Definition
The region of the airspeed range, above the speed for minimum drag (L/Dmax), in which an increase in airspeed requires an increase in thrust or power, and a decrease in airspeed requires a decrease in thrust or power. In this region the aircraft exhibits speed stability: if disturbed, it tends to return to its trimmed airspeed.
Plain English
The normal speed range where flying faster needs more power and flying slower needs less. The aircraft naturally settles back to its trimmed speed if it gets nudged off.
Context Anchor
Seen in instrument flying when discussing speed stability and how the airplane responds to pitch and power changes.
Derivation
Called 'normal' because this is the everyday speed range pilots fly in. 'Command' refers to the fact that thrust commands speed in the expected way — push the throttle forward, the aircraft speeds up; pull it back, it slows down.
Why Pilots Care
Pilots must recognize this region to maintain stable speeds during instrument approaches and avoid entering the reversed command area near stall speeds.
Intuition Check
Normal command does not mean an autopilot or computer is commanding the airplane. Here, it means the normal speed range where more power is needed for more speed and less power is needed for less speed in level flight.
Example Sentence 1
During cruise the aircraft is operating in the normal command region, so a small power reduction produces a small, predictable decrease in airspeed.
Example Sentence 2
During cruise flight, the aircraft operates in normal command, responding predictably to power changes for speed adjustments.