Re: Density Altitude calculation......
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">Rather than use Math, most use something like this
[url="http://www.americanflyers.net/aviationlibrary/pilots_handbook/images/chapter_9_img_12.jpg"]http://www.americanflyers.net/aviationlibrary/pilots_handbook/images/chapter_9_img_12.jpg[/url][img]
If you come across something that requires long hand math in the field, chances are there is an easier way to do it, if not I would suspect you don't need it.
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That's okay to use, but you have to account for pressure altitude, which is known elevation +/- air pressure factor. Depending on how accurate you're trying to be, neglecting air pressure could put you off by a few thousand Use this instead, I use this when I'm out flying and it's more exact. Pretty simple too. Even with dirty math, you'll be far more accurate and it only take ~15 seconds to do.
1 determine known elevation
2 read barometer and find pressure altitude conversion factor
3 if barometer is BELOW 29.92, add to known elevation, if ABOVE, subtract from known elevation. This is your pressure altitude
4 determine air temp
5 draw a line up from air temp to the pressure altitude contour you calculated
6 draw a horizontal line, this is your density altitude
Enjoy
[img]http://www.cfinotebook.net/graphics/performance/Density-Altitude.jpg