Rotorcraft Vertical Rate Command's Impact on Workload and Handling Qualities and its Implementation-Practicality

An advanced Vertical Rate Command (VRC) flight control augmentation is prototyped and applied to the CH-53K™ King Stallion to investigate its impact on workload and handling qualities and to further the implementation-practi-cality vertical augmentation for fly-by-wire rotorcraft. The Vertical Response Augmentation for CH-53K™ (VRAK) prototype applies a model following controller to effect a VRC response type and includes a split force-displacement (SFD) control method to address challenges to the practical, rather than theoretical, implementation of rotorcraft ver-tical augmentation. The impact of VRC on workload and handling qualities was evaluated in formal piloted evalua-tions conducted in the CH-53K™ flight simulator at NAS Patuxent River using a sequence of six maneuvers flown by US Marine Corps test pilots. Results demonstrate that VRC delivers substantial benefits to workload and handling qualities in the majority of the maneuvers evaluated. Observations from independent engineering tests show that SFD enables practical application of vertical augmentation. Altogether, VRAK is demonstrated to be a logical next step in fly-by-wire rotorcraft vertical control.