In aircraft design and aviation, the “Altitude Indicator,” often referred to as the “Altimeter,” is an instrument used to measure and display an aircraft’s altitude above a reference point, typically sea level. Here’s the definition and SI unit for the altimeter in aircraft design:
Formula: The altimeter operates based on the principle that atmospheric pressure decreases with increasing altitude. The instrument contains an aneroid barometer, which is a sealed chamber that expands or contracts as atmospheric pressure changes with altitude. As the aircraft ascends or descends, the aneroid chamber’s size changes, which is translated into an altitude reading on the instrument’s scale.
- Altitude is the aircraft’s indicated altitude above sea level.
- Pressure Altitude is the altitude calculated based on atmospheric pressure, typically in feet or meters.
- Altitude Correction accounts for adjustments based on local atmospheric conditions and any altimeter errors.