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Stretcharmstrong
15th Apr 2010, 05:54
Hi

First post! I am hoping to do my navigation exam very shortly and woking through AFE books and the confuser. I'm ok with the revision except when it comes to working out 'variation' using the map. I totally understand how to complete the plog, which I have now done many times and understand variation etc. What I'm stuck with is which variation figure(s) I need to include in my PLOG on a longer route crossing various different magnetic variations. For example, if I plan a route with say 5 route sectors, I might cross a magnetic variation of 2.5w, 3.5w, 4.5w etc on the way. On some of the sectors it falls right on the magnetic variaiton line, others more closer to say 2.5w rather than 3.5w. One one of my route sectors I have to plan to say Town A which falls in between a variation of 2.5w and 3.5w so I would normally choose variation as 3w. However as I fly to Town B that falls just after 3.5w. So when I PLOG the part of the route from town A to town B which variation do I use as technically ir covers a range of magnetic variations?

Is it just a case of 'best guess' which one I include? Its just that if I get it wrong I'm a degree out with my answer. This isn't a huge problem but some answers fall 1 degree one way or another.

I hope I'm making sense with this question!

Mark1234
15th Apr 2010, 09:57
Find the middle of the leg, and take the deviation there - it will be the average of the leg. Also remember that .5, or even 1 degree is largely irrelevant as you can't fly that accurately. Can't comment on the exam tho..