Definition
A metallic covering, usually a braided wire mesh or solid metal sheath, placed around electrical wiring or components to block electromagnetic interference from radiating outward or being picked up from outside sources. The shield is bonded to the aircraft structure so that stray electrical energy is carried safely to ground.
Plain English
A metal sleeve wrapped around a wire or part to stop electrical noise from leaking out or sneaking in. It protects radios, instruments, and avionics from interference.
Context Anchor
Seen in aircraft maintenance when inspecting ignition leads, engine wiring, and radio-noise problems related to the powerplant.
Derivation
From the Old English 'scield' meaning a protective barrier carried in battle. In electrical work, the metal layer 'shields' sensitive signals from interference the same way a physical shield blocks blows.
Why Pilots Care
Breaks or missing shielding allow ignition noise to create static or complete loss of radio reception, directly affecting communication and navigation safety.
Analogy
Like wrapping a noisy speaker cable in foil so the sound does not leak out and interfere with nearby electronics.
Intuition Check
Do not read shielding here as only a cover that protects against dents, heat, or dirt. In this context, it usually means protection against unwanted electrical interference.
Example Sentence 1
The technician inspected the shielding on the magneto leads for breaks before signing off the ignition harness.
Example Sentence 2
Proper shielding on the spark plug wires eliminated the static that had been interfering with the COM radios.