Airspace Classification, Control Zones, and Operating Rules
Airspace classification decides what you need before you enter a piece of sky: nothing at all, a radio call, or a full ATC clearance. PSTAR questions in this domain are short and precise, usually asking for the class, the altitude band, and the permission or equipment required.
The classes used in Canada
- Class A: 18,000 ft ASL and above; IFR only, transponder required. VFR is not permitted.
- Class B: 12,500 ft ASL to 17,999 ft ASL; controlled. VFR requires an ATC clearance and a transponder.
- Class C: controlled; VFR requires an ATC clearance and a transponder.
- Class D: controlled; VFR requires two-way radio communication established and maintained with the controlling agency. An explicit clearance is not required.
- Class F: advisory (CYA) or restricted (CYR).
- Class G: uncontrolled.
- Class E is not used in Canada. This is a favourite exam trap.
Control zones
- Surround controlled aerodromes, normally a 7 NM radius to 3,000 ft AAE, and are Class C or D.
Altimetry and transponder
- The transition altitude is 18,000 ft: use the altimeter setting below it, and 29.92 inHg at and above it.
- Transponder airspace includes Classes A, B, C and designated Class D airspace.
Worked example
You plan a VFR cruise at 15,500 ft. That is Class B airspace, so you need an ATC clearance and a serviceable transponder. If you filed 19,500 ft instead, the answer changes completely: Class A is IFR only, so no VFR altitude exists there. The correct response is to stay below 18,000 ft or file IFR.
Traps that cost marks
- Quoting 10,000 ft as the transition altitude; in Canada it is 18,000 ft.
- Assuming a control zone is 5 NM across.
- Believing Class D requires a clearance rather than radio contact.
- Forgetting that Class B sits between 12,500 and 18,000 ft.