Canadian airspace

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Canadian airspace is the region of navigable airspace above the surface of the Earth that falls within a region roughly defined by the Canadian land mass, the Canadian arctic, the Canadian archipelago, and areas of the high seas.^[1] 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.^[2]

1 Canadian Domestic Airspace
2 Airspace classes
3 Other important features
4 References

[edit] Canadian Domestic Airspace

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. Most importantly, 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 altimeter 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 h Pa) 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" headings are always used in the NDA while magnetic headings 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.

[edit] Airspace classes

There are seven classes of airspace in Canada, and each is 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 FL 270 (formerly 280) in the ACA. The airspace between FL180 and the beginning Class A airspace is designated Class G airspace.
- For entry into Class A airspace, an aircraft needs a functional Mode C transponder and an IFR clearance.

Class B airspace is any controlled airspace between 12,500 ft. and 18,000 ft. 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 3,000 ft. 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 radius and a height of 3,000 ft. AAE. Airports in extremely busy airspace may have only a 3 nautical mile 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.
- 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.

[edit] 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.