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Altitudes and barometer settings
Posted: Sat Feb 12, 2011 11:11 pm
by Daddy O
I have been wondering about variance between airport altitude and rreported barometer settings. I use real weather with a 30 minute update, but if I use the barometer setting that PE controllers report, my indicated altitude is not correct. I also noticed that I get the same issue when I try t use the ATIS reported setting in Xplanes. To compensate I always set my altimeter to the published airport altitude.
So, does PE get it's weather reports from the same source as Xplanes?
Re: Altitudes and barometer settings
Posted: Sun Feb 13, 2011 8:15 am
by Keith Smith
PE uses the same weather source as xplane. What I don't know is what xp does with the weather info in v9.
Re: Altitudes and barometer settings
Posted: Sun Feb 13, 2011 5:43 pm
by David Carman
How far off is the altitude you get when setting to the controllers altimeter setting? The weather controllers have to report (METARs) can be up to an hour old, and can vary accordingly (however, I think xplane gets the same out-dated weather so this shouldn't actually be an issue?).
Re: Altitudes and barometer settings
Posted: Mon Feb 14, 2011 7:10 am
by Keith Smith
A test would be to go to a field that has weather reporting, far away from other fields that have weather reporting (some of GCN, of IFP would be good examples, I have to think), switch on real weather, then go to the weather screen and find out exactly what weather was set (winds, clouds, barometer). Compare that to the current metar for that airport.
Re: Altitudes and barometer settings
Posted: Mon Feb 14, 2011 12:12 pm
by Alex Stjepanovic
I've been getting similar problems. Last nite during the canyon run, I kept getting reports from ATC that the setting was around 30.22, which when set on the ground, showed an elevation of around 7000ft, while in fact GCN is only 6609.
Re: Altitudes and barometer settings
Posted: Mon Feb 14, 2011 1:46 pm
by Keith Smith
Alex, were you using real weather in xplane?
Re: Altitudes and barometer settings
Posted: Mon Feb 14, 2011 3:45 pm
by Alex Stjepanovic
Yep.
Re: Altitudes and barometer settings
Posted: Mon Feb 14, 2011 3:49 pm
by Keith Smith
Interesting, I don't know of many weather reporting stations around GCN, other than GCN.
If you have time, I would run a basic test where you plop yourself at an airport, let XPlane download the weather then check to see what settings it has come up with, comparing them with the current weather.
Re: Altitudes and barometer settings
Posted: Mon Feb 14, 2011 8:08 pm
by Daddy O
I have seen the same thing in XP9 standalone using the settings from ATIS. It was because of this that I just use airport altitude.
Usually the altitude is off by a hundred feet or more if I use the altimeter setting in XP9.