Geometric Altitude for EGPWS

Geometric Altitude for EGPWS

Geometric Altitude is a computed aircraft altitude designed to help ensure optimal operation of the EGPWS Terrain Awareness and Display functions through all phases of flight and atmospheric conditions. Geometric Altitude uses an improved pressure altitude calculation, GPS Altitude, Radio Altitude, and Terrain and Runway elevation data to reduce or eliminate errors potentially induced in Corrected Barometric Altitude by temperature extremes, non-standard altitude conditions, and altimeter miss-sets. Geometric Altitude also allows continuous EGPWS operations in QFE environments without custom inputs or special operational procedures. Since no single sensor can provide an accurate geometric altitude through all phases of flight and atmospheric conditions, the EGPWS computes an estimated average altitude using Pressure and GPS Altitudes, aircraft position, and the internal runway and terrain databases. This is the Geometric Altitude function.