Plain English Meaning

The small metal bumps you can see all over the outside of the airplane. They are the tops of the fasteners holding the metal skin onto the airframe. During a walkaround, you look at them to make sure none are missing, loose, or leaving a dark smudge.

Full Definition

The visible, rounded or flush ends of the rivets that fasten the airplane's metal skin to its underlying structure. On a preflight inspection, rivet heads are checked to confirm they are present, tight, undamaged, and not showing signs of working loose, popping out, or smoking (a dark stain trailing from the rivet that indicates movement).

Context Anchor

Seen during preflight inspection of the wings, tail, and other outside surfaces of the airplane.

Derivation

A rivet is a metal pin used to join two pieces together; the 'head' is the wider end that sits on the and stops the rivet from pulling through. The word rivet comes from the Old French 'river,' meaning to or fasten.