Drift Lines
 

What is the general opinion on drawing drift lines on a chart when the legs are short <15nm ? I find they mask the features on the chart and over complicate the area you are looking at.

My opinion is:

1) Follow the requirements of your instructor, examiner, and the aircraft owner.

I have drawn drift lines on charts on the following occasions: During grounschool, whem it was being taught, for practice cross country flights with the instructor, and for flight tests.

2) For me, other than that, not so much....

I've never done it, and never felt short of anything. But neither have I ever flown 15NM without any visual ground reference so I am perhaps not saying very much.

I would draw one reference line at 10 degrees to about halfway along the track. This will give you something to judge how far off track you are, if it's the side you didn't draw the line you can still judge it from one line.

Drawing four fan lines in a kite shape is rather excessive, but I see a lot of other instructors teaching to do this for every single leg. In my experience, one line is enough for any leg and just gives a reference to make a calculated correction. Otherwise, come test you're left saying "I'm off track, so will turn 10 degrees to the left" and if the examiner quizzes you on where that figure came from it seems rather plucked from the air. It is better to have a method to fall back on at least for test, then you can do whatever you want once you pass.

What's a drift line?

A single sentence typed as a response, which greatly changes the subject of the original post....

I bow to your superior wit sir....:)

I think I've worked out what one is in the interval between this post and my original. I certainly wasn't taught them during my PPL.

Tomboo,

You should not normally need to put drift lines on a leg of less than 15 nm. As a simple practical matter, on a leg of less than 15 miles you should pretty much be able to see your next turning point before you set off; since you can see the turning point you can very quickly determine and correct the drift by "eye".

Drift lines are useful on long sectors where the end point is too far to see, and therefore you need an interim "how goes it" in order to update your heading. Even so, they are not widely used - you'll get better at map reading with practice, and although they may actually be doing more or less the same adjustments, with better situational awareness most pilots do it without drawing drift lines.

As others have noted, an examiner on a test MAY ask you to demonstrate a drift line technique on a very short sector, but that's only becase he doesn't feel like sitting there while you fly a 100 nm sector! ;)

If you feel the need for drift lines and don't want to clutter your map, then get a strip of acetate or clear plastic and a sharpy pen and draw a pair of lines intersecting at 10 degrees.
When you have marked a position fix on your map, drop over the overlay and interpolate your track error and/or closing angle.
Alternative is to ignore them completely and use a standard closing angle technique. I know that you still want to know the track error to set the new heading required.
Better still, use a GPS and don't get off track in the first place. But that's after you finish your training ;)