Simulated landings in turbulence - Motion, predictive modelling, and psychometric aspects

Abstract

To maintain control in approach/land ings under turbulence, the pilot requires prompt attention. The lead provided by non-visual cues is then important. One objective of two studies was to analyse whether a moving base dome simulator could produce more realistic cues than a fixed base simulator. In the first study half of 60 landings were performed with the motion system disengaged. The pilots rated risk, difficulty, workload, performance, handling qualities, and induced oscillations. Stick activity and difficulty were higher and performance lower under the motion condition. In a second study the importance of motion in turbulent landings was verified and analyses of the pilots' control responses showed that there were inter-individual differences. Model analyses showed that turbulence affects workload, and that workload, in its turn, influences performance. We found that handling qualities and induced oscillations could be predicted from the other variables. The variables turbulence and motion of the aircraft explains 65 percent of the variance in handling qualities ratings and 36 percent of the variance in ratings of pilot induced oscillations. Accordingly, handling qualities and pilot induced oscillations can be estimated and predicted in situations 'without man in the loop'. The analyses present psychological aspects related to and underlying aircraft handling qualities and pilot induced oscillations. General background Flying is characterised by often extreme motion, and even the simplest simulator presents motion cues to the pilot. The pilot exercises control over his aircraft by sensing, processing, and interpreting information provided by the aircraft, its environment, and by his own control inputs. * This paper presents the results of two studies performed at NLR by Saab AB in co-operation with Defence Research Establishment. Mr. E. Kullberg, Saab, and Mr. J. Ersson, FOA, have made contributions to conclusions and analyses, respectively. f Copyright © 2000 by Defence Research Establishment, Sweden. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission. Motion can aid the pilot in controlling and manoeuvring the aircraft by confirming that the response of the aircraft matches the pilot's internal model of the expected response (i.e., can give him adequate sensory feed-back), and it can help him to recognise failures of the system. Motions, such as those resulting from turbulence and vibration, also make the pilot's task more difficult and increase his mental workload, perceived risk, and psychological stress. Senses as vestibular, proprioceptive (in muscles, viscera, and joints), and tactile are also stimulated, primarily by motions of the cockpit. Visual cues of motion are probably the most important 'low frequency cues', while the cues from the vestibular, proprioceptive, and tactile senses are the most important 'high frequency cues'. The non-visual receptors respond more quickly than the visual system, since they are sensitive to motion onset rather than to sequential events. In conventional aircraft, manoeuvre cues are of comparatively low frequency, and these cues can generally be provided visually.1'% 3'4'5'6> 7'8> 9