Definition
A moment value divided by a reduction factor (typically 100, 1,000, or 10,000) to produce a smaller, more manageable number for use in weight and balance calculations. The moment index is used in place of the raw moment to simplify arithmetic on loading charts and worksheets.
Plain English
It's the moment (weight times arm) shrunk down by dividing it by a set number, so the figures on the loading chart stay small and easy to add up.
Context Anchor
Seen on aircraft weight-and-balance forms, loading charts, and center-of-gravity calculations before flight.
Derivation
Moment' comes from Latin 'momentum,' meaning a turning effect or influence — in physics, the tendency of a force to rotate something around a point. 'Index' comes from Latin for 'pointer' or 'indicator,' and in math means a number that represents or stands in for a larger value. So 'moment index' is a stand-in number that points to the real moment.
Why Pilots Care
Accurate use keeps the center of gravity inside safe limits and prevents loss of control.
Analogy
It is like writing 2.5 instead of 2,500 when everyone agrees the number is being shown in thousands. The meaning is the same, but the smaller number is easier to work with.
Intuition Check
Moment does not mean a short period of time here; it means the turning or balancing effect of weight around a reference point. Index does not mean a book list here; it means a scaled-down number used to represent that balancing effect.
Example Sentence 1
After loading the baggage, she added each moment index from the chart to find the total and confirm the airplane was within limits.
Example Sentence 2
After loading fuel, the crew recalculated the total moment index on the form.