Helicopter Pilot Use of a See-Through, Head-Mounted Display With Pathway Guidance for Visually Guided Flight: Observations of Navigation Behavior and Obstacle Avoidance

Factors Influencing the Effectiveness of Simple Obstacle-Related Graphical Depictions for Head-Mounted Displays

“…When the HITS terminated at 200 ft AGL and a further descent would place them under power-lines at 120 ft AGL between the aircraft and the helipad, the pilots continued the approach UNDER the power-lines represented in the HMD. This preliminary observation of pilot behavior is consistent with findings from Beringer et al (2009), where the participants flew through power-line areas at the end of a guided approach or dropped below the 6-degree glide slope after the entry point to the approach without the remainder of the HITS guidance. We found categorically similar behavior in the use of high-resolution NEXRAD data (attempts to shoot the gaps between cells), in flying HITS guidance within 200 ft of a ridgeline, despite a forward-looking terrain display warning of the approaching terrain, and in studies looking at the use of weather data.…”

“…Consistent with our previous study (Beringer, et al, 2009), we used a stereoscopic see-through HMD presenting very simple overlaid synthetic imagery of obstructions (Foyle, Ahumada, Larimer, & Sweet, 1992). This is in contrast to a literal synthetic-vision (SV) representation of obstructions (Hughes, 2005;Rash, Russo, Letowski, & Schmeister).…”

Head-mounted displays for civil helicopter navigation and obstacle avoidance

“…Thus, adding the ground-plane reference for power lines was not as advantageous as a simple graphic, particularly as this was only a factor when close to 120 feet AGL. Proximity to Towers Figure 3 shows a plot of the closest approach, on the initial flight to the NW field of obstacles, by participants from both the study reported by Beringer et al (2009) and the present study. Note that those points indicated by blue arrows were those individuals in the previous study having no HMDpresented obstructions but having the destination synthetic helipad visible (obstacles only visible in the out-the-window view with towers but no wires).…”

“…Accidents involving obstacles to flight occur more frequently in Helicopter Emergency Medical Services (HEMS) operations than in other flight operations (Beringer, Luke, Quate, & Walters, 2009;NTSB, 2002NTSB, & 2006. This is largely due to the operation of the aircraft into unprepared and/or confined areas and often in challenging weather conditions or marginal visibility.…”

“…Previous research (Beringer, et al, 2009;Beringer & Holcomb, 2010) discussed pilot ratings of graphics that represented obstructions and the inherent advantages of the HMD. That work demonstrated that pilots could effectively use simple graphics (per Foyle et al, 1992) to follow highway-in-thesky (HITS) guidance cues to a synthetic landing pad but that they had difficulty using out-the-window obstacle information, as shown by flying through or under implied power lines on the final approach.…”