Which instrument's readings are fundamentally based on pitot pressure in a sailplane?

• A. Airspeed indicator
• B. Vertical speed indicator
• C. Altimeter
• D. Turn coordinator

Answer: (A)

Pit's pressure concept is about stagnation pressure from air hitting a forward-facing opening. The airspeed indicator uses that stagnation pressure from the pitot tube and compares it to the ambient static pressure from the static port. The difference between the two pressures is dynamic pressure, which increases with speed. The instrument is calibrated to translate this dynamic pressure into indicated airspeed.

Left with just static pressure, the vertical speed indicator measures how quickly the pressure changes as you climb or descend; the altimeter uses static pressure to show altitude; the turn coordinator relies on a gyroscope to indicate rate of turn, not pressure readings. So the reading tied directly to pitot pressure is the airspeed indicator.