Definition
The full range of motion of the primary flight controls — ailerons, elevator, and rudder — from one extreme position to the other. Adequate primary control travel must be available throughout the aircraft's loaded weight and balance envelope so the pilot retains full authority over pitch, roll, and yaw in all phases of flight.
Plain English
How far the ailerons, elevator, and rudder can move from one stop to the other. The aircraft must be loaded so the pilot can still move these controls through their full range without anything blocking or limiting them.
Context Anchor
Seen in weight-and-balance and center-of-gravity discussions, where the airplane must still have enough control movement available to be flown safely.
Derivation
‘Primary controls’ are the three main flight controls (aileron, elevator, rudder) — called primary because they are the principal means of flying the aircraft. ‘Travel’ here keeps its everyday sense of distance moved from one point to another.
Why Pilots Care
It determines how much authority the pilot has to change the aircraft's attitude and how quickly the airplane can be maneuvered.
Grounding Statement
Picture pulling the yoke back until it cannot move any farther; that available movement is part of primary control travel.
Intuition Check
Do not read travel as the distance the airplane flies. Here, travel means the distance the controls themselves can move.
Example Sentence 1
Loading the aircraft with the center of gravity too far aft reduces the elevator's primary control travel needed to lower the nose during stall recovery.
Example Sentence 2
Reduced primary control travel after an aileron stop was installed made the airplane slower to roll out of a bank.