Definition
The flight instruments that derive their indications from the aircraft's pitot-static system, which senses ram air pressure (from the pitot tube) and ambient static pressure (from static ports). The three standard pitot-static instruments are the airspeed indicator, the altimeter, and the vertical speed indicator.
Plain English
These are the cockpit instruments that work by measuring outside air pressure. They tell the pilot how fast the airplane is going, how high it is, and whether it is climbing or descending.
Context Anchor
You encounter pitot static instruments during preflight checks, normal cockpit scanning, and troubleshooting when airspeed, altitude, or climb/descent readings do not look right.
Derivation
Pitot is named after Henri Pitot, the 18th-century French engineer who designed the tube that measures the pressure of moving air. Static simply means 'still' -- in this case, the still air pressure surrounding the aircraft. Together, the two pressures drive the instruments.
Why Pilots Care
These instruments supply the pilot with essential speed, height, and climb information that is required for safe takeoff, cruise, approach, and landing.
Intuition Check
Do not read “static” as meaning the instruments are inactive or not moving. In this term, “static” means the outside air pressure around the airplane, separate from the pressure caused by forward motion.
Example Sentence 1
During the preflight, the pilot checked that the pitot tube cover was removed and the static ports were clear so the pitot static instruments would read correctly.
Example Sentence 2
Before flight the instructor had the student check the pitot static instruments for correct readings on the ground.