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  2. Pressure altitude - Wikipedia

    en.wikipedia.org/wiki/Pressure_altitude

    It indicates altitude obtained when an altimeter is set to an agreed baseline pressure under certain circumstances in which the aircraft’s altimeter would be unable to give a useful altitude readout. Examples would be landing at a high altitude or near sea level under conditions of exceptionally high air pressure.

  3. International Standard Atmosphere - Wikipedia

    en.wikipedia.org/wiki/International_Standard...

    The equation that relates the two altitudes are (where z is the geometric altitude, h is the geopotential altitude, and r 0 = 6,356,766 m in this model): = Note that the Lapse Rates cited in the table are given as °C per kilometer of geopotential altitude, not geometric altitude.

  4. U.S. Standard Atmosphere - Wikipedia

    en.wikipedia.org/wiki/U.S._Standard_Atmosphere

    Comparison of the 1962 US Standard Atmosphere graph of geometric altitude against air density, pressure, the speed of sound and temperature with approximate altitudes of various objects. [ 1 ] The U.S. Standard Atmosphere is a static atmospheric model of how the pressure , temperature , density , and viscosity of the Earth's atmosphere change ...

  5. Flight level - Wikipedia

    en.wikipedia.org/wiki/Flight_level

    Therefore, a pressure altitude of 32,000 ft (9,800 m) is referred to as "flight level 320". In metre altitudes the format is Flight Level xx000 metres. Flight levels are usually designated in writing as FLxxx, where xxx is a two- or three-digit number indicating the pressure altitude in units of 100 feet (30 m). In radio communications, FL290 ...

  6. Barometric formula - Wikipedia

    en.wikipedia.org/wiki/Barometric_formula

    Pressure as a function of the height above the sea level. There are two equations for computing pressure as a function of height. The first equation is applicable to the atmospheric layers in which the temperature is assumed to vary with altitude at a non null lapse rate of : = [,, ()] ′, The second equation is applicable to the atmospheric layers in which the temperature is assumed not to ...

  7. Altimeter setting - Wikipedia

    en.wikipedia.org/wiki/Altimeter_setting

    SPS/STD - 'Standard Pressure Setting' or just 'Standard' refers to the altimeter being set to the standard pressure of 1013.25 hPa. It is the setting that causes an altimeter to read the aircraft's flight level (FL). Flight levels are given in hundreds of feet (for example: FL100 = 10 000 ft). Atmospheric pressure changes over time and position.

  8. Standard temperature and pressure - Wikipedia

    en.wikipedia.org/wiki/Standard_temperature_and...

    In aeronautics and fluid dynamics the "International Standard Atmosphere" (ISA) is a specification of pressure, temperature, density, and speed of sound at each altitude. At standard mean sea level it specifies a temperature of 15 °C (59 °F), pressure of 101,325 pascals (14.6959 psi) (1 atm ), and a density of 1.2250 kilograms per cubic meter ...

  9. Reference atmospheric model - Wikipedia

    en.wikipedia.org/wiki/Reference_atmospheric_model

    Typical usages are as a basis for pressure altimeter calibrations, aircraft performance calculations, aircraft and rocket design, ballistic tables, and meteorological diagrams." [1] For example, the U.S. Standard Atmosphere derives the values for air temperature, pressure, and mass density, as a function of altitude above sea level.