OP, a previous poster gave you the link to the Student Rights and Responsibilities handbook which will give you useful information about general rights, rights of students with IEPs etc. but does not mention AAP by name as far as I could find.
I suggest you read that link but then also contact the Advanced Academics office for FCPS:
http://www.fcps.edu/is/aap/directory.shtml
That link shows you the contact number. If you have exhausted your discussions with the school itself you can try the AA office. I would expect that office to ask you first if you have done certain things with your child's school before they get involved.
My child is about to be done with AAP (about to start HS) but in the six years he's been in it, I have never heard of a child being "kicked out" per se so it's hard for me to picture what you mean. But I do know of kids whose
parents moved them out of it for other reasons, such as the child not being motivated to do the work and the parents choosing to leave AAP, or the child just not clicking with the AAP center school and moving back to a base school nearer home, etc. Since we don't know your specific circumstances -- you should ask FCPS.