Thanks for the info on the IAS gauges. That makes much mores sense. The pictures give the impression that only the right hand seat has the detailed IAS indicator and would therefore be the one calling/operating the flaps/slats.
@Kulverstukas thanks for your very helpful contribution. I was asking for the max. speeds allowed (Vfe) with flaps/slats in the 15 and 28 degree detention. That is the speed your instructor tells you that they will fall off if exceeded. In the table are the nominal speeds V2 and Vref.
Vfe is of interest to get an impression about the timing of normal procedures during TO.