Definition
A dynamic value set by air traffic management that specifies the number of aircraft that can depart from an airport in a given period of time, usually expressed as departures per hour. It is used by traffic flow planners to balance demand against available runway, airspace, and downstream capacity.
Plain English
The maximum number of planes that can take off from an airport each hour, as set by air traffic control. It changes throughout the day depending on weather, runway use, and how busy the system is.
Context Anchor
You may see ADR in traffic management discussions, delay programs, airport operations planning, and air traffic control coordination for busy airports.
Why Pilots Care
It directly influences expected departure delays and slot availability when planning flights into or out of capacity-constrained airports.
Intuition Check
ADR is not the speed of one aircraft departing. It is the number of aircraft the airport can depart in a set time.
Example Sentence 1
The tower advised that the ADR had been cut to 30 per hour because of the runway configuration change, so we should expect a longer wait at the hold short line.
Example Sentence 2
We adjusted our departure time after checking that the current ADR would keep us on the ground for another forty minutes.