(aviation) A usually-unintentional crash of an aircraft in which the aircraft flies into the ground while under full control by its pilots or autopilot.

plural of controlled flight into terrain

plural of all-terrain vehicle

A motor car or motorcycle that is designed to operate on rough ground, and is not necessarily street-legal

(radio) The height of a radio transmitter, including the antenna, as compared to the average terrain height in the surrounding area between three and sixteen kilometers from the antenna site.

plural of height above average terrain

(aviation) An onboard system used to avoid controlled flight into terrain (CFIT).

plural of terrain awareness and warning system