The Generic Engine block has a "Maximum speed" parameter, if using the default polynomal parameterization. For the other 2 tabular parameterizations, it assumes that maximum speed is the final value in the speed vector lookup table. In any case, you will see an error message if this value is exceeded during simulation.
You can either increase the block's maximum speed (if it makes sense) or add some kind of control to your engine to reduce throttle such that the maximum speed is not exceeded.
- Sebastian