Calypte 14 Posted January 19, 2022 Share Posted January 19, 2022 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. Please login to display this image. Please login to display this image. Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted January 19, 2022 Aerosoft Share Posted January 19, 2022 Yes but is that not exactly the difference between a HSI and a magnetic compass? Link to comment Share on other sites More sharing options...
Calypte 14 Posted January 19, 2022 Author Share Posted January 19, 2022 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. Link to comment Share on other sites More sharing options...
jake-m190 6 Posted January 19, 2022 Share Posted January 19, 2022 To me this is correct. Remember the HSI and standby compass rotate in opposite directions... # Â Link to comment Share on other sites More sharing options...
Calypte 14 Posted January 19, 2022 Author Share Posted January 19, 2022 I am not commenting on the rotation, but on the indication which is off by several degrees Link to comment Share on other sites More sharing options...
jake-m190 6 Posted January 19, 2022 Share Posted January 19, 2022 6 minutes ago, Calypte said: I am not commenting on the rotation, but on the indication which is off by several degrees I challenge you to find a real Twotter with a perfect standby compass... Link to comment Share on other sites More sharing options...
Ethreven 8 Posted January 19, 2022 Share Posted January 19, 2022 Question is simple: Regarding two compass indications, what is direction I'm flying to, 268 or 271 deg? Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted January 19, 2022 Aerosoft Share Posted January 19, 2022 Just now, Ethreven said: Question is simple: Regarding two compass indications, what is direction I'm flying to, 268 or 271 deg? Â 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. Link to comment Share on other sites More sharing options...
Calypte 14 Posted January 19, 2022 Author Share Posted January 19, 2022 Just now, Mathijs Kok said: Well the magnetic compass is a standby system, so not your first choice to pick. Â Â 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" Â Â Â Link to comment Share on other sites More sharing options...
Ethreven 8 Posted January 19, 2022 Share Posted January 19, 2022 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 Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted January 19, 2022 Aerosoft Share Posted January 19, 2022 Both instruments use the simvars given, so it was not planned, but not unrealistic and probably intended by the sim to look like this. Link to comment Share on other sites More sharing options...
Crog 1 Posted January 19, 2022 Share Posted January 19, 2022 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. Link to comment Share on other sites More sharing options...
Finn 873 Posted January 19, 2022 Share Posted January 19, 2022 I see no noticable difference - both indicates around 266-268°C Link to comment Share on other sites More sharing options...
Calypte 14 Posted January 19, 2022 Author Share Posted January 19, 2022 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. Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted January 19, 2022 Aerosoft Share Posted January 19, 2022 Let's cut this short. We use the default simvars for this and do not plan to make our own magnetic world model. So it will stay as it is. Link to comment Share on other sites More sharing options...
Calypte 14 Posted January 19, 2022 Author Share Posted January 19, 2022 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  Please login to display this image. Please login to display this image. Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted January 20, 2022 Aerosoft Share Posted January 20, 2022 As explained, we use the standard simvars for these indications and at this moment not planning to change that. So let's call it a feature. I will see if Microsoft has any comment though. Link to comment Share on other sites More sharing options...
Dopster198 131 Posted January 21, 2022 Share Posted January 21, 2022 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. Link to comment Share on other sites More sharing options...
Aerosoft Aerosoft Team [Inactive Account] 51558 Posted January 22, 2022 Aerosoft Share Posted January 22, 2022 No, not simulated. But I added it ti the suggestion list. Link to comment Share on other sites More sharing options...
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