In aviation, this refers to the ground, mountains, valleys, and other topographical features that an aircraft must avoid. It is a critical factor in navigation, radar systems, and low-altitude flight planning. Pilots rely on specialized warning systems to monitor their clearance above these ground features.
We got a terrain pull-up warning when we descended into the valley.
Pilots distinguish between terrain, which is the physical dirt and rock, and obstacles, which are man-made structures like towers.
Related terms
Ground proximity warning system
An avionics system designed to alert pilots if their aircraft is in immediate danger of flying into the ground.
Approach
The final phase of a flight where an aircraft aligns with the runway for landing.
Radar cross section
A measure of how detectable an aircraft or object is to radar systems.