Page 775 - PPL-engelsk 2025

Aircraft general knowledge

The static pressure in the cabin will be slightly less than the static pressure that

you would otherwise get via the static port. This will cause the altimeter to read

too much and the air speed indicator to read too high a speed.

You cannot use this “trick” if you are flying in an aircraft with a pressurized cabin!

And if you do it in our airplanes in the club you will not be popular

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8.12.8 Gyro instruments

Gyros are made up of a flywheel with a fairly large mass. This is mounted in a

gimbal, which allows the flywheel to spin freely in any direction.

Rigidity in space is one of the principles used gyros. It is based on the fact that

the gyro, which rotates at a very high rotational speed relative to space (a star

or similar), will maintain the same position. However, due to the rotation of the
earth, it will appear as if the gyro is “wandering” or turning.

Consider the two illustrations below.

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 775