Definition
A moment divided by a constant (such as 100, 1,000, or 10,000) to produce a smaller, more manageable number for use in weight and balance calculations. The constant is chosen by the manufacturer and is shown on the loading chart for that aircraft.
Plain English
A shrunk-down version of a moment. Instead of working with very large numbers when figuring out weight and balance, the manufacturer divides each moment by a set number so the math is easier and the values fit cleanly on the loading chart.
Context Anchor
Seen on aircraft weight-and-balance charts, loading forms, and sample loading problems.
Derivation
Moment' comes from Latin momentum, meaning 'movement' or 'turning effect.' 'Index' comes from Latin index, meaning 'pointer' or 'indicator.' Together it points to a scaled-down number that represents the turning effect of a load — easier to read and add up.
Why Pilots Care
Using the correct moment index keeps the center of gravity inside allowable limits, which directly affects stability, control feel, and stall recovery.
Analogy
It is like writing $12.50 instead of 1,250 cents. The value is the same, but the smaller-looking number is easier to work with.
Intuition Check
Moment does not mean a brief period of time here; it means the balance effect of weight at a distance. Index does not mean a book listing here; it means a scaled-down number used in the balance calculation.
Example Sentence 1
After loading the baggage, the pilot looked up the moment index for that station on the loading chart and added it to the running total.
Example Sentence 2
After fueling, the crew consulted the moment index chart to confirm the new center of gravity position remained safe for takeoff.