Controlled airspace
Dimensions within which ATC services are provided
Controlled airspace is airspace of defined dimensions within which air traffic control (ATC) services are provided. The level of control varies with different classes of airspace. Controlled airspace usually imposes higher weather minimums than are applicable in uncontrolled airspace. It is the opposite of uncontrolled airspace.
Classes
The International Civil Aviation Organization divides airspace into seven classes, from A to G, in order of decreasing ATC regulation of flights. Classes A to E are considered controlled airspace. Flight under instrument flight rules (IFR) is allowed in all controlled airspace, and flight under visual flight rules (VFR) is permitted in all airspace except class A.
Types
Certain special types of controlled airspace exist to protect aircraft in the vicinity of a busy airport.
Control Zone (CTR)
A control zone is a volume of controlled airspace, normally around an airport, which extends from the surface to a specified upper limit, established to protect air traffic operating to and from that airport. Because CTRs are by definition controlled airspace, aircraft can only fly in them after receiving a specific clearance from air traffic control. This means that air traffic control at the airport know exactly which aircraft are in that airspace, and can take steps to ensure aircraft are aware of each other, either using separation or by passing traffic information.
The public source identifies “Controlled airspace” as dimensions within which ATC services are provided. This brief keeps that definition visible, then builds a research path around Controlled, airspace and Dimensions.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Feb 27, 2026. The linked authority identifier is Q3044019. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Controlled airspace” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.