AVIATION SPATIAL ORIENTATION IN RELATIONSHIP TO HEAD POSITION AND ATTITUDE INTERPRETATION

Background: Conventional wisdom describing aviation spatial awareness assumes that pilots view a moving horizon through the windscreen. This assumption presupposes head alignment with the cockpit ''Z'' axis dur ing both visual (VMC) and instrument (IMC) maneuvers. Even though this visual paradigm is widely accepted, its accuracy has not been verifie d. The purpose of this research was to determine if a visually induced neck reflex causes pilots to align their heads toward the horizon, ra ther than the cockpit vertical axis. Hypothesis: Based on literature d escribing reflexive head orientation in terrestrial environments it wa s hypothesized that during simulated VMC aircraft maneuvers, pilots wo uld align their heads toward the horizon. Methods: Some 14 military pi lots completed two simulated flights in a stationary dome simulator. T he flight profile consisted of five separate tasks, lour of which eval uated head tilt during exposure to unique visual conditions and one ex amined occurrences of disorientation during unusual attitude recovery. Results: During simulated visual flight maneuvers, pilots tilted thei r heads toward the horizon (p < 0.0001). Under IMC, pilots maintained head alignment with the vertical axis of the aircraft. Conclusion: Dur ing VMC maneuvers pilots reflexively tilt their heads toward the horiz on, away from the Ct axis of the cockpit. Presumably, this behavior st abilizes the retinal image of the horizon (1 degrees visual-spatial cu e), against which peripheral images of the cockpit (2 degrees visual-s patial cue) appear to move. Spatial disorientation, airsickness, and c ontrol reversal error may be related to shifts in visual-vestibular se nsory alignment during visual transitions between VMC (head tilt) and IMC (Ct head stabilized) conditions.