How is a runway numbered in southern domestic airspace?

Runways are numbered based on their magnetic bearing, which is measured in degrees from true north and rounded to the nearest ten degrees. For example, a runway that is oriented towards the north would be numbered 36, since it has a magnetic bearing of approximately 360 degrees. This system allows pilots to easily identify and differentiate runways based on their orientations, especially during takeoff and landing situations where directional awareness is crucial.

Using magnetic bearing also accounts for the earth's magnetic variation, which can change over time. Therefore, runway numbers can be updated to reflect these changes, ensuring they remain accurate for navigation purposes.

Options concerning runway elevation, geographical location, or length do not accurately contribute to the runway numbering system, as they serve different purposes in aviation. Ensuring clarity through standardized runway numbers based on orientation aids in safety and communication within aviation operations.