If the outside air temperature is higher than standard for a given pressure altitude, is density altitude higher or lower than pressure altitude?

• A. Higher
• B. Lower
• C. The same
• D. Not affected

Answer: (A)

Warmer-than-standard air reduces air density at a given pressure altitude. Density altitude is the altitude in the standard atmosphere that would have the same air density as the current air. Since higher outside air temperature lowers density, the current density matches a higher altitude in the standard atmosphere. So the density altitude is higher than the pressure altitude. In practice, this means aircraft performance behaves as if you were at a higher elevation: reduced engine and aerodynamic performance, longer takeoff distances, and slower climb. If the temperature were cooler than standard, density altitude would be lower than the pressure altitude.