Definition
A concept describing two distinct ranges of airspeed in which an aircraft behaves differently with respect to power and drag. Above the speed for minimum drag (L/Dmax), the aircraft is in the region of normal command, where adding power increases speed and reducing power decreases speed in the expected way. Below that speed, the aircraft is in the region of reversed command, where more power is required to fly at a slower speed because induced drag rises rapidly as airspeed decreases.
Plain English
Aircraft have two airspeed zones that behave differently. In the upper zone, things work the way you'd expect: more power equals more speed. In the lower zone, things flip: flying slower actually requires more power, not less, because of how drag changes at low speeds.
Context Anchor
Used in instrument flying when discussing pitch, power, airspeed control, and slow-speed approaches.
Derivation
The phrase uses 'command' in the sense of 'control' or 'authority over.' Each region describes a range of airspeeds where the pilot's control inputs (power and pitch) command the aircraft's response in a particular pattern. The two regions are named for whether that response is normal or reversed compared to pilot intuition.
Why Pilots Care
Helps pilots anticipate power changes and avoid stalls or excessive drag during slow flight, approaches, and go-arounds.
Grounding Statement
At very slow speeds, the airplane can need extra power just to stay level, even though the pilot may expect slower flight to need less power.
Intuition Check
Do not read “command” as an instruction from ATC or an order from the pilot. Here it means the airplane’s response pattern to pitch and power in a certain speed range.
Example Sentence 1
On a short final at low airspeed, the pilot recognized she was in the region of reversed command and added power immediately to arrest the sink rate.
Example Sentence 2
In cruise flight the airplane remained in the region of normal command where reducing power produced a lower but stable airspeed.