A Pitot–Static system is a system of pressure-sensitive instruments that is most often used in aviation to determine an aircraft's airspeed, Mach number, altitude, and altitude trend. A Pitot–Static system generally consists of a Pitot tube, a Static port, and the Pitot–Static instruments.

The Pitot–Static system of instruments uses the principle of air pressure gradient. It works by measuring pressures or pressure differences and using these values to assess the speed and altitude. These pressures can be measured either from the Static port (Static pressure) or the pitot tube (Pitot pressure/Total pressure). The Static pressure is used in all measurements, while the Pitot pressure is used only to determine airspeed.

Pitot/Static Heads is an open-ended tube parallel to the longitudinal axis of the aircraft is used to sense the Total pressure (Static plus Dynamic). This device is a ‘Pitot Tube’ mounted in a ‘Pitot Head’. The open end of the tube faces into the moving airstream, the other end leading to the airspeed capsules in the ASI and Machmeter.

The moving airstream is thus brought to rest in the tube, generating the extra (Dynamic) pressure which together with the Static pressure already in the tube provides the required Total (pitot) pressure.

Static Head consists of a tube with its forward end sealed but with holes or slots cut in the sides. These slots do not face into the airflow and therefore, in theory, they sense only the Static pressure. In fact, of course, there will be a suction effect and the sensed Static pressure will be slightly lower when the aircraft is moving. This pressure supplies the Static ‘line’ to the pressure instruments.

The pressure sensed by the Pitot tube is Total air pressure.