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This study examined the effects of conflict type, time pressure, and display design on operators' ability to make informed decisions about proposed machine goals and actions in a management-by-consent context. A group of 30 B757 pilots were asked to fly eight descent scenarios while responding to a series of air traffic control clearances. Each scenario presented pilots with a different conflict that arose from either incompatible goals contained in the clearance or inappropriate implementation of the clearance by automated flight deck systems. Pilots were often unable to detect these conflicts, especially under time pressure, and thus failed to disallow or intervene with proposed machine actions. Detection performance was particularly poor for conflicts related to clearance implementation. These conflicts were most likely to be missed when automated systems did more than the pilot expected of them. Performance and verbal protocol data indicate that the observed difficulties can be explained by a combination of poor system feedback and pilots' difficulties with generating expectations of future system behavior. Our results are discussed in terms of their implications for the choice and implementation of automation management strategies in general and, more specifically, with respect to risks involved in envisioned forms of digital air-ground communication in the future aviation system. Actual or potential applications of this research include the design of future data link systems and procedures, as well as the design of future automated systems in any domain that rely on operator consent as a mechanism for human-machine coordination.

This research examined performance in a single-axis discrete positioning task using three different mappings for the visual display of the movement space. In a normal display condition, displayed distance was proportional to actual distance. In a split-screen condition, 66.5% of the initial distance to the target was mapped into 50% of the visual space and 33.5% of the distance (containing the target) was mapping into the remaining 50% of visual space. Finally, in a log screen condition there was a logarithmic mapping from actual to visual space. The split-screen and log screen conditions resulted in magnification of the space containing the target and compression of space distance from the target. Results for movement time (MT) showed a significant effect of target width. MTs were longer for smaller targets. Performance with normal and log screens was equivalent in terms of overall level and in terms of rate of increase in MT with reduction in target size. A smaller rate of increase, however, was found for the split-screen display. MTs for the smallest target were faster with the split-screen display. Evidence suggests that fewer corrective movements were required for the smaller targets when using the split screen.