Definition
A specific takeoff time assigned to a flight by air traffic control as part of a traffic management program, used to meter the flow of aircraft into a congested airport, airspace, or route. The aircraft must depart at (or very close to) this assigned time so that it arrives at the constrained point in its proper sequence.
Plain English
An exact time you are told to take off so that the busy airspace or airport you are heading to does not get overloaded. Leave too early or too late and you lose your slot in the line.
Context Anchor
Seen in flight planning, clearance delivery, and traffic-flow delay information when ATC is managing how many aircraft depart toward a busy route or airport.
Why Pilots Care
Prevents congestion and ensures safe, orderly departures.
Intuition Check
Controlled does not mean the airplane is being physically controlled by ATC. Here it means the departure time is being managed or assigned by ATC as part of the traffic plan.
Example Sentence 1
Ground control advised us our CDT was 1845Z, so we planned to push back at 1820Z to allow time for taxi and run-up.