Rotorcraft Pitch–Surge Motion Cueing Considerations for a Simulated Offshore Approach Task: A Preliminary Investigation

This paper describes the findings from a preliminary rotorcraft pitch–surge motion fidelity study conducted using the University of Liverpool's HELIFLIGHT-R flight simulator. Two test pilots flew a decelerating offshore approach maneuver during which a disturbance was encountered. The approach was own without simulator platform motion as a "baseline" case and with simulator motion using different combinations of pitch and surge motion filter coefficients. Pilot-awarded handling qualities and motion delity ratings for each motion conflguration, along with task performance and control activity data, were gathered. The study concluded that for the approach own without motion, the dominant driver of workload was vertical rate control, and this was most significant during the approach at airspeeds less than 50 kt. When the approach was own with a disturbance, good motion cues were judged to be achieved through careful selection of the motion lter scaling factors, the most favored combination being when the surge filter scaling factor was equal to the pitch filter scaling factor. Additionally, pilots preferred pitch–surge motions that were in the correct sense, that is, absent of detectable washout or mismatched cues, rather than particularly "strong" initial motions. Consequently, increasing the pitch filter scaling factor was only beneficial with a moderate value of pitch break frequency of 0.4 rad / s. The research has emphasized the importance of tuned motion and highlighted the consequences of poor tuning to degradation in task performance and handling qualities when ying tasks with multiple, and potentially conflicting, motion demands; in this case pitch, surge, and heave.