What is density altitude?

Density altitude is defined as pressure altitude corrected for nonstandard temperature. This concept is crucial for pilots because it significantly affects aircraft performance. As temperature increases, the density of the air decreases, which means that for a given pressure altitude, the actual density of the air is lower than standard conditions. This has direct implications for takeoff distance, climb performance, and engine efficiency, as lower air density results in reduced aircraft performance.

When determining density altitude, pilots use the current pressure altitude and apply a correction based on the actual temperature compared to the standard temperature at that pressure altitude. This process allows them to identify how high the aircraft will perform in terms of the air density it will encounter, thus ensuring safer and more effective flight operations.

In contrast, pressure altitude is simply the height above the standard datum plane, not accounting for temperature variations. Air pressure being standard or altitude being measured in a vacuum environment does not accurately reflect the conditions pilots deal with in actual flying scenarios, which are influenced by temperature variations.