Design and Simulator Evaluation of an Ecological Synthetic Vision Display

摘要

A synthetic vision display is generally believed to support pilot terrain awareness. Many studies have shown, however, that the bias in perspective views can cause pilots to make judgment errors regarding the relative location, height, and ultimately the avoidance of terrain obstacles. Therefore, alerting systems are required to keep pilots at safe distances from the terrain. These systems provide explicit guidance commands to circumvent terrain conflicts, which is far from optimal regarding pilot terrain awareness as it fails to present the rationale of the terrain separation problem. Consequently, this can affect the trust in and the reliance on these systems and pose a potential safety risk, especially in events or situations unfamiliar to the alerting system. This paper presents the design and evaluation of an extension to a synthetic vision display that aims to make the constraints of the alerting automation more transparent in order to help pilots better understand why, how, and when they should act. A pilot-in-the-loop experiment, using 16 glass-cockpit pilots in a fixed-based flight simulator, showed that the constraint-based overlays indeed improved the overall pilot terrain awareness compared to a command-based display. The decision-making only improved in the unanticipated events introduced in the experiment. The utility of the energy angle was found to be important for recognizing the offnormal events and to prevent terrain crashes. However, the pilot response time, flight safety in terms of low-altitude flying, and pilot workload are better when using the command display. This indicates that a last-resort alerting and advisory system would still be required in operations at the periphery of safe system performance.