QNH

QNH is a measurement used by pilots to determine the altitude of an aircraft relative to the average sea level pressure at a specific location. It’s the barometric pressure set on the aircraft’s altimeter so that, when calibrated correctly, the display shows the correct elevation above sea level. This helps pilots compare their altitude to other aircraft and navigation charts. Essentially, QNH standardizes altitude readings by accounting for local atmospheric pressure variations, ensuring safe and accurate altitude measurement during flight operations.