Weight Point Weight (lb) Arm (in) Moment (lb-in) CG 106, 240 107,008 17,000 230,248 114.8 Right side Left side Nose Total 830 836 340 2,006 128 128 50 Figure 10-6.  Specifications for determining the CG of an airplane using weight and arm. Some weight and balance problems involve weights and arms  to determine the moments. Divide the total moment by the  total weight to determine the CG.  Figure 10-6  contains the  specifications for determining the CG using weights and arms. Determining CG, Given Weights, and Arms CG using weights and moments indexes. Determine the CG by using the data in  Figure 10-7 and  following these steps: Determine the CG by using the data in  Figure 10-6 and  following these steps: This airplane weighs 2,006 pounds and its CG is 114.8 inches  from the datum. This airplane weighs 2,006 pounds and its CG is 114.8 inches  from the datum. The CG of this airplane is located at 36.3 percent MAC. For a helicopter, it is often necessary to determine not only  the longitudinal CG, but the lateral CG as well. Lateral CG is  measured from butt line zero (BL 0). All items and moments  to the left of BL 0 are negative, and all those to the right of  BL 0 are positive.  Figure 10-8  contains the specifications for  determining the lateral CG of a typical helicopter. Determining Lateral CG of a Helicopter 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 by the total  weight and multiply the answer by the reduction factor.  Figure 10-7  contains the specifications for determining the  Figure 10-7.  Specifications for determining the CG of an airplane  using weights and moment indexes. 10-5 Weighing Point Weight (lb) Moment/100 CG 114.8 Right side Left side Nose Total 830 836 340 2,006 1,062.4 1,070.1 170 2,302.5 3. Determine the total moment and divide this by the  total weight: 1. Determine the total weight and record this number: 2. Determine the moment of each weighing point and record them: • The loaded CG is 42.47 inches aft of the datum. • MAC is 61.6 inches long. • LEMAC is at station 20.1. 1. Determine the distance between the CG and LEMAC: 2. Then, use this formula: 1. Determine the total weight and record this number: 2. Determine the total moment index, divide this by the  total weight, and multiply it by the reduction factor  of 100: Determining CG in Percent Mean Aerodynamic  Chord (MAC) (830)(×)(128)(=) 106,240 (836)(×)(128)(=) 107,008 (340)(×)(50)(=) 17,000 (830)(+)(836)(+)(340)(=) 2,006 (106240)(+)(107008)(+)(17000)(=)(÷)(2006)(=)  114.8 (22.37)(×)(100)(÷)(61.6)(=) 36.3 (42.47)(–)(20.1)(=) 22.37 (1062.4)(+)(1070.1)(+)(170)(=)(2302.5)(÷)(2006)(=) (1.148)(×)(100)(=) 114.8 (830)(+)(836)(+)(340)(=) 2,006