Pilot Assessments of Terminal-Area Logic and Equipage-Specific Symbols While Using the Airborne Collision Avoidance System Xr During Uncrewed Operations

Remotely Piloted Aircraft Systems (RPAS) operations are expected to increase traffic complexity in terminal-area airspace, creating new challenges for tactical separation assurance and pilot decision-making. This study evaluated subjective pilot responses to the latest version of the Airborne Collision Avoidance System for rotorcraft (ACAS Xr) during simulated RPAS operations in approach, departure, and en-route conditions. Eleven IFR-rated fixed-wing pilots completed simulated flight scenarios using ACAS Xr, including encounters involving cooperative and non-cooperative traffic and dynamic terminal-area logic. Subjective measures were collected and included workload, usability, and operational acceptability. Pilots rated ACAS Xr positively for guidance effectiveness, safe separation support, and traffic-symbol clarity for aircraft equipped and not equipped with Automatic Dependent Surveillance-Broadcast. However, terminal-area warning alerts were sometimes perceived as untimely or operationally inappropriate, particularly Level Off and Descend advisories. Results support continued development of ACAS Xr while highlighting areas requiring refinement for terminal-area operations.