Definition
A flight condition in which the airplane's airspeed, altitude, heading, attitude, power setting, and control inputs are not changing over time. All forces and moments acting on the airplane are balanced, so the aircraft is neither accelerating nor decelerating in any axis.
Plain English
Everything is holding steady. The airplane is flying along with its speed, direction, and attitude unchanging, and the pilot is not having to add or change any control input to keep it that way.
Context Anchor
Seen in the Airplane Flying Handbook discussion of how minimum control speed is derived for multi-engine airplanes.
Derivation
From 'steady' (unchanging) and 'state' (a set of conditions). Borrowed from physics and engineering, where a steady-state system is one whose properties are not changing with time. In aviation, it describes the moment when the airplane has finished any transition and is flying in equilibrium.
Why Pilots Care
Required for accurate VMC determination and safe single-engine climb performance calculations.
Grounding Statement
Picture the airplane after the first upset has been stopped: the speed, direction, and control pressures are no longer changing rapidly.
Intuition Check
Steady-state does not mean easy, safe, or relaxed. It means the condition is stabilized and not changing during the measurement or analysis.
Example Sentence 1
VMC is determined under steady-state conditions, with the airplane trimmed and flying at a constant airspeed before the critical engine is failed.
Example Sentence 2
Once in steady-state conditions after engine failure, the pilot could assess directional control limits without further changes in speed or bank.