N585 is taken. It's currently assigned to a 1976 Rolladen-Schneider Ohg LS1-F registered in Waterford, PA.
See the full aircraft record →A tail number only frees up if the owner deregisters the aircraft or moves it to a different N-number — and even then the FAA holds it before releasing it to the public.
N585 has been worn before. Past registrations from FAA deregistration records:
Tails one nudge away from N585 that aren't assigned or reserved: