Definition
An aircraft bolt with a six-sided head designed to be tightened or loosened with a wrench. Hexagon head bolts are the most common general-purpose structural bolt in aircraft construction, used where the load is primarily in tension or where the bolt is subject to a combination of tension and shear.
Plain English
A bolt with a six-sided head that you turn with a wrench. It is the standard, general-purpose bolt used throughout an aircraft.
Context Anchor
Seen in aircraft maintenance manuals, parts catalogs, and inspection tasks when identifying or replacing standard hardware.
Derivation
From Greek 'hex' meaning six and 'gonia' meaning angle or corner -- so 'hexagon' literally means 'six-cornered.' The head has six flat sides, which is what lets a wrench grip it from any of three positions.
Why Pilots Care
Pilots performing preflight inspections or owner-allowed maintenance need to recognize standard aircraft bolts and confirm they are the correct type, properly torqued, and safetied. A wrong or loose bolt in a structural location is a flight safety issue.
Intuition Check
Do not assume “hexagon head” tells you the bolt is approved for any location. It only describes the six-sided head shape; the correct bolt also depends on size, strength, length, thread, and approved use.
Example Sentence 1
The mechanic torqued each hexagon head bolt on the engine mount to the value specified in the maintenance manual.
Example Sentence 2
Torque the hexagon head bolts securing the control surface hinge to the value listed in the maintenance manual.