Differential pressure refers to which of the following?

• A. A difference between two pressures
• B. The angle between the wing and fuselage
• C. A weather briefing system
• D. An oxygen delivery method

Answer: (A)

Differential pressure is the difference between two pressures. In aviation, this concept shows up in a couple of key ways. For example, the airspeed indicator relies on the difference between pitot (total) pressure and static pressure to determine dynamic pressure and thus airspeed. Another important use is cabin pressurization, where the pressure inside the cabin is kept higher than outside; the aircraft must withstand that pressure difference, which is called the cabin differential pressure. Those are both about comparing two pressures to get a useful measurement or ensure safe operation.

The other descriptions don’t fit—an angle between the wing and fuselage is a geometric orientation, a weather briefing system is about information delivery, and an oxygen delivery method concerns how oxygen is supplied.