Page 767 - PPL-engelsk 2025
P. 767
Aircraft general knowledge
The pitot tube is usually covered by a pitot cover when the aircraft is parked.
Remember to remove this before flying, otherwise the air speed indicator will
not work!
The pitot tube is usually equipped with a heater to prevent icing.
8.12.4.1 Dynamic pressure
Dynamic pressure is used to show the aircraft's speed - the higher the speed, the
greater the dynamic pressure.
If you have not turned on the pitot heat and the pitot tube becomes iced up and
blocked,
The airspeed indicator will act as an altimeter. This means that if the aircraft
climbs and the static pressure decreases, the enclosed dynamic pressure will
have a relatively larger value, and it will look as if the aircraft's speed is
increasing.
Fortunately, there are other instruments in the aircraft, but it has had fatal
consequences if a static or dynamic air intake was blocked.
8.12.4.2 Static pressure
One or more static inlets supply the altimeter, variometer and airspeed indicator
with static air pressure.
Static air pressure is used in the altimeter to determine the aircraft's altitude -
the lower the pressure, the higher - and in the variometer to determine the
change in air pressure.
The inlet for the static air pressure is located
where the air is relatively undisturbed.
On Cessna 172, it is located on the left side of
the cockpit.
Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 767
