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True Course, Magnetic Course, Magnetic Heading, Compass Heading…Help!

Posted by on June 16, 2008 32 Comments Category : Flight Instructor Blog

This question comes from Josh:

I’ve had a little confusion with cross-country planning. It is with the magnetic and true courses. Can you tell me if this is right. When I plot the route and use my plotter, the course I get is a TRUE heading. I then add or subract the variation degree which converts it to MAGNETIC. Now, I need to put in the wind correction. The problem here is I do not know whether the wind I get from Flight Service is in magnetic or true. Could you please possibly explain this to me, sorry if my question sounds a little confusing.

Sure Josh, I’d be happy to help. I think the best way to help you is to define the terms we are dealing with a little better. I put these in the order that you would use when planning your cross country flight. We refer to this kind of navigation as dead reckoning. A lot of pilots don’t trust dead reckoning, but remember that dead reckoning is all that Charles Linbergh, Amelia Earhart and many other famous pilots had when planning some record breaking flights.

1) True Course (TC): This is the course measured from your navigation plotter when you plot your flight on your map. Remember that because of the projection of the map, it is best to read this course in the middle of the leg.

2) True Heading (TH): Now that you have a true course, we need to correct for winds which will give us a true heading. You can use a E6B or similar flight computer and forecast winds aloft to correct your true course to determine a true heading. To answer your other question, Forecast Winds and Temperature Aloft charts (FD) are given in reference to true north.

3) Magnetic Heading (MH): The difference between true north and magnetic north is known as variation. Lines of variation are shown on a sectional chart as dashed magenta lines and called isogonic lines. By adding or subtracting variation from your true heading you will get your magnetic heading.

4) Compass Heading (CH): Items from inside the airplane can actually affect the performance of the compass. Aircraft technicians take account for this and will place a placard beneath the compass displaying the errors for certain headings. These errors are referred to as deviation. By adding or subtracting deviation from your magnetic heading this will give you a compass heading. A compass heading is the direction you could turn the aircraft to that has been corrected for winds, variation and deviation. In an ideal world, this would have you following your true course perfectly that you had plotted earlier on the map.

So in review:

Course: Is always the line drawn on the chart

Heading: The direction which the airplane is pointed

Hopefully these definitions will help in the flight planning process. Most navigation logs have this laid out pretty well to help you keep the terms straight.

Thanks for the question Josh. Good luck with your training and cross country trips and…

Fly Safe!

32 Comments



  1. PlasticPilot on Jun 16, 2008

    Thank you for this short review. Flying in western Europe makes it easier. The variation here is approximately one degree, so it can be neglected ;-)

    Keep going with this good job.

    PlasticPilot



  2. Chris on Jun 16, 2008

    I can’t remebmer where I heard this but I like it

    “If it’s written, It’s True”

    So if you get it off a piece of paper its true, if you call someone on the radio, its magnetic.



  3. instructor on Jun 16, 2008

    PlasticPilot: That’s pretty easy then!

    Chris: I like that. I’ll have to remember that. Thanks.



  4. Steve on Aug 23, 2008

    winds aloft and forecast winds are true, ATIS and real time ATC will give you magnetic wind direction



  5. Brandon on Dec 13, 2008

    When you use a VOR signal, I assume you log that as Magnetic Heading?



  6. Paul on Jan 04, 2009

    Brandon,

    If you are trying to fill in a NAVLOG based on a victor airway or radial off of a VOR you need to be careful. Remember that magnetic variations change over time. So it might be that “course” off of a VOR might have shifted since that VOR was last calibrated. You need to use your course plotter. Find the true course of that radial using the plotter and then subtract or add the variation found nearby by referencing the isogonic lines (dashed magenta) to get the magnetic course.

    TC -/+ Variation = MC

    To find your Magnetic Heading (MH) you would also have to account for winds which are given in reference to true north so then it would be:

    TC -/+ WCA = True Heading (TH)
    TH -/+ Var = Magnetic Heading (MH)
    MH -/+ Dev = Compass Heading (CH)



  7. derm on Mar 31, 2009

    That was perhaps the lamest answer I could imagine. He asked a simple, specific question and you gave him a general overview that did not answer the question.

    Chris in the comments sums it up in one sentence.

    Hmmmm…should I trust the other things I see on this site?



  8. Paul on Mar 31, 2009

    Hi Derm,

    Wow. I’m sorry if you thought my answer was lame or too verbose. I do have a tendency to carry on a bit (ask my students) and it is something I’m working on.

    I do my best to be thorough and try to provide complete answers but maybe I’ll start trimming it back a bit.

    Thanks for your honest feedback.



  9. derm on Mar 31, 2009

    Sorry about that comment, paul. I came into your site from google and hadn’t read anything but that one answer. I do think it totally didn’t answer the question, but there’s no reason for me to be a jerk about it. I browsed around and looks like you’ve got some cool stuff here.



  10. Paul on Mar 31, 2009

    No worries. That’s the nice thing about the internet. Everyone has a voice right? I could have never learned to fly if I didn’t know how to accept constructive criticism and suggestions. I appreciate all the feedback I get from users. That’s the only way this site will get any better.

    Let me know if you need anything else.



  11. Niku on Apr 25, 2009

    Poul i find your asnswers very helpful but just a question since im a biginner..
    What is the WCA? I know its the wind but what does the abreviation stand for?



  12. Paul on Apr 25, 2009

    WCA stands for Wind Correction Angle. This is usually measured in degrees of correction either positive or negative. This value is generated on the wind side of your E6B. You take your true course and then compensate for winds. If you have a left or right crosswind you’ll have to crab into the wind in order to maintain a certain course across the ground.



  13. Kharl on Oct 16, 2009

    Hi!
    I found very very helpfull alll the info posted here
    i use to know each concept;
    TC true course
    TH true heading
    MC magnetic course
    MH magnetic heading
    CH compas heading

    but i use to forget it many times too…

    im lot more clear now (thanks) but i still have not understood 100%
    the magnetic course (MC) and/or my question about this would be; could a course (line drawn/ plotted on a chart) not be magnetic, i mean if is not magnetic course what other course would be?

    and studying ADF i found this too:
    RH relative heading
    RB relative bearing

    i know relatevie bearing is the degrees you must turn clockwise the plane to flight in straight line to the NDB, but so, what is relative heading?

    Thanks and sorry for my poor english



  14. Rudy on Dec 13, 2009

    I am confused about all things “BEARING” Need help diferentiating between headings and bearings… thank you!!!



  15. dope32 on Jan 19, 2010

    prove it steve in the far aim
    winds aloft and forecast winds are true, ATIS and real time ATC will give you magnetic wind direction



  16. Justin on May 29, 2010

    Many nav logs have MC in a bigger section than the planning area that involves WCA, VAR, DEV, etc, but why do we have a MC section on the log? I’ve heard other CFI’s and students alike trying to use the CH, but completely ignoring MC to the point of not even filling it out. So, why then, is it on the nav log if it’s not being used for navigation and is not part of the planning? Even many wiz wheels don’t use it. They use TC+/-WCA = TH +/- VAR = MH +/- DEV = CH, but never say anything about MC. So why is it not in any of the formulas?

    My understanding is this: Heading is the direction of the longitudinal axis of the aircraft. In navigation, the reference direction is mag norht and the heading is known as mag heading (MH). Wind can change the aircraft’s path over the ground to differ from its heading, the result being the ground track. MC is based on mag north. (Some countries refer to it as desired track.) VOR and ILS CDI’s show the aircraft’s actual ground track is deviating from the MC.



  17. Justin on Jun 02, 2010

    To answer “dope32″…..if everything had to be proven against the FAR & AIM then that would be the only books pilots would need, study or reference for aviation knowledge and continuous learning. Not sure about you, but I use all available resources. You do know that the FAR & AIM are really two separate books, right? Companies like ASA will combine them to make them easier to reference.

    Anyway, you might want to open your copy of the FAR AIM and on page 821 in Chapter 7 “Safety of Flight”, Section 1 “Weather”, page 821 you’ll find the ASOS/AWSS (Metar) says wind direction in ten of degrees from TRUE north. The ASOS is Metar information which is written. This is just one example.

    Additionally the Weather Services book AC 00-45F (Oct. 2007) Section 3:Observed Text Products Page 3-6 “It is coded in tens of degrees relative to true north using three figures.” Also on pages 5-21, 5-47, 5-57 etc. are good pages for you to look at. This is an Advisory Circular and while ACs are not necessarily regulatory in nature like the FAR, you’d have to agree that neither is the AIM. Yet you use that.

    What I’m saying is that you can’t simply demand someone to “prove it” against only the FAR / AIM. Especially when Steve’s question was not even about regulations, but rather about information.



  18. Jason Labrum on Aug 14, 2010

    Paul,
    When preparing for an instrument checkride should I be filling out a navigation log?
    Or, can I simply print a Duats flight plan or use the dauntless-soft.com ifr flight planning form?
    Thanks for your help



  19. ramus on Sep 13, 2010

    ok thank you



  20. syao on Sep 28, 2010

    may i know what track is? it is different from magnetic hdg and true course right?



  21. Noobie on Jun 17, 2011

    Guys,

    where I am flying to, when I am flying the compass heading?



  22. Private PILOT on May 10, 2012

    thanks. this is very helpful to my private pilot examination



  23. tobepilot on Jul 26, 2012

    Hi

    Could someone explain me this:

    when air traffic controller asks me ” Report heading”

    Do I answer with TH or TC

    TC -/+ WCA = True Heading (TH)
    TH -/+ Var = Magnetic Heading (MH)
    MH -/+ Dev = Compass Heading (CH)

    Thanks



  24. Mike M. on Jul 27, 2012

    tobepilot… Take a moment and think about what a controller has to work with… they most likely have you on radar, right? So what they care about is your ground track. They could care less about where your spinner is pointed. So if you reply with your True Course they will be happy.

    Mike M.



  25. Tom on Oct 03, 2012

    Hey Mike,

    I do not agree. If a controller asks for a Heading, he wants to know the Heading you read on your instruments, which is the heading you are flying. Of course many planes can view the track as well, but as all airplanes get headings to follow by the controller, it does not make any sense telling the controller the track. If they want to know the track, they will ask for a track ;-)

    cheers Tom



  26. Michael on Nov 11, 2012

    I would like to see more reference material where wind direction reported form atc or atis
    is in magnetic.



  27. Marius on Nov 16, 2012

    Yeah… I have to second that. When ATC states “report heading” they want your actual heading. All their vectors are given as headings.



  28. Karl on Nov 28, 2012

    There was no talk above of Mag Track but I need to know Mag Track for proper VFR cruising altitudes(especially important near 180 and 360) I assume that is just your true track plus variation. Is that correct? Thanks



  29. Jose Lopez on Nov 29, 2012

    Thank you for the review, really helpful.



  30. Boll Weevil on Mar 10, 2013

    This is a great site. Thanks for all the information.



  31. Garry on May 26, 2013

    Some of you need to spend more time reading Airplane Flying Handbook & Aviation Weather books from FAA.gov. All the questions asked here are explained there. Never heard of ‘Magnetic Track’ as Karl referred to…? You mean Ground Track? That’s the line you’re tracing (tracking) over the ground. “Only the man in the tower is untrue”. Only ATIS is Magnetic direction; ALL others (METARS, TAF, FA ) are TRUE!



  32. BC on Mar 13, 2014

    1) True Course (TC): This is the course measured from your navigation plotterwhen you plot your flight on your map. Remember that because of the projection of the map, it is best to read this course in the middle of the leg.

    What do mean because of projection?
    Also if I plan a long XC, does TC change throughout, why or why not?

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