The International Cessna^® 170 Association

I have a question about the W&B chart in the TCDS. It doesn't look anything like the electronic W&B charts floating around here. The number at the bottom of the chart says "Index Units" and the scale is from 40-120. What unit is that? A few searches of Weight and Balance info didn't reveal what I was looking for. Thanks,.

So after looking around for hours, I posted my question. As soon as I clicked "Submit", I looked down at my TCDS and saw the loading graph below has a note that says "Index Units= Moment/1000"! That was easy...

There you go. Once again the forum has proved it's weight in gold. Had it not been around you wouldn't have had anything to click thus forcing you to look down at the note in the TCDS.

The TCDS has what I would consider a normal scale of actual weight and arm as can be seen below for the A and B model. The '48 looks the same but the CG range is slightly different
In the Owners Manual however, in a effort to make the math easier, Cessna developed a graph using an index number. Using this method the degree of angle of the line on the graph does the more complicated multiplication required weight using the weight and arm method. Using the index graphs only requires addition and subtraction. It works well once you understand it until you have weight added or subtracted that is not on a line in the index graph.

Index= Moment/1000 so here is an example of an item 10 lbs on the floor in front of the rear seat at +60 inchs from the datum. The moment of the item would be 10 x 60 or 600 and the index would be 600/1000 or .6. The weight of 10lbs and the .6 would then be added to all the other weights and indexs and plotted on the graph.

Here is the graphs from the '53 B model.