Design and Evaluation of Vertical Situation Display Reflecting Configuration Changes

Loss of control is the largest contributor to the yearly aviation death toll, with energy mismanagement in low-energy conditions as one of its main causal factors. This has led to a large emphasis from both scientific and aviation safety communities on the prevention of aircraft upset conditions. Changes in aircraft configuration largely impact performance, and improved insight therein should allow pilots to better predict potentially dangerous situations, maintain suitable safety margins and more effectively react to unforeseen events. This paper presents the design and experimental evaluation of a Vertical Situation Display (VSD) with enhancements visualizing changes in the flight performance envelope. Sixteen pilots were tasked to fly approach and go-around scenarios with both a baseline and an ecological VSD, some of the scenarios containing flight control failures. Results show that the new display makes pilots maintain larger margins in velocity, thus spending less time below the advised minimum speed limit in final approach. However, these larger velocity margins also led to larger errors with respect to target velocities. Flight control failures were more often and more quickly discovered, and pilots reported feeling better able to predict dangerous situations. No significant differences in workload were recorded. These results conclude that the new VSD design enhances safety performance, but simultaneously raise the question whether the effect of enlarged safety margins is desirable if it causes a reduction in velocity tracking.