How Canadian Airspace Is Organized

Why it matters

Look at a VFR navigation chart and the sky over Canada seems carved into shapes: shaded rings around airports, corridors between cities, blocks with cryptic labels. Every one of those shapes answers three questions for you before you fly into it: do I need permission to be here, what equipment must I carry, and what weather is enough? Airspace organization is the index to the rest of air law — the VFR minima, the transponder rules and the radio rules all key off the type and class of airspace you occupy.

Controlled versus uncontrolled

The fundamental split in CAR 601.01 is between controlled airspace — where air traffic control services are provided and ATC can impose clearances — and uncontrolled airspace, where nobody issues clearances and pilots coordinate directly with each other. Controlled types include control zones, terminal control areas, low level airways, control area extensions, transition areas and the high level control areas; uncontrolled airspace covers most of everything else, including the low-level air routes.

Being "controlled" does not automatically mean you must talk to anyone. In much controlled airspace (Class E, as the next unit explains) VFR flights proceed without any clearance at all — what changes is the weather minima you owe (the controlled-airspace numbers from the previous chapter) and the possibility that ATC service exists there.

High level and low level, south and north

Two more divisions matter to how you fly:

• High level airspace is all airspace from 18,000 feet ASL and up; below that is low level airspace. The 18,000-foot surface is also where the standard pressure region begins and where altitudes turn into flight levels — the altimeter procedures of the previous chapter.
• The Canadian Domestic Airspace is split into the Southern Domestic Airspace (SDA) and the Northern Domestic Airspace (NDA). The practical differences you already know: cruising altitudes use the magnetic track in the SDA and the true track in the NDA (where the magnetic compass is unreliable near the pole), and the NDA is standard pressure region at all altitudes.

Where the official boundaries live

The CARs deliberately do not draw the map. CAR 601.01 and 601.02 delegate the geography: the horizontal and vertical limits of each piece of designated airspace, and its class, are the ones published in the Designated Airspace Handbook (DAH) — with air-route dimensions shown on aeronautical charts. For day-to-day flying you read the results off the VNC/VTA charts and the Canada Flight Supplement, but when an exam asks where the dimensions and classifications are specified, the answer is the Designated Airspace Handbook.