What is Altimeter ?

An altimeter is a device used to measure altitude above a specific reference point, usually the Earth’s surface. It’s commonly found in aircraft, both commercial and private, as well as in other applications like hiking and mountaineering. Altitude is the vertical distance above a given level, often measured in feet or meters.

In aircraft, altimeters are crucial instruments for navigation and maintaining safe flight levels. They work based on the principle that atmospheric pressure decreases with increasing altitude. A typical altimeter uses an aneroid barometer, which consists of a sealed chamber with a flexible diaphragm inside. As the aircraft ascends or descends, the difference in atmospheric pressure between the outside air and the sealed chamber causes the diaphragm to expand or contract, moving mechanical linkages that drive the display on the altimeter.

To ensure accurate altitude readings, pilots often need to adjust the altimeter setting based on the current atmospheric pressure. This setting is usually obtained from air traffic control or automated weather stations and is used to calibrate the altimeter to a standard reference level (usually sea level), allowing pilots to accurately determine their altitude above the Earth’s surface.

Altimeters play a crucial role in aviation safety and navigation, helping pilots maintain proper altitude separation from terrain and other aircraft, especially during takeoff, landing, and during flight in changing weather conditions.