Definition
A ground-based communications system that uses digital data link rather than voice radio to exchange routine information between air traffic control at a terminal facility and aircraft operating in that terminal area. Typical exchanges include departure clearances, taxi instructions, ATIS broadcasts, and similar pre-departure or arrival information.
Plain English
A system that lets the control tower send and receive routine messages to and from aircraft as text on a screen instead of over the radio.
Context Anchor
Seen in airport, tower, clearance delivery, and data communication discussions, especially when a pilot receives a clearance or airport information electronically before departure.
Derivation
Terminal refers to the airport-area phase of flight, as opposed to en-route. Data link means a digital connection that carries information as data rather than voice. Together: a system that links the terminal-area controllers and aircraft by data.
Why Pilots Care
It reduces radio congestion, creates a written record of instructions, and lowers the chance of misheard clearances.
Intuition Check
Do not read terminal here as only the airport passenger building. In this term, terminal means the airport operating area where arriving and departing aircraft are being handled.
Example Sentence 1
The crew received their departure clearance through the terminal data link system and confirmed it on the cockpit display before calling for taxi.
Example Sentence 2
After a runway change, the controller used the Terminal Data Link System to send the new departure instructions.