PPL » Aircraft Tech Knowledge (A) » Weight and Balance - Definitions, Terminology and Abbreviations
12.106 Definitions, Terminology and Abbreviations
12.106.2 Define the following terms:
(a) arm (moment arm);
The arm (moment arm) is the distance between the reference point and the center of gravity of an object. It is used to calculate the moment of an object.
Datum is a reference point from which all measurements are taken. In aviation, the datum is usually a point on the aircraft that is used as a reference for weight and balance calculations.
(c) moment (including units used);
Moment is the product of the weight of an object and its arm. The unit used for moment is pound-feet (lb-ft).
(d) centre of gravity (C of G);
Center of gravity (C of G) is the point on an aircraft where the weight is evenly distributed. It is the point where the aircraft would balance if it were suspended in the air.
(e) longitudinal C of G range and associated limits;
Longitudinal C of G range and associated limits refer to the acceptable range of longitudinal positions for the center of gravity of an aircraft. The limits are determined by the aircraft manufacturer and are based on the aircraft's design and performance.