Garmin G5 Static - Altitude

ten4teg · #1 10-26-2020, 03:42 PM

Just got a Garmin G5. When I set the Baro to field elevation, the baro does not match the current pressure. It looks like it needs adjustment. Anybody know a way to do this? I don't need IFR accuracy. Thanks tom.gregorski@gmail.com

bkervaski · #2 10-26-2020, 03:43 PM

How far off is it? Mine is off like 10 feet.

ten4teg · #3 10-26-2020, 04:17 PM

Mine is off about 70 feet.

Walt · #4 10-26-2020, 06:33 PM

Quote:

Originally Posted by ten4teg

Mine is off about 70 feet.

They can easily be calibrated with a (high accuracy RVSM preferred) pitot static test box, you have to take it up to 20K for the cal procedure. I find they can drift a bit but have not seen anywhere near 70'.

Desert Rat · #5 10-26-2020, 07:13 PM

Not saying it's right, because a 70' error would really bother me as well, but even for IFR the allowable error on an altimeter is shockingly large. Going out on a limb here, but I seem to recall the AIM talking about +-75'. Does that sound right?

Also, is it possible that the error isn't actually that large? My home runway looks dead flat, but according to the approach plates, field elevation is 1408, measured at the threshold for rwy 19, and drops about 40' by the time it gets to the other end. The runup pad (about midfield) consistently shows 20' lower than published field elevation, which seem logical based on what the plate shows.

MacCool · #6 10-26-2020, 07:20 PM

I added a G5 to my panel as a backup, in addition to my AFS EFIS and to the old round gauge still in the panel. I just had the entire suite IFR-certified. Interestingly, the EFIS and the G5 were exact, and matched. I still have to set three different altimeters, but the old round gauge didn't make the cut and got placarded as "VFR only".

newt · #7 10-26-2020, 07:41 PM

When you have one altimeter, you always know exactly how high you're flying.

When you have two, you're never quite sure.

- mark

Walt · #8 10-27-2020, 07:07 AM

Quote:

Originally Posted by Desert Rat

Not saying it's right, because a 70' error would really bother me as well, but even for IFR the allowable error on an altimeter is shockingly large. Going out on a limb here, but I seem to recall the AIM talking about +-75'. Does that sound right?

Also, is it possible that the error isn't actually that large? My home runway looks dead flat, but according to the approach plates, field elevation is 1408, measured at the threshold for rwy 19, and drops about 40' by the time it gets to the other end. The runup pad (about midfield) consistently shows 20' lower than published field elevation, which seem logical based on what the plate shows.

Allowed error (91.411) depends on altitude.
With 2 altimeters the split could be double the error if one was on the minus side limit and the other was on the positive side limit.

ALTITUDE / ERROR

0 / 20
500 / 20
1,000 / 20
1,500 / 25
2,000 / 30
3,000 / 30
4,000 / 35
6,000 / 40
8,000 / 60

Desert Rat · #9 10-27-2020, 07:12 AM

Thanks Walt!

g3xpert · #10 10-28-2020, 07:28 AM

Quote:

Originally Posted by ten4teg

Just got a Garmin G5. When I set the Baro to field elevation, the baro does not match the current pressure. It looks like it needs adjustment. Anybody know a way to do this? I don't need IFR accuracy. Thanks tom.gregorski@gmail.com

Tom,

While there is a static cal procedure provided in the installation manual, you should not have to perform it right out of the box. Reach out to us via email at G3Xpert@Garmin.com and we can get an exchange set up for you if you would like.

Thanks,

Justin