Aircraft Trivia: How do airplanes measure altitude while flying?

 Altimeter is indispensable for safe operation of airplanes

During the flight, a TV monitor in the passenger compartment displays the time required to reach the destination, outside temperature, altitude, and other information.

Passengers see without question that they are now at an altitude of 10,000 meters, etc. How does an airplane measure its altitude in flight in the first place?

There are two main types of altimeters used in airplanes: radio altimeters and high-pressure altimeters. Radio altimeters are used at low altitudes and measure altitude by emitting radio waves toward the ground and receiving back radio waves.

This instrument is very accurate, but it can only be used at altitudes of a few hundred meters.

Therefore, the main device used is a barometric altimeter.

It measures altitude by taking advantage of the atmospheric characteristic that air pressure becomes lower as altitude increases.

Incidentally, the same principle is also used in watches for outdoor use.

However, atmospheric pressure is not always constant.

Barometric altimeters also have some errors, but this is not a problem when operating airplanes.

This is because all airplanes use barometric altimeters, and thus there is uniformity among airplanes.

As long as each aircraft is flying based on the values of the barometric altimeter, there is no problem with safe operation because each aircraft can determine its own altitude.