Editing Density altitude (section)

==Aircraft safety==

Air density is perhaps the single most important factor affecting aircraft performance. It has a direct bearing on:<ref name="A">AOPA Flight Training, Volume 19, Number 4; April 2007; Aircraft Owners and Pilots Association; {{ISSN|1047-6415}}</ref>
* The efficiency of a propeller or rotor – which for a propeller (effectively an [[airfoil]]) behaves similarly to lift on a wing.
* The power output of a normally-aspirated engine – the power output depends on the oxygen intake, so the engine output is reduced as the equivalent dry-air density decreases, and it produces even less power as moisture displaces oxygen in more humid conditions.

Aircraft taking off from a “[[hot and high]]” airport, such as the [[Mariscal Sucre International Airport|Quito Airport]] or [[Mexico City International Airport|Mexico City]], are at a significant [[aerodynamic]] disadvantage. The following effects result from a density altitude that is higher than the actual physical altitude:<ref name="A" />
* An aircraft will accelerate more slowly on takeoff as a result of its reduced power production.
* An aircraft will climb more slowly as a result of its reduced power production.

Due to these performance issues, an aircraft's takeoff weight may need to be lowered, or takeoffs may need to be scheduled for cooler times of the day. The wind direction and the [[runway]] slope may need to be taken into account.