Perceptual Modeling as a Tool to Prevent Aircraft Upset Associated with Spatial Disorientation

Abstract

Controlled flight into terrain (CFIT) and spatial disorientation (SD) constitute the first and second largest categories of loss of control (LOC) mishaps for helicopters. Since SD mishaps tend to result in the death of the pilots, SD is inferred as the primary cause of a mishap via a process of elimination, i.e., it is considered only when a materiel cause cannot be ascertained. In SD mishaps, the information required to maintain control of the aircraft is available to pilots, but they are either not attending to the information or unable to manage or assimilate it rapidly enough to prevent the mishap. For the past 18 years, we have responded to requests from military and civilian aviation accident investigation communities to conduct perceptual analyses of mishaps when SD is inferred as a possible cause. The perceptual models we have employed evaluate data from a variety of sources to predict the orientation and motion perception a pilot will experience when subjected to the physical forces of flight. The algorithm has been developed based on both ground and inflight experimental data and is able to predict the perceived attitude of the pilot which is critical to the pilot’s mental model of the location of the ground prior to a mishap. The model also can make predictions about reflexive gaze control during acceleration. The next step is to incorporate voluntary gaze into the model. When pilots fly in challenging conditions of instrument flight, at least half of the visual attention time is directed to the attitude orienting instruments, as demonstrated by experiments in which the pilots’ gaze direction is monitored using head-mounted cameras. Gaze monitoring technology has improved considerably over the past 25 years so that it is now easy to monitor the gaze of pilots unobtrusively using panel-mounted cameras. It is possible to not only measure which instrument is being monitored, but also whether the pilot is directing gaze away from the panel and for how long. We propose that by using the perceptual model in conjunction with eye gaze, one can predict perception more accurately and determine when the pilot should be alerted to redirect attention to the attitude orienting instruments.