Definition
A threaded metal fastener consisting of a head at one end and a straight cylindrical shank with machine threads at the other, designed to be used with a nut or threaded hole to clamp two or more parts together. Aircraft bolts are manufactured to precise specifications for strength, material, and dimensions, and are identified by standards such as AN, NAS, or MS part numbers.
Plain English
A strong threaded pin with a head on one end. You pass it through parts that need to be joined and tighten a nut onto the threaded end to hold everything together.
Context Anchor
Seen during aircraft maintenance, preflight inspections, and discussions of aircraft hardware such as engine mounts, control connections, landing gear, and structural fittings.
Derivation
From Old English 'bolt,' originally meaning a short, heavy arrow or shaft. The sense carried over to any short, stout cylindrical piece of metal — which is exactly what a bolt is.
Why Pilots Care
Aircraft bolts are not interchangeable with hardware-store bolts. Using the wrong grade, length, or type can cause structural failure. Pilots and mechanics must verify that any bolt installed during maintenance matches the specification called for in the maintenance manual.
Intuition Check
Do not read bolt here as lightning, running away, or a door lock. In aircraft maintenance, a bolt is a specific metal fastener used with parts such as nuts and washers.
Example Sentence 1
During the preflight inspection, the mechanic checked that every bolt securing the engine mount was properly torqued and safety-wired.
Example Sentence 2
During preflight the pilot checked that every visible bolt on the control surfaces was secure.