Definition
A small structural or plumbing component used to connect, terminate, or join two or more parts — most commonly the end-pieces that attach fluid lines (fuel, hydraulic, oil, pneumatic) to each other or to system components, or the metal hardware that joins structural members of an airframe.
Plain English
A connector. It's the piece of hardware that joins two parts together — usually the end of a hose or tube, or a bracket that ties one airframe part to another.
Context Anchor
Seen in aircraft maintenance manuals, inspection checklists, repair instructions, and descriptions of fuel, oil, hydraulic, control, or structural connections.
Derivation
From the verb 'fit,' meaning to make something the right shape to join with another. A fitting is literally the part that makes two things 'fit' together.
Why Pilots Care
Fittings are common leak points and failure points. A loose or cracked fuel or hydraulic fitting can lead to fluid loss, fire risk, or system failure, so they're a routine focus during preflight and inspection.
Intuition Check
Do not read “fitting” as meaning “suitable” or “appropriate” here. In this maintenance context, a fitting is an actual aircraft part used to connect, attach, or secure something.
Example Sentence 1
The mechanic tightened the hydraulic fitting at the brake line to stop a slow leak.
Example Sentence 2
All structural fittings must be inspected for corrosion during the annual inspection.