Effectiveness of 3-D Audio for Warnings in the Cockpit

We investigated the application of 3-dimensional (3-D) audio for presenting auditory warnings in the cockpit in two simulator experiments. Pilots had to respond to warnings of the Traffic Alert and Collision Avoidance System and to system malfunction warnings. Visual warning displays were always present. The first experiment showed 12% faster response times when 3-D audio was used compared to mono sound. This was only observed when flight path error information was presented on a visual head-down display. No effect was observed when an auditory error display was used because this enabled pilots to pay more attention to the visual warning displays. In the second experiment, only a visual error display was employed, and the effects of 3-D audio and verbal directional information (e.g., "up") were tested. Each type of cue resulted in a 12% reduction of response times. The combination of 3-D audio and verbal cues resulted in the best performance, with response time reductions of approximately 23%. These results indicate that 3-D audio displays can improve flight safety.