Definition
The ability of the elevator (or stabilator) to produce enough aerodynamic force to change the airplane's pitch attitude when the pilot moves the control column. Elevator authority depends on airspeed, air density, control surface size, and how much airflow is reaching the tail; when any of these is reduced, the elevator's effectiveness is reduced.
Plain English
How much pitch control the elevator actually gives you. When airspeed is high and airflow over the tail is strong, the elevator has a lot of authority and the nose responds quickly. When airspeed is low, the elevator has less authority and the nose responds slowly or not at all.
Context Anchor
Used in discussions of slow flight, landing, loading, and speed margins, where the airplane may have less airflow over the tail and less ability to move the nose as commanded.
Derivation
Authority' comes from the Latin 'auctoritas', meaning power or command. In aviation, a control surface has 'authority' when it has the power to actually do its job. Saying the elevator has 'authority' is shorthand for saying it has enough force to command the pitch change the pilot is asking for.
Why Pilots Care
Insufficient elevator authority at low airspeeds reduces the ability to raise the nose during stall recovery or maintain pitch control, increasing the risk of a secondary stall or loss of altitude.
Grounding Statement
As airspeed decreases, less air flows over the elevator, so the elevator may have less ability to move the nose.
Intuition Check
“Authority” does not mean permission here. It means how much control effect the elevator can actually produce.
Example Sentence 1
As the airplane slowed during the soft-field landing, the pilot held the yoke fully aft to use the last of the elevator authority to keep the nosewheel off the runway.
Example Sentence 2
During stall recovery the pilot applied full power while using remaining elevator authority to raise the nose just enough to break the stall without pitching up excessively.