ILS course True or Magnetic

[twistking]

Hello,
sweet and short little question:
Does the ILS course in the viper expect Magnetic or True heading?
Bonus question: What's the easiest way to get precise runway heading in DCS? I know that on Caucasus the airport map kneepad pages have all the info, but on other maps i just use the ruler tool on the F10 map. Feels archaic. Simpler ways to do it?

[Sr.]

https://youtu.be/uveL-HA_AHU

[skywalker22]

For ILS, Course field (CRS on ICP/ILS(1) button) requires Magnetic heading.

For getting Tacan and Heading info of airports which support ILS, it is best to use these kneeboard, simply the best and simple: 

 

Edited May 13, 2023 by skywalker22

[Frederf]

It's magnetic. Theoretically you could have an ILS localizer charted, surveyed in true (in fact it's possible that officially it has a true heading documented). But even if you were to come across such a true heading beast you would want to enter is the best available magnetic heading into the avionics if the airplane is in magnetic, which it usually is. The ILS localizer beam itself doesn't have any heading information in it. There's just a left beam and a right beam and a mixing zone so even if your heading completely fails left is still left and right is still right. The purpose of the CRS value in the DED is for the wind-corrected-heading caret and (I think) steering cue on the HUD and the CRS knob on the HSI is just makes it easier to read. You can absolutely fly an ILS with any or no CRS values in either place provided you don't care about the wind caret, steering cue, or the HSI being upright for ease of reading.

It is possible to operate the F-16 in true heading (or any arbitrary heading offset) by setting the magnetic variation variable can simply be set to 0 (or anything). The INS itself operates in true. Any conversion for display of magnetic is a shift applied according to entered variation data. In this case you'd use the heading of your ILS under your custom heading convention be that true, magnetic, or other. The tricky part comes in with TACAN because TACAN does contain information in the signal which pertains to a particular heading calibration. Most TACAN (and all in DCS) are calibrated to magnetic but there are some calibrated to true. If your airplane isn't using the same heading convention as the TACAN station you get mixed information. The bearing works as normal but the CDI lineup will happen under the TACAN's heading convention, not your airplane's, which will have funny but predictable effects.

[twistking]

big thanks to all, special thanks to @Frederf: that answered some question that i did not know i had before. thx!