Definition
Unwanted electrical signals that interfere with the desired signal in an aircraft electrical or avionics circuit. Electrical noise can be generated by motors, generators, ignition systems, switching contacts, lightning, or radio-frequency interference, and it appears in a circuit as random or repetitive voltage fluctuations superimposed on the intended signal.
Plain English
Stray electrical signals that get mixed in with the signal you actually want, making it harder for equipment to read it cleanly.
Context Anchor
Seen in aircraft electrical and electronic equipment troubleshooting, especially with radios, sensors, instrument wiring, and wire shielding.
Derivation
The word 'noise' originally referred to unwanted sound. Engineers borrowed it to describe any unwanted disturbance in an electrical signal, because the effect on a clean signal is similar to the way background sound clutters speech.
Why Pilots Care
Can cause erratic instrument readings, loss of navigation signals, or communication failures if not isolated and shielded.
Analogy
Electrical noise is like background chatter during a radio call: the message may still be there, but the unwanted disturbance makes it harder to understand.
Intuition Check
Noise does not mean sound here. In this context, it means unwanted electrical disturbance in a circuit or signal.
Example Sentence 1
The technician installed a shielded cable to reduce electrical noise affecting the VHF radio.
Example Sentence 2
Adding proper shielding around the power leads eliminated the electrical noise affecting the comm radio.