All airspace is divided into FIRs (flight information regions) that are responsible for their airspace. The airspace is either controlled or uncontrolled. In controlled airspace, the air navigation service provider is responsible for separating the aircraft and ensuring safety, while in uncontrolled airspace the pilot in command is solely responsible for flight safety and the air navigation service can provide flight information if requested.
Controlled airspace exists around the larger airports and is only established when the air navigation service is staffed. The airspace may also contain various limitations for air traffic such as restriction areas, hazardous areas and prohibited areas. Airspace is divided internationally into airspace class A-G, which determines which traffic may be present and what rules apply. In Sweden airspace class C are used for controlled airspace and G for uncontrolled airspace.
Map: Flight map with controlled and uncontrolled airspace, restriction areas and ATS flight routes.
Airspace closest to the airport: Control zone (CTR)
The area closest to the airport, the purpose of which is to protect air traffic during the start and landing phase, is called the control zone. Within this there are several previously mentioned obstacle-limiting surfaces. The control zone is relatively small and extends from the ground up to a height of about 450 meters. The control zone can almost be considered a “protective area” for the airport, which should be free of obstacles to the greatest possible extent.
Corresponding airspace for uncontrolled airports is called Traffic Information Zone or TIZ.
Map: Control zone (CTR) for Norrköping Airport. Triangles are entry and exit points for VFR traffic (except DOCKAN).
Terminal area (TMA)
During the approach and departure phase to the airport air traffic is most often guided in a controlled airspace, known as the terminal area. This has a lower limit of about 450 meters or more above the ground. Wind power and pylons below TMA may not be built higher than will allow for maintaining sufficient obstacle clearance for radar guidance.
The corresponding zone for uncontrolled airports is called the Traffic Information Area, or TIA.
Map: Östgöta Terminal Area (TMA).