Plain English Meaning

Pumping air into the cabin so it stays denser than the thin air outside, letting people breathe and feel okay at high altitudes.

Full Definition

The process of maintaining a higher air pressure inside an aircraft cabin than the outside atmospheric pressure at altitude, allowing occupants to breathe normally and remain comfortable during flight at altitudes where the outside air is too thin to support normal respiration.

Context Anchor

Seen in high-altitude aircraft systems and in air data computer discussions where outside air pressure must be measured accurately.