Aircraft Systems Flashcards
Tell me about the airspeed indicator. How does it work?
This is the only instrument that uses both the pitot and static ports. It measures the difference between dynamic pressure (ram air entering the pitot tube) and static pressure (air that is unaffected by the aircraft’s flight path). Ram air exerts a force
on a diaphragm inside of the instrument. The instrument case is full of static air.
Tell me about the Altimeter. How does it work?
This measures the difference between static pressure inside of the instrument case and standard pressure (29.92” Hg) sealed inside of an aneroid wafer. When the airplane is climbing and ambient pressure begins to decrease, the wafer is able to expand
because the air that is sealed inside is now of higher pressure. The altimeter is a sensitive altimeter meaning that it can be calibrated to the local barometric pressure by adjusting the Kollsman window.
Tell me about the VSI. How does it work?
Measures the difference between static pressure and static pressure that is subject to a calibrated leak approximately every 6-9 seconds.
How are the Gyroscopic Instruments powered?
The Gyroscopic instruments are powered by an engine-driven vacuum pump with the exception of the turn coordinator which is electrically powered.
What is Rigidity in space?
While spinning, a gyroscope will tend to stay fixed in its plane of rotation. Think of a bicycle wheel. With enough momentum, you are able to stay naturally balanced.
What is precession?
When a force is applied to a gyroscope, the resultant force is felt 90° ahead in the direction of the rotation.
How does the vacuum system operate?
An engine driven vacuum pump creates suction. Air is pulled through a filter and then directed to the instrument case. Rotor vanes on the gyros catch the air like a water wheel and cause it to rotate at a high speed. In the Archer IIIs, there is also an electrical vacuum pump to be used as a backup.
