Definition
A list shown on the ARTS III / DBRITE radar display that contains aircraft data tags the system is temporarily holding because radar is no longer receiving fresh position updates for them. The system 'coasts' a track by continuing to display its last known data for a short period, and 'suspends' it when updates remain missing, moving the tag off the active radar picture and into this side list until contact is reestablished or the track is dropped.
Plain English
A small list on the controller's screen that holds aircraft the radar has briefly lost track of, so their information isn't lost while the system waits to pick them up again.
Context Anchor
Seen in descriptions of older air traffic control radar displays, especially the ARTS III/DBRITE display shown in the Instrument Flying Handbook.
Derivation
Coast' comes from the idea of continuing to move forward without active power — the system keeps showing the track for a moment without new radar input. 'Suspend' is from Latin 'suspendere,' to hang or hold up — the track is held in place, not deleted, while the system waits.
Why Pilots Care
Understanding what controllers see helps pilots interpret why ATC may ask them to confirm position, ident, or recycle a transponder — the aircraft may have dropped into this list due to a radar gap or transponder issue.
Intuition Check
Do not read coast as meaning the aircraft is near the ocean, and do not read suspend as meaning the flight is canceled. Here, coast means the display is briefly carrying the track forward without a new radar update, and suspend means normal handling of that displayed track is temporarily paused.
Example Sentence 1
When the aircraft's transponder briefly failed, its data tag dropped into the coast/suspend tabular list on the controller's display.
Example Sentence 2
After the brief radar outage, several targets appeared in the coast/suspend tabular list on the DBRITE.