Controlled Airspace is an airspace of defined dimensions within which air traffic control service is provided in accordance with the airspace classification.
There are 3 services available in controlled airspace;Flight Information Service, Alerting Service, Radar Control Service.
Flight Information Service
A Flight Information Service (FIS) is a non-radar service provided, either separately or in conjunction with other services, for the purposes of supplying information useful for the safe and efficient conduct of flights. Under a FIS the following conditions apply:
An alerting service is provided to notify appropriate organisations regarding aircraft in need of search and rescue aid, and assist such organisations as required.
Radar Control Service
A radar control service may be provided to aircraft operating IFR, SVFR or VFR. When providing the service controllers issue instructions to which:
Above FL 195 in Class C airspace the semi-circular rule shall apply. Flight levels 200, 220, 240, 260 and 280 shall be westbound; Flight levels 210, 230, 250 and 270 shall be eastbound. Above FL290, cruising levels are allocated according to the RVSM system.
Cruising levels at or above FL 410 up to FL 660 shall be selected according to the semi-circular rule, therefore, flight levels available are: