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9.8.3.2 The inner part of the scale side

Now we have to calculate how long it takes to fly 22 NM at the speed found. The

hour mark is the small on the inner scale / rotating scale.

GS was 103, so we placed the hour mark next to
103 (3 lines after 10).

Next to 22 (we have to fly 22 NM) on the distance

scale we place the red line in the arm.

We can now read on the inner scale how long the

trip will take to fly.

The time is read as 12.8 minutes.

Time is given in minutes and seconds, so the 0.8

must be converted to seconds.

0.1 minute corresponds to 6 seconds, so we get: 8x6 seconds = 48 seconds.

Under the given weather conditions, it therefore takes 12 min and 48 sec to fly

the 22NM.

9.8.3.3 From IAS to CAS

Task:

You are flying at a pressure altitude

of 6000 feet, temperature is ÷10°C,

IAS/CAS is 130 KT.

What is TAS?

- Place -10 over 6 in the AIR

SPEED window

- Turn the lever so that the red center line is at 13 (corresponding to 130 KT)

- Read TAS on the outer scale = 139 KT

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 861