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Compass indication incorrect


Calypte
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Compass shows slightly different direction compared to the HSI. HSI is correct (I compared the indications with airport charts). Compass is usually several (2-4) degrees off. The problem shows especially in places where magnetic variation is more significant (Alaska for example). Screenshots taken in PAJN. Runway direction - 265. HSI - 265. Compass - 269. I noticed a similar problem in CRJ.

Compass.png

HSI.png

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I don't understand your question?

Both the HSI and the compass should indicate the same heading. Ok - there could be a slight difference to account for magnetic deviation of the compass, but the deviation is not simulated as far as I am aware and the deviation card you provided in the Twotter shows that it is 0 at this heading.

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Just now, Ethreven said:

Question is simple: Regarding two compass indications, what is direction I'm flying to, 268 or 271 deg?

 

Well the magnetic compass is a standby system, so not your first choice to pick.

Besides, flying to a degree exactly on that small compass is not something I think many pilots can do.

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Just now, Mathijs Kok said:

Well the magnetic compass is a standby system, so not your first choice to pick.

 

 

Yes. But at the same time this standby compass is used to verify whether your main compass / repeater or HSI indications are correct. This "instrument check" point in preflight checklist refers to exactly that. In this case I should just glance at these two instruments and say "instrument check, compass indication wrong, let's go flying, we have GPS" ;) 

 

 

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Mathijs I understand it but from the dev's point of view answer is simple. Either we have planned slight difference between compasses, and we have achieved our goals or we need make a little revision and that approach is ok as well :)

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40 minutes ago, Calypte said:

I am not commenting on the rotation, but on the indication which is off by several degrees ;)

The HSI is indicating 265 degrees, and the standby compass is indicating 267-268 degrees. With magnetic variation, and influence of metallic structures it is not uncommon to see this much and even more of a difference between the two. I have performed compass swings in real aircraft a number of times and can tell you that you will never get a HSI and a standby compass to agree. In fact the tolerances on a standby compass when calibrating are massive by comparison.

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1 hour ago, Finn said:

I see no noticable difference - both indicates around 266-268°C

 

Check it somewhere in Alaska (or any other place where magnetic variation is around 15-20 degrees). Somehow the magnetic variation is connected to this. The screenshots haven't been doctored - this is how compasses differ in PAJN.

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4 hours ago, Crog said:

I have performed compass swings in real aircraft a number of times and can tell you that you will never get a HSI and a standby compass to agree

 

Tell me that this is a feature and not a bug and I will be quite happy. But it doesn't seem so. It is an unintended behavior that reasons couldn't be traced so we are left with "the default simvars". I compared several planes and it's Aerosoft's Twotter and SWS's Kodiak that show this behavior. The CRJ is much worse (check the screenshots). And most other planes I fly do not suffer from that.

 

What I am worried about is a bug that will be caused by this and that will be even harder to explain (we all know about the issues CRJ has with its autopilot and how difficult or impossible they were/are to trace). This is a bug in a nav system of the aircraft. In the nav system that is actually quite buggy. Take a glance on two threads about radionavigation bug - seems unrelated but it is impossible to shoot a VOR approach using an outbound radial.

This is why I think that correcting small bugs is important. And if we are to have compass deviation in MSFS, maybe it should be coded instead of bugged ;) 

CRJ Compass.png

CRJ Displays.png

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In the Compass section, on page 71, the manual states the following : " ... above it, you will find the correction card; this corrects the deviation values of the compass, which can occur due to magnetic fields in the vicinity of the compass. If the windshield heater is on, the compass information is useless." (emphasis mine)

 

Is this currently simulated? Just wondering if this is relevant to OPs question.

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