Abstract: A high-lift system of an aeroplane is described, including one or more high-lift flaps, an activation device with an activation function for generating adjustment commands for adjusting the adjustment state of the high-lift flaps, and a drive device coupled with the high-lift flaps, which is configured such that on the basis of activation commands the high-lift flaps are adjusted between a refracted adjustment state and an extended adjustment state. The activation function, on the basis of input values, generates adjustment commands and transmits these to the drive device for adjusting the high-lift flaps. The activation function has a function for the automatic retraction of the high-lift flap in flight, which in a flight condition in which the high-lift flap has assumed an extended adjustment state, whilst taking into account an engine thrust and a minimum flight altitude, generates an activation command, in accordance with which the high-lift flap retracts.