Strange baro pressure behaviour

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kleistad
Posts: 43
Joined: Fri Apr 24, 2015 7:12 am
Location: Alta, Norway

Strange baro pressure behaviour

Post by kleistad »

Had something interesting happening to me on my last flight.

ATC asked me if I really was on my assigned altitude, 5000ft. I confirmed I was, and that I was using real weather and my altimeter was set to the correct pressure. The controller just said ok and didn`t query more about this. But I figured something wasn`t right since he asked.
So I opened the little bar in X-Plane which shows the weather. And sure enough, while atis on myflighroute.com and skyvector said the pressure was 30.25, my sim was 29.47. Corrected my altimeter settings and let ATC know what the issue was.
Then as I was getting closer to my arrival airport the pressure started rising. And then stabilized at 30.21 which was what was the pressure in real life.

The controller queried me maybe 5nm from OCN. The pressure started rising right after OCN.
http://peaware.pilotedge.net/flight.cfm?id=186262

Could this be accurate? Or did something go wrong with the weather enginge?
Never experienced to fast changes before.
Last edited by kleistad on Thu Jan 26, 2017 2:08 am, edited 1 time in total.
Kristoffer L.
N187KT
Balu0
Posts: 28
Joined: Wed Dec 28, 2016 5:43 am

Re: Strange baro pressure behaviour

Post by Balu0 »

Happened to me. I was flying to OCN too.

My tip is someone mistyped the pressure in the METAR, some stupid number that X-Plane could not handle or something along the line.

I was 5000ft as per my instruments but on the map it show 4400
RyanK
Posts: 148
Joined: Mon Dec 22, 2014 11:00 am
Location: Stevens Point, WI

Re: Strange baro pressure behaviour

Post by RyanK »

I'm thinking you mean the data display showed sea level pressure of 29.47" (not 20.47"). Then it's probably an issue with your weather engine or the data it's getting. Your altimeter would've indicated about 700' too high if you set it to 30.21" in that case.
kleistad
Posts: 43
Joined: Fri Apr 24, 2015 7:12 am
Location: Alta, Norway

Re: Strange baro pressure behaviour

Post by kleistad »

RyanK wrote:I'm thinking you mean the data display showed sea level pressure of 29.47" (not 20.47"). Then it's probably an issue with your weather engine or the data it's getting. Your altimeter would've indicated about 700' too high if you set it to 30.21" in that case.
Correct it was showing 29.47. Just a spelling mistake
Kristoffer L.
N187KT
Matthias Geiss
Posts: 149
Joined: Wed Sep 02, 2015 2:24 am

Re: Strange baro pressure behaviour

Post by Matthias Geiss »

It often happens that the in-sim real world weather differs more or less from the "official" Pilotedge conditions. I always set the altimeter according to what X-Plane is showing, just to be on the safe side. If a controller states a QNH in a call, i acknowledge it but don't set it in the sim, unless it's the same QNH as in X-Plane, of course.
kleistad
Posts: 43
Joined: Fri Apr 24, 2015 7:12 am
Location: Alta, Norway

Re: Strange baro pressure behaviour

Post by kleistad »

Matthias Geiss wrote:It often happens that the in-sim real world weather differs more or less from the "official" Pilotedge conditions. I always set the altimeter according to what X-Plane is showing, just to be on the safe side. If a controller states a QNH in a call, i acknowledge it but don't set it in the sim, unless it's the same QNH as in X-Plane, of course.
Never had it happen before, but will check what X-Plane is showing the next time :D
Kristoffer L.
N187KT
kleistad
Posts: 43
Joined: Fri Apr 24, 2015 7:12 am
Location: Alta, Norway

Re: Strange baro pressure behaviour

Post by kleistad »

Just did a flight from KSNA, no problem with the pressure, but I were heading north this time and not south.
I heard the controller talking to an pilot who was having the same problems, I think he was close to OCN vor just like I was when it happened.

If the ZLA controller who was on around 10:30AM PST reads this, it would be nice if you could confirm if it was the same problem :)

Installed xEnviro a month ago, thinking it might be that. Will do some testing offline tomorrow.
Kristoffer L.
N187KT
kleistad
Posts: 43
Joined: Fri Apr 24, 2015 7:12 am
Location: Alta, Norway

Re: Strange baro pressure behaviour

Post by kleistad »

Just did a test flight.

Flew the same route to OCN. And 17nm from the vor the pressure started dropping.
Turned off xEnviro and reloaded current weather. And what happened???

You guessed it, Pressure was showing the same as the real world metar was.

Gonna file it as a bug with xEnviro
Kristoffer L.
N187KT
rtataryn
Posts: 344
Joined: Wed Mar 04, 2015 10:19 pm
Location: Spokane, WA

Re: Strange baro pressure behaviour

Post by rtataryn »

Flying right now from KMYF to KVNY just past the OCN VOR. XEnviro off: Baro with actual RW weather is 30.16. Turn on xEnviro and it drops to 29.76. Plane dives 400 feet. Turn off xEnviro and bck to normal.
Rod
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