Originally Posted by Jetmart
Why 3 way versus 4 directions? I would like a copy of your XLX sheet.
The 3 directions should form a triangle. Not just 3 directions. An EFIS with gps inputs makes things even far easier than doing this:
Go straight into the wind. Wait for speed to stabilize. Record GS, TAS, and wind.
Do a 180, and record the same. The GS, TAS, and wind should be the same. If not you probably have a pitot static error.
The only "measured" value is GS. TAS and wind are calculated. The easy indication that tells you something is amiss is the wind has changed significantly.
If you need to do a 3 way, it needs to be a triangle. By that I don't mean a geometric triangle over the ground, but 3 headings/legs that form a triangle.
And yes, it can be don't with just 3 headings that don't form a triangle, but the math gets a lot harder.