Garmin G5 wind speed and direction

[Wagondriver]

It was 2 years ago I installed the oat probe and gad13, from day one the wind speed has seemed to be almost always in error, by about a factor of 10. On occasion it appears to read correctly, but how can one tell for sure? Shortly after install the avionics shop swapped the gad13, there was no change. It was suggested that I move the oat probe out further on the wing, currently it is just inboard of the strut on an inspection plate. I have the parts to move the probe, but just haven't had the motivation to get into it all. At Buckeye I stopped and talked to the Garmin booth, they suggested I call the customer service department, which I did. They gave me the resistance readings that the oat probe should have at various temperatures, I checked with ice and water and a liquid that should be 98.6F, both readings appeared to be about 4 ohms too high. That little doesn't seem like it should make any difference, best I can tell is that is about 2C high. And usually the Garmin oat and the JPI oat are 2 degrees different, but who knows which is right.
I can't think of why the wind speed would read 35 knots when its blowing less than 5, or why on some days It reads 35kts, because it is blowing 35kts or there about. True airspeed seems to be right, compared with ground speed on days where best I can tell there is very little wind.

The warranty on the oat probe runs out soon, that's what got me to try to figure it out. I just gave up on it and quit trying (spending money) to figure it out. I might get right back there again, but just maybe someone has a suggestion that will work?

OAT probe is located on an inspection plate, a suggestion has been made to mount it directly to the wing. I'd rather not drill another hole in the airplane and think if its a ground issue I could make a ground wire from the inspection plate to an existing ground in the wing.

 

[Gary Ward]

I don't think you can expect it to be accurate all the time?
Mine is always moving around but overall I feel it's gives me good info.
My shop putmy probe in the wing just inside the strut where you can not hit your head on it.
Mine has been in since 2019 and 1200 hours.

 

[Llewtrah381]

Remember it’s calculating the wind value by comparing your heading and track and using your ground speed and airspeed. If the heading is off (i.e. the magnetometer isn’t properly calibrated) you could get the results you’re seeing, I believe.

Add: have you compared your heading to that on your whiskey compass in level flight, smooth air?

 

[Wagondriver]

Its not that its not accurate all the time, its not accurate most of the time, and grossly so.

I am going to calibrate the G5's again, and after talking to the Garmin guys, the GFC500 needs to be calibrated too, preferably at the same time as the G5's, preferably with the airplane level in roll and pitch. The Garmin guy said its better to level the plane than adjust for pitch attitude on the ground. On the ground my plane sits 13 degrees pitch up, during initial calibration I had trouble with the numbers not adding up, I adjusted until it worked. A new Calibration for all components at zero should make them play nicer together, at least that's what I am told.

I have not noticed that the magnetic compass and the G5's are off, someone suggested that a couple years back. Pretty sure the magnetometer is correctly calibrated, but it all could be off a tiny bit that all add up to something bigger. But, the windspeed number is so grossly off, like there is a decimal point missing.

I had given up on fixing these issues, I'll have to document all the goings on next flight.

 

[eman1200]

 

[Dixiebluesky]

Testing an OAT probe with urine, that is some real "use what's available" testing right there.

 

[Gary Ward]

Pictures of my temp probe location. It was possible to get a drill in there and connection to the canbus since it runs to the wing tip for the magatometer.


I have relied on the the shop that installed it to keep it up to date.
Scott at the shop is a avionics/Garmin expert and I am so lucky to have him supporting my garmin panel. He would be one of those guys who would be hard to replace.