What are the three primary instruments associated with the Pitot-Static System?

The Pitot-Static System is crucial for supplying information about an aircraft's performance, specifically altitude and airspeed. The three primary instruments associated with this system are indeed the altimeter, vertical speed indicator (VSI), and airspeed indicator.

The altimeter uses static air pressure to determine the aircraft's altitude above sea level. It measures the external air pressure, which decreases with altitude, allowing pilots to gauge their altitude accurately.

The VSI measures the rate of climb or descent, providing information on how quickly the aircraft is gaining or losing altitude. This instrument also relies on static air pressure, reacting to changes in the pressure caused by climbs and descents.

The airspeed indicator measures the speed of the aircraft relative to the surrounding air. It uses both information from the Pitot tube, which measures dynamic pressure from the air entering the tube, and static pressure from the static ports to calculate the indicated airspeed.

Thus, the correct choice encompasses the key instruments that rely on the information from the Pitot-Static System to provide critical flight data to the pilot.