Canadian Domestic Airspace

Canadian Domestic Airspace (CDA) is the airspace over Canada and over the territorial waters of Canada, from the surface to unlimited altitude. It encompasses all airspace within Canadian jurisdiction and is divided into the Northern Domestic Airspace (NDA) and the Southern Domestic Airspace (SDA), each with different magnetic variation thresholds that determine the cruising altitude half-track rule.

SDA vs. NDA

• Southern Domestic Airspace (SDA): South of approximately 60°N; magnetic compass is reliable; cruising altitudes based on magnetic track
• Northern Domestic Airspace (NDA): North of approximately 60°N; magnetic compass unreliable near the pole; cruising altitudes based on true track

Significance for VFR Cruising Altitudes

The VFR cruising altitude rule (odd/even thousands + 500 ft based on track) uses magnetic track in the SDA and true track in the NDA. This is tested on both PPL and CPL written exams.

Related Terms

See also: Northern Domestic Airspace, Southern Domestic Airspace, Cruising Altitude.