Airport runway names shift with magnetic field
Why is it desirable to correlate runway names with the Earth's magnetic fields?  Is it because the navigational equipment breaks / becomes inaccurate when there's a field shift?It seems like it could be confusing over time to keep updating runway names as flight paths are repeatedly flown by generally the same sets of pilots, and as paths becomes familiar.  For fancy autopilot setups most of the in-the-moment thinking is avoided and this may become a very minor detail.Edit: Thanks for the quick info everyone!  Now this makes sense. 
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