What is pressure altitude defined as?

Pressure altitude is defined as the altitude in the standard atmosphere at which a particular pressure is measured. Specifically, it is the altitude corrected for non-standard atmospheric pressure. This means that when the atmosphere does not conform to standard conditions, the pressure altitude gives a more accurate representation of the altitude based on pressure than simply the geometric altitude above mean sea level.

In aviation, pressure altitude is crucial for flight operations, as it impacts aircraft performance, navigation, and safety. This standardized measurement helps pilots and air traffic controllers ensure proper altitude separation and performance calculations.

Thermal variations and the altitude itself can cause discrepancies between the actual altitude and pressure altitude, so understanding this correction is essential for accurate flight operations. The other definitions provided involve concepts that, while related to altitude and flight, do not specifically address the definition of pressure altitude as accurately as the correct answer.