Hello
RCCP is the capacity planning on SOP. Check the following document for an example:
SOP: Rough-Cut Capacity Planning
I have never heard about LTCP and I could not find any reference on the documentation. Not even on google. Maybe you are refering to capacity planning on long-term planning. In this case, it is a completely different tool and it is basically a capacity evaluation based on CM38.
BR
Caetano