Editing Hot and high (section)

{{Short description|Condition of low air density}}
{{Refimprove|date=September 2014}}
[[File:Hot and high takeoff.png|thumb|440px]]

In [[aviation]], '''hot and high''' is a condition of low [[air density]] due to high [[ambient temperature]] and high airport [[elevation]]. Air density decreases with increasing temperature and altitude. The lower air density reduces the power output from an [[aircraft engine|aircraft's engine]] and also requires a higher [[true airspeed]] before the aircraft can become airborne. Aviators gauge air density by calculating the [[density altitude]].<ref>https://www.faasafety.gov/files/gslac/library/documents/2011/Aug/56396/FAA%20P-8740-02%20DensityAltitude{{Dead link|date=January 2020 |bot=InternetArchiveBot |fix-attempted=yes }}[hi-res]%20branded.pdf</ref>

An airport may be especially hot ''or'' high, without the other condition being present. Temperature and [[pressure altitude]] can change from one hour to the next. The fact that temperature generally decreases as altitude increases mitigates the "hot and high" effect to a small extent.