Definition
A short, cylindrical metal pin with a flat or rounded head on one end and a small cross-hole near the other end, used to join components that must pivot or be quickly disassembled. The pin passes through a U-shaped clevis fitting and a matching hole in a mating part, and is held in place by a cotter pin or safety clip inserted through the cross-hole.
Plain English
A removable pin that holds two parts together so they can swivel or be taken apart easily. It slides through a U-shaped bracket and is locked in place by a small cotter pin pushed through a hole near its end.
Context Anchor
Pilots may see clevis pins during preflight inspections or maintenance discussions involving flight controls, control cables, brake linkages, or other moving aircraft connections.
Derivation
The word 'clevis' comes from an Old English root meaning 'to cleave' or split, describing the U-shaped (forked) fitting the pin passes through. So a clevis pin is simply 'the pin that goes through the forked fitting.'
Why Pilots Care
Provides a secure, easily removable connection that maintains precise control movement while preventing accidental separation in flight.
Analogy
A clevis pin works much like the pin in a simple door hinge: it holds the two sides together while still letting them move around the pin.
Intuition Check
Do not picture a sharp sewing pin. A clevis pin is usually a blunt metal fastening pin used to hold aircraft parts together at a movable joint.
Example Sentence 1
During preflight, the pilot checked that the clevis pin connecting the elevator pushrod to the bellcrank was secured with a cotter pin.
Example Sentence 2
During the annual inspection, each clevis pin was checked for wear and properly secured with a new cotter pin.