A method for operating a controller apparatus for controlling a drive apparatus having a load moment and a moment of inertia, includes determining an estimated load value of the load moment by a load moment estimator during a constant-running phase, when a drive speed of the drive apparatus is kept to a constant setpoint value by the controller apparatus, using a model to describe an association between the moment of inertia and the load moment and generating an estimated inertia value of the moment of inertia as a pilot control of the moment of inertia based on the model during the constant-running phase. Further disclosed are a controller apparatus and a drive apparatus designed to carry out the method.