On what principle does the altimeter operate?

The altimeter operates on the principle of measuring changes in atmospheric pressure. As an aircraft ascends, the pressure decreases; conversely, as it descends, the pressure increases. The altimeter is designed to detect these variations in pressure and translate them into altitude readings.

The altimeter's operation relies on the standard atmospheric model, which assumes a predictable decrease in pressure with an increase in altitude under normal atmospheric conditions. By calibrating the altimeter to a known pressure at sea level (often referred to as altimeter setting), pilots can accurately determine their altitude above sea level or above ground level.

Understanding this principle is essential for pilots because maintaining awareness of altitude is critical for navigation, terrain avoidance, and adherence to air traffic control instructions. The ability to interpret and respond to altitude readings directly impacts flight safety and aircraft performance.