Plain English Meaning

The older style of cockpit navigation gear that relies on signals from ground stations on the ground, not from satellites or computer-generated waypoints.

Full Definition

Avionics equipment that uses ground-based navigation aids — such as VOR, DME, NDB, and ILS — to navigate, rather than satellite-based or area navigation (RNAV) systems. An aircraft equipped only with conventional avionics can fly procedures defined by ground stations but cannot fly RNAV or GPS-based routes and approaches.