Is intended for use in the calibration of aneroid/manometer type instruments used by aircraft and in laboratory tests. Consists of six tables which relate geopotential altitude to atmospheric pressure: geopotential altitude as function of barometric pressure between 5 and 1 2OO kPa and between 5 and 900 mmHg and barometric pressure in hectopascals and in millimetres of mercury as a function of geopotential altitude for altitudes between -1 000 and +4 600 m above sea level.