What is the implication of a runway number changing due to magnetic variation?

The selection of the answer highlights a critical aspect of aviation navigation related to magnetic variation. When a runway's number changes, it typically reflects a shift in the magnetic heading due to gradual changes in the Earth's magnetic field. Runway numbers are determined based on the magnetic azimuth, rounded to the nearest 10 degrees. If this magnetic variation leads to a change in the runway's designation, it could result in confusion for pilots who are not aware of the updated information.

In aviation, runway numbers serve as vital references for pilots during takeoff, landing, and taxi operations. If pilots are not informed about a change in the runway number, they may misinterpret which runway to use, leading to potential safety risks and operational inefficiencies. This is why keeping pilots informed about such changes is essential for maintaining situational awareness and ensuring safe operations.