What is pressure altitude?

• A. The altitude indicated when the barometric pressure scale is set to 29.92.
• B. The altitude above sea level.
• C. The altitude corrected for humidity.
• D. The altitude indicated when QNH is used.

Answer: (A)

Pressure altitude is the altitude shown on the altimeter when the barometric pressure scale is set to the standard value of 29.92 inches of mercury. That fixed setting corresponds to the standard datum plane in the International Standard Atmosphere, so the reading represents how high you are above that plane, regardless of the actual sea-level pressure at your location. This makes pressure altitude a stable reference for flight levels and performance planning, independent of local weather conditions.

So the statement that matches is the one describing the altitude indicated when the altimeter is set to 29.92. The other ideas describe altitude above mean sea level (which uses the local QNH setting), or density altitude (which accounts for temperature and humidity), rather than pressure altitude.