Understanding Altitude: Difference between revisions

Understanding Altitude (view source)

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 ==== Pressure Altitude ====
-'''Pressure''' altitude is a reading on an your [[Instruments/altimeter|altimiter]]. When you reset it to 29.92 inHg, which is the ''International Standard Atmosphere'' ('''ISA''') pressure for ''mean sea level''. In [[flight levels]], often, but not always, above 18,000 ft '''MSL'''. Pilots are required to set their altimeters to ISA and fly by pressure altitude. 18,000 feet above a beach is very high so this is a way to calculate it.
+'''Pressure''' altitude is the altitude shown on an aircraft [[Instruments/altimeter|altimeter]] when it is set to the ''International Standard Atmosphere'' ('''ISA''') standard pressure" (29.92 inches of Mercury).  When flying in Class-A airspace (above 18,000 MSL) pilots are required to set their altimeters to ISA, and fly at a "flight level" assigned by Air Traffic Controllers.  Using this standard setting helps pilots to maintain more accurate vertical separation between aircraft at higher altitudes.  Pressure altitude is also used to calculate density altitude.
-Pressure altitude is important for altimetry and for calculating density altitude.
 == Density Altitude ==