Controlled airspace

{{Short description|Areas served by air traffic control}}

{{distinguish|area control center}}

{{Use dmy dates|date=October 2021}}

{{Use Canadian English|date=October 2021}}

Image:Controlled_airspaces.png ("Terminal Control Area" outside Europe)]]

Controlled airspace is airspace of defined dimensions within which air traffic control (ATC) services are provided.{{cite web |url=https://www.tc.gc.ca/eng/civilaviation/opssvs/secretariat-terminology-glossary-835.htm |title=Aviation Glossary C |publisher=Transport Canada |date= |accessdate=2012-08-13}}{{cite web |url=http://laws-lois.justice.gc.ca/eng/regulations/SOR-96-433/FullText.html#s-101.01 |title=Canadian Aviation Regulations (SOR/96-433) - Part I (General Provisions) - Subpart 1 (Interpretation) |publisher=Government of Canada |accessdate=2016-11-30 |url-status=live |archive-url=https://web.archive.org/web/20120403125803/http://laws-lois.justice.gc.ca:80/eng/regulations/SOR-96-433/FullText.html |archive-date=3 April 2012 }} The level of control varies with different classes of airspace. Controlled airspace usually imposes higher weather minimums than are applicable in uncontrolled airspace.{{cite web |url=http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part6-602-2436.htm#602_114 |title=Canadian Aviation Regulations - Part VI - Section 602.114 - General Operating and Flight Rules |publisher=Transport Canada |accessdate=2012-08-13 |archive-url=https://web.archive.org/web/20120919144314/http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part6-602-2436.htm#602_114 |archive-date=2012-09-19 |url-status=dead }} It is the opposite of uncontrolled airspace.

Controlled airspace is established mainly for three different reasons:

• high-volume air traffic areas, e.g. near airports{{Citation needed|date=August 2012}}
• Instrument flight rules traffic under ATC guidance{{Citation needed|date=August 2012}}
• security, e.g. within an air defense identification zone{{Citation needed|date=August 2012}}

Controlled airspace usually exists in the immediate vicinity of busier airports, where aircraft used in commercial air transport flights are climbing out from or making an approach to the airport, or at higher levels where air transport flights would tend to cruise. Some countries also provide controlled airspace almost generally, however in most countries it is common to provide uncontrolled airspace in areas where significant air transport or military activity is not expected.{{Citation needed|date=August 2012}}

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 controlled airspace. Flight under instrument flight rules (IFR) is allowed in all controlled airspace. Some countries also permit IFR in uncontrolled airspace). Flight under visual flight rules (VFR) is permitted in all airspace except class A.{{cite web |url=http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-rac-2-0-2599.htm#2-5 |title=TP 14371 - Transport Canada Aeronautical Information Manual (TC AIM) - RAC - 2.0 AIRSPACE – REQUIREMENTS AND PROCEDURES |publisher=Transport Canada |date=2012-04-11 |accessdate=2012-08-13 |archive-url=https://web.archive.org/web/20110218033451/http://www.tc.gc.ca/eng/civilaviation/publications/tp14371-rac-2-0-2599.htm#2-5 |archive-date=2011-02-18 |url-status=dead }}