Head-mounted displays for civil helicopter navigation and obstacle avoidance: Is what you see what you don’t get, or is seeing not believing?

Civilian helicopter pilots flew simulated Helicopter Emergency Medical Service (HEMS) scenari-os using a head-mounted display (HMD) with guidance and/or obstruction imagery. Obstructions were detected and avoided earlier when shown in the HMD than those shown only out the win-dow, and highway-in-the-sky (HITS) guidance reduced subsequent maneuvering in the terminal phase of arrival. The HMD depictions of power lines (passive representation) reduced wire strikes but did not eliminate them. An active warning presentation (red warning fence) overlaid on the power-line graphic at the point it transected the flight path completely eliminated flights in-to that obstruction. Pilots preferred the active warning representation, indicating that the passive one was ambiguous. Pilots ’ preference tended towards the simplified representations of power lines but towards the complex “realistic ” representations of broadcast towers. A strong prefer-ence was also expressed for integrated cockpit systems (HMD, MFD, PFD) that depicted the same obstruction information and warnings on each display. Accidents involving obstacles to flight occur more fre-quently in Helicopter Emergency Medical Services (HEMS) operations than in other flight operations (Beringer, Luke