Definition
The network of air-pressure tubing, ports, and fittings that carries ram (pitot) air pressure and ambient (static) air pressure from sensing ports on the outside of the aircraft to flight instruments or to an Air Data Computer. The pitot side measures the pressure of air being forced into a forward-facing tube as the aircraft moves through it; the static side measures the undisturbed atmospheric pressure surrounding the aircraft. Together these two pressure sources feed the airspeed indicator, altimeter, vertical speed indicator, and modern air data computers.
Plain English
It's the set of small air tubes that carry two kinds of outside air pressure into the cockpit: the pressure caused by the airplane moving forward, and the pressure of the still air around it. The flight instruments use those two pressures to figure out how fast and how high the airplane is flying.
Context Anchor
Seen in instrument-system and air data computer discussions, especially where pitot and static pressure lines connect to the equipment that calculates or displays flight information.
Derivation
Pitot comes from Henri Pitot, the 18th-century French engineer who invented the forward-facing pressure tube used to measure fluid flow. Static comes from the Latin staticus, meaning 'at rest' — referring to the still, undisturbed air pressure around the aircraft. Pneumatic comes from the Greek pneuma, meaning 'breath' or 'air,' and describes any system that operates using air pressure. So the name literally describes an air-pressure system that uses both a moving-air source (pitot) and a still-air source (static).
Why Pilots Care
Blockages or leaks produce false airspeed and altitude readings that can lead to loss of control or airspace violations.
Analogy
Think of it like very small plumbing, but for air pressure instead of water. The lines do not carry fuel or electricity; they carry pressure information.
Intuition Check
Static does not mean electrical static here. It means outside air pressure used as a reference, separate from the pressure created by the airplane moving forward.
Example Sentence 1
During preflight, the pilot checked that the pitot cover was removed and the static ports were clear, since both feed the pitot-static pneumatic system.
Example Sentence 2
After entering icing conditions the crew monitored the pitot-static pneumatic system closely because ice could block the pressure sources.