Effects of Data-Link Modality and Display Redundancy on Pilot Performance: An Attentional Perspective

Abstract

The effectiveness of three different data link interfaces, involving auditory, visual, and redundant presentation of Air Traffic Control (ATC) information, was evaluated in a single pilot general aviation simulator. Fifteen certified flight instructor pilots flew a Frasca flight simulator with full visual display of the outside world, through a series of ATC-instructed maneuvers, while scanning outside for traffic. ATC instructions, of various lengths, were delivered through a text based data link display, through synthesized voice (similar to the current system), or through a redundant voice-text format. Pilots read back the instructions and then complied with whatever maneuver was instructed, while monitoring for traffic. Visual scanning was measured. The results revealed that the visual display provided greatest accuracy of communications readback, and was least disruptive of both traffic monitoring and flight path tracking. The auditory-only condition was most disruptive of these tasks, in part because the pilot's visual attention was drawn into the cockpit for longer periods while note taking, when compared with the visual text display. The redundant display condition provided many of the same benefits as the visual-only display, but was not associated with better performance than that display, and was sometimes inferior to it. This resulted, in part, because the arrival of the discrete auditory communications appeared to disrupt performance of the ongoing visual flight task. Across all conditions, the pilots allocated approximately 60% of their visual attention to monitoring the instrument panel and their communications accuracy was degraded by the longer ATC instructions. The results are interpreted in terms of mechanisms of attention and working memory in information processing, and in terms of the pilot's task priority hierarchy.