Due to a magnetic variation change (MAGVAR), McCarran International Airport has renumbered runways 7L/25R and 7R/25L. The airport’s two longest runways will now be designated as Runway 8L/26R and Runway 8R/26L, effective 1700 local time Aug. 16.
Runway numbering, navigational aids and flight procedures are based on magnetic headings. True magnetic headings change over time, so every five years the FAA reevaluates shifts in the poles, which is known as magnetic variation. If the true heading changes more than 3 degrees at any airport, it has to renumber its runways.
The FAA also takes a number of actions when the magnetic headings change, including but not limited to updating airport directories and charts used by pilots, and alerting pilots to the planned changes so a pilot looking to land on Runway 25 isn’t surprised to see a “26” painted on the runway, for example. The FAA has standard procedures and checklists it goes through when making these changes which McCarran staff utilized for the transition.
In the last few years, magnetic variation has required renumbering runways at several other U.S. airports, including in Tampa, Fla., and Orange County, Calif.
