Definition
The visual display of unwanted signals on a radar screen — such as returns from terrain, precipitation, ground vehicles, or other non-target objects — that can obscure or interfere with the display of wanted aircraft returns.
Plain English
Extra blips and noise on a radar screen, caused by things the controller isn't trying to track, that make it harder to see the actual aircraft.
Context Anchor
Seen in radar, air traffic control, and weather discussions when unwanted radar returns may hide or confuse the target being monitored.
Derivation
From radio detection and ranging (radar) plus 'clutter,' meaning a disorderly mass of objects. The word captures the idea of a screen 'cluttered up' with returns the controller doesn't want.
Why Pilots Care
Radar clutter can hide nearby traffic, weather returns, or terrain features, reducing situational awareness and raising the chance of undetected conflicts or missed hazards.
Grounding Statement
On a radar screen, clutter may look like patches, speckles, or false-looking areas that compete with the real target for attention.
Intuition Check
Do not think of clutter as just a messy-looking screen. In radar use, clutter means unwanted radar signals that can hide, imitate, or confuse the target being observed.
Example Sentence 1
Heavy precipitation along the route was causing significant radar clutter, and the controller advised that traffic advisories might be limited.
Example Sentence 2
Controllers adjusted the radar sensitivity to reduce ground clutter and keep aircraft targets clear during low-level operations.