Soar to New Heights with the 2026 Commercial Pilot License (CPL) Practice Exam – Ready for Takeoff!

Pressure altitude is determined by the height above the standard datum plane, which is established as sea level with an air pressure of 29.92 inches of mercury (Hg). When an altimeter is set to this standard pressure setting, it reads the altitude at which the atmospheric pressure equals 29.92 inches of Hg. This measurement is critical in aviation, especially for determining aircraft performance and navigational purposes, as it provides a consistent reference for pilots operating at various altitudes and in different weather conditions.

The use of the standard pressure setting ensures that all aircraft are using the same reference point, facilitating safe distance separation and consistent altitude reporting among aircraft in flight. This also means that pressure altitude can vary based on ambient air pressure conditions; therefore, adjusting the altimeter to 29.92 in. Hg provides a reliable and uniform method to communicate and understand aircraft altitude.