A broken uplink or downlink is defined as what?

A broken uplink or downlink is best defined as a "lost link." In the context of unmanned aerial systems (UAS), the uplink refers to the communication signal sent from the ground to the drone, while the downlink pertains to the signal sent from the drone back to the ground station. When either of these links is compromised, it signifies that the connection has been interrupted or lost, which is critical in maintaining control and receiving telemetry data from the aircraft.

The term "lost link" specifically indicates that the communication pathway has failed, preventing the operator from sending commands to the drone or receiving data, which can have serious implications for operational safety and control. Understanding this terminology is essential for operators, as it directly relates to how they monitor and manage the aircraft's connectivity and ensure safe operations.