Definition
A coiled spring designed to resist a pushing force along its length. When a load is applied to its ends, the coils are pressed closer together, and the spring stores energy that pushes back to return the spring to its original length when the load is removed.
Plain English
A spring that gets shorter when you push on it and pushes back to return to its full length when you let go.
Context Anchor
Seen in aircraft parts that must return to position or keep pressure on something, such as latches, valves, brake parts, and some control or landing gear mechanisms.
Derivation
From Latin 'comprimere', meaning 'to press together'. The name describes exactly what happens to the spring under load -- its coils are pressed together.
Why Pilots Care
Provides reliable restoring force in load-bearing mechanisms, preventing binding or loss of function during ground operations and flight.
Analogy
A common example is the small spring inside a click pen. When you press the button, the spring is squeezed; when you release it, the spring pushes back.
Intuition Check
A compression spring is not just any spring in an aircraft. It specifically works by being squeezed shorter, not by being pulled longer.
Example Sentence 1
The compression spring in the oleo strut helps cushion the aircraft during landing.
Example Sentence 2
Compression springs in the mixture control linkage keep the lever from creeping during cruise flight.