Welcome Guest. Sign in or Signup

3 Answers

Calculating/ applying the variation QDM, QDR, QTE, QUJ

Asked by: 3060 views , , , ,
General Aviation, Student Pilot

Dear CFIs

Is there an easy-to-remember rule only applying the variations to calculate the QDR, QDM, QTE, QUJ?

Merely subtract east/ add west does not seem to work. Based on the answers, I am assuming it is something to do with applying the variation to the heading vs. the true course.

But I am unable to ping the logic.

Grateful for any advice!

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

3 Answers



  1. Benni2000 on Jan 19, 2023

    PS. Not sure how to edit my post, but having gone through some logic, would I be correct if I said:

    If True, add west, subtract east. If Magnetic, do the opposite?

    In other words, add west, subtract east works only on true and for magnetic do the opposite?

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  2. Loic2404934 on Feb 27, 2023

    Hi Benni,

    I see your question was posted a little while ago and I hope my answer will still be of some interest to you.

    To keep things simple just remember that a west variation is negative while an east variation is positive. To go from magnetic to true you simply need to add.

    eg: You are reading on your compass (that isn’t affected by any deviation) a magnetic heading of 090° and according to your chart the variation in your region is 6°W. 6°W is equal to -6°. Now you need to add this to your magnetic heading: 090 + (-6) = 084 . 084° is your true heading.

    If you want to go from true to magnetic just subtract the value instead of adding.

    Same applies with deviation which is negative for west and positive for east.

    And we can say:

    Compass heading + deviation = Magnetic heading
    Magnetic heading + variation = True heading

    True heading – variation = Magnetic heading
    Magnetic heading – deviation = True heading

    0 Votes Thumb up 0 Votes Thumb down 0 Votes



  3. Loic2404934 on Feb 27, 2023

    Benni,

    QDM and QDR are MAGNETIC and QUJ and QTE are TRUE.

    So if you read my previous post, to go from MAGNETIC to TRUE you need to ADD the variation. Hence to calculate a QUJ from a QDM you need to ADD the variation. Once again, variation is negative if West and positive if East.

    If your QDM is 270° and variation is 5°W (iow -5°) then your QUJ will be 270 + (-5) = 265°
    It is exactly the same logic for QDR and QTE.

    Now I need to \”correct\” you on something: Don\’t mistake heading for course.
    The difference between the heading and the course is the wind correction.

    If you have a true heading (measured from the true north) and apply a wind correction, you will obtain a true course. If you apply the same wind correction to a magnetic heading heading, you will obtain a magnetic course.

    0 Votes Thumb up 0 Votes Thumb down 0 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.