Changing Runway Numbers at John Wayne (KSNA)

Maybe they were expecting an earthquake that never came?
 
My guess it is a contractor/coordination issue. Changing all that signage overnight and having it coincide with a chart cycle change (which I assume is what they are trying to do) has got to be a logistical nightmare at a major airport.
 
On the military fields, the magnetic changes are corrected every 10 years. It's done by means of a formula that uses the past as a guide to the future.
 
Earth is going to swap poles next month so they figured they'd wait until then to repaint since they'll have to swap ends as well.
 
I guess they decided the cost of tearing up the existing runways and re-paving them at a 10 degree angle wasn't worth it ;)
 
tinerj said:
On the military fields, the magnetic changes are corrected every 10 years. It's done by means of a formula that uses the past as a guide to the future.
Click to expand...

That's the World Magnetic Model. Not just military....

Current is WMM2010.

It's a spherical harmonic expansion where every coefficient has a 2010 value and a rate of change.

It's a pretty rough approximation. SH's are a great theoretical tool, but they converge a bit slowly for practical use. You need a lot of them.
 
[email protected] said:
A while back, the John Wayne (KSNA) entry gates carried big banners announcing that on 7/24 the runways would change from 19L and 19R to 20L and 20R:

http://airsoc.com/articles/view/id/...t-ksna-prepares-to-change-runway-designations

7/24 came and went, the banners are gone, but the runways are still 19L and 19R.

Anybody know what happened?
Click to expand...

I heard they are waiting until the new charts come out to change them. Although I've been hearing that for over a year now.
 
MAKG1 said:
That's the World Magnetic Model. Not just military....

Current is WMM2010.

It's a spherical harmonic expansion where every coefficient has a 2010 value and a rate of change.

It's a pretty rough approximation. SH's are a great theoretical tool, but they converge a bit slowly for practical use. You need a lot of them.
Click to expand...

My group at the Defense Mapping Agency Aerospace center applied that formula to airports to see if the markings needed changed. (DMA has since changed names a few times.) We also updated the airport diagrams using FORTRAN code. We were about the only mathematicians in the whole DMA, most others were geodesists, cartographers, or surveyors. The others in the office were geodeists and went around talking about 180 x 180 earth gravity model -- they were hard at work on 360 x 360 model when I left -- or the point gravity anomaly file, and how sea mounts were messing up the gravity model.
 
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