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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. 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 ...

  4. Pressure altimeter - Wikipedia

    en.wikipedia.org/wiki/Pressure_altimeter

    The greater the altitude, the lower the pressure. When a barometer is supplied with a nonlinear calibration so as to indicate altitude, the instrument is a type of altimeter called a pressure altimeter or barometric altimeter. A pressure altimeter is the altimeter found in most aircraft, and skydivers use wrist-mounted versions for similar ...

  5. Altimeter setting - Wikipedia

    en.wikipedia.org/wiki/Altimeter_setting

    TA [3] - Transition Altitude - altitude at which the pilot changes the aircraft's altimeter setting (usually from QNH) to standard pressure (1013.25 hPa) TL - Transition Level - the lowest flight level available for use above the transition altitude; TLY - Transition Layer - the airspace between the transition altitude and the transition level

  6. Flight level - Wikipedia

    en.wikipedia.org/wiki/Flight_level

    In aviation, a flight level (FL) is an aircraft's altitude as determined by a pressure altimeter using the International Standard Atmosphere. It is expressed in hundreds of feet or metres. The altimeter setting used is the ISA sea level pressure of 1013 hPa or 29.92 inHg. The actual surface pressure will vary from this at different locations ...

  7. Altimeter - Wikipedia

    en.wikipedia.org/wiki/Altimeter

    Reference pressure of about 29.92 inHg (1013 hPa) is showing in the Kollsman window. An altimeter or an altitude meter is an instrument used to measure the altitude of an object above a fixed level. [1] The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth under water.

  8. QFF - Wikipedia

    en.wikipedia.org/wiki/QFF

    QFF is derived from the barometric pressure at the station location by calculating the weight of an imaginary air column, extending from the location to sea level, assuming the temperature and relative humidity at the location are the long term monthly mean, the temperature lapse rate is according to ISA and the relative humidity lapse rate is ...

  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.