Page 323 - PPL-engelsk 2025

Meteorology

Ice on the aircraft can:

- Change the shape of the profile – affecting lift and drag

- Increase weight

- Alter propeller performance

- Obscure visibility through the windshield
- Block the pitot tube

The illustration below shows how ice on the aircraft reduces lift and thrust

while increasing drag and weight.

These combinations increase the stall speed and thus the risk of stalling.

It is crucial to ensure that no frozen ice clumps are inside the control surfaces,

as it will disrupt balance.

Here’s a wing with about 1 to 2

millimeters of rim frost.

Such a layer of rim frost reduces
lift by up to 33% and increases

drag by up to 40%, so it must be

removed before flying.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 323