HUD Climb/Dive Ladder Configuration and Unusual Attitude Recovery

Abstract

Twelve head-up display (HUD) experienced pilots participated in a study that examined the effects of articulated lines versus parallel, tapered lines in the top and bottom halves of the climb/dive ladder for recovering from nose-down unusual attitudes in a flight simulator. These configurations were assessed using a moving climb/dive marker (CDM) on half of the trials and a fixed pitch reference for the remaining trials. The results indicated that the climb/dive ladder configuration did not affect a pilot's reaction time to initiate a recovery. However, in terms of accuracy of the initial, significant stick input, the articulated lines in the bottom half of the HUD with a moving CDM resulted in significantly poorer performance (about 12% worse) than that associated with the other three configurations. Subjective data suggest that pilots preferred the articulated lines in the bottom half of the HUD even though their preferences did not correlate with their performance. These findings suggest that articulated lines in the bottom half of the HUD are detrimental to a pilot's ability to recover from nose-down unusual attitudes.