What is a pressure altimeter?
pressure altimeters are devices primarily used in aircraft to measure altitudes. The pressure altimeter is basically just a barometer that has been calibrated to measure the current altitude of the plane rather than barometric pressure. The altimeters must usually be determined by the pilot before take -off and sometimes modified in the flight.
Barometers measure air pressure using mercury, air or sometimes water. Air pressure, also called barometric pressure, is simply the air pressure at a given level. The air particles push the air and on the ground below and create pressure. Therefore, barometric pressure on the sea level is higher than in the mountains. Barometric pressure is not constant, so the pilot will have to adjust the pressure on the sea level at the altimeter before takeoff. There are two ways to set the pressure: the first is Vokno Kollsman, which sets the thumbs of mercury, or the second is to manually adjust the dial on the altimeter to set the current altitude above the sea on the ground floor level. Air traffic controls in the tower generally providePilot correctly set up before take -off.
Many times the change in height does not create a change in the pressure to the sea level, but sometimes there are times when the pressure on the sea level changes from take -off to landing. For example, drastic weather changes cause a change in barometric pressure. If this happens, the pilot must adjust the air pressure on the sea level in the flight to ensure that reading altitude is accurate.
The elevation is mechanical. Its main case is attached to the outside of the plane, while the display on the deduction is inside the cockpit. Reading is similar to an analog speedometer: graded circle, usually marked in hundreds or thousands, along with small plastic indicators that show the real altitude.
Small air valve on the back of the housing allows air to enter the altitude. Mechanical tools called aneroid barometers, expand or download depending on nand air pressure. This movement causes a number of gears, springs and pinion and finally turns the crankshafts connected to the indicators when deducting. The crankshaft shifts these indicators around the dial to show the correct height.
There are several types of errors that relate to when using pressure altimeter. Mechanical errors, scale errors and hysteresis errors are usually caused by a problem with internal gears or material elasticity. Reversal errors and installation or position errors cause fake pressure reading due to air stream problems.