Are runway numbers based on true heading or magnetic heading?

Runway numbers are based on the magnetic heading of the runway as it aligns with the Earth's magnetic field. This is important for pilots as they use magnetic headings while flying to ensure correct navigation and alignment with the runway during approach and takeoff. The runway number is derived from the compass heading, rounded to the nearest whole number and then divided by ten; for example, a runway with a magnetic heading of 240 degrees would be assigned the number 24.

Using magnetic headings is essential since pilots reference their navigation instruments, which are calibrated to magnetic north rather than true north. By using the magnetic heading system, pilots can accurately align themselves with the runway during operations. This is why understanding runway orientation in terms of magnetic headings is crucial for successful and safe flying.