in JAAland..not allowed unless it is simply a scenic flight, but if it is a trial 'lesson' where the ' potential student ' is being demonstrated and taking the controls or even in advanced lesson... 'passangers' cannot be carried...unless they are 'flight crew members' necessary for the operation of the aircraft.
another 'student' is not a necessary flight crew member at any time and cannot be carried AT ALL when flight instruction is being given.
dean.