Aviation Terms->Controlled Airspace
Aviation term used to describe airspace in which ATC has the authority to control air traffic, the level of which varies with the different classes of airspace. Controlled airspace is established mainly for three different reasons: 1- high-volume air traffic areas (e.g. near airports), 2- IFR traffic under ATC guidance, 3- security. According to the airspace classes set by ICAO, Class A, B, C, D, and E airspace are controlled. It is the opposite of uncontrolled airspace.