Evaluation of a Slung Load Control System for Piloted Winch Operations

Helicopter operations with winch suspended loads are highly demanding for the flight crew. Without having a direct view on the load, pilots require assistance from a winch operator for load handling to achieve operational requirements (e.g. precise and safe positioning of a suspended person). An automatic load stabilization and positioning system for winching operations has been designed with the aim to reduce pilot and winch operator workload, damp load pendulum motion and to improve the load positioning performance. This system uses the concept of load motion feedback. To allow the winch operator to interact with the automatic positioning functions, a dedicated control interface is used. The system was implemented and evaluated in DLR’s Air Vehicle Simulator (AVES). Three pilots and one winch operator evaluated the system in different control law and crew task configurations in an offshore hoisting scenario. Handling Qualities (HQs) and pilot workload were evaluated using the Cooper-Harper Rating Scale and NASA Task Load Index respectively. The results show that the system can improve HQs, allowing better task performance and lower workload for the pilot and the winch operator when compared to an unassisted configuration.