Definition
A ground-based radar system used by air traffic controllers to detect and track aircraft and vehicles on the airport surface, including taxiways and runways. It provides a continuously updated visual display of surface movement, particularly useful in low visibility conditions such as night, fog, rain, or snow when controllers cannot see the movement areas directly from the tower.
Plain English
It is a special radar that lets the tower see where every aircraft and vehicle is on the ground, even when they cannot see the airport through the tower windows.
Context Anchor
Seen in instrument flying and control tower discussions about low-visibility ground operations at towered airports.
Derivation
“Surface” comes from roots meaning the outer face or outside part of something. In this term, it means the airport’s ground surface, not the outside of an aircraft. “Detection” means finding or noticing something, so the term points to equipment that finds traffic moving on the airport ground.
Why Pilots Care
Reduces the risk of runway incursions and collisions during taxi in poor visibility by giving controllers precise location data they can relay to pilots.
Grounding Statement
Picture a tower controller watching a display that shows airplanes and vehicles moving across runways and taxiways, even when fog makes them hard to see out the window.
Intuition Check
Do not read “surface” as the outside skin of an airplane. Here, it means the airport ground area that controllers monitor, especially runways and taxiways.
Example Sentence 1
In dense fog, the tower used ASDE to track our taxi route to Runway 27.
Example Sentence 2
During the low-visibility taxi, the controller reported seeing another aircraft on the Airport Surface Detection Equipment display and held us short until it passed.