In an airspeed indicator, its static ports were located on an exterior part of an aircraft at a certain location that is chosen to help in detecting the prevailing atmospheric pressure with minimum disturbance from the aircraft’s presence. The open end on a pitot tube is mounted on the aircraft wing facing the flow of water or air. The airspeed indicator measures the existing differences between a sensor in the air stream and the static senor not in the air stream. When an aircraft is in standing mode, the pressure in each of the tubes is always equal. The airspeed indicator reads zero. In a flight, the rush of air leads to the differential pressure between the pitot tube and the static tube. This difference in pressure causes the pointer at an air indicator speed to move. Any increase in the forward speed causes the pressure at the pitot tube to raise. This in turn causes the air pressure to push against a diaphragm, which moves the mechanical pointer connected on the indicator. This indicator is calibrated in such a way that it compensates for winds flowing in the air current.&nbsp.Most airspeed indicators were calibrated to be used in a sea-level standard atmosphere.