Instrument Scanning and Subjective Workload with the Peripheral Vision Horizon Display

Abstract

The Peripheral Vision Horizon Display (PVHD) is an expanded artificial horizon line that is intended to provide the pilot with orientation information through peripheral vision. The potential advantage is a reduction in the requirement to constantly refer to the attitude indicator (AI) in order to maintain awareness of orientation during instrument meteorological conditions (IMC). Four helicopter pilots flew two types of instrument approaches to determine whether the degree to which pilots rely on the AI would be altered when the PVHD was in operation. Only two pilots showed a reduction in the visual workload associated with the need to scan the AI. The general trend in the data indicated an increase in subjective workload with the PVHD. It was argued that motion of the PVHD distracted the pilots from their routine instrument scan, although this result might not generalize to pilots more experienced with the display. It was concluded that the PVHD might be of significant benefit in situations where the pilot must look outside the cockpit and stable orientation cues are not visible.