Definition
A condition of flight in which the airplane's velocity, altitude, and attitude remain constant over time, meaning all forces acting on it (lift, weight, thrust, drag) are in equilibrium and there is no acceleration in any direction.
Plain English
Flight where nothing is changing — the airplane is holding its speed, height, and attitude steady because all the forces on it are balanced.
Context Anchor
Seen in airplane performance, trim, and maneuver discussions when comparing a changing flight condition with one that has settled and is being held.
Derivation
Steady' means unchanging; 'state' means a condition or set of circumstances. So 'steady state' simply means a condition that stays the same. Aviation borrowed the phrase from physics and engineering, where it describes any system whose properties are not changing with time.
Why Pilots Care
Allows accurate performance calculations and confirms the aircraft is in balanced, predictable flight during cruise or other constant-parameter phases.
Analogy
Like driving on a flat highway at a fixed speed with no acceleration, braking, or steering changes.
Grounding Statement
Picture the airplane trimmed so it keeps the same speed and attitude without the pilot constantly chasing changes.
Intuition Check
Steady state flight does not mean the airplane is motionless. It means the airplane’s condition is staying constant while it continues flying.
Example Sentence 1
Once established in cruise at 6,500 feet and 110 knots with the power set, the airplane was in steady state flight.
Example Sentence 2
In steady state flight the forces of lift, weight, thrust, and drag remain equal.