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QFE - is the barometric altimeter setting that causes an altimeter to read zero when at the reference datum of a particular airfield (in practice, the reference datum is either an airfield center or a runway threshold). In ISA temperature conditions the altimeter will read the height above the airfield/runway in the vicinity of the airfield.
Diagram showing the face of the "three-pointer" sensitive aircraft altimeter displaying an altitude of 10,180 ft (3,100 m). 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]
A chart showing how much the true altitude of an aircraft is below the altimeter reading ("indicated altitude") without correcting for temperature. The colder the ambient temperature, the lower the plane is — thus the saying "From hot to cold, look out below". [8] Modern aircraft use a "sensitive altimeter".
Altitude is a vertical measurement between a reference datum and an object. Altitude is a distance measurement, usually in the vertical or "up" direction, between a reference datum and a point or object. The exact definition and reference datum varies according to the context (e.g., aviation, geometry, geographical survey, sport, or atmospheric ...
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.
The tropospheric tabulation continues to 11,000 meters (36,089 ft), where the temperature has fallen to −56.5 °C (−69.7 °F), the pressure to 22,632 pascals (3.2825 psi), and the density to 0.3639 kilograms per cubic meter (0.02272 lb/cu ft). Between 11 km and 20 km, the temperature remains constant.
Geopotential height differs from geometric height (as given by a tape measure) because Earth's gravity is not constant, varying markedly with altitude and latitude; thus, a 1-m geopotential height difference implies a different vertical distance in physical space: "the unit-mass must be lifted higher at the equator than at the pole, if the same ...
The shadow square, also known as an altitude scale, [1] was an instrument used to determine the linear height of an object, in conjunction with the alidade, for angular observations. An early example was described in an Arabic treatise likely dating to 9th or 10th-century Baghdad . [ 2 ]