Two different headings to the runway?

[Dudester22]

I have just finished practicing the ILS landing and I am confused about the heading number I am supposed to dial in on the HIS. Look at the two pictures I have posted below. The trainer tells me to set it to 130, but looking on the map it says it says it is 125. can someone tell me which one it is supposed to be and why are they both different?

[Boris]

I can't seen it say 125 anywhere on that map?

 

You can also see the headings of the runways on the CDU screen you have in your first screenshot. 13 (130) and 31 (310), which is the reverse heading for landings from the opposite direction.

 

The heading HSI has no effect on the ILS by the way, it's just to help you line up for the approach. Once you pick up ILS you'll go by that.

[Dudester22]

I can't seen it say 125 anywhere on that map?

 

You can also see the headings of the runways on the CDU screen you have in your first screenshot. 13 (130) and 31 (310), which is the reverse heading for landings from the opposite direction.

 

The heading HSI has no effect on the ILS by the way, it's just to help you line up for the approach. Once you pick up ILS you'll go by that.

 

Jeez, it doesn't show up for some reason on a screen shot. Please just start a training mission and choose the landing one. Then click F10 and click on Batumi and look at the heading in the popup box, it says it is 125 and not 130 like the trainer is saying. I also heard that you don't go by whats on the CDU because that is incorrect. Can someone clarify this please?

[Scarecrow]

The difference is caused by the magnetic variance in the region[citation needed], as Boris said once you pick up the ILS glideslope use that for steering cues and forget the HSI. So just use 130 it doesnt make a difference.

[311Gryphon]

I have just finished practicing the ILS landing and I am confused about the heading number I am supposed to dial in on the HIS. Look at the two pictures I have posted below. The trainer tells me to set it to 130, but looking on the map it says it says it is 125. can someone tell me which one it is supposed to be and why are they both different?

 

Don't they round up (or down) and truncate the last digit for runways though? So if the actual runway is pointed 125° they'll call it runway 13?

 

I could be wrong and it may have no bearing on the actual discussion.

[cichlidfan]

There is a heading/mag var issue with Batumi, and some other airfields, that has existed for years. Apparently, nobody actually knows what the problem is.

[EvilBivol-1]

There are a couple of issues here that cause a lot of confusion and that I hope we'll be able to rectify sooner or later. First of all the ME/F10 map shows True headings, not Magnetic. That means what you see on the map is about 6-8 degrees greater than what you see in the cockpit (of Western aircraft, since Russian aircraft display True headings in the cockpit as well). For example in Batumi the map is showing 126 degrees True, so the actual cockpit heading for landing is actually 120.

 

Specifically in the Landing mission, the instructor says 130 simply based on the CDU page, which rounds up the True heading from the database.

 

We've made a suggestion for ED to add a True/Magnetic switch to the ME/F10 map, so we are aware of the need.

[towsim]

Whatever you are measuring on the map with the ruler is unfortunately grid North. Grid north is in dependence of the used map projection and the North direction in this case is always parallel to the vertical map border (window ). This can be tested if you draw a perfect vertical line with the built-in ruler on the map. It will always point to zero (360) degrees, regardless of the location. If you want to see true North, then draw a line with the ruler along a meridian. A meridian goes always to true north. At Batumi you will notice a direction of 354 deg (grid), at Anapa 357 deg (grid) and at Mozdok 352 deg (grid). So the directions measured with the ruler are useless in navigation. If you want to have the true heading of Batumi RWY 12, you take the measured 126 deg (grid) and add the grid variation of 6 deg at this location and you have the result of 132 deg (true) according to the DCS Map.

If you are not confused up to now, I can give you some other numbers:

Google Earth shows a direction of 131 deg true for Batumi. (which is pretty close to the reality)

The HSI of the A-10C, which should normally be calibrated for magnetic north shows 119 deg ????

So the conclusion is, discussing the directions used is waste of time. If you use ILS then align with the runway direction on ground and dial the course in so as to have the deviator vertical on the HSI. Then you can be sure that the ILS will work. At least for the A-10C you can trust the GND & VAD charts published by 10thGF_Schleudi. All directions are measured out and can be used directly.

Regards

Mike

[cichlidfan]

At least for the A-10C you can trust the GND & VAD charts published by 10thGF_Schleudi. All directions are measured out and can be used directly.

 

That is what I always use. :thumbup:

[Dudester22]

At least for the A-10C you can trust the GND & VAD charts published by 10thGF_Schleudi. All directions are measured out and can be used directly.

 

Where will I find these charts? But all I really want is the correct numbers to dial in.

[Leto]

Where will I find these charts? But all I really want is the correct numbers to dial in.

 

 

As Mike said, all you need is the charts provided by 10th GunFighters:

 

http://ariescon.com/ <--- 7th point: Ground & VAD Charts

 

They offer every information you need, whether you're flying DCS:A10 or FC3, magnetic or true heading.

 

Direct download link: http://ariescon.com/DCS_GND_VAD_Charts_v36_030513.zip

Edited June 24, 2013 by Leto

[Boris]

I did an approach on Sukhumi this morning and I noticed this issue quite strongly.

 

Could it be, that we even have to adjust the bearings given by ATC? The heading ATC gave me to line up for approach was off. Should you always subtract 6 degrees from any bearing ATC gives you?

Also, setting the HSI to 120 did not coincide with the direction of the runway.

[towsim]

The 6 degrees is the grid variation for Batumi. It differs over the entire map. Even if you get the grid variation for a specific location, the result is the true heading. You would need the local magnetic variation to come to a heading which is usable for the compass in reality. And here the miracle starts. Only DCS knows to what north direction their compass points. They probably invented a new one or the aircraft mechanic was drunk. In case of Batumi, the mag variation measured from the map and compared to the compass reading would be 13 deg east. This is more than unreal. The official mag variation published is 5 deg 44.9 E at April 2008. So finally the question cannot be answered successfully. In addition there is a difference in compass indication between FC3 aircraft and the A-10C, KA50 and P51. I think this mechanic was busy with all aircraft in DCS World and later he changed over to ATC. The only solution would be to request vectors more than one time. The headings would not be that correct but the position deviation decreases as closer you come to the airfield. You approach the field on a dog curve. The other is the correct runway heading. In this case I would consult the VAD charts published by 10thGF_Schleudi.

Regards

Mike

PS

What I forgot to say: A runway designator does not specify the correct runway heading. It is a rounded number to the closest 10 degree step. So runway 12 is not 120 deg mag necessarily. The designator can even change over the time if the magnetic pole moves. We had this case at my home base. It changed from RWY 21 to RWY 20 any when in the 60th.

Edited June 25, 2013 by towsim

[Leto]

I did an approach on Sukhumi this morning and I noticed this issue quite strongly.

 

Could it be, that we even have to adjust the bearings given by ATC? The heading ATC gave me to line up for approach was off. Should you always subtract 6 degrees from any bearing ATC gives you?

Also, setting the HSI to 120 did not coincide with the direction of the runway.

 

Ok, take Sukhumi as an example and have a look at the charts we mentioned. It is

- Ground charts page 18

- VAD charts page 19

 

You mentioned RWY 12 which just tells you the name of the RWY because it's roughly direction 120°.

 

On the ground charts you find following information near the threshold of RWY 12:

 

a) 12

b) 110°

c) 116°T

 

a) is the name and roughly the direction of the runway

b) is magnetic heading, that is what you want to dial your HSI at when you're flying A-10C

c) is "true" heading as used by RU-aircraft in DCS

 

 

ATC: Let's say ATC says something like "Fly heading 090 for 25nm to RWY 12..." this is not ment as a point which is ligned up with the runway heading. It's a point ATC wants you to start your entry from. Nothing more. ATC is kind of useless at the moment.

 

And have a look at this website: http://www.ngdc.noaa.gov/geomag/GeomagneticPoles.shtml

This gives you an impression on the shift of the north pole. At the moment, the magnetic north pole travels at a speed of 55km per year. So if you want a precise heading on the runway you would have to repaint it every month ;)

Edited June 25, 2013 by Leto

[lxsapper]

Ok I hadn't seen this before and opened another thread (http://forums.eagle.ru/showthread.php?p=1872893#post1872893) but I'm now better informed, after reading this and other similar treads.

I still have some questions, in the example Leto gives above for Sukhumi the runway designator is derived from the true heading. I know this is not the case for western airfields, it's the magnetic heading that's used. Is this correct for IRL do Eastern contries airfields use the true heading as base since their instruments show true heading by default? Or has DCS placed all it's airfields wrong having referenced as true heading what should have been a magnetic heading?

[Hamblue]

Always think of the scarecrow in wizard of oz pointing his fingers both directions. Most runways have 2 directions that you can take off. A number is given for each direction. I believe only 1 is given If there is only 1 direction available.

[lxsapper]

Always think of the scarecrow in wizard of oz pointing his fingers both directions. Most runways have 2 directions that you can take off. A number is given for each direction. I believe only 1 is given If there is only 1 direction available.

 

I think you missed the point of the discussion.

[roadrabbit]

Where will I find these charts? But all I really want is the correct numbers to dial in.

 

:cry: It is very simple - check out:

 

...... Eagle Dynamics>DCS World>Doc>Charts

 

Use the 'VAD charts' specified 'A-10C'. All these charts use Magnetic North as the reference, which is what you should be putting in your OBS track (or 'course' if you are a North American :lol:) box on your HSI. As mentioned earlier some other charts in DCS Worlduse True North.

 

When I first started out in DCS World I was also unaware of all that I had downloaded - its all there, just waiting to be found!

Edited September 19, 2013 by roadrabbit
clarification

[lxsapper]

:cry: It is very simple - check out:

 

...... Eagle Dynamics>DCS World>Doc>Charts

 

Use the 'VAD charts' specified 'A-10C'. All these charts use Magnetic North as the reference, which is what you should be putting in your OBS track (or 'course' if you are a North American :lol:) box on your HSI. As mentioned earlier some other charts in DCS Worlduse True North.

 

When I first started out in DCS World I was also unaware of all that I had downloaded - its all there, just waiting to be found!

 

Yes I know about the charts. What I am asking is if eastern airfields (IRL), unlike western aifields, are referenced for True north. Because if they are not they are in DCS.

Edited September 19, 2013 by lxsapper

[roadrabbit]

Yes I know about the charts. What I am asking is if eastern airfields (IRL), unlike western aifields, are referenced for True north. Because if they are not they are in DCS.

 

When I flew in Eastern Europe, Russia and China we used 'western' produced maps and charts: Aerad or Jeppesen. These had all directions given in degrees magnetic. As described by others, this means that they had to be reprinted on a regular basis to keep up with changes in magnetic variation. We never saw eastern bloc produced maps - so I don't even know if they were ever produced in English. I suspect that the DCS maps are 'translations' from eastern bloc maps, but in any event, being in degrees true cancels the need for continuous updating within the DCS World arena.

 

At the end of the day all maps are constructed by reference, at some point, to lines of latitude and longitude, i.e. the construction reference is true north. Magnetic variation is then added to 'directional' lines because, prior to inertial navigation systems, the only on-board directional reference was a magnetic compass based one.

 

Does this help to answer your question?

Edited September 19, 2013 by roadrabbit
clarification

[lxsapper]

Roadrabbit, that doesn't really answeer it but you can probably help me understand this. Since you are a pilot you know that airfields have their runway designators referenced on the magnetic heading. Take Kobuleti as an example, with a magnetic heading of 064º, that makes the closest decimal aproximtion 06, therefore if it was an airfield that follows ICAO rules (I don't know what rules ICAO follows, but im sure military interests are above those) the runway would infact have the designator 06, however, and this can be changed as the magnetic north changes, airfields change it's runways designors. However Kobuleti in game is 07 references by it's true north heading. As far as I know IRL kobuleti is indeed 07. So the question is the same, do they follow diferent rules for referencing airfields in Russia and other former eastern block nations.

[roadrabbit]

Take Kobuleti as an example, with a magnetic heading of 064º, that makes the closest decimal aproximtion 06, therefore if it was an airfield that follows ICAO rules ......... (and) would infact have the designator 06 ....... However (if) Kobuleti in (DCS) game is 07 (then it is) reference(d) by it's true north heading. As far as I know IRL kobuleti is indeed 07. So the question is the same, do they follow diferent rules for referencing airfields in Russia and other former eastern block nations.

 

Hi, again! It's not a proper answer, but they might well do so and use true north in eastern bloc countries. The problem is that it could just be an error within the DCS World simulation.

 

To fully answer the question you need someone who has used Russian produced aviation charts to enter the thread OR one of the DCS developers to give their views.

 

As an interesting side-piece, even the runways at London Heathrow did historically have the incorrect designator for while - they were still being called 28L and 28R when the 'rounding' up or down process would have made them 27L and 27R.

[EvilBivol-1]

AFAIK Russian runways are also marked according to rounded-off magnetic headings. However another question entirely is how often these numbers get repainted...

[lxsapper]

Thank you both, that is more information than before. Still it would be nice to have someone from ED to give a statement on this.

[deaconjb]

As Mike said, all you need is the charts provided by 10th GunFighters:

 

http://ariescon.com/ <--- 7th point: Ground & VAD Charts

 

They offer every information you need, whether you're flying DCS:A10 or FC3, magnetic or true heading.

 

Direct download link: http://ariescon.com/DCS_GND_VAD_Charts_v36_030513.zip

 

 

I just wanted to say thanks for this great work and your contribution.