TM 1-1520-240-10 6-6-20            Figure  6-6-11.  Cargo Door Cranking 6-6-42.  Load Planning. Before loading cargo, the placement of individual items of cargo in the helicopter should be planned and then checked to determine if the planned arrangement falls within the C.G. limits. there are three basic steps involved in load planning. The first step is to decide which method will be used to compute C.G. of the load. If the compart- ment method is to be used, each item of cargo must be assigned a location in one of the three compartments. If the station method is to be used, specific station loca- tions must be assigned to each item of cargo. The sec- ond step is to compute the C.G. of the load. If the load consists of a number of items of cargo, the compartment method should be used. If the load consists of only a few bulky items, the station method should be used. The third step is to check if the C.G. falls within the allowable limits. If it does, the cargo can be loaded; if not, the location of individual items should be rearranged until an acceptable loading plan is obtained. 6-6-43.  Compartment Loading. Loading  by  compartments  provides  a  rapid  means  of computing the C.G. of a load and can be used whenever the cargo load consists of a number of items. The heli- copter cargo compartment is divided into three compart- ments (fig. 6-6-12). The centroid, or center of balance, of each compartment is located at station 181, 303, and 425, respectively. When using the compartment method, it  is  assumed  that  the  weight  of  all  the  cargo  in  the compartment  is  concentrated  at  the  centroid  of  the compartment.  If  an  item  of  cargo  extends  into  two  or three compartments, the weight of the item should be proportionately  distributed  in  each  compartment.  The C.G. of the cargo load is computed as follows: a. Record  the  weight  of  cargo  in  each  compart- ment. b.   Calculate the compartment moment by multiply- ing the total weight in each compartment by the station number of the compartment centroid. c. Add the compartment moments. d. Add the weight in all compartments. e. Divide the sums of the cargo moments by the total weight of the cargo. The result is the arm or the C.G. location of the load. 6-6-44.  Station Loading. Loading by stations provides a more precise method of computing the C.G. of a load and should be used when- ever possible (fig. 6-6-13). To use this method, it is nec- essary to know the C.G. of each item of cargo. If the C.G. of an item is not marked, it can be determined by the procedure  given  in  TM  10-450-2.  Station  loading  re- quires that the C.G. of each item placed on the helicopter coincides with a fuselage station number. The C.G. of the load is calculated as follows: a. Record the weight and station number of each item of cargo. b. Calculate the moment of each item by multiplying the weight of the item by the station number of its C.G. c. Add the moment of each item to obtain the total load weight. d. Add the weights of each item to obtain the total load weight e. Divide  the  total  load  moment  by  the  total  load weight to obtain the arm or the C.G. location of the load. 6-6-45.  Vehicle Loading. The same procedures observed in cargo loading apply to vehicle loading. 6-6-46.  Shoring. Shoring is used to protect the cargo floor and to distribute load pressure over a greater area of the floor. Shoring can  often  make  the  difference  between  being  able  to carry a given load and not being able to; however, it is important not to exaggerate the effectiveness of shoring. Some vehicles have a tread width too narrow to allow the wheels to rest on the treadways. In this case, shoring must  be  used  to  reduce  the  contact  pressure  on  the walkway  to  an  allowable  figure.  In  general,  shoring  is required for all wheeled platforms and dollies and for any item of cargo whose contact pressure exceeds the floor limitations.