Pressure Instrument Theory

Basically there are 3 instruments that rely on pressure differences in order to measure speed and altitude. These instruments are the Airspeed Indicator (ASI), the Vertical Speed Indicator (VSI) and Altitude Indicator (AI)(figure 1.1). In general there are three kinds of pressure, namely: static pressure, dynamic pressure and total pressure. In the next chapters we'll get into detail on these specific pressures. From here we will continue to explain the just mentioned instruments.