Is the following a legal datum call out?
A FCF has only two frames, A-B in the first and C in the second. -A- is an axis datum, -B- is a centerplane datum and -C- is a surface datum.
A-B are co-datums used to control F/A. -C- is a surface datum used to control U/D. -A- is also used to control C/C.
My question is, is it proper (legal) to use -A- this way, since it seems to me it's being used as a primary datum in one case and also being used as a tertiary datum in the other? My idea is to use -A- as a centerplane for F/A and have the same feature called out as -D- centerplane to control C/C. This way the FCF would read A-B , C, D, in three frames.