Barometric pressure setting wrong?

Big Flapper

New Member
Joined
Jul 10, 2019
Messages
6
When I leave our private airstrip I adjust the barometer setting so I get the correct altitude reading on my skyview.
As I pass over a class D airport, 10 miles away, I always get a barometric reading 6 numbers lower from the awos.
Can I adjust the Dynon system to agree with the airport reading?
 

XPRSAV8R

Member
Joined
Jul 9, 2019
Messages
80
Location
Houston Area
Sorry if I misinterpret your question.
First, your altimeter reading should be +/- 75' of published field elevation. Now, if you're using Class Delta's ATIS for your altimeter setting, it could be as much as 60 minutes old since it's typically updated around the top of the hour. That said, you can always manually change the altimeter setting so that you're reasonably within the accepted range.
 
Last edited:

kellym

I love flying!
Joined
Sep 29, 2013
Messages
273
When I leave our private airstrip I adjust the barometer setting so I get the correct altitude reading on my skyview.
As I pass over a class D airport, 10 miles away, I always get a barometric reading 6 numbers lower from the awos.
Can I adjust the Dynon system to agree with the airport reading?
I would suggest you fly to the Class D airport after you have studied the airport diagram to know where the airport reference elevation is located.
Then get the tower to let you taxi to as near the reference point as you can. If you have an error after setting to the tower's most current altimeter setting, then go into setup to add or subtract perhaps half of the error. Don't go by ATIS, ask ground control..they have the instrument in front of them. I frequently see differing altimeter settings between my home drome and airports that are less than 15 min flight away, usually .02-.04 in.
I don't worry about it. My altimeter is usually about 10-20 ft off on startup, and after 5 min will be pretty darn close to field elevation. I did add 30 ft to the unadjusted altitude to gain that accuracy.
 

airguy

Well-Known Member
Joined
Nov 10, 2008
Messages
1,096
Location
Gods Country - west Texas
The problem is that the Skyview baro sensor drifts slightly between cold and warm. I see 30 feet pretty commonly between a cold winter morning startup and 5 minutes later once the screen has warmed up a bit. As noted above you have a +/- 75' window of acceptable accuracy, so taking off with a known good field elevation and then getting the nearest ATIS (or ADSB WX) should be fine.

Alternatively, most AWOS/ATIS stations have a phone number you can call to listen to the data - you could get the altimeter setting that way on the ground.
 
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