Definition
A Controller-Pilot Data Link Communications message sent from air traffic control to the aircraft. The message appears as text on a cockpit display, where the pilot reads it and responds using the data link system rather than by voice on the radio.
Plain English
A text message from the controller to the pilot, sent and received through the aircraft's data link system instead of being spoken over the radio.
Context Anchor
Seen in data link operations when a controller sends a clearance, instruction, or message to the flight crew through the aircraft’s communication display.
Derivation
Uplink refers to a signal travelling up from the ground to the aircraft. Downlink is the reverse — aircraft to ground. So an uplink CPDLC message is one going up to the cockpit from the controller.
Why Pilots Care
Provides a permanent text record of ATC instructions, reduces frequency congestion, and lowers the chance of misheard clearances.
Intuition Check
Uplink does not mean the airplane is climbing. Here, it means the message is traveling from the ground side of the system to the aircraft.
Example Sentence 1
The crew received an uplink CPDLC message reassigning them to flight level 360 and acknowledged it through the data link.
Example Sentence 2
During busy airspace, the controller sent an uplink CPDLC altitude assignment to avoid voice congestion.