PitotStaticSystem

The Pitot-Static System is an aircraft pressure-sensing assembly used to determine airspeed, altitude, and vertical speed by measuring pressures of the surrounding air. It typically includes pitot tubes, static ports, associated tubing and valves, and, in many cases, an air data computer that processes the signals for cockpit instruments and flight systems.

The pitot tube measures stagnation (ram) pressure as air enters a forward-facing opening. Static ports measure ambient atmospheric pressure at static conditions away from the influence of the aircraft’s motion. The difference between pitot (total) pressure and static pressure provides the input for airspeed indication, while static pressure alone feeds altimeter and vertical speed indicators. In modern installations, signals from the pitot and static sources are routed to an air data computer that supplies calibrated data to the airspeed indicator, altimeter, vertical speed indicator, and digital flight displays.

Airspeed is calculated from the dynamic pressure (the pitot minus static pressure) and is corrected for air density. The altimeter translates static pressure into altitude relative to sea level, using a reference pressure setting. The vertical speed indicator shows the rate of change of static pressure, indicating climb or descent.

The system is susceptible to blockages and leaks. Pitot-tube icing or obstruction can cause erroneous airspeed readings; static-port icing or leaks can produce altitude and vertical-speed errors. Redundancy is common, with multiple pitot tubes and static ports, and many aircraft use backup instruments or alternate data sources when anomalies arise. Regular maintenance, inspection, and drainage are essential to ensure accurate measurements. Modern aircraft often integrate the pitot-static system with electronic flight instrumentation and auto­pilot systems through an air data computer.