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9.7.5.1 Specifying the wind

We know from earlier that the wind direction and speed (W/V) is 190/20.

We draw the wind from EKSD by setting off 190 degrees.

The wind is blowing at a speed of 20 Kt, so in the direction 190 we set off 20 mm,

as each millimeter is 1 Kt.

From the point 20 mm down the red line that indicates the wind in an hour, we

must use a compass to set off a distance that hits our track between EKHG and
EKSD (if you don't have a compass, you can probably get by with a ruler).

The distance we need to set off is our TAS of 100 Kt. We set off 100 mm.

9.7.5.2 TAS and GS

Now we need to find GS. We do this by measuring the length of the line from

EKSD to the red arc.

As you can see, GS on the TT line
is measured to be 89 Kt.

9.7.5.3 TH and WCA

To find TH, we first need to find WCA.

With the protractor, WCA is measured to be 10° (referred to as ÷ 10° when it is

to the left in relation to TT).

This gives us a TH of 254° ÷ 10° = 244°.

9.7.5.4 MH, CH, deviation and variation

Now we only need to calculate magnetic (MH) and compass headings (CH).

In the plane, the deviation is shown in the direction we are moving in.

Here it is ÷4° (the same as 4° W).

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 853