Definition
A change in an aircraft's weight that is small enough to have no meaningful effect on its weight and balance, performance, or flight characteristics, and therefore does not require a new weight and balance computation or amendment to the aircraft records.
Plain English
A weight change so small that it doesn't matter for how the aircraft flies or balances, so no new paperwork or recalculation is needed.
Context Anchor
Seen in weight-and-balance discussions when equipment is added, removed, repaired, or replaced.
Derivation
From Latin negligere, meaning 'to disregard' or 'not to pick up.' A negligible change is one small enough to be disregarded — in this case, disregarded for weight and balance purposes.
Why Pilots Care
Allows pilots to avoid unnecessary recalculations for insignificant items while still recognizing that many small changes can accumulate and eventually matter.
Analogy
Like adding one more sock to an already-packed suitcase; the extra weight makes no real difference to how you carry it or how it rides in the car.
Intuition Check
Do not read negligible weight change as “no weight change.” It means there was a change, but it is small enough that it does not practically change the aircraft’s loading or balance.
Example Sentence 1
Replacing a cabin light bulb with an identical model is considered a negligible weight change and requires no update to the weight and balance record.
Example Sentence 2
The addition of one approach chart to the kneeboard was treated as a negligible weight change for this light aircraft.