TAWS uses a GPS positioning and a database of terrain and obstructions to provide true predictability of upcoming terrain and obstacles. Which data source best describes TAWS?

• A. Weather radar data only
• B. Ground-based navigation aids only
• C. GPS positioning and terrain/obstruction database
• D. Pilot reports only

Answer: (C)

TAWS determines terrain awareness by knowing exactly where the airplane is and what terrain or obstacles lie ahead, then predicting what will be ahead along the flight path. It does this by using the aircraft’s GPS position to determine location and a digital terrain/obstacle database to know elevations and obstacles. With that data, the system can forecast potential conflicts and alert the pilot before they are reached. Weather radar data shows weather, not terrain; ground-based navigation aids help locate the aircraft but don’t supply the terrain database itself; pilot reports aren’t reliable for real-time terrain prediction. So the combination of GPS positioning and a terrain/obstruction database best describes TAWS.