What are the three pitot-static instruments?

• A. Airspeed Indicator (ASI), Altimeter, and Vertical Speed Indicator (VSI)
• B. Airspeed Indicator, Attitude Indicator, Turn Coordinator
• C. Altimeter, Heading Indicator, VSI
• D. Attitude Indicator, Turn Coordinator, Altimeter

Answer: (A)

The pitot-static system provides pressure inputs that power a set of instruments used to measure airspeed, altitude, and the rate of climb or descent. The airspeed indicator uses both pitot (ram air) pressure and the static pressure to determine airspeed; the difference between these pressures moves the instrument’s diaphragm to show speed. The altimeter relies on static pressure alone, using it to feed a sealed, aneroid capsule that expands or contracts as pressure changes with altitude, giving you the altitude readout. The vertical speed indicator also uses static pressure, but it’s calibrated to sense how quickly that pressure is changing, so it shows the rate of climb or descent.

Attitude indicator and turn coordinator aren’t pitot-static instruments—they’re gyroscopic instruments that depend on spinning gyros to indicate orientation and turn rate, not pressure measurements from the pitot-static system.