The magnetic compass (MC) and DG values of DA40TDI do not match.
This phenomenon occurs between 290° and 080°.
For example, when DG is 030°, MC shows 015°.
We know that in the real world there is an error in MC, but this phenomenon is so far off that it cannot be called an error.
This phenomenon does not occur in DA40NG or DV20.
Yea, the compass card only shows a couple of degrees off, but the actual error seems to be significantly more than that!
Regards
If you now think about why the heading indicator has an adjustment knob, you will realize that this is a feature and not a bug. No vote from me, because no error.
Edit: See also here under point 10.
Unfortunately, this isn’t a precession error, since the time on my test was about 10 seconds between when I set the DG to match the mag compass, and when I moved the aircraft to the new heading (on the ground). You definitely don’t need to reset the DG that frequently, and if it was off by that much, the DG would be pulled and in the maintenance shop!
Regards
The knob on the DG corrects the gyro’s precession error, usually used once every 15 minutes.
This bug is like a compass deviation, but usually it is about 3° no matter how big it is.
It is important not to confuse Drift and Precession. Drift is an mechanical imperfection in all gyroscopes, it is an error that accumulates over time and in unknown direction. Drift becomes more severe during aircraft rotations (roll, pitch, yaw).
Precession is an effect that is due to the rotation of the earth, and movement of the aircraft. The rotation precession is strongest near the poles and zero at the equator, the movement precession increases with speed.
he DG knob simply moves the scale, and is nor Drift correction neither Precession correction.
Unfortunately, after some preliminary study, I’m still uncertain as to which effects Asobo implemented and how…
