Navigational tools

[notimejeff]

Does this apply to offline missions? Should I add 10 deg to the mag compass reading before setting the DG? Or is it just for the Nav tools?

I guess you're the same freak just like me who recognizes true missions only if they start and end on a runway/an airfield

[IvanK]

All headings measured on the map are true. So you need to add 10 degrees to obtain the magnetic heading to fly both on line or off line. Your dg can be aligned on any refrence true or magnetic. However since the only refrence you have in the cockpit is the magnetic compass the convention is to align the dg to a magnetic refrence.

So measure in true convert to magnetic, set dg refrence magnetic heading and fly magnetic.

[Redroach]

why not just substract 10 deg on your course heading indicator thingy (at least for the RAF, which have such an instrument) and go for true north directions?

[IvanK]

Because the ONLY heading refrence you have in the cockpit (the compass) is magnetic. Because the dg is subject to gyro drift/precession it needs ro be reset or synched regularly.
The only refrence you have in the cockpit to refrence and synch with is magnetic. Hence magnetic is always used.

Modern nav systems (inertial/gps etc)
can use any refrence however the normal convention is still to use magnetic.

[Redroach]

Yes, I understand, but still, all you need is to always remember: "minus 10 deg" when setting, or re-setting the gyro. It's no additional work when resetting or resynching.
Then, you can just *read* the map, without any further calculations.

Again, I understand that convention is magnetic, because the magnetic compass is "always right" (within its 10° error). However, I might deviate from original protocol in this one case