Rans Inc.
Section 1
Model S-7LS COURIER
General Information
Revision - B May 8, 2007
1- 19
WEIGHT AND BALANCE TERMINOLOGY
REFERENCE
DATUM
Reference Datum is an imaginary vertical plane from which all
horizontal distances are measured.
STATION
A location along the airplane fuselage given in terms of distance
from the reference datum.
ARM
The horizontal distance from the reference datum to the center of
gravity of an item.
MOMENT
The product of the weight of an item multiplied by its arm.
(Moment divided by the constant 1000 is used in this handbook to
simplify calculations by reducing the number of digits.)
CENTER OF
GRAVITY
The point at which an airplane would balance if suspended. Its
distance from the reference datum is found by dividing the total
moment by the total weight of the airplane.
STANDARD
EMPTY
WEIGHT
Weight of a standard airplane including unusable fuel, full
operating fluids and full engine oil.
BASIC
EMPTY
WEIGHT
Standard empty weight plus optional equipment.
USEFUL
LOAD
Difference between takeoff weight and basic empty weight.
MAXIMUM
TAKEOFF
WEIGHT
Maximum weight approved for the start of the takeoff run.
MAXIMUM
LANDING
WEIGHT
Maximum weight approved for the landing touchdown.
