Welcome Guest. Sign in or Signup

2 Answers

Magnetic Compass Dip Erros

Asked by: 2861 views Aircraft Systems

For the magnetic compass, I understand the theory behind dip error and the famous UNOS, what I'm a little confused over is in which headings does it lag and lead. The reason I ask is because the FAA publications (Instrument flying handbook pg. 5-13, PHAK pg. 8-26) say it leads in the north and lags in the south, while everywhere else says the opposite, it leads going through sough and lags in the north. What am I missing here? 

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.

2 Answers

  1. Best Answer


    Russ Roslewski on Aug 01, 2017

    Wow. yes, the FAA publication is incorrect. It does appear that the two documents are literally a cut-and-paste of each other, so one was typed in incorrectly and the other as a result matches it.

    While the paragraphs explain the reasoning backwards, they do get the actions correct. In a northerly turn, roll out before you get to the desired heading (Undershoot it, because it Lags). Vice versa in a southerly turn.

    It’s really easy to see this effect in flight. A few minutes of visual turns somewhere with nice north/south roads will make it immediately clear what is happening, regardless of erroneous descriptions of why.

    +1 Votes Thumb up 1 Votes Thumb down 0 Votes



  2. KDS on Aug 05, 2017

    I won’t weigh in on this topic, but I recommend that you follow the guidance in the publication where it says:

    Comments regarding this publication should be sent, in email form, to the following address: AFS630comments@faa.gov

    Then, let us know what they tell you.

    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.