Page 525 - PPL-engelsk 2025
P. 525
Principles of flight
5.10.7.5 Runway slope and surface
The slope of the runway and the surface of the runway have a great impact on
the braking of the aircraft.
If the friction of the runway is low, it is an advantage to make the air resistance
as large as possible. This is done with full flaps and a high angle of attack.
When the speed has decreased, the flaps are raised, so that the lift is reduced
and the weight is increased, so that the aircraft appears heavier and brakes
better.
The figure shows 2 examples of landings. One on a dry runway, and one on ice.
On a dry runway, friction increases greatly as speed decreases and the aircraft
reduces lift, and the pressure on the ground increases.
On ice, aerodynamic resistance is greatest in the first part of the descent, and
when the braking effect becomes noticeable, you can raise the flaps.
Aquaplaning and wet grass also give very poor braking effect and, in some cases,
asymmetric braking, so you have to use the brakes with care.
Back to table of contents
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 525
