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airernie

Runway alignment

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I would like to align a FSX default (KSUX) runway with the current airport diagram.

 

According to ADE, runway 31 of KSUX is aligned to 315.7350°   According to the airport diagram, the actual alignment should be 312.6°. 

 

The airport diagram displays two arrows labeled VAR 3.1° E.

 

I assume that I would need only rotate the airport to align it to 312.6°, but is that correct?  Do I need to concern myself with the variance. 

 

Also, by rotating the airport, do the ILS, etc. alignments change also?

 

Thanks,

Ernie

 


Ernest Pergrem

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312.6 on the airport diagram is magnetic, 315.7350 is true.

 

According to AirNav ( http://www.airnav.com/airport/KSUX ) true is 316. That figure would be rounded to the nearest full degree, so it indicates the runway heading in FSX is correct. Info on AirNav is intended for pilots, not airport designers. :wink:

 

So it appears that there is nothing to be changed.

 

BTW, according to ADE 1.67, on my PC RWY 13/31 is 135.740005. Are you looking at the default airport or an addon?

 

I am looking at FSX/A.

 

regards,

Joe

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In ADE, when you look at an runway's properties, the heading given is based on True North, so Runway 31's "True" heading is 315.735 degrees.  The arrows you are talking about show the variance between True North (the double pointed arrow) and Magnetic North (the single-sided arrow), so 3.1 degrees East. 

 

Also notice the annual rate of change of 0.1 degree West every year.  That's how much magnetic north will change relative to True North, which never changes.  The variance noted was as of January 2015.  Since that is an annual change and the change is to the West, as of January 2016 the variance was 3.0 degrees East

 

Therefore, the magnetic heading given for Runway 31 of 312.6 is only one/tenth of a degree off from magnetic north (315.7T minus 3.0 equals 312.7 degrees).  The runway is fine just the way it is.  And remember, runways don't change direction.  The magnetic pole is constantly moving so the runway heading changes, but not it's true direction relative to true north (unless they dig it up and build a new one).  That's why every so often, like at Oakland Metropolitan in California and John Wayne Orange County recently, the runways are renumbered.  Not rebuilt, just renumbered.  KOAK's 11/29 became 12/30 and KSNA's 1/19L/R became 2/20L/R.  A couple of years ago Fairbanks 1/19's did the same and not too long ago Anchorage change 14/32 to 15/33.  But in every case the runway stayed right where it was.  The magnetic Pole moved enough to finally justify renumbering.

 

If the aeronautical charts are in anything other than Magnetic North it will specifically say something along the lines of "Headings and Bearings are relative to True North".  You see this a lot once you get past 60 degrees North or South Latitude.

 

Randy

 

Edit: Joe beat me to it.  Guess I'm just long-winded.  ADE9X shows my default FSX runway to be 135.74005/315.74005 also.


Randy Tyndall

You never lose the buzz of flying. Every time you take off, it feels a bit naughty, as if you're doing something you shouldn't do...Matt Jones, Boultbee Flight Academy

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Randy & Joe,

Thank you for excellent responses.  Much better understanding now..

 

So, it is time to put away ADE and get back to flying, :-)

Ernie


Ernest Pergrem

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