Autopilot not following true north heading

[TomCatMucDe]

Hello,

 

I don't know if this is a bug or if it's has been reported but the autopilot heading will always follow magnetic heading even if true north is selected. Is this the correct behavior?

 

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[EAF602 Red]

Dont understand the question, You can make it head any direction you like.

 

Red

[Flamin_Squirrel]

I see what OP is saying; it doesn't seem quite right.

 

That said, I don't see why would you be using true anyway.

[TomCatMucDe]

I see what OP is saying; it doesn't seem quite right.

 

That said, I don't see why would you be using true anyway.

Because almost all other modules, AWACS and airbases use true north

 

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[TomCatMucDe]

Dont understand the question, You can make it head any direction you like.

 

 

 

Red

Whatever you enter in the autopilot is always magnetic north and not true north. The autopilot will turn to a wrong heading

 

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[Shuenix]

Whatever you enter in the autopilot is always magnetic north and not true north. The autopilot will turn to a wrong heading

 

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Thats correct. F 18 uses magnetic.

[TomCatMucDe]

Thats correct. F 18 uses magnetic.

But you can change it in HSI > DATA > A/C. It will then show you true north headings, only the autopilot won't. It doesn't seem right.

 

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[Flamin_Squirrel]

Because almost all other modules, AWACS and airbases use true north

 

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None of the US aircraft, including the hornet, use true.

[Flamin_Squirrel]

IRL. IIRC I don't believe any references should be to true; if there are I think it's a bug.

[Flamin_Squirrel]

I didn't say the option to switch doesn't exist.

[TomCatMucDe]

I didn't say the option to switch doesn't exist.

You said if there is an option to switch to true heading it's a bug. What's your source that this option doesn't exist ?

 

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[Flamin_Squirrel]

Sorry I wasn't very clear. I meant that you wouldn't navigate referencing true*, not that I meant that there are no references to the option being there. Nor should ATC/AWACS or anything else reference it either. If they are, that's what I believe is a bug**.

 

*except perhaps in very high latitudes - not applicable in DCS at this time.

 

**at least western/US aircraft.

[majapahit]

True is used in strategic pre-operations planning with maps involved and GPS data, because these data are precise.

When this needs to get executed in real world, everything is translated to magnetic because all parts move like ships on compass.

[tweet]

In 38 years of flying jets over six continents, every one except Antarctica, ranging from 40 south latitude to 88 north latitude I've only seen two uses for True. Navigators of bombers and tankers used it for grid navigation when practicing for operations in extreme northern latitudes during the cold war years. I used frequently it in airline ops in Northern Canada, primarily between the Pacific Northwest and Northern Europe. The 747-400 (could have been the classic 747 though - not sure) also required us to be in true anytime above 73 north IIRC. It had to do with an automatic change of heading reference function within the IRUs. Three IRUs would invariably change to true at different times, each has it's own position after even short operating times, so we had a procedure to change the heading reference manually to avoid a problem.

 

 

 

These areas have rapidly changing magnetic variation and lines of longitude are very close together both of which create navigation errors when using magnetic. Switching to true eliminates potential errors.

 

 

I've been trying to figure out why the JF-17 needs to input true heading into the IRUs during preflight. Every INU I ever used only required a current position input. The units could sort out heading during alignment. An error inputting the current position would be detected by the units during alignment resulting in an error message. Needing to survey every parking place that a fighter might use seems like a horrible burden. Even slight parking misalignments could effect the alignment quality or generate an error.

 

 

 

The only thing I can come up with is it's a way to reduce alignment time. Surveying alert parking sites isn't a big deal and training could reduce errors. This seems likely since the early access procedure for alignment is the quick alignment rather than a full alignment.

 

 

As far as DCS is concerned forget true headings. They're operationally useless in the operating areas in the sim. The only thing any of us needs to use true for in game is to follow the IRU quick alignment procedure in "Jeff".

Edited December 26, 2019 by tweet

[majapahit]

"all parts move like ships on compass." :noexpression: What does that even mean?

"In 38 years of flying jets over six continents, every one except Antarctica, ranging from 40 south latitude to 88 north latitude I've only seen two uses for True. .. above 73 north IIRC .." etc

Is what it means

[Flamin_Squirrel]

What pages?

 

Also, how things are in DCS doesn't mean they are correct.

 

.... and the thread goes wild. (Over true vrs mag)

 

More context:

Controlling agencies give vectors in magnetic, V ways/J routs are magnetic, VOR/TACAN radials are magnetic (station declination, another nuance in context), ATIS winds are given in magnetic (METARS, TAFS etc, are true, done for other nuanced reasons), airfield runways are in magnetic. Athough chart lat longs are true (not sure how they could be anything but), the heading values on charts are magnetic. Approach plates are magnetic to include RNAV and VNAV (per part 97.3 something) and if courses are true on a plate it is accompanied by a "t" to indicate the nuanced difrences.

 

Aviation (as of today, with the chance it may very well change in the GPS future) still operates in a predominantly "magnetic " world.

Im sure someone can wikipedia up more exceptions somewhere but that doesn't change the normative, and i am sure each exception has its own nuance context. The point of my response was to give context to the realities of the flying environment, how that has shaped navigational equipment, and how a game can give false perceptions on what that environment is.

 

Thus, why the 18 hud defaults to magnetic.

 

:)

[Flamin_Squirrel]

What pages? I already specified, do you even read posts?

 

You cannot apply rl techniques and procedures to this game because the world in the game doesn't correlate.

 

-DCS world is flat. That fact alone makes almost all rl navigational techniques useless in dcs. Only very short legs somewhat hold correlation to rl.

 

-DCS world doesn't even have north reference. Irl, two aircraft, in northern hemisphere and on different longitudes, tracking true North would converge. In DCS they fly parallel.

 

-DCS practically operates in grid system. When we are talking about true North, it's actually grid North.

 

-DCS ATC uses grid North reference for vectors and when reading winds.

 

-DCS AWACS uses grid North reference for reporting contacts, both BRAA and BE.

 

-DCS Carrier, I suspect because it's somewhat new code, applies magvar to the grid North reference when reporting BRC. It's still not magnetic North reference, just a slightly rotated grid system.

 

-DCS FC3 aircraft use grid North reference.

 

There are exactly 0 reasons to use "a slightly rotated grid system" in F-18.

 

Pretty rude considering your vague reference to the HSI page (singular) hardly qualifies as an answer to my question.

 

Regardless, I knew DCS maps used to be a flat grid system, although I thought this changed with DCS 2? Again, genuine question, and would appreciate if you mind your manners.

[Flamin_Squirrel]

Well, I do consider your continuous unwillingness to read my posts rude as well. Post #10 references two (plural) pages.

 

To precisely answer your second paragraph, Caucasus map in DCS 2 is flat grid. I do not have other maps installed. If you have, you can test and report. It's valuable info.

 

My manners are completely in place, I do not court a lady here. I'm trying to be factual and precise, despite English not being my native language.

 

Manners in place, really? You put more effort into being rude than simply pointing me to your post that I'd missed. If you're really that touchy, you need to learn to calm down.

 

If you're able to do that, and perhaps describe your methodology for map testing, I'll look into the other maps.

[TomCatMucDe]

Sorry I wasn't very clear. I meant that you wouldn't navigate referencing true*, not that I meant that there are no references to the option being there. Nor should ATC/AWACS or anything else reference it either. If they are, that's what I believe is a bug**.

 

 

 

*except perhaps in very high latitudes - not applicable in DCS at this time.

 

 

 

**at least western/US aircraft.

Hey Flamin_Squirrel,

 

I didn't write to the pentagone to ask them to change to true north or magnetic north. I wrote to ED to correct a possible bug in their module... I suspect that like the real aircraft you can indeed change the heading to true north, but it's weird that only the tape changes but not the other systems like the auto pilot.

 

Your comment about Western aircraft in real is a bit out of topic, nobody argued about how it is done in real. Fact is that AWACS and F15 use true north heading, for this reason I want to be in sync with them.and chose also true north.

No more, no less.

 

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[TomCatMucDe]

In 38 years of flying jets over six continents, every one except Antarctica, ranging from 40 south latitude to 88 north latitude I've only seen two uses for True. Navigators of bombers and tankers used it for grid navigation when practicing for operations in extreme northern latitudes during the cold war years. I used frequently it in airline ops in Northern Canada, primarily between the Pacific Northwest and Northern Europe. The 747-400 (could have been the classic 747 though - not sure) also required us to be in true anytime above 73 north IIRC. It had to do with an automatic change of heading reference function within the IRUs. Three IRUs would invariably change to true at different times, each has it's own position after even short operating times, so we had a procedure to change the heading reference manually to avoid a problem.

 

 

 

These areas have rapidly changing magnetic variation and lines of longitude are very close together both of which create navigation errors when using magnetic. Switching to true eliminates potential errors.

 

 

I've been trying to figure out why the JF-17 needs to input true heading into the IRUs during preflight. Every INU I ever used only required a current position input. The units could sort out heading during alignment. An error inputting the current position would be detected by the units during alignment resulting in an error message. Needing to survey every parking place that a fighter might use seems like a horrible burden. Even slight parking misalignments could effect the alignment quality or generate an error.

 

 

 

The only thing I can come up with is it's a way to reduce alignment time. Surveying alert parking sites isn't a big deal and training could reduce errors. This seems likely since the early access procedure for alignment is the quick alignment rather than a full alignment.

 

 

As far as DCS is concerned forget true headings. They're operationally useless in the operating areas in the sim. The only thing any of us needs to use true for in game is to follow the IRU quick alignment procedure in "Jeff".

Thanks for the heads-up, but my opening post wasn't about comparing what Western aircrafts use in flying. It's about a functionality that is probably bugged.

 

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[Flamin_Squirrel]

Hey Flamin_Squirrel,

 

I didn't write to the pentagone to ask them to change to true north or magnetic north. I wrote to ED to correct a possible bug in their module... I suspect that like the real aircraft you can indeed change the heading to true north, but it's weird that only the tape changes but not the other systems like the auto pilot.

 

Your comment about Western aircraft in real is a bit out of topic, nobody argued about how it is done in real. Fact is that AWACS and F15 use true north heading, for this reason I want to be in sync with them.and chose also true north.

No more, no less.

 

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With specific reference to the autopilot not following true, I suspect this is a bug.

 

However, with respect to AWACS/F15 I think you're asking for the wrong module to be fixed. They should be fixed to use magnetic, not the hornet to use true. Hopefully that makes sense, and why it's not off topic for this discussion.

[TomCatMucDe]

With specific reference to the autopilot not following true, I suspect this is a bug.

 

 

 

However, with respect to AWACS/F15 I think you're asking for the wrong module to be fixed. They should be fixed to use magnetic, not the hornet to use true. Hopefully that makes sense, and why it's not off topic for this discussion.

I never asked for the hornet to follow true by default, but if you select the option on the HSI, it should follow true, which it does, only the AP doesn't which as you say is probably a bug.

 

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[TomCatMucDe]

FYI. On the bug reporting subforum, the devs confirmed that the current implementation is correct and follow the real aircraft.

 

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[Flamin_Squirrel]

Thanks for the update.