How is density altitude defined?

Density altitude is defined as pressure altitude corrected for non-standard temperature. This concept is crucial for pilots as it directly affects aircraft performance, including takeoff and landing distances, climb rates, and engine performance.

When the temperature deviates from the standard atmosphere, it affects how dense the air is at a given altitude. Higher temperatures result in less dense air, which means that the aircraft will not perform as efficiently. By using the pressure altitude value and adjusting it based on the current temperature, pilots can determine the density altitude. This more accurately reflects the aircraft's performance capabilities in the current atmospheric conditions.

In contrast, the other choices do not correctly describe density altitude. Altitude corrected for airspeed or weight, and altitude at sea level only do not factor in the essential relationship between temperature and air density, which is vital for understanding aircraft performance in varying conditions.