Definition
A device built into an aircraft's flight control system that mechanically locks the control surfaces (ailerons, elevator, and rudder) in a neutral or fixed position when the aircraft is parked, preventing them from being moved by wind. The lock is engaged and released from inside the cockpit, typically through the control column or a dedicated lever, and is designed so that the aircraft cannot be flown with the lock still engaged.
Plain English
A built-in lock, operated from inside the cockpit, that holds the flight controls still while the aircraft is parked so wind gusts can't slam them around and damage them.
Context Anchor
Seen during preflight, shutdown, parking, and tiedown procedures, especially when checking that the controls move freely before flight.
Derivation
"Internal" because it is operated from inside the cockpit, as opposed to an external gust lock that is clamped onto the control surfaces from outside the aircraft. "Control lock" because it locks the flight controls.
Why Pilots Care
Protects control linkages and surfaces from gust damage and keeps the aircraft stable while unattended.
Intuition Check
Internal does not mean the lock is hidden inside a wing or control surface. Here, it means the lock is part of the aircraft’s own control system or cockpit equipment, rather than a separate outside lock attached after parking.
Example Sentence 1
Before starting the engine, the pilot disengaged the internal control lock and confirmed that the ailerons, elevator, and rudder all moved freely through their full range.
Example Sentence 2
During the preflight inspection the pilot removed the internal control lock and confirmed the controls moved freely in all directions.