What does the runway number represent?

The runway number represents the compass heading of approaching aircraft. Each runway is designated by a number that corresponds to its magnetic azimuth, rounded to the nearest ten degrees. For instance, a runway labeled as 27 would have an approximate heading of 270 degrees, indicating that aircraft approaching this runway would be doing so from the west. This designation is crucial for pilots as it helps them understand the orientation of the runway and allows for safe landing approaches aligned with their flight paths.

Understanding runway numbers is vital for airport operations and ensures that air traffic control can guide aircraft efficiently, especially in busy airport environments where multiple runways may be in use simultaneously. The other options do not accurately relate to the designation of runway numbers, as they either pertain to wind direction or the physical attributes of the runway itself, rather than its directional heading.