Evaluation of Pilot Workload for Helicopter Optimal Autorotation Landing Procedure in One Engine Failure

This paper intends to evaluate the pilot workload of helicopter optimal autorotation landing procedure in the event of one engine failure to provide a reference for the pilot conducting the actual autorotation landing maneuver. The UH-60A helicopter is taken as the sample for demonstration. The autorotation landing procedure is formulated into a nonlinear optimal control problem (NOCP) based on an augmented six-degree-of-freedom rigid-body flight dynamics model, solved by collocation and numerical optimization method. The optimal landing trajectory and controls are compared with those from the flight test data. Metrics called aggressiveness and pilot cutoff frequency are applied to quantify and evaluate the pilot workloads respectively in time domain and frequency domain, based on the pilot control inputs of the optimal solution and the flight test data. The results show that optimal landing procedure is close to the flight test data, and the analysis of the metrics indicates that the pilot workload evaluated can be considered consistent with that from the flight test.