Title: Describe various types of altitude as related to aircraft.
Course: Aircraft Pilot Training I (20053-I) > Section: Examining Aircraft Instruments, Components, Systems, and Performance

Description should include the concept that pilots are mainly concerned with five types of altitude:

- Indicated altitude—read directly from the altimeter (uncorrected) when it is set to the current altimeter setting.
- True altitude—the vertical distance of the aircraft above sea level—the actual altitude; it is often expressed as feet above mean sea level (MSL). Airport, terrain, and obstacle elevations on aeronautical charts are true altitudes.
- Absolute altitude—the vertical distance of an aircraft above the terrain, or above ground level (AGL)
- Pressure altitude—the altitude indicated when the altimeter setting window (barometric scale) is adjusted to 29.92" Hg. This is the altitude above the standard datum plane, which is a theoretical plane where air pressure (corrected to 15 °C) equals 29.92" Hg. Pressure altitude is used to compute density altitude, true altitude, true airspeed (TAS), and other performance data.
- Density altitude—pressure altitude corrected for variations from standard temperature

PLT023