Cross wind speed reading to high

[Charlrv9]

Can some tell me why my cross wind speed is read to high is telling me wind speed is 75 knots

 

[dynonsupport]

Your magnetic heading is off.

To calculate winds, you need accurate True airspeed, magnetic heading, GPS ground speed, and GPS track.

GPS doesn't need any calibration. True airspeed is Airspeed + Altitude + OAT. So if any of those are off you will have an issue, but not 75 knots.

So, 99% of the time you have an issue with winds it's because your magnetic heading is off. It only takes a few degrees of error to make a big difference.

 

[Battson]

So, 99% of the time you have an issue with winds it's because your magnetic heading is off. It only takes a few degrees of error to make a big difference.

Can undertaking long flights north-south cause this error to occur in a measurable way, as the manetic field changes with latitude (I'm talking within fuel range - say 700 miles or something in that order or magnitude):
If I take-off and fly north cross-country 7 hours from my calibrated location, will there be a noticible error in calculated wind speed and direction at my destination?

 

[Dynon]

No - it you have innacuracy in your heading indication, it will be there all of the time.

 

[dynonsupport]

And I think to answer your question more directly: Flying to a new place does not affect the compass calibration. Magnetic north is magnetic north no matter where you are. SkyView has a equation inside that allows it to correct GPS for your position so it can calculate magnetic ground track and compare this with magnetic heading.

 

[Battson]

The calibration considers the field angle (declination), and that changes with your location. That was the reason for my question.

 

[dynonsupport]

Yep, understand where the question would come from, but those numbers are only used during calibration, not after the compass is calibrated.