Plain English Meaning

A type of sensor that 'sees' the heat-like energy that everything naturally gives off at very short radio wavelengths. It builds a picture from that energy, and because those wavelengths cut through fog and cloud better than light does, the pilot can see the runway when the eyes alone cannot.

Full Definition

A passive sensing technology used in some Enhanced Flight Vision Systems (EFVS) that detects natural electromagnetic energy emitted by objects and surfaces in the millimeter wavelength band (roughly 1 to 10 millimeters), and converts those emissions into a real-time image of the scene ahead of the aircraft. Because it senses energy at wavelengths that pass through fog, cloud, and precipitation more readily than visible light, it can produce a usable image of the in .