Effects of visual and motion cues in flight simulation of ship borne helicopter operations

Good visual cues are necessary in flight simulation of ship borne helicopter operations. Operating in a degraded visual environment has a negative impact on pilot workload and task performance. However, the need for motion cues in piloted flight simulation is still a widely debated issue. This paper describes a preliminary piloted flight simulation study into the effects of visual and motion cues on the operation of ship-borne helicopters and pilot workload. Unsteady CFD airwakes have been computed and integrated into the FLIGHTLAB modelling and simulation environment with a simulated rotorcraft model, configured to be representative of an SH-60B helicopter. A series of ship-deck landing and hover manoeuvres have been conducted using the University of Liverpool's HELIFLIGHT-R motion-base flight simulator representing different visual and motion cues, for a range of ship airwakes and sea states (ship deck motions). The usable cue environment (UCE), handling quality and pilot workload ratings were assessed using visual cue ratings (VCR), handling quality rating (HQR) the Bedford workload rating scale and the Deck Interface Pilot Effort Scale (DIPES). This paper presents the results from simulation trials with two test pilots examining the effect of the simulation cueing on task performance and workload. Visual cues were found to have a significant impact both on the usable cue environment ratings and pilot workload ratings. In degraded visual environments, the pilot's ability to make corrections in attitude and translational rates was reduced. Pilot experienced higher workload in terms of compensatory control inputs to complete the same mission task compared to operations in a good visual environment. Analysis of the pilots' workload ratings and control activity shows that motion cueing can cause differences in the perceived pilot workload. For the simulation of ship borne operations, the motion cueing effects are dependent on other simulation conditions, which include visual environments, airwake, sea states and ship deck motion. The effect of motion cueing on pilot workload and control activity was found to be more significant when the visual cueing was degraded. The variation in pilot workload ratings and control activities under different motion and visual cues indicate that the Ship Helicopter Operating Limits (SHOL) can be affected by the simulation cueing fidelity.