Lost Link (LL)

An interruption or loss of the control link, or when the pilot is unable to effect control of the aircraft and, as a result, the UA will perform a predictable or planned maneuver. Loss of command and control link between the Control Station and the aircraft. There are two types of links:
  1. An uplink which transmits command instructions to the aircraft, and
  2. A downlink which transmits the status of the aircraft and provides situational awareness to the pilot.

Source: Pilot Contoller Glossary (PCG)