Definition
Unwanted electromagnetic energy on or near a radio frequency that disrupts the normal reception or transmission of a desired radio signal, causing degraded audio, erratic navigation indications, or loss of usable signal.
Plain English
Stray radio energy that gets in the way of the signal you are trying to use, making it noisy, unreliable, or unusable.
Context Anchor
Seen in instrument navigation discussions, especially near changeover points where a pilot switches from one navigation station to another.
Derivation
From Latin radius (ray, beam) and frequentia (a crowding, repeated occurrence). 'Frequency' came to mean how often a wave repeats per second. 'Interference' is from Latin inter (between) and ferire (to strike) — literally 'striking between.' So the phrase describes one radio wave 'striking between' and disrupting another.
Why Pilots Care
It can cause loss of ATC communications or inaccurate navigation guidance, directly affecting flight safety and decision-making.
Grounding Statement
If unwanted radio energy reaches the receiver along with the desired signal, the receiver may not be able to separate the signal clearly.
Intuition Check
Radio frequency interference does not always mean someone is deliberately blocking the radio. It can be any unwanted radio energy that weakens, distorts, or covers up the signal you are trying to use.
Example Sentence 1
As they neared the changeover point, radio frequency interference caused the VOR needle to swing intermittently, so the crew switched to the next station earlier than planned.
Example Sentence 2
Proper shielding of the aircraft electrical system helps prevent radio frequency interference during IFR operations.