Page 261 - PPL-engelsk 2025

Meteorology

In the phase of heavy rain, downdrafts are pulled out of the CB at up to 200

feet per minute.

But not only the CB itself can be dangerous.

Many kilometers before a CB, there can be a "gust front," where the wind

suddenly changes direction and strength.

Thus, a plane may go from having a headwind of 20 knots to a tailwind of

perhaps 60 knots in no time. This has caused crashes for both small and large

planes!

Hail is shown at the top right of the image, but it can also occur just under the

cloud where heavy rain is indicated.

At our latitudes, CB (Cumulonimbus) activity is not as intense as further south
but maintains a distance of at least 10 NM from an active CB. Be cautious during

takeoff and landing if CB clouds are close to the airport; downdrafts can slam

the plane to the ground.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 261