Static pressure is the pressure of air that is still or not moving, measured perpendicular to the surface of the aircraft.

• A. Pressure caused by the motion of air.
• B. The difference between total and dynamic pressure.
• C. The pressure inside the cabin.
• D. Pressure of air that is still or not moving, measured perpendicular to the surface of the aircraft.

Answer: (D)

Static pressure is the ambient air pressure—the pressure of the air as if it were at rest relative to the aircraft. It represents the force the air exerts on surfaces in all directions and is read through ports designed to sense pressure perpendicular to the aircraft’s surface, minimizing the influence of the wind sliding past. This is distinct from dynamic pressure, which comes from the air’s motion and increases with speed, and from total pressure, which is the sum of static and dynamic pressures. While the relationship Pt = Ps + q shows how static relates to total and dynamic pressures, the statement that static pressure is the pressure of air that is still or not moving, measured perpendicular to the surface, best captures the practical meaning and measurement of static pressure.