As it happens, I don't require the knowlege for the ATPL exams - more is the pity. Not got time to start those yet! I am just trying to get some of the more puzzling theory elements behind me. I know that some things happen - says so in my revision notes, but I would like to know WHY. It helps me remember stuff!
For the definitive answer, refer to the curriculum under the chapter title PFM.
Erm, Foggy, for the dumb Brit, please elaborate!