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Submitted By aerosibin
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Density altitude
• The efficiency of the propeller or rotor — which for a propeller (effectively an airfoil) behaves similarly to lift on wings.
• The power output of the engine — power output depends on oxygen intake, so the engine output is reduced as the equivalent “dry air” density decreases and produces even less power as moisture displaces oxygen in more humid conditions.
Aircraft taking off from a "hot and high" airport such as the Quito Airport or Mexico City are at a significant aerodynamic disadvantage. The following effects result from a density altitude which is higher than the actual physical altitude:[2]
• The aircraft will accelerate slower on takeoff as a result of reduced power production.
• The aircraft will need to achieve a higher true airspeed to attain the same lift - this implies both a longer takeoff roll and a higher true airspeed which must be maintained when airborne to avoid stalling.

Density Altitude Computation Chart[1]

Density altitude is the altitude relative to the standard atmosphere conditions (ISA) at which the air density would be equal to the indicated air density at the place of obser• The aircraft will climb slower as the result of revation. In other words, density altitude is air density given duced power production and lift. as a height above mean sea level. “Density altitude” can also be considered to be the pressure altitude adjusted for
Due to these performance issues, a plane’s takeoff weight non-standard temperature. may need to be lowered or takeoffs may need to be schedBoth an increase in temperature, decrease in atmospheric uled for cooler times of the day. Wind direction and pressure, and, to a much lesser degree, increase in runway slope may need to be taken into account. humidity will cause an increase in density altitude. In hot and humid conditions, the density altitude at a particular…...

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