Plain English Meaning

An instrument that shows the airplane's nose-up or nose-down angle and its bank, and overlays small bars or cues that tell the pilot which way to fly to follow a chosen course or path.

Full Definition

A primary flight instrument that displays the aircraft's pitch and bank attitude relative to the horizon, and combines that display with steering commands derived from the flight director or navigation system. The ADI shows the pilot both where the aircraft is pointed (attitude) and where it should be pointed ( or steering cues) on a single instrument .