Canadian airspace is the region of airspace above the surface of the Earth that falls within a region roughly defined as either Canadian land mass, the Canadian Arctic or the Canadian archipelago, as well as areas of the high seas. Airspace is managed by Transport Canada and detailed information regarding exact dimensions and classification is available in the Designated Airspace Handbook which is published every fifty-six days by Nav Canada.
Canadian Domestic Airspace
|This section is missing information about the boundaries of NDA and SDA. (November 2015)|
The "Canadian Domestic Airspace" includes all of Canada and extends out over the Pacific, Arctic, and Atlantic Oceans. It is broadly divided into the "Northern Domestic Airspace" (NDA) and the "Southern Domestic Airspace" (SDA).
There are three main differences between the two areas, the most important of them being that the NDA is designated as a "standard pressure" region while the SDA is an "altimeter setting" region. This means that pilots operating in the SDA will calibrate their altimeters to atmospheric pressure according to information available at airports and through weather services. Conversely, in the NDA, pilots calibrate their altimeters to 29.92 inches of mercury (1013 hPa) regardless of the actual atmospheric pressure. This is done because weather information is not available for all areas of the far north, so it is better that all pilots use a standard setting in order to avoid collisions.
Another major difference between the NDA and SDA is that magnetic declination is not used in the NDA. Because the magnetic north pole is in the NDA, magnetic declinations are very large; sometimes even 180°. This is further complicated by the fact that magnetic north moves approximately 200 miles (320 km) in an elliptical path every day. For these reasons, "true" tracks are always used in the NDA while magnetic tracks are frequently used in the SDA for convenience.
The final difference between the NDA and the SDA has to do with the location of Class A airspace in each region. This is explained in more detail below.
There are seven classes of airspace in Canada, each designated by a letter (A through G).
- Class A airspace exists exclusively between FL180 and FL600. In the SDA, it begins at 18,000. However, in the NDA, it does not. The NDA is divided into two Control Areas: the "Arctic Control Area" (ACA) and the "Northern Control Area" (NCA). In the NCA, Class A airspace extends upwards from FL230, and from FL270 (formerly 280) in the ACA.
- Class B airspace is any controlled airspace between 12,500 ft (3,800 m) and 18,000 ft (5,500 m) Occasionally, Class B airspace exists in other locations, though this is unusual.
- For entry into Class B airspace, an aircraft needs a functional Mode C transponder and either an IFR or a CVFR (Controlled VFR) clearance.
- Class C airspace is usually a control zone (CZ) for a large airport. These areas usually have a 10 nautical mile radius and a height of up to 12,500 above aerodrome elevation (AAE).
- For entry into a Class C control zone, an aircraft needs a functional Mode C transponder and an ATC clearance.
- Class D airspace is usually a control zone for smaller airports or aerodromes that has a 5-nautical-mile (9.3 km) radius and a height of 3,000 ft (910 m) AAE. Airports in extremely busy airspace may have only a 3-nautical-mile (5.6 km) radius control zone.
- For entry into a Class D control zone, an aircraft needs to contact ATC. Some Class D control zones require transponders, and NORDO flight is not permitted at night in a Class D zone.
- Class E airspace is used for low-level flight routes and for aerodromes with very little traffic. ATC is available, but is not required. Some Class D control zones change to Class E at night if the control tower shuts down. It is also high level controlled airspace above FL600.
- Any aircraft may fly in Class E airspace.
- Class F airspace is restricted. Any Class F zone will be designated either CYR, CYD, or CYA. CYR stands for restricted, CYD means danger (usually used for CYR areas over international waters), and CYA stands for advisory. CYA zones will also have a letter identifying the type of activity in the zone: A - aerobatics, F - aircraft testing, H - hang gliding, M - military, P - parachuting, S - soaring, T - training.
- For entry into a CYR or CYD zone, an aircraft needs the permission of the operating authority. Pilots may enter CYA zones at their discretion, but are encouraged to avoid them unless taking part in the activity.
- Any airspace that is not designated is Class G airspace. This airspace is uncontrolled, and ATC is not usually available (though exceptions are made).
- Any aircraft may fly in Class G airspace.
Airspace classes A through E are controlled. Class F can be controlled or uncontrolled. Class G is always uncontrolled. Airspace is managed by Transport Canada and detailed information regarding exact dimensions and classification is available in the Designated Airspace Handbook which is published every fifty-six days by Nav Canada.
type A- more than 6 aeroplanes, more the 20 passengers, maximum gross take off wight is 45,455kg or more, complex operation type B- 20 or more passenger, less than 45,455kg, 6 or less airplanes, not complex operations type C- Cargo only airplanes or operating airplanes, have passengers seating less than 20, 30 or less propeller driven
Other important features
Some control zones have unique procedures because of terrain or air traffic demands. These procedures are published in the Canada Flight Supplement. Another important feature of Canadian airspace is the Air Defense Identification Zone (ADIZ) that surrounds North America.
Saint Pierre and Miquelon
- The class E airspace ranges from 6000 feet AGL to 12,500 feet within the area demarcated by a line beginning at and ending at , then running clockwise along a circle with a radius of 10 miles centred on .
- The Control Area for St-Pierre is the airspace to 2000 feet (2000´ AAE) within a circle with a radius of 6 miles centred on .
- The area above 12,000 feet is controlled by Nav Canada. 
- Transport Canada Aeronautical Information Manual (TC AIM). Transport Canada. RAC 2.2.
- "NAV CANADA Aeronautical Information Products". Nav Canada. Retrieved 2007-06-20.
- Transport Canada Aeronautical Information Manual (TC AIM). Transport Canada. RAC 2.8.