Definition
An ADAR is a pre-coordinated, computer-stored standard route between a specific departure airport and a specific arrival airport, used by air traffic control to issue a complete clearance from takeoff to landing without the controller having to build the route segment by segment. ADARs are typically used for short, frequently flown city pairs and are stored in the ATC computer system so they can be assigned automatically.
Plain English
A ready-made flight path between two airports that controllers can hand to a pilot as a single, pre-built clearance instead of stitching together waypoints one at a time.
Context Anchor
You are most likely to see ADAR in the Pilot/Controller Glossary or in material about how ATC systems handle flight plans and route changes.
Derivation
“Adapted” here means tailored and stored in the ATC computer system for a specific airport pair. “Departure and Arrival Route” describes what it covers — the whole path from one airport to the other. The word “adapted” is worth pausing on: in ATC usage it refers to data that has been pre-loaded into the computer for a particular facility, not something modified on the fly.
Why Pilots Care
Pilots may receive these routes to reduce delays or navigate around temporary restrictions while staying within the controlled airspace system.
Intuition Check
Do not read “adapted” as meaning the pilot personally adjusted the route. Here it means the route has been set up in the ATC system for that operating area.
Example Sentence 1
Center cleared us via the ADAR from KBWI to KPHL, so the full routing came down as one item instead of a long string of fixes.
Example Sentence 2
The dispatcher filed an ADAR to optimize the flight path for fuel efficiency under current traffic conditions.