Definition
A combined sensing unit, mounted on the outside of the aircraft, that contains both a pitot tube (which faces forward to capture ram air pressure from the aircraft's motion) and static ports (which sense the undisturbed ambient atmospheric pressure). The two pressure signals are fed to the pitot-static instruments — airspeed indicator, altimeter, and vertical speed indicator.
Plain English
It's a single small probe sticking out of the airplane that measures two kinds of air pressure at once: the pressure pushing against the front of the aircraft as it flies, and the still pressure of the surrounding air. Those two readings drive the airspeed, altitude, and climb/descent instruments.
Context Anchor
Seen during preflight inspection and in discussions of the instruments that depend on outside air pressure, especially the airspeed indicator.
Derivation
Pitot is named after Henri Pitot, the 18th-century French engineer who invented the forward-facing tube to measure flowing fluid pressure. Static comes from Latin staticus, meaning 'standing still' — referring to the calm, undisturbed air pressure being measured. Head here means the sensing end or fitting of the device, like the head of a tool.
Why Pilots Care
Blockages or damage here produce false airspeed and altitude readings that can lead to loss of control in instrument conditions.
Intuition Check
Do not read “head” as a computer or brain of the system. Here it means the outside sensing probe that collects air pressure.
Example Sentence 1
During preflight, the pilot removed the cover from the pitot-static head and checked that the openings were clear of debris.
Example Sentence 2
A blocked pitot-static head caused the airspeed indicator to read zero during the approach.