Again smaller aircraft will typically have one Static Port, larger aircraft with redundant systems will have two. This is typically on the side of the fuselage but can also be on the back side of the Pitot Tube or any other number of locations, it varies by the aircraft. The Static Port is located in a position on the aircraft that will not be affected by air flow as the aircraft moves through the air. Static pressure is the measurement of the ambient barometric pressure at the aircraft’s CURRENT location AND CURRENT Altitude.

The Pitot Tube is connected directly to the back of the airspeed indicator (the Pitot input) and if the aircraft is so equipped also to the Air Data Computer via a hose which is typically either plastic or rubber Also on larger aircraft, those that fly at higher altitudes, the Pitot Tube is heated in order to prevent icing, smaller aircraft typically do not have this function. The most common manufacturer of these tubes is Rosemont Corp. Most small aircraft have only one tube, larger aircraft have a redundant system and will have two tubes. Pitot tubes are mounted on the aircraft facing forward so that air is forced into them. Pitot pressure is the measurement of the air forced into the Pitot Tube by the movement of the aircraft through the air. Keep in mind that this is for your basic vanilla airspeed indicator and does not include calculations for TRUE Airspeed for which you must include the variables of True Temperature and True Altitude. the conditions under which airspeed indicators are calibrated. The values for and are consistent with the ISA i.e. This expression is based on the form of Bernoulli’s equation applicable to a perfect, incompressible gas.

Units other than knots and inches of mercury can be used, if used consistently. Is 661.4788 knots:, speed of sound at standard sea level Is 29.92126 inches Hg static air pressure at standard sea level, Is the impact pressure (inches Hg) sensed by the pitot tube,

Minus position and installation error correction. Airspeed is calculated as a function of the difference between Pitot Pressure and Static Pressure as follows:Ĭalculated or Indicated airspeed is indicated airspeed corrected for instrument errors, position error (due to incorrect pressure at the static port) and installation errors.Ĭalibrated airspeed values less than the speed of sound at standard sea level (661.4788 knots) are calculated as follows:

Ram pressure