Define static pressure.

• A. ambient pressure
• B. pressure inside a sealed cabin
• C. ambient pressure at a fixed location
• D. total pressure

Answer: (A)

Static pressure is the ambient atmospheric pressure of the air surrounding the aircraft at its current location. It’s the pressure the air exerts on surfaces perpendicular to the flow and is what the static ports sense to provide the instruments with the undisturbed air pressure. This pressure is outside the airplane (not inside the cabin) and does not include the dynamic effect of the aircraft’s motion. The total pressure, by contrast, combines this static pressure with dynamic pressure from the speed of the aircraft. So describing static pressure as ambient pressure best captures the idea of the surrounding air’s pressure at the aircraft’s location.