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High measuring precisions, temperature compensation, linear dialgaugegradations, insensitive to shock and vibration, simple zero adjustement.
Altimeters measure static air pressure, which decreases with altitude. The pressure-sensitive measuring element is a diaphragm capsule from which the air has been removed (aneroid capsule), which reacts to the effect of changing air pressure as the aircraft changes altitude. Tempered, aged copper-beryllium diaphragms ensure highly accurate readings. Diaphragm movement is transmitted to the instrument pointers by a linkage and gearwheels – the whole is insensitive to shock and vibration. A bimetal link compensates the effects of temperature change.