Definition
The inherent constraints on what air traffic control radar can detect, display, and resolve, including range limits, line-of-sight blockage by terrain or the curvature of the earth, beam width effects, weather attenuation, target resolution between closely spaced aircraft, and reduced or no coverage at low altitudes or in remote areas. These limitations affect the accuracy and reliability of radar services provided to pilots.
Plain English
Radar cannot see everything. It can be blocked by terrain, weakened by heavy weather, and may not show aircraft that are too low, too far away, or too close together. Pilots and controllers both have to keep these blind spots in mind.
Context Anchor
Seen in instrument flying and ATC discussions when learning what radar services can and cannot provide.
Derivation
Radar comes from “radio detection and ranging,” meaning finding objects and measuring their distance using radio waves. Limitations means boundaries or restrictions. Together, the phrase points to the boundaries of what radar can reliably show.
Why Pilots Care
Recognizing these boundaries prevents over-reliance on radar-derived information and supports better decision-making in instrument conditions.
Grounding Statement
If an aircraft is too low behind terrain or too far from the radar site, the radar picture may be incomplete or unavailable.
Intuition Check
Do not assume radar means ATC can always see you clearly. Radar limitations mean there are real conditions where radar information may be reduced, delayed, blocked, or unavailable.
Example Sentence 1
Because of radar limitations in the mountainous sector, the controller advised the pilot that radar contact would be lost below 9,000 feet and to report level at the assigned altitude.
Example Sentence 2
Heavy precipitation created additional radar limitations that reduced the ability to track traffic behind the storm.