Definition
The angle, measured from the horizontal, at which an aircraft descends along a specified flight path, typically depicted on the profile view of an instrument approach procedure chart.
Plain English
How steeply the aircraft is going down, measured as the angle between its descent path and a level line.
Context Anchor
Seen in the profile view of an instrument approach chart, where the chart shows the vertical shape of the approach.
Derivation
From Latin angulus (corner) and descendere (to climb down). Together: the 'corner' formed between level flight and the path going down.
Why Pilots Care
It determines how far out a descent must begin to reach the runway at the correct altitude and airspeed.
Analogy
Think of a road going downhill. The angle of descent is like the steepness of that downhill road, not how fast the car is driving on it.
Intuition Check
Do not confuse angle of descent with rate of descent. The angle is the steepness of the path; the rate is how many feet per minute the airplane is going down.
Example Sentence 1
The approach chart shows a 3.00-degree angle of descent from the final approach fix to the runway threshold.
Example Sentence 2
The profile view on the approach chart shows the expected angle of descent to the runway threshold.