In GPWS, which system is among those monitored in the landing configuration?

In GPWS, which system is among those monitored in the landing configuration?

• A. Pitot static system
• B. Gyroscopic instruments
• C. Magnetic compass
• D. Radar altimeter

Answer: (D)

The key idea is that GPWS needs a reliable height reference above the terrain, especially during approach and landing. The radar altimeter provides that exact information: height above the ground. With this input, GPWS can assess how close you are to the terrain and whether you’re descending too rapidly, triggering warnings or advisories appropriate for the landing phase. Other sensors don’t give the required terrain-proximity information in the landing setup. The pitot-static system measures airspeed and altitude relative to the atmosphere, not height above the ground, which is critical once you’re near the surface. Gyroscopic instruments and the magnetic compass relate to attitude and heading, not the distance to terrain. So the radar altimeter is the system monitored in the landing configuration because it directly informs GPWS about your closeness to the ground and helps prevent controlled flight into terrain.

The key idea is that GPWS needs a reliable height reference above the terrain, especially during approach and landing. The radar altimeter provides that exact information: height above the ground. With this input, GPWS can assess how close you are to the terrain and whether you’re descending too rapidly, triggering warnings or advisories appropriate for the landing phase.

Other sensors don’t give the required terrain-proximity information in the landing setup. The pitot-static system measures airspeed and altitude relative to the atmosphere, not height above the ground, which is critical once you’re near the surface. Gyroscopic instruments and the magnetic compass relate to attitude and heading, not the distance to terrain. So the radar altimeter is the system monitored in the landing configuration because it directly informs GPWS about your closeness to the ground and helps prevent controlled flight into terrain.