Definition
The metal pins or latches that engage the seat rails to hold the pilot's or passenger's seat in a fixed fore-and-aft position. When properly engaged, they prevent the seat from sliding along the rails during flight, particularly during takeoff acceleration or pitch changes.
Plain English
The small locking pins underneath an aircraft seat that hold the seat in place on its rails so it cannot slide forward or backward once you set the position.
Context Anchor
Checked during the cockpit portion of the visual preflight assessment, usually after adjusting the seat and before engine start.
Why Pilots Care
An unlocked seat can slide during takeoff, landing, or turbulence, reducing control effectiveness and creating a hazard.
Analogy
They work like a pin in an adjustable exercise machine: once the pin is fully in the hole, the part stays where you set it.
Intuition Check
Do not assume the seat is locked just because the handle feels down or the seat seems still. The seat lock pins must actually be engaged, and the seat should not move when you try to slide it.
Example Sentence 1
After adjusting the seat, the pilot tugged it forward and back to verify the seat lock pins were fully engaged.
Example Sentence 2
After the hard landing, the instructor found one seat lock pin partially disengaged and re-secured it before the next flight.