Definition
A symbol displayed on a Head-Up Display (HUD) or Primary Flight Display (PFD) that marks the desired flight path angle the pilot intends to fly, used as a target against which the actual flight path vector is flown. When the flight path vector symbol is aligned with the reference cue, the aircraft is tracking the intended angle of climb or descent.
Plain English
A small marker on the display that shows the up-or-down angle you want the aircraft to fly. You steer so that the symbol showing where the aircraft is actually going sits right on this marker.
Context Anchor
Seen on advanced flight displays, especially during instrument approaches, managed descents, or other operations where the pilot is flying to a specific climb or descent angle.
Derivation
‘Reference cue’ comes from ‘reference’ (Latin referre, to carry back to) meaning a fixed point used for comparison, and ‘cue’ meaning a visual prompt. Together it is the marker the pilot refers to when flying a chosen path angle.
Why Pilots Care
Allows precise control of the aircraft's vertical path, critical for safe landings and efficient flight.
Grounding Statement
If the actual flight path symbol is aligned with the reference cue, the airplane is tracking the selected path angle.
Intuition Check
Do not confuse the Flight Path Angle Reference Cue with the airplane’s nose position. It refers to the airplane’s actual path through the air, not simply where the nose is pointed.
Example Sentence 1
On final approach, the captain set the reference cue to a three-degree descent and flew the flight path vector onto it.
Example Sentence 2
Maintaining alignment with the flight path angle reference cue ensured the aircraft stayed on the required descent profile.