What is GPWS and how does it work?

GPWS relied on the airplane’s radio altimeter, which determines the aircraft’s altitude by bouncing a radar signal off the ground and measuring the duration of the signal’s round trip. TAWS uses the Global Positioning System to determine the aircraft’s position, ground speed, and ground track.

How does a radio altimeter work?

Early radio altimeters determined altitude by measuring the time between transmission of a radio signal from the aircraft and reception of the reflected signal. Modern systems use other means, for example, measurement of the change of phase between the transmitted and reflected signal.

How does the radar altimeter operate?

The system transmits radio waves down to the ground and measures the time it takes them to be reflected back up to the aircraft. The altitude above the ground is calculated from the radio waves’ travel time and the speed of light.

What are GPWS callouts?

GPWS callouts are aural alerts that are played through speakers in the cockpit to warn pilots about potential flight into terrain. The EGPWS Caution Callouts are: “Terrain Terrain”, “Too Low Terrain”, “Terrain Ahead”, “Obstacle Ahead”, Sink Rate, Sink Rate”, “Too Low – Gear”, “Too Low – Flaps”, and “Glide Slope”.

What are altimeters used for?

An altimeter is a device that measures altitude—a location’s distance above sea level. Most altimeters are barometric, meaning they measure altitude by calculating the location’s air pressure. Air pressure decreases as altitude increases.

What is the purpose of GPWS?

The Ground Proximity Warning System (GPWS) generates advisory Alerts and mandatory response Warnings to the flight crew in respect of their proximity to terrain.

How does predictive windshear work?

The predictive windshear system uses the weather radar to detect where there is a doppler shift in the precipitation ahead of the airplane. If there is a significant shift measured, it warns the pilots. (Typically, a downburst spreads out when reaching the ground and can cause windshear.