Why are runway numbers and orientation important in aviation?

Runway numbers and orientation are critical in aviation primarily because they indicate the runway's heading from magnetic north. This information is vital for pilots during takeoff and landing, as it helps them align their aircraft with the correct direction relative to the Earth's magnetic field. The runway number is usually derived from the magnetic heading of the runway rounded to the nearest ten degrees, providing a straightforward reference point for pilots and contributing to precise navigation.

Knowing the runway's orientation enhances situational awareness as it allows pilots to understand wind conditions, approach paths, and potential obstacles in the vicinity. For instance, if a runway is numbered 27, it is oriented roughly 270 degrees magnetic, which indicates the direction toward which a pilot will take off or land. This understanding helps ensure safety by allowing pilots to make informed decisions based on the runway's alignment relative to the wind direction and overall flight path.