Can someone translate please?

[Tomislav Haramincic]

Hello,

Just to add a small correction. "Trudeln" doesn't have to result in a spin if the controls are kept neutral. The term "Trudeln" simply means that the flow of air is separating from the airfoil, and so the amount of lift is reduced or completly lost. Generally, Peter si right when saying that the loss of speed is the main cause. More precise, the speed of the air flowing around the airfoil (wings or control surfaces) is important. Trudeln of the control surfaces is maybe more dangerous because the control surfaces than lose their efficiency.
For example when pulling the aircraft up after a steep dive following a combat roll at low speed - the rapid movement of the elevator causes the airflow around it to brake of the elevator is uneffective and you continue strait into the ground.
Trembling at the wing or control surfaces followed by a characteristic sound is the first sign of Trudeln.

All the best,
Tomislav