You've got the story in a nutshell.

Good Afternoon,
if is a forward limit question, can i use the forward limit formula and then use that in the flow chart,
for example if I have a weight of 2550kg and Index units of 530, and cargo has to be moved from the front to the back, can I use the forward limit formula to find the CoG limit, and then use the flow chart to find the weight to be shifted?

kind regards,
Esha

[color=blue][i][b]if I have a weight of 2550kg and Index units of 530, and cargo has to be moved from the front to the back, can I use the forward limit formula to find the CoG limit, and then use the flow chart to find the weight to be shifted?[/b][/i][/color]

As I don't have a copy of Bob's text, I don't know the details of the flow chart process. I'm sure someone will tie up the following to the text process for you in due course.

However, there exist several ways to tackle the problem (one of which, no doubt, is described in the flow chart process).

(a) in line operations, you would read off the forward limit in IU from the chart. More than accurate enough for purpose if you then move just a little more weight than the minimum absolutely required to ensure you are back to the limit line.

This then gives the moment (or IU) change required to bring the CG back into the envelope. It is then a simple exercise to move x kg from up front to down back to obtain the required moment change.

Caveat - always keep an eye on the aircraft load limits to ensure that you don't try to take more weight than exists from a compartment or put more weight than the maximum permissible in another. Often you will need to run the exercise multiple times to get a solution if the moment change required is large.

(b) if you want a bit more precision (as distinct from accuracy) you can run the calculation via CG figures as you have suggested. Once you have the two CG values, again it is a simple exercise to figure the weight to be moved to achieve the CG change

(c) although I don't recommend it, as an alternative to (b), you can use the same sort of approach with the IU chart. The equation for the forward upper limit is a simple quadratic and, once you have the two moment (IU) values, you proceed to figure the weight movement to achieve the requirement as in (a).