The objective of this work is to develop an autonomous autorotation landing system for an unmanned helicopter. Three-dimensional autorotation flight paths are obtained from a parametric optimization method (developed in previous work) to guide the aircraft through the three phases of a successful autorotation: entry, descent, and flare to landing at a desired location. In this study, the path planning algorithms are integrated with a flight control law and demonstrated in high fidelity simulations. Details of the autonomous autorotation trajectory following control law and analytical autorotation flight path implementation are presented. Simulation results demonstrate the feasibility of tracking complex three-dimensional autorotation trajectories from engine failure to safe touchdown at a pre-specified landing location.