TAWS. See terrain awareness and warning system.
TCAS. See traffic alert collision avoidance system.
TCH. See threshold crossing height.
Terrain Awareness and Warning System
The movement of an airplane under its own power on the surface of an airport.
(Terrain Awareness and Warning System) An advanced type of GPWS that provides the flight crew earlier aural and visual warning of impending terrain, forward looking capability and continued operation in the landing configuration.
 Sample Warnings from GPWS and EGPWS/TAWS
"WHOOP WHOOP! Pull Up!"
"Too Low, Flaps"
"Too Low, Gear"
"Too Low, Terrain"
"WHOOP WHOOP! Terrain!"
"Windshear, Windshear, Windshear!"
"Sink rate" ...
Terrain Awareness and Warning Systems (TAWS) have been developed with increased capabilities to replace GPWS. In addition, less capable but cost effective TAWS have been developed for the smaller aircraft market.
For those worried about terrain, a Class-B TAWS and detailed topographic maps are included-you pick the scale. Traffic information comes from TIS Mode-S data with provisions for future traffic avoidance technology (like ADS-B).
Terrain awareness and warning system (TAWS)
Threshold crossing height (TCH) ...
See also: Pilot, Speed, Weather, Flight, Warning