Definition
An event in which the airplane no longer responds normally to pilot control inputs and begins to move in ways the pilot is not commanding, typically following a stall, spin entry, or extreme upset. The aircraft has left the regime of flight where the pilot can predictably manage its attitude, heading, and flight path through the flight controls.
Plain English
The moment the airplane stops doing what the pilot is telling it to do. Instead of climbing, turning, or descending in response to the controls, it starts pitching, rolling, or yawing on its own.
Context Anchor
Seen in stall and spin awareness training, especially when discussing how a stall can develop into a spin if the airplane is not recovered promptly.
Derivation
"Departure" here carries its older sense of leaving or moving away from something. The airplane is leaving the state of controlled flight, not departing an airport. This older usage helps explain why the term sounds unusual in everyday English.
Why Pilots Care
Early recognition allows immediate recovery inputs that can prevent a full spin or loss-of-control accident.
Analogy
Like a car suddenly losing traction on ice and no longer turning when the driver steers.
Grounding Statement
The essential idea is: the airplane has crossed from normal, predictable handling into abnormal motion that requires immediate recovery.
Intuition Check
Do not read “departure” here as a takeoff or a flight leaving an airport. Here it means the airplane has left normal controlled flight.
Example Sentence 1
If the pilot fails to reduce angle of attack at the stall, the airplane can experience a departure from controlled flight and enter a spin.
Example Sentence 2
Proper airspeed and bank management help avoid departure from controlled flight during steep turns.