pitotstatic

The Pitot-static system is a method used in aircraft to determine airspeed, altitude, and vertical speed by measuring pressures of the surrounding air. It uses a Pitot tube to measure ram air pressure and static ports to measure ambient atmospheric pressure.

The Pitot tube, located on the aircraft nose or wing, faces forward to capture ram air pressure (total pressure). Static ports, typically placed on the fuselage, measure ambient pressure. The difference between the total pressure and the static pressure is dynamic pressure, which is used by the airspeed indicator to display airspeed.

The pressure readings are fed to the aircraft’s instruments. The airspeed indicator displays Indicated Airspeed (IAS) based on dynamic pressure. The altimeter uses static pressure through an aneroid chamber to show altitude. The vertical speed indicator uses the rate of change of static pressure to indicate climb or descent rate. Modern aircraft often use an air data computer to compute calibrated airspeed, true airspeed, and other data from the Pitot-static measurements.

Common issues include blockage of the Pitot tube or static ports due to ice, debris, or insects, which can cause erroneous readings. Ice can be mitigated with heating for the Pitot tube and by maintaining clean static ports. If a blockage is suspected, pilots may rely on an alternate static source and rely on standby instruments. Regular maintenance and preflight checks verify instrument accuracy.

The Pitot tube is named for Henri Pitot, who developed the concept in the 18th century; the Pitot-static system remains a foundational method for air data in aviation.