and that is a 100% perfect example of tyhe total misunderstanding I am talking about.
FlyingStone,
Why on earth would you solely rely on DR when you can look out the window and see exactly where you are? i.e. Visual Navigation.
When you look out the window you see exactly where you are - 100% accurate. No errors you are absolutley 100% where your eyes see that you are when you look out the window.
The problem comes when you want to name the village you are over and you are unable to corelate what you see on the map and what you see out the window.
Visual navigation presents the user with two pictures of the same situation - one out the window and on on a piece of paper. They are the same. However, some skill is required to map read and sadly it is lacking. map reading is essential for visual navigation - in it's most basic form following roads, railways and rivers. This basic skill is missing in those that can not use this method.
If you only know how to use DR, havent tracked a radial/QDM/QDR for ages and GPS is the worst sin on Earth you could possibly commit, then whenever the wind forecast is wrong, you will get either lost or at least enormous drift.
Now why would anyone get lost using visual navigation if the wind is different from planned (which it is a lot of the time).
navigation exercise:
Fly from Atown (VOR at it's centre) to Btown (VOR at it's centre) which is directly East 60nm in your 120Kt aircraft. The two towns are joined by a wandering railway track.
1. Visual navigation - follow the railway track. Works 100% but not very efficient due to the wandering track. Hard to work out ETA
2. Visual navigation - calculate a heading and time that you expect will work and after 6 minutes check your progress, adjust back onto track and fly directly to Btown.
3. VOR/dme - calculate a heading and time that you expect will work and if the heading does not work adjust back onto track (and the eta if applicable) and fly directly to Btown.
4. GPS - calculate a heading and time that you expect will work and if heading does not work adjust back onto track (and eta if applicable) and fly to Btown.
Perhaps it is me but 2, 3 and 4 above are exactly the same navigation technique but with different sources of information - Visual information, VOR/DME or GPS.
May questions for anyone who dismisses the pre-calculation of headings for a navigation exercise / crosscountry flight are;
1. How do you determine how much fuel you are going to require; and
2. How do you determine that a) the aid you are using is working and that the flight is proceeding (close to) as planned?
Finally, I have to point out that on most commonally used navigation charts at PPL level when one draws a straight line it is a great circle. Therefore following the pencil line on your half million will cause you to fly a great circle - just like the GPS will do so provided one can navigate visually one can fly as accurately and as efficiently as when using a GPS.
PS GPS is part of the PPL sylabus and should be included in the practical aspects of visual navigation i.e. DR is only one aspect of the overall sylabus and not the only piece that should the taught simply because that specific element is what people find difficult and is guaranteed to be tested.