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Assuming that :

  • You are flying on a compass heading of 141°,
  • The compass deviation is given as +3°,
  • The variation read on the chart is 3° East,
  • The wind correction angle is +10° and
  • The relative bearing to the airport is 307°

what would the radial from the station be to the true north?

I thought QTE was a standard term. I did not know that American pilots did not know it.

*QTE: True Eminent from station — What is my true bearing from you? QTE = Reciprocal of true bearing to station.

To derive the true bearing I did the following.

I assume that since compass heading is 141° and deviation is +3°

  1. Magnetic heading should be 141-3 = 139°

  2. True heading (would be without the variation given as 3°E) = 139 +3 = 141°

  3. True bearing to station = True heading + relative bearing = 141+307 = 448°

  4. True bearing = 448-360 = 88°

  5. True eminent from station = 268°

However the answer given is 274°.

I want someone with more aviation knowledge to tell me if I am wrong and if so, where is the "break" in my logic?

Reason for question: Navigation problem with an answer given, however I believe the answer to be wrong - Needed an expert opinion.

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    $\begingroup$ Welcome to Aviation.SE, can you give a bit more information about your question? It sounds very much like an exam question. What have you tried so far? I'd recommend you read the help center for information on what you can ask here and what makes a good question. $\endgroup$
    – Notts90
    Oct 21, 2016 at 11:12
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    $\begingroup$ Also welcome to Aviation.SE. These kinds of questions are often frowned upon because you need to show some effort and ask specific questions about where your methodology may be flawed. Please give us as much as you can work out and explain where you are stuck. Just giving you the answer doesn't help you understand, and it isn't within the scope of the site to work through the process just given the exam question. Don't get discouraged, you can edit this into an acceptable question! $\endgroup$
    – Ron Beyer
    Oct 21, 2016 at 19:34
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    $\begingroup$ Welcome to aviation.SE! We have no problem with calculation questions in general, but I suggest you give a little more information. For example, "QTE" means nothing to American pilots. It would be great if you could explain/link to more details. It would also help if you explain why you can't do the calculation yourself, e.g. you can't find the formula; or you can find it, but it gives the wrong answer for you. $\endgroup$
    – Pondlife
    Oct 21, 2016 at 21:28
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    $\begingroup$ Thanks for the edit. I changed the header so it doesn't sound like a homework question. It might attract more answers that way. It you don't agree with the edit feel free to roll it back. I've drummed up some reopen votes. I think it just needs one more $\endgroup$
    – TomMcW
    Oct 22, 2016 at 1:22
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    $\begingroup$ I agree with @mins. The Q-codes don't usually stand for anything in particular. A series of them will be assigned for different types of use and the series will proceed alphabetically. So it appears that QTE indicates true bearing and "eminent" is just a pnemonic. That's my bad, I'll edit the header to reflect that. $\endgroup$
    – TomMcW
    Oct 23, 2016 at 2:12

2 Answers 2

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You are quite close to the answer, you just made a mistake with the sign of east compass deviation, hence underestimated the true heading by 6°. The actual angles are like this:

enter image description here

The compass deviation is given as +3° while it should be given as 3° east, like the variation. It could be misleading.

Exactly as you then developed, the unknown yellow angle is equal to:

  • True heading + (relative bearing - 180)

  • 147 + (307 - 180) = 147 + 127 = 274°

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    $\begingroup$ What did you use to create the image? Looks good and very helpful. $\endgroup$
    – Notts90
    Oct 24, 2016 at 7:05
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    $\begingroup$ The error was in the compass deviation. He subtracted 3 deg from the compass heading when he should have added it. Compass heading + Compass deviation = mag heading. $\endgroup$
    – Gerry
    Oct 24, 2016 at 12:35
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    $\begingroup$ @Gerry. Corrected, thanks! $\endgroup$
    – mins
    Oct 24, 2016 at 19:06
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    $\begingroup$ @Notts90: There is a very good open source to produce SVG (vector) graphics: Inkscape. This is a good example of how to use some relatively simple vector tools. $\endgroup$
    – mins
    Oct 24, 2016 at 19:13
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I found this answer and think it could be explained a little different to the answer above which is perfectly correct to see the difference between compass/magnetic/true north moving inversely to true/magnetic/compass heading.

I think one part to understand this is, that headings behave different to the north positions. The best way I have found to remember calculating correct headings is, to start with true heading (TH) and continue to magnetic heading (MH) and then to compass heading (CH). Everything else can be computed from this sequence of two formulas:

TH - variation = MH -> MH - deviation = CH

So:

  • compass heading is referenced to true north
  • magnetic heading is referenced to true north (compass + deviation)
  • true heading is referenced to true north (magnetic + variation)

or the other way round as in the the other answer:

  • true north is referenced to true heading
  • magnetic north is referenced to true heading (true - variation)
  • compass north is referenced to true heading (magnetic - deviation)

I hope this picture visualizes all the concepts:

enter image description here

This still means, that magnetic north in this example is to the east (3°E or +3°) of true north, and compass north is to the east (3°E or +3°) of magnetic north. So if you think about it, moving the north pole further east, reduces the compass heading by the variation and deviation, but only relative to the true heading. And moving the heading towards eastern variation or deviation reduces it as well, but only relative to true north.

So overall the phrase "east is least" can be seen and understood that way.

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