Author: Wg Cdr Rajagopal

Altimetry Height Above Mean Sea Level Mean sea level (MSL) is the reference sea level taking the average of tides MSL is the datum for measuring altitude and elevation Altitude is the vertical distance of a movable object from MSL Elevation is the vertical distance of a point on surface of earth from MSL Altitude and elevation are referred as Above mean sea level (AMSL) Height Above Ground Level Airfield Reference Point (ARP) is the reference point for an airfield Height is the vertical distance from specified datum ARP is…

Pressure Altimeter Introduction to Pressure Altimeter Pressure altimeter is the basic instrument for measuring altitude It is basically an aneroid barometer which measures pressure Altimeter senses change in static air pressure and displays as altitude Principle of Pressure Altimeter Static or atmospheric pressure reduces with height at a non uniform rate This is due to the reduction in weight of air column at higher altitudes Static pressure is also affected by temperature and pressure variations These need to be understood and corrected during height measurement Construction of a Simple Altimeter…

Air Speed Indicator Purpose of Air Speed Indicator Air Speed Indicator is designed to detect dynamic pressure ASI measures dynamic pressure and displays it as air speed Units of measurement are normally Knots or Kilometers per hour Principle of Air Speed Indicator ASI senses Pitot pressure and static pressure Pitot pressure is a combination of dynamic and static Dynamic pressure is obtained by subtracting static pressure Dynamic pressure = Pitot pressure – Static pressure Formula for Dynamic pressure = ½ density x velocity2 Construction of ASI Static pressure is provided…