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.
Controlled airspace is established mainly for three different reasons:
- high-volume air traffic areas, e.g. near airports
- Instrument flight rules traffic under ATC guidance
- security, e.g. within an Air Defense Identification Zone
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.
The International Civil Aviation Organization classifies airspace in 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.
- "Aviation Glossary C". Transport Canada. Retrieved 13 August 2012.
- "Canadian Aviation Regulations (SOR/96-433) - Part I (General Provisions) - Subpart 1 (Interpretation)". Government of Canada. Archived from the original on 3 April 2012. Retrieved 30 November 2016.
- "Canadian Aviation Regulations - Part VI - Section 602.114 - General Operating and Flight Rules". Transport Canada. Archived from the original on 19 September 2012. Retrieved 13 August 2012.
- "TP 14371 - Transport Canada Aeronautical Information Manual (TC AIM) - RAC - 2.0 AIRSPACE – REQUIREMENTS AND PROCEDURES". Transport Canada. 11 April 2012. Archived from the original on 18 February 2011. Retrieved 13 August 2012.