Definition
An onboard system that uses aircraft position, altitude, and a stored terrain and obstacle database to alert the pilot when the aircraft is approaching or in danger of impacting terrain or obstacles. It provides both cautionary and warning alerts, typically through aural callouts and visual displays, and is required equipment on certain turbine-powered aircraft under U.S. regulations.
Plain English
A system in the aircraft that watches where you are flying compared to the ground and tall obstacles, then warns you with sounds and screen alerts if you are getting too close to hitting something.
Context Anchor
Seen in instrument flying, avionics discussions, aircraft equipment lists, and procedures for avoiding terrain when visibility is poor or the pilot cannot see the ground clearly.
Derivation
The name describes the function directly: 'terrain awareness' (knowing where the ground is) plus 'warning system' (alerts the pilot). It is the modern successor to the older Ground Proximity Warning System (GPWS), with added forward-looking capability using a terrain database.
Why Pilots Care
It helps prevent controlled flight into terrain accidents by giving advance warning of rising terrain or obstacles.
Grounding Statement
If the aircraft is descending toward rising ground that the pilot cannot see, TAWS is designed to warn the pilot before the situation becomes unrecoverable.
Intuition Check
TAWS is not just a terrain map. The key idea is warning: it actively alerts the pilot when the aircraft’s path may become unsafe.
Example Sentence 1
As we descended through the clouds toward the airport, the TAWS called out 'CAUTION TERRAIN' and we leveled off until we confirmed our position on the approach.
Example Sentence 2
Pilots rely on TAWS during night instrument flights to maintain safe clearance from obstacles.