Uncrewed Aircraft System Lost Command and Control Link Procedures with Simulated Air Traffic Control Resolution Maneuvers

This paper presents an analysis of Uncrewed Aircraft Systems (UAS) contingency management procedures, focusing on loss of command and control link off-nominal scenarios in Fort Worth Alliance terminal airspace. This work is the first known simulation study of Lost Command and Control (C2) Link (LC2L) UAS procedures in a realistic airspace environment with realistic Air Traffic Control (ATC) conflict resolution maneuvers. It aims to inform LC2L procedure development and refinement by standards organizations by identifying scenarios that could be potentially disruptive and challenging for air traffic controllers. 72 unique scenarios were run in which a UAS experienced an LC2L event and ATC resolutions were enacted using a validated conflict management capability. Metrics including the number of unique Loss of Separation (LOS) events, the number and locations of ATC resolutions, and the number of additional ATC communications were evaluated in terms of the impact of the LC2L UAS on non- UAS traffic in the airspace. Scenarios with up to eight unique LOS events, up to five simulated ATC resolutions, and up to 15 additional ATC communications were observed. Critically, the path between the end of the Standard Terminal Arrival Route (STAR) and the beginning of the final approach was identified as a key issue area for the LC2L procedures. Mitigation to these challenges could strategic flight planning and the development of UAS-specific contingency procedures that avoid other routine procedural areas.