Abstract
Pilots flew a GA simulator based on ATC-instructed maneuvers, while scanning outside for traffic. Various length ATC instructions were delivered through a textual, voice, or redundant data link format. Pilots read back the instructions, then complied with the maneuver. Visual scanning was measured. Results indicated the visual display provided greatest accuracy of communications read back and least disruption of traffic monitoring and flight-path tracking. The voice-only condition was most disruptive, partially because the pilot's eyes were drawn into the cockpit longer while note taking, compared to the two visual text displays. The redundant display never supported better performance than the visual display. This cost resulted, partially because arrival of the discrete auditory communications disrupted flight-path performance. Pilots allocated ∼60% of visual attention to the instrument panel, and communications accuracy was degraded by longer ATC instructions. Results are interpreted referencing mechanisms of attention, working memory, and the pilot's task priority hierarchy.