Current aircraft flight deck interfaces do not provide information on how a performance-altering failure constrains an aircraft’s flight envelope. As a result, it is difficult for flight crews to plan maneuvers in order to reach navigation targets. This study presents the results of the conceptual development of constraint-based interface symbology that aims to address this issue. The proposed symbology is designed to integrate with both the primary flight display and navigation display. A small-scale, pilot-in-the-loop experiment (N=9) was conducted to assess the effectiveness of the used symbology in terms of flight performance and pilot usability. A simplified dynamic model with an asymmetric flight envelope was used to purposefully manipulate various levels of damage severity and corresponding flight envelopes. Results show that although the modifications to the primary flight display generally did not show statistically significant improvements, presenting flight envelope constraints as a reachable navigation envelope on the navigation display generally did do so for severe failures. The visualized envelope occasionally resulted in improved tactical control decisions at reduced workload levels. A future study involving a lager sample size and increased simulation realism should substantiate the discovered results.@en