Definition
An area from which radio transmissions cannot be received, or in which radar coverage is unavailable, due to terrain, distance, or the geometry of the transmitting or receiving equipment. Also called a shadow area or blind spot.
Plain English
A spot where the radio or radar signal can't reach you, usually because something like a mountain is in the way or you're too far from the antenna.
Context Anchor
Seen in air traffic control and radar coverage discussions, especially when explaining why radar contact may be limited in certain areas.
Derivation
‘Blind’ here uses the older sense of ‘unable to see or sense’ — the controller or transmitter is effectively blind to anything in that zone. ‘Zone’ comes from the Greek zōnē, meaning a belt or defined area. Together: a defined area where the equipment can't see or hear you.
Why Pilots Care
Requires pilots to provide position reports when radar contact is lost to maintain separation and flight following.
Analogy
It is like a car’s blind spot: the other vehicle may be present, but it is not visible from that viewing angle.
Intuition Check
Do not assume “blind zone” means the pilot cannot see outside the aircraft. Here it means the radar system may not be able to detect or display the aircraft in that area.
Example Sentence 1
While crossing the ridge at low altitude, we entered a blind zone and lost contact with Center for several minutes.
Example Sentence 2
After passing the blind zone the controller regained radar contact and resumed flight following.