Which term describes the air pressure environment around the aircraft used to infer altitude?

• A. Altimeter setting
• B. Ambient pressure
• C. Dynamic pressure
• D. Static pressure

Answer: (B)

Altitude is determined from the pressure of the air surrounding the airplane. The instruments sense the ambient (environmental) pressure in the air around the aircraft through the static ports. As you climb, this surrounding pressure decreases, and the altimeter translates that change into an altitude reading, using a reference to sea level via the altimeter setting. The ambient pressure is the actual input that reflects how high you are. Dynamic pressure, which comes from your speed, doesn’t tell you altitude, and the altimeter setting is just the reference adjustment used to convert that sensed pressure into a usable altitude value.