Aviation Mechanic - General, Airframe, and Powerplant › I. General › Task C. Weight and Balance

AM.I.C.K4

Knowledge

Procedures for calculation of the following: arm, positive or negative moment, center of gravity (CG), or moment index.

Study note

Get a short, cited explanation of this element written from the FAA handbooks: the core idea, the numbers that matter, common test traps, and a quick self-check.

From the FAA library

Aircraft Weight and Balance Handbook p. 7-5
Chapter 7: Center of Gravity Change After a Repair or Alteration › Weight Changes Caused by a Repair or Alteration › Computations Using Weight and Moment Indexes
Computations Using Weight and Moment Indexes If the weight and balance data uses moment indexes rather than arms and moments, this same alteration can be computed using a chart such as the one in Figure ... determine the total weight and the total moment index. To determine the position of the new CG in inches aft of the datum, multiply the total moment index by 100 to get the moment, and divide this…
Aircraft Weight and Balance Handbook p. 10-5
Chapter 10: Use of Computer for Weight and Balance Computations › Tailwheel Airplane With Datum Behind the Main Wheels › Determining CG, Given Weights, and Moment Indexes
Other weight and balance problems involve weights and moment indexes, such as moment/100 or moment/1,000. To determine the CG, add all the weights and all the moment indexes. Then, divide the total moment index ... weights and moments indexes. Determine the CG by using the data in Figure 10-7 and following these steps: 1. Determine the total weight and record this number: 2. Determine the total moment index, divide this…
Aircraft Weight and Balance Handbook p. 6-3
Chapter 6: Multiengine Aircraft Weight and Balance Computations › Determine the Loaded CG › The Chart Method Using Weight and Moment Indexes
Chart Method Using Weight and Moment Indexes As mentioned in the previous chapter, anything that can be done to make careful preflight planning easier makes flying safer. Many manufacturers furnish ... charts in the Pilot’s Operating Handbook/Aircraft Flight Manual (POH/AFM) that use weight and moment indexes rather than weight, arm, and moments. The charts also help reduce errors by including tables of moment indexes for the various…