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PPL studies NAVIGATION. Dead Mental Reckoning, Clock Code!

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I have just learn't the MDR chapter of navigation and i thought i grasped the basics, but i was wrong! Once i got the mock questions at the end i didn't have a clue. It seems i'm lost with the clock code method.


Here the question and answers...


You plan to fly a cross country flight at 2,000 feet at a true airspeed of 120 knots. Your track is 270* (TRUE) and the wind is from 225* (TRUE) at 24 knots using the mental dead reckoning clock code, what true heading would you steer and what would be your magnetic heading if the local magnetic variaton is 4* west?







The answer is B


I can work out the drift angle 60 / 120 true AS = 0.5 X 24 knots wind = 12


Now this is where i get confused when applying it to the clock code? Can someone help please!

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I'll have a go...


270 - 225 = 45 degrees difference


Clock code as I understand it


15 minutes past the hour (3 o'clock position) -> 1/4 of the clock

30 minutes past the hour (6 o'clock position) -> 1/2 of the clock

45 minutes past the hour (9 o'clock position) -> 3/4 of the clock

60 minutes (12 o'clock position) -> ALL of the clock


As the difference between the track and heading is 45 degrees, you multiply the max drift (12 as you've calculated) by 3/4 = 9 degrees which is the drift you require to get the answer.


variation west -> magnetic best so add 4 degrees to get magnetic heading.


Hope that helps.



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Right think i have got it, check out Q 4, 5 ?


Do you always have to takeaway track heading away from wind heading?

In the book it never mentioned that?

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