 1g, i.e.
level flight. It corresponds to the Cl max
Vs is the lowest speed attained during stall testing of the airplane.
The pilots were able to reach this speed lower than Vs1g, but the
plane was already losing altitude.
The way I ...