Definition
The amount of effective control a pilot has over the airplane's attitude and flightpath through movement of the flight controls. Control authority depends on airspeed and airflow over the control surfaces — at higher airspeeds the controls produce strong, immediate response, while at low airspeeds the same control inputs produce weaker, slower response.
Plain English
How much actual control you have over the airplane when you move the stick, yoke, or rudder. The faster the air is moving over the control surfaces, the more the airplane responds. The slower it's moving, the less the airplane listens.
Context Anchor
Seen in climb, slow-flight, takeoff, landing, and climbing-turn discussions, especially when the airplane is at a higher nose attitude or lower airspeed.
Derivation
Authority' comes from the Latin auctoritas, meaning power or command. Here it describes the controls' power to command the airplane — strong at high airspeed, weak at low airspeed.
Why Pilots Care
Loss of control authority at low speed or high altitude is a leading contributor to stall-spin accidents and loss-of-control events.
Grounding Statement
When less air flows over the airplane’s control surfaces, those controls have less force available to move or hold the airplane’s attitude.
Intuition Check
Control authority does not mean legal permission to control the airplane. Here, it means how much physical effect the flight controls have on the airplane’s movement.
Example Sentence 1
As airspeed decreased during the climb, the pilot noticed reduced control authority and made larger rudder inputs to keep the airplane coordinated.
Example Sentence 2
At high altitude the thinner air reduced control authority, so the pilot used greater control deflections to achieve the same rate of turn.