Definition
An open-end or box-end wrench head without a handle, designed to attach to the square drive of a ratchet or torque wrench extension. It allows a fastener to be tightened or loosened in a location where a conventional wrench will not fit.
Plain English
A wrench head with no handle of its own. You clip it onto a ratchet or torque wrench so you can reach nuts and bolts in tight spots that a normal wrench can't get to.
Context Anchor
Seen in aircraft maintenance, especially when working around fuel lines, hydraulic lines, engine accessories, or other fittings with limited access.
Derivation
Named for its shape — the open jaws resemble the splayed toes of a crow's foot.
Why Pilots Care
Enables precise torque application to fasteners in hard-to-reach aircraft areas, preventing improper assembly that could affect safety.
Intuition Check
Do not think of a crowfoot wrench as a complete wrench with a handle. It is the wrench head only, used with another driving tool.
Example Sentence 1
The mechanic used a crowfoot wrench on a torque wrench extension to tighten the fuel line fitting behind the engine accessory case.
Example Sentence 2
During landing gear inspection, the crowfoot wrench allowed access to the recessed bolt without removing surrounding parts.