The Ground Station Control (GCS) failsafe controls how UAVs will behave if contact with the GCS is lost. The GCS failsafe monitors the time since the last MAVLink heartbeat from the GCS. If no heartbeat is received FS_GCS_TIMEOUT seconds (Default seconds), the GCS failsafe event will trigger based on your parameter settings. Note that if no GCS is ever connected, the GCS failsafe will remain inactive regardless of parameter settings.