Which statement about pitot-static system pressures is true?

• A. The system reads total pressure only
• B. The system uses static pressure and dynamic pressure
• C. The system uses ambient pressure only
• D. The system uses dynamic pressure only

Answer: (B)

The key idea is that airspeed is determined from dynamic pressure, which comes from the difference between total (pitot) pressure and static (ambient) pressure. The pitot tube supplies total pressure, while the static ports supply ambient pressure. The airspeed indicator uses the difference between those two pressures, meaning the system relies on both static pressure and the dynamic pressure that results from motion. Therefore, the statement that the system uses static pressure and dynamic pressure best describes how it works, since dynamic pressure is essentially the portion used to indicate speed (derived from total minus static). It’s not just ambient pressure alone, and it isn’t only dynamic pressure directly, nor is it merely total pressure in isolation.