Page 509 - PPL-engelsk 2025

Principles of flight

5.10.1.3 Density altitude

The density altitude also has a lot to do with the take-off run.

For example, if you are going to take off at 2000 ft., a higher speed is required

before the lift is the same as at MSL, because the distance between the
molecules at that height is greater.

In addition, the engine has lost some of its power in the thinner air.

5.10.1.4 Performance tables

Performance tables indicate take-off run (ground roll), which is the length of the

runway used before an aircraft gets into the air.

In addition, it also indicates how far the aircraft must travel in the horizontal
plane, from the time the aircraft begins its take-off run until it passes 50 feet

during the climb.

We call this distance the take-off distance. These distances are often specified

at different altitudes and in different wind conditions.

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5.10.2 Climbing

The excess thrust is used for climbing.

It is not because the lift is greater than the weight of the aircraft that the aircraft

climbs, but because of

the oblique upward

thrust, which together

with the lift has a
magnitude so that the

aircraft climbs (see blue

and green arrows in the

illustration).

Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 509