Designing Head-Up Displays (HUDs) to Support Flight Path Guidance While Minimizing Effects of Cognitive Tunneling

This study investigates the effects of varying the conformality of the flight path HUD symbology on flight path tracking and cognitive tunneling. Partially conformal and conformal symbology sets were created for the approach/landing (air-based) and taxi (ground-based) phases of flight. The partially conformal approach symbology was a flight director consisting of crosshairs and transitioned into the taxi symbology, which was a plan-view of the runway and taxiway. The conformal approach symbology was a tunnel-in-the-sky followed by runway symbology, which was scene-linked, conformal runway pylons. Twenty pilots flew 25 approaches with each symbology set. The conformal, tunnel-in-the-sky symbology was more effective in supporting the pilots in navigating complex curved approaches than the partially conformal flight director. In addition, flying with the tunnel-in-the-sky also lead to better performance on secondary target detection tasks. On the ground, the conformal symbology set supported landing and taxi navigation tasks with approximately equal efficiency and precision as the partially conformal plan-view symbology. To investigate cognitive tunneling, pilots were introduced to three separate and unanticipated events. Pilots had extremely slow response times to all three events using both the conformal sets. However, trends indicated that when differences existed between the two symbology sets it was the tunnel that lead to suboptimal performance. Analyses revealed that pilots had little need to reference the outside environment to obtain precise flying with the tunnel-in-the-sky symbology and therefore were less likely to detect unexpected events. However, the scene-linked conformal symbology (ground) set supported the scan between the symbology and the environment and led to a trend of faster response times to the unexpected taxiway traffic. Though both symbology sets are considered conformal only the scene-linked symbology set is truly conformal since it has a far-domain counterpart to bind the instrumentation to the scene. We postulate the notion that only truly conformal symbology can combat the effects of cognitive tunneling.