Definition
Sharing a common central axis. In aviation, the term most often describes coaxial cable, in which an inner conductor and an outer conductor share the same centerline, separated by an insulator and enclosed in an outer jacket. It can also describe mechanical assemblies, such as coaxial rotors, where two components rotate around the same shaft or axis.
Plain English
Two things lined up so they share the same center line, one inside or around the other.
Context Anchor
Seen in airframe maintenance when describing coaxial cables, antenna cables, shafts, bearings, or parts that must be centered on the same line.
Derivation
From Latin co- meaning 'together' and axis meaning 'axle' or 'center line.' So 'coaxial' literally means 'sharing the same axis' — which is exactly what a coaxial cable or coaxial rotor does.
Why Pilots Care
Coaxial cables carry the radio and antenna signals the aircraft depends on. A damaged or poorly connected coax run can cause weak transmissions, noisy reception, or navigation signal problems.
Analogy
Think of a pencil inside a drinking straw, with both perfectly centered. The lead, the wood, and the straw all share one center line — that's coaxial.
Intuition Check
Coaxial does not just mean “next to each other.” It means sharing the same center line.
Example Sentence 1
The technician replaced a damaged coaxial cable running from the COM radio to the antenna.
Example Sentence 2
A loose coaxial connector can cause weak or garbled transmissions during flight.