Landings in phase 1 of flight test

I am having some trouble finding the rules.
I have a friend that is ready for the DAR. When discussing the flight
test area, my friend was trying to include some local airports if
possible. The DAR responded that he would not be able to land there in
phase 1.
While I have seen that this type of restriction has been added to the
operating limitations on other aircraft in phase 1, I have not yet
found the rule that says that is necessary.

Can someone here enlighten me on this issue?

Thanks