Definition
An L-shaped piece of structural aluminum formed by forcing heated metal through a shaped die, producing a length of stock with a uniform angled cross-section. Extruded angles have legs that meet at a sharp 90-degree corner and are commonly used as stringers, longerons, and reinforcing members in aircraft structures.
Plain English
A long strip of aluminum shaped like the letter L, made by squeezing hot metal through a mold so the cross-section comes out the same the whole way along. It's used as a structural piece inside the airframe.
Context Anchor
Seen in aircraft sheet-metal repair, structural repair drawings, parts lists, and maintenance instructions for stiffeners, supports, and brackets.
Derivation
Extruded' comes from the Latin extrudere, meaning 'to push or thrust out.' The metal is literally pushed out through a shaped opening, the way toothpaste is pushed out of a tube. 'Angle' refers to the L-shaped cross-section the die produces.
Why Pilots Care
Maintenance technicians need to recognize extruded angles when inspecting structure or selecting replacement stock for repairs, because the way a part is made affects its strength and how it can be reformed or repaired.
Analogy
Think of squeezing dough through a pasta machine fitted with an L-shaped cutter. Whatever length comes out has the same L-shape from end to end. That's how an extruded angle is made.
Intuition Check
Do not read “angle” here as a measurement in degrees. In this term, an angle is a physical L-shaped piece of metal.
Example Sentence 1
The repair called for a section of extruded angle to reinforce the damaged stringer along the fuselage.
Example Sentence 2
Stock extruded angles in different thicknesses are kept on hand for quick bracket fabrication.