![]() The atmosphere is in a constant state of flux due to global and local weather phenomena. Local temperature variations: higher temperatures are associated with lower air density, and cooler temperatures with higher air density.Higher pressures result in more dense air and lower pressures less dense air. Local pressure variations: regions of high and low pressure associated with local weather phenomena result in density variations.Altitude: An increase in altitude results in a decrease in air density with a corresponding drop in static pressure and temperature.Humidity also has an effect on the air density but to a lesser extent. These are altitude, local pressure variations, and local temperature variations. Factors Affecting Air DensityĪir density is driven by three primary factors. Losses in aircraft performance are most noticable during takeoff and climb out at high altitudes, and on hot days. Propeller driven aircraft will see an additional loss in thrust due to a drop in air density as a result of the propeller being unable to extract as much thrust at a given RPM (a propeller acts in the same way as a wing with an airfoil section designed to generate a force due to the pressure variation over the upper and lower surfaces).A drop in air density results in a loss in power generated by the engine (especially true in normally aspirated general aviation aircraft engines).A drop in air density results in less lift being produced by a wing at a given airspeed and angle of attack.Conversly, a reduction in the air density results in less engine power being produced, and less lift generated by the wings, which will result in a loss in performance at critical phases in flight such as takeoff. ![]() Air Density and Aircraft PerformanceĪn increase in the air density is associated with an improvement in both the aerodynamic performance and the thrust generated by an aircraft. These changes in the local environmental conditions cause associated changes to the air density, which plays a crucial role in determining aircraft performance. Our atmosphere is a dynamic system with variations in pressure, temperature, humidity and precipitation typically seen throughout the day across a relatively small area. The Importance of Density Altitude in Aviation
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