What is the function of an altimeter?

The function of an altimeter is to measure the aircraft's altitude by comparing the atmospheric pressure inside the altimeter to a preset standard pressure. This is accomplished through the principles of barometric pressure; as the aircraft ascends or descends, the external air pressure changes. The altimeter detects these pressure changes and translates them into altitude readings based on the standard atmosphere model, which defines how pressure decreases with altitude.

This operation is crucial for pilots, as maintaining and verifying altitude is essential for safe navigation, avoiding obstacles, and complying with air traffic control regulations. The altimeter serves as a vital instrument in a pilot's cockpit, providing real-time data that helps ensure safety during all phases of the flight.