Northern Domestic Airspace (NOA)

Northern Domestic Airspace (NDA) is the portion of Canadian Domestic Airspace north of approximately 60°N latitude where magnetic variation is so large or variable that magnetic north cannot be used as a reliable directional reference for aviation. In the NDA, cruising altitudes are based on true track rather than magnetic track.

NDA Cruising Altitude Rule

In the NDA: 0°–179° TRUE track — fly at odd thousands + 500 ft; 180°–359° TRUE track — fly at even thousands + 500 ft. The rule is identical to the SDA rule except it references true track. Navigation in the NDA often requires grid navigation rather than magnetic headings.

Related Terms

See also: Canadian Domestic Airspace, Southern Domestic Airspace, Grid Navigation, Arctic Control Area.