Page 452 - PPL BEG-engelsk

Principles of flight

5.3.4 The 4 forces that affect an aircraft during flight

Above, you can see the forces that act on the aircraft during flight (more details

in section 5.5):

- Lift
- Weight
- Drag
- Thrust

Note that the relative wind is 180 degrees opposite to the direction of the

aircraft's movement.

If we reduce the throttle, the aircraft will start moving both downward and
forward, and the forces will look different.

In the diagram here, the thrust is reduced, and the aircraft has changed its

direction of motion but maintains the same position in the air.

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© marts 2026 452