Which system provides ram air pressure for the airspeed indication?

• A. Pitot-static system
• B. Total air temperature probe
• C. Static port
• D. Airspeed indicator

Answer: (A)

The main idea is that airspeed indication comes from dynamic (ram) pressure captured by the pitot tube as the airplane moves. As air flows into the pitot tube, it creates impact pressure, which is sent to the airspeed indicator. The static port provides the reference ambient pressure, and the airspeed indicator responds to the difference between the pitot (ram) pressure and static pressure to display speed. The total air temperature probe measures temperature, not pressure used for airspeed. The static port alone doesn’t provide ram pressure, and the airspeed indicator is the display, not the pressure source. So the pitot-static system provides the ram air pressure used for the airspeed indication.