Definition
The cockpit display that shows the steering commands generated by the flight director system. It combines an attitude indicator with command bars (or a single cue) that move to show the pitch and bank the pilot must fly to satisfy the selected flight director mode, such as a heading, course, altitude, or approach path.
Plain English
It is the screen that shows you, with moving bars or a symbol, exactly how to pitch and bank the airplane to fly the path the flight director has worked out for you.
Context Anchor
Seen during instrument flying and when using the flight director or autopilot system to follow a selected heading, course, climb, descent, or approach path.
Derivation
Flight director points to the idea of something directing the flight — telling the pilot which way to go. Indicator simply means the instrument that shows it. Together: the instrument that shows the flight director's instructions.
Why Pilots Care
It reduces workload and improves precision during instrument flight by turning complex navigation data into simple steering cues the pilot can follow directly.
Intuition Check
Do not assume the FDI flies the airplane by itself. It is an indicator: it shows steering commands for the pilot or autopilot to follow.
Example Sentence 1
After selecting the heading mode, the pilot banked the airplane until the command bars on the FDI were centered.
Example Sentence 2
With the flight director engaged, the FDI guided the airplane down the ILS glide slope without further adjustments from the autopilot.