What type of air pressure is used to describe the cabin pressure altitude during a flight?

Cabin pressure altitude during a flight is described using absolute pressure. This is because cabin pressure is typically a measure of the actual atmospheric pressure of the air within the cabin at a given altitude, rather than a comparison to the surrounding pressure. Absolute pressure provides a true value that reflects the total pressure exerted by the atmosphere, which is critical when maintaining comfortable and safe conditions for passengers and crew during flight.

Using absolute pressure allows for a consistent reference point regardless of external atmospheric conditions, aiding in accurately setting and maintaining cabin pressure at levels that support passenger health and comfort. This understanding is vital for flight safety and operational efficiency, as it informs decisions regarding altitude assignments and pressurization requirements throughout the flight.