What is the purpose of the aircraft's altimeter?

The altimeter is an essential instrument in aviation that serves the primary function of measuring the altitude of the aircraft above sea level. It achieves this by using changes in air pressure; as an aircraft ascends, the atmospheric pressure decreases, and this change is translated by the altimeter into altitude readings. Understanding altitude is crucial for pilots to maintain safe flight levels, comply with air traffic control regulations, and ensure safe clearance over terrain and obstacles.

By providing pilots with accurate altitude information, the altimeter plays a vital role in navigation, especially during climbs, descents, and landings. This information also assists in maintaining proper separation from other aircraft and adhering to airspace regulations, particularly when flying at higher altitudes. Therefore, the primary purpose of the altimeter helps ensure the safety and efficiency of flight operations.