Definition
A small, rapid, and unwanted oscillation or fluctuation in a signal, instrument indication, or mechanical component. In avionics and electronic displays, jitter refers to brief variations in the timing or position of a displayed value; in mechanical instruments, it refers to a quick trembling motion of a needle or pointer.
Plain English
A small, fast shaking or wobble in a reading, signal, or part that should normally be steady.
Context Anchor
Seen during cockpit instrument checks, avionics troubleshooting, and maintenance write-ups when a needle, display, or electronic reading will not hold steady.
Derivation
From the English verb 'jitter,' meaning to move nervously or shake slightly. The aviation use keeps the everyday sense — a quick, unsteady twitching — and applies it to instruments and signals that should be holding still.
Why Pilots Care
Excessive jitter can degrade the accuracy of radar, transponder, or navigation signals, reducing situational awareness in instrument conditions.
Intuition Check
Do not read jitter as just a person feeling nervous. In aviation, it usually means an indication, display, signal, or part is making small unwanted movements or changes.
Example Sentence 1
The pilot noticed a slight jitter in the attitude indicator and wrote it up for the avionics shop to inspect.
Example Sentence 2
Maintenance traced the erratic altitude readout to jitter in the encoder output.