Definition
In sheet metal work, to deliberately deform or set a rivet, fastener, or joint so that it locks into position and resists rotation or loosening. More broadly, to lock or secure one part to another so that relative movement is prevented.
Plain English
To lock something in place so it cannot turn or slip. When a technician keys a rivet or fastener, they make sure it stays put.
Context Anchor
Seen in aircraft surface preparation, composite repair, sealing, painting, and corrosion-control procedures.
Derivation
From the noun 'key,' something that locks or secures (as in a key that fits a lock, or a keyway that prevents a shaft from rotating). Used as a verb, it means to apply that locking action — to fix one thing to another so it cannot move.
Why Pilots Care
If a surface is not keyed correctly before repair or coating, the new material may not stick well, which can lead to peeling, leaks, corrosion, or a weak repair.
Analogy
It is like lightly sanding a smooth wall before painting it. The paint holds better because the surface is no longer slick.
Intuition Check
Key does not mean to unlock something here. As a verb in maintenance, it means to roughen a surface so another material can hold onto it.
Example Sentence 1
The technician keyed the rivet to ensure it would not back out under vibration.
Example Sentence 2
Key the ignition switch only after confirming all personnel are clear of the propeller.