Which statement about the pitot tube is correct?

• A. Inside the cabin, used to measure humidity
• B. In the tail, used for navigation
• C. A device measuring cabin temperature
• D. On the outside of the fuselage used to indicate airspeed; it is heated

Answer: (D)

The pitot tube is a sensing probe mounted on the outside of the aircraft to sample undisturbed air and measure dynamic pressure. This pressure, combined with the static pressure from the aircraft’s static ports, feeds the airspeed indicator to show airspeed. It must be located outside so it isn’t affected by the aircraft’s body and is heated to prevent ice from forming, which would block the opening and give false readings. The other descriptions describe cabin sensors or tail/navigation equipment that don’t measure airspeed, so this outside, heated probe that indicates airspeed is the correct concept.