View Single Post
  #2  
Old January 16th 09, 08:09 PM posted to rec.aviation.piloting
terry
external usenet poster
 
Posts: 215
Default Density Altitude Calculator

On Jan 17, 5:39*am, Rajat Garg wrote:
Guys,

I just came across this -

http://www.pilotoutlook.com/calculat...ude-calculator

It may be useful for other students.

They also have other flight planning tools at -http://www.pilotoutlook.com/flight_planning/calculators

Thanks Rajat. Its fun to play with but I dont know many pilots that
actually worrry too much about the moisture effect on density. Its not
that great except for very humid and hot days where it will be no more
than 10%. Its best to calculate the density altitude when you are
actually at the airfield ready to go, in which case you prollly wont
have a computer. Easiest way is to just set the Kollsman window for
1013.2 ( or 29,92 if you are still behind the times :) ) .
which of course gives you your pressure altitude then just correct for
temp. Add or subtract 120 ft for each 1 deg C above or below the ISA
temp for that pressure altitude. With a bit of practice you should be
able to do it in your head in less than a minute
eg set 1013.2 and say your altimeter reads 1500 ft that is your
pressure altitude. ISA temp would be 15-2x1.5 or 12 deg C. if your
actual temp read off the aircrafts outside temp gauge is say 20 deg
C , then add 8 x120 or 960 ft to get 2460 ft density altitude.
Terry
PPL Downunder

..