Altimeter: What instrument is a barometer that calculates height above ground level?

Altimeter: What instrument is a barometer that calculates height above ground level?

• A. Altimeter
• B. Airspeed Indicator
• C. Vertical Speed Indicator
• D. Altitude Indicator

Answer: (A)

An altimeter is essentially a sealed barometer that converts ambient air pressure into an altitude reading. As you climb, the surrounding pressure drops, and the instrument uses that pressure change to display how high you are. It’s calibrated with the local pressure setting (QNH) so the readout corresponds to altitude above mean sea level, and you can determine height above ground by subtracting the airport elevation from that value. This is why the altimeter fits the description best: it directly uses atmospheric pressure to calculate altitude. The other instruments measure different things—airspeed, rate of climb/descent, or are simply different terms for a similar device—so they don’t match the barometric altitude function.

An altimeter is essentially a sealed barometer that converts ambient air pressure into an altitude reading. As you climb, the surrounding pressure drops, and the instrument uses that pressure change to display how high you are. It’s calibrated with the local pressure setting (QNH) so the readout corresponds to altitude above mean sea level, and you can determine height above ground by subtracting the airport elevation from that value. This is why the altimeter fits the description best: it directly uses atmospheric pressure to calculate altitude. The other instruments measure different things—airspeed, rate of climb/descent, or are simply different terms for a similar device—so they don’t match the barometric altitude function.