M

mavmitchell

Member
Hi All. I just did a quick and dirty tool to plot TAS and Ground speed to visualise any ASI errors. Takes G3X Logs. Just add Airspeed correction to centre the AS Diff circle. It does need enough data in opposite directions..

ASICalc.jpg



Find it Here
Cheers.
 
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Does it account for the effect of crosswind? I.e., if you have a wind from the west, the average GS from two runs on 090 and 270 degrees will be different from the average GS from two runs on 000 and 180 degrees, assuming the same TAS on all legs.
 
Hi Kevin,

This is a graph of the TAS without alteration. The idea is to adjust the "Air Speed Correction" to centre the "AS Diff"(red) on the rose. With it centred, the "Air Speed Correction" is the error in the pitot/static system. This actually means the "AS Diff" in the crosswind is ignored because it is always at or near zero.

Cheers..
 
What difference is acceptable?

I am a little confused as to the scale for reading the airspeed difference on this graph. Will it clearly show 2 knots difference?

And - what difference is considered acceptable?
 
Hi Bill,

I have looked at a number of logs. This is just a visualisation, but it seems easy to see errors as low as 1kt.

What's acceptable is up to you, but I would be happy with anything less than 2Kts.

Cheers..
 
G3X True Air Speed correction possible?

I have calibrated my WOT True Airspeed at 116k however the G3X shows 113k. Is there a way to put a correction factor into the Garmin resulting in the TAS displaying 3k higher?

Thanks from Steve Chase
 
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