Definition
A radar return caused by a fixed, stationary object on the ground — such as a building, tower, hill, or mountain — that consistently appears in the same position on a radar display.
Plain English
A blip on the radar screen that never moves because it's coming from something solid and stationary on the ground, like a tall building or a hill.
Context Anchor
Used in radar and air traffic control discussions when describing radar marks that come from fixed objects instead of moving aircraft.
Derivation
From Latin permanere, 'to remain through,' and echo from Greek ēkhō, 'returned sound.' In radar, the 'echo' is the reflected signal — and a permanent echo is one that stays put because the reflector itself never moves.
Why Pilots Care
Controllers use permanent echoes as fixed reference points to verify radar accuracy and to separate stationary returns from moving aircraft targets.
Intuition Check
Do not read “echo” here as a sound. In this context, it means a reflected radar signal. “Permanent” also does not mean forever; it means the return is tied to a fixed object and appears repeatedly in the same place.
Example Sentence 1
The controller identified the cluster of returns near the ridge as permanent echoes from the surrounding terrain, not aircraft.
Example Sentence 2
During the approach briefing the instructor pointed out how permanent echoes on the scope could be mistaken for slow-moving traffic if not identified.