Pilot sensitivity to flight model dynamics in rotorcraft simulation

The use of Synthetic Training Devices (STDs) for rotary wing pilot skill acquisition and development is an integral part of both military and civil flight crew training. The confidence in the capability of an STD to replicate flight rests on quantitative and qualitative standards and regulations that deem them fit for purpose. However, the engineering science base behind these standards is lacking at present. To amend this, the Lifting Standards research project is underway at the University of Liverpool addressing the deficiencies in the standards through the development of predicted and perceptual fidelity metrics. In this study, the application of these metrics to rotorcraft training simulators is of primary interest. A Simulator Fidelity Rating (SFR) scale has been developed, and is used to examine pilot sensitivity to variations in the training environment. The work detailed in this paper focuses on variations in flight model dynamics. In order to utilise the SFR scale, simulator trials at UoL and collaborative flight trials at the National Research Council‟s (NRC), Flight Research Laboratory (FRL) in Ottawa have been conducted. To ensure only effects of flight model fidelity were being measured and assessed, the flight model variations were implemented into a 'baseline' simulation and then compared against one another (simulator vs. simulator). A selection of test variations were then repeated in a variable stability helicopter at the FRL. Perceptual fidelity was rated for these model variants against the baseline model using the SFR scale and perceptual fidelity metrics used to quantify pilot control activity and performance. Results from these simulation and flight trials are presented in this paper. It was found that subjective ratings and pilot strategy adaptation are affected by both the nature of the task being flown and the level of pilot aggressiveness. It has been demonstrated that this methodology can be used to establish simulator functional fidelity tolerances.